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sneak/dnswatcher:main sneak/dnswatcher:next sneak/dnswatcher:fix/98-security-headers sneak/dnswatcher:prod sneak/dnswatcher:fix/117-bootstrap-pin sneak/dnswatcher:fix/121-lint-cache-isolation sneak/dnswatcher:fix/115-cibuild-cache sneak/dnswatcher:fix/empty-targets-validation sneak/dnswatcher:fix/67-readme-api-endpoints sneak/dnswatcher:fix/issue-39-repo-policies sneak/dnswatcher:fix/issue-35-retry-timeout sneak/dnswatcher:fix/mock-resolver-tests sneak/dnswatcher:fix/dns-timeout-and-root-fanout sneak/dnswatcher:fix/query-timeout-and-recursive-resolution sneak/dnswatcher:fix/make-check-resolver-tests
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compare: sneak/dnswatcher:fix/121-lint-cache-isolation
Branches Tags
sneak/dnswatcher:next sneak/dnswatcher:fix/98-security-headers sneak/dnswatcher:main sneak/dnswatcher:prod sneak/dnswatcher:fix/117-bootstrap-pin sneak/dnswatcher:fix/121-lint-cache-isolation sneak/dnswatcher:fix/115-cibuild-cache sneak/dnswatcher:fix/empty-targets-validation sneak/dnswatcher:fix/67-readme-api-endpoints sneak/dnswatcher:fix/issue-39-repo-policies sneak/dnswatcher:fix/issue-35-retry-timeout sneak/dnswatcher:fix/mock-resolver-tests sneak/dnswatcher:fix/dns-timeout-and-root-fanout sneak/dnswatcher:fix/query-timeout-and-recursive-resolution sneak/dnswatcher:fix/make-check-resolver-tests
1 Commits
bb7d56cd9a .. fix/121-lint-cache-isolation
Author SHA1 Message Date
sneak 520ce79709 build: isolate golangci-lint cache and lock per checkout (closes #121)
check / check (push) Successful in 54s
Details 
script/lint used golangci-lint's per-user global state, which breaks
when several checkouts on one host lint concurrently. Two independent
failure modes, two causes:

- Cross-contamination. The analysis cache (GOLANGCI_LINT_CACHE,
  default ~/.cache/golangci-lint) is keyed by content, not by
  checkout, so a hit written by another checkout is replayed with
  that checkout's file paths. A run reports findings for files it
  never linted.

- Lock collision. golangci-lint locks os.TempDir()/golangci-lint.lock
  (pkg/commands/run.go, acquireFileLock), which is NOT in the cache
  directory, with a 5s timeout. Peers that hold it longer make the
  run abort with "parallel golangci-lint is running" - a non-result
  that reads as a lint failure. Isolating the cache does not move it.

Point GOLANGCI_LINT_CACHE and TMPDIR at .lint-cache/ under the
checkout root, using the existing $ROOT idiom. TMPDIR is what makes
the lock per-checkout, so the lock keeps serialising the runs that
actually share a cache instead of being disabled. .lint-cache/ is
git-ignored and Docker-ignored, and the cache persists across runs in
a checkout, so caching is not lost.

Reproduced both modes on the unfixed script across 12 copies of this
tree: 10 of 12 concurrent runs void with the lock error, and 11 of 12
sequential runs reported findings at ../w1/... after an identical
lint-failing file was added to every copy. After the fix, 20-way
concurrency gives 0 void and 0 foreign paths, and each copy reports
only its own relative path.
 2026-08-09 14:35:42 +00:00
75 changed files with 1712 additions and 8135 deletions
Expand all files Collapse all files
.dockerignore
+2 -4
View File
@@ -1,9 +1,7 @@
.git/
bin/
node_modules/
# No .md may be excluded: Dockerfile.fmt checks every document with
# prettier, and an exclusion here would drop a file from that check while
# prettier still reports every file it was handed clean.
.lint-cache/
*.md
LICENSE
.editorconfig
.gitignore
.gitignore
+1 -1
View File
@@ -1,7 +1,7 @@
bin/
node_modules/
vendor/
data/
.lint-cache/
.env
*.exe
/dnswatcher
.golangci.yml
+2 -70
View File
@@ -10,20 +10,14 @@ run:
linters:
default: all
enable:
# Successor to the deprecated gomodguard. Named explicitly, rather than
# left to `default: all`, because it carries the module policy below.
- gomodguard_v2
disable:
# Genuinely incompatible with project patterns
- exhaustruct # Requires all struct fields
- depguard # Dependency allow/block lists
- godot # Requires comments to end with periods
- wsl # Deprecated, replaced by wsl_v5
- wrapcheck # Too verbose for internal packages
- varnamelen # Short names like db, id are idiomatic Go
# Deprecated: the warning is attached to the old name, so it is
# silenced by disabling that name, not by enabling the successor.
- wsl # Deprecated, replaced by wsl_v5
- gomodguard # Deprecated, replaced by gomodguard_v2
settings:
lll:
line-length: 88
@@ -34,68 +28,6 @@ linters:
max-complexity: 15
dupl:
threshold: 100
depguard:
# Test-support code must not be compiled into the shipped binary. A
# test-support package exists to hand a test privileges the program
# itself must never have, so a file that is not a test must not import
# one. Test files, and the files inside a package whose directory name
# ends in `test`, are where that code belongs, and are exempt.
#
# The deny list below is the one part of this file a repository is
# expected to extend, and the only part it may. depguard matches an
# import path against a list of prefixes, so it cannot be told "any path
# whose last segment ends in test"; a repository's own test-support
# packages have to be named here one at a time, by full import path,
# under a module path that differs from repository to repository. Add
# them; change nothing else.
rules:
test-support:
list-mode: lax
files:
- "$all"
- "!$test"
- "!**/*test/**"
deny:
- pkg: net/http/httptest
desc: >-
Test-support code belongs in test files and in packages whose
directory name ends in test, not in the shipped binary.
- pkg: sneak.berlin/go/dnswatcher/internal/livednstest
desc: >-
Live-DNS test support belongs in test files and in packages
whose directory name ends in test, not in the shipped binary.
# Only decisions already recorded in the Go package defaults are
# listed here. Every entry matches the module path exactly.
gomodguard_v2:
blocked:
- module: github.com/rs/zerolog
recommendations:
- log/slog
reason: "Structured logging is stdlib log/slog."
# One entry per pre-fork module path, because the later releases
# are separate paths. A prefix match would be shorter but would
# also reach github.com/go-redis/redismock, the test double for
# the successor these entries recommend.
- module: github.com/go-redis/redis
recommendations:
- github.com/redis/go-redis/v9
reason: "Pre-fork module; use the maintained go-redis v9."
- module: github.com/go-redis/redis/v7
recommendations:
- github.com/redis/go-redis/v9
reason: "Pre-fork module; use the maintained go-redis v9."
- module: github.com/go-redis/redis/v8
recommendations:
- github.com/redis/go-redis/v9
reason: "Pre-fork module; use the maintained go-redis v9."
- module: github.com/sergi/go-diff
recommendations:
- github.com/aymanbagabas/go-udiff
reason: "No unified diff output; use go-udiff."
- module: github.com/hexops/gotextdiff
recommendations:
- github.com/aymanbagabas/go-udiff
reason: "Unmaintained fork; use go-udiff."
issues:
max-issues-per-linter: 0
.prettierignore
-5
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@@ -1,5 +0,0 @@
bin/
data/
node_modules/
.claude/
static/css/tailwind.min.css
.prettierrc
-4
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@@ -1,4 +0,0 @@
{
"tabWidth": 4,
"proseWrap": "always"
}
Dockerfile
+15 -52
View File
@@ -1,31 +1,13 @@
# Lint stage - fast feedback on lint issues, before the build starts.
# The linter is invoked directly rather than through `make lint`: that
# target shells out to `docker build -f Dockerfile.lint`, and there is
# no docker daemon inside a docker build. For the same reason this stage
# runs only the Go half of `make fmt-check`; script/cibuild runs the
# markdown half after this build.
# script/cibuild and script/docker name this stage in --no-cache-filter.
# golangci/golangci-lint:v2.12.2 (Debian-based), 2026-08-10
FROM golangci/golangci-lint:v2.12.2@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240 AS lint
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN script/fmt-check-go
RUN golangci-lint run --config .golangci.yml ./...
# Build stage
# script/cibuild and script/docker name this stage in --no-cache-filter.
# golang 1.25-alpine, 2026-02-28
FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
RUN apk add --no-cache git make gcc musl-dev binutils-gold
# Force BuildKit to run the lint stage before proceeding
COPY --from=lint /src/go.sum /dev/null
# golangci-lint v2.12.2, 2026-08-07
RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5
# goimports v0.42.0
RUN go install golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0
WORKDIR /src
COPY go.mod go.sum ./
@@ -33,46 +15,27 @@ RUN go mod download
COPY . .
# Run the tests - build fails if any test fails
RUN make test
# Run all checks - build fails if any check fails
RUN make check
# Build the binary. .dockerignore leaves out .git, so `git describe` in
# the Makefile cannot find the version here: script/docker passes it as
# --build-arg VERSION, and a build that passes none reports `dev`.
ARG VERSION=dev
RUN make build VERSION="${VERSION}"
# Build the binary
RUN make build
# Runtime stage
# alpine 3.21, 2026-02-28
FROM alpine@sha256:c3f8e73fdb79deaebaa2037150150191b9dcbfba68b4a46d70103204c53f4709
RUN apk add --no-cache ca-certificates tzdata su-exec
RUN apk add --no-cache ca-certificates tzdata
COPY --from=builder /src/bin/dnswatcher /usr/local/bin/dnswatcher
COPY deploy/docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
WORKDIR /app
# dnswatcher runs as this unprivileged user. The entrypoint creates the
# data directory and gives it to this user on every start.
RUN addgroup -S -g 10001 dnswatcher \
&& adduser -S -G dnswatcher -u 10001 dnswatcher
COPY --from=builder /src/bin/dnswatcher /app/dnswatcher
# Create data directory
RUN mkdir -p /var/lib/dnswatcher
ENV DNSWATCHER_DATA_DIR=/var/lib/dnswatcher
# Config loading also reads a `.env` file and a file named `dnswatcher`
# (any config extension, or none) from the working directory. `/` holds
# neither, so every setting comes from the environment. Do not make the
# data directory, or the binary's directory, the working directory.
WORKDIR /
# No USER: the entrypoint must start as root to set up the data
# directory; it then runs dnswatcher as the dnswatcher user.
EXPOSE 8080
# busybox wget (already in alpine) probes the health endpoint every 10
# seconds, so the container is healthy well before upaas reads its health
# 60 seconds after a deploy and fails the deploy unless it is healthy.
HEALTHCHECK --interval=10s --timeout=5s --start-period=10s --retries=3 \
CMD wget -q -O /dev/null "http://127.0.0.1:${PORT:-8080}/.well-known/healthcheck" || exit 1
ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]
ENTRYPOINT ["/app/dnswatcher"]
Dockerfile.fmt
-55
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@@ -1,55 +0,0 @@
# prettier over the markdown, in a container, so it is never installed
# on the host. script/fmt-check-markdown builds the fmt-check stage;
# script/fmt builds fmt-out and takes the formatted files back.
# node:22-bookworm-slim, 2026-09-05
FROM node:22-bookworm-slim@sha256:83f487e0a63425e5b4d146fb5e5be574bcbe1b7b843d3ebafdd95eaf7767a7e5 AS nodedeps
# prettier lives outside /src so that a `COPY . .` of the repo cannot
# overwrite it, and so that node_modules never appears in the tree
# prettier is about to walk.
WORKDIR /tools
# package.json pins the version and yarn.lock pins the bytes:
# --frozen-lockfile installs exactly the lockfile's resolution and fails
# if package.json disagrees with it, so the tool cannot float between
# runs. yarn is the one in the image above.
COPY package.json yarn.lock ./
RUN yarn install --frozen-lockfile --non-interactive --no-progress
ENV PATH="/tools/node_modules/.bin:${PATH}"
WORKDIR /src
# Read-only markdown check. Must match $stage in
# script/fmt-check-markdown.
FROM nodedeps AS fmt-check
COPY . .
# --config, not discovery: a .prettierrc that failed to arrive would
# otherwise leave prettier on its defaults, where proseWrap is "preserve"
# and every wrap this check exists to enforce passes. Missing the file is
# a hard error instead. --no-editorconfig for the same reason in reverse:
# .editorconfig is not in the build context, so honouring it here and on
# a developer's machine would be two different answers.
RUN prettier --config .prettierrc --no-editorconfig --check "**/*.md"
# Write path. Not a check: script/fmt builds this and takes the files.
FROM nodedeps AS fmt
COPY . .
RUN prettier --config .prettierrc --no-editorconfig --write "**/*.md"
# Only the markdown leaves, with its paths intact, so that the export
# below cannot put anything else back over the caller's working tree.
RUN mkdir -p /out && cd /src && \
find . -name '*.md' -type f -exec cp --parents '{}' /out/ ';'
# Export target: `docker build --target fmt-out --output type=local`
# writes /out's tree into a directory on the client, which is how
# script/fmt gets formatted markdown back without a bind mount.
# Must match $stage in script/fmt.
FROM scratch AS fmt-out
COPY --from=fmt /out/ /
Dockerfile.lint
-29
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@@ -1,29 +0,0 @@
# Lint-only image: used by script/lint. golangci-lint is never run on
# the host — the repo is COPYed into the build context and the linter
# runs as a build step, so a successful build IS a clean lint. This
# also works where the docker daemon is remote and bind mounts are
# impossible.
#
# `golangci-lint config verify` is deliberately NOT run here: it
# fetches its JSON schema over a live, unpinned HTTPS call, which would
# make linting network-dependent and defeat hash-pinning. The cost of
# that: unknown top-level keys in .golangci.yml are silently ignored,
# so a mistyped or wrong-schema key lints clean while applying nothing.
#
# golangci/golangci-lint:v2.12.2 (Debian-based), 2026-08-10
FROM golangci/golangci-lint:v2.12.2@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240 AS deps
WORKDIR /src
# Dependencies first, so this stage stays cached across lint runs.
COPY go.mod go.sum ./
RUN go mod download
# Everything below is invalidated on every run by the
# --no-cache-filter=lint that script/lint passes: caching is explicitly
# waived for linting, and a cached build lints nothing.
FROM deps AS lint
COPY . .
RUN golangci-lint run --config .golangci.yml ./...
LICENSE
-21
View File
@@ -1,21 +0,0 @@
MIT License
Copyright (c) 2026 sneak
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
Makefile
-2
View File
@@ -1,8 +1,6 @@
.PHONY: all bootstrap setup build lint fmt fmt-check test check clean hooks docker
BINARY := dnswatcher
# `make build VERSION=...` overrides this; the Dockerfile does so, as the
# image has no .git to describe.
VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
LDFLAGS := -X main.Version=$(VERSION)
README.md
+200 -523
View File
@@ -1,20 +1,16 @@
# dnswatcher
dnswatcher is an MIT-licensed, pre-1.0 Go daemon by
[@sneak](https://sneak.berlin) that monitors DNS records, TCP port availability,
and TLS certificates, delivering real-time change notifications via Slack,
Mattermost, and ntfy webhooks.
dnswatcher is a pre-1.0 Go daemon by [@sneak](https://sneak.berlin) that monitors DNS records, TCP port availability, and TLS certificates, delivering real-time change notifications via Slack, Mattermost, and ntfy webhooks.
> ⚠️ Pre-1.0 software. APIs, configuration, and behavior may change without
> notice.
> ⚠️ Pre-1.0 software. APIs, configuration, and behavior may change without notice.
dnswatcher watches configured DNS domains and hostnames for changes, monitors
TCP port availability, tracks TLS certificate expiry, and delivers real-time
dnswatcher watches configured DNS domains and hostnames for changes, monitors TCP
port availability, tracks TLS certificate expiry, and delivers real-time
notifications via Slack, Mattermost, and/or ntfy webhooks.
It resolves the names it watches itself via iterative (non-recursive) queries,
tracing from root nameservers to authoritative servers directly—never relying on
upstream recursive resolvers.
It performs all DNS resolution itself via iterative (non-recursive) queries,
tracing from root nameservers to authoritative servers directly—never relying
on upstream recursive resolvers.
State is persisted to a local JSON file so that monitoring survives restarts
without requiring an external database.
@@ -23,43 +19,21 @@ without requiring an external database.
## No DNS mocking. Ever.
**DNS is never mocked in this project — not in tests, not anywhere else.** No
mock resolvers, no fake DNS servers, no stubbed lookups.
**DNS is never mocked in this project — not in tests, not anywhere else.**
No mock resolvers, no fake DNS servers, no stubbed lookups.
dnswatcher's entire purpose is correct behavior against the real DNS. Tests
exercise real iterative resolution against live nameservers by design; a test
suite that passes against a mock proves nothing about the one thing this program
exists to do.
dnswatcher's entire purpose is correct behavior against the real DNS.
Tests exercise real iterative resolution against live nameservers by
design; a test suite that passes against a mock proves nothing about the
one thing this program exists to do.
When live tests are flaky, that is a robustness problem, and it gets fixed with
robustness: retries with backoff, querying multiple independent nameservers,
longer timeouts — or explicit opt-in gating decided by the project owner. Never
with mocks.
When live tests are flaky, that is a robustness problem, and it gets
fixed with robustness: retries with backoff, querying multiple
independent nameservers, longer timeouts — or explicit opt-in gating
decided by the project owner. Never with mocks.
Contributions that introduce mocked, faked, or stubbed DNS will be rejected.
---
## Getting Started
You need git and Docker. This builds the image and runs dnswatcher watching
`example.com` and `www.example.com`:
```sh
git clone https://git.eeqj.de/sneak/dnswatcher.git
cd dnswatcher
docker build -t dnswatcher .
docker run -d --name dnswatcher \
-p 8080:8080 \
-v dnswatcher-data:/var/lib/dnswatcher \
-e DNSWATCHER_TARGETS=example.com,www.example.com \
dnswatcher
```
The build also runs the linter and the test suite, which queries live DNS. Once
the container is running, the dashboard is at <http://localhost:8080/>. With no
notification endpoint set, changes show only on the dashboard; see
[Configuration](#configuration) to add one.
Contributions that introduce mocked, faked, or stubbed DNS will be
rejected.
---
@@ -69,112 +43,74 @@ notification endpoint set, changes show only on the dashboard; see
- Accepts a list of DNS domain names (apex domains, identified via the
[Public Suffix List](https://publicsuffix.org/)).
- Every **1 hour** by default, performs a full iterative trace from root servers
to discover all authoritative nameservers (NS records) for each domain.
- Every **1 hour**, performs a full iterative trace from root servers to
discover all authoritative nameservers (NS records) for each domain.
- Queries **every** discovered authoritative nameserver independently.
- Stores the domain's NS record set, as its parent zone's servers delegate it,
and the IPv4 and IPv6 addresses each nameserver's name resolves to.
- Stores the NS record set as observed by the delegation chain.
- Any change triggers a notification:
- NS added to or removed from that set.
- NS address change: a nameserver that stays in the set resolves to
different addresses than on the previous check. A nameserver added or
removed gets only the NS change notification. When the lookup of a
nameserver's addresses fails or finds none, its previous addresses are
kept and nothing is sent.
- NS added to or removed from the delegation.
- NS IP address changed (glue record change).
### DNS Hostname Monitoring (Subdomains)
- Accepts a list of DNS hostnames (subdomains, distinguished from apex domains
via the Public Suffix List).
- Every **1 hour** by default, performs a full iterative trace to discover the
authoritative nameservers of the zone the hostname is in, which is not always
its last two labels (a name under `co.uk`, or in a delegated subdomain).
- Queries **each** authoritative nameserver independently for **all** record
types: A, AAAA, CNAME, MX, TXT, SRV, CAA, NS.
- Stores results **per nameserver**. The state for a hostname is not a merged
view — it is a map from nameserver to record set.
- DNS names inside record values (CNAME, MX, SRV and NS targets) are stored in
lower case, because names are case-insensitive and nameservers may answer in
any letter case. TXT and CAA values keep their letter case; they are not
lower-cased.
- Any observable change in any nameserver's response triggers a notification.
This includes:
- **Record change**: A nameserver returns different records than it did on
the previous check (additions, removals, value changes).
- **NS query failure**: A nameserver that previously responded becomes
unreachable (timeout, SERVFAIL, REFUSED, network error). This is distinct
from "responded with no records": a nameserver that answers NXDOMAIN or
with no records has responded. The alert is sent once, on the check where
it starts failing. A failing nameserver gives no records, so it is not
reported as a record change or compared for inconsistency. A nameserver
that is already failing on the first check that sees it is recorded
silently.
- **NS recovery**: A previously-unreachable nameserver starts responding
again. Its records are not compared with those from before it failed, so a
change made while it was failing is not reported as a record change.
- **Inconsistency detected**: Two nameservers return different record sets
for the same hostname and did not already differ on the previous check.
Every pair of nameservers is compared. The alert is sent once for each
such pair, on the check where they start to disagree, and not again while
they keep disagreeing, including after a restart. A nameserver that was
not in the previous check (newly added, or back after dropping out), or
failed on it, and answers differently is reported on the check where it
answers. If a pair agrees again and later disagrees, the alert is sent
again.
- **CNAME address change**: The addresses at the end of a name's CNAME chain
differ from those of the previous check. They are found when its
nameservers answer with a CNAME and no address; a name that answers with
an address has none. A change from or to no addresses is sent too, as when
a name moves between A records and a CNAME. Nothing is sent when the
previous addresses were kept because the chain could not be followed or
none of the name's nameservers answered. The first check after loading a
state file without `cnameAddresses` sends nothing: it saves the addresses
it finds for the next check to compare.
- Accepts a list of DNS hostnames (subdomains, distinguished from apex
domains via the Public Suffix List).
- Every **1 hour**, performs a full iterative trace to discover the
authoritative nameservers for the hostname's parent domain.
- Queries **each** authoritative nameserver independently for **all**
record types: A, AAAA, CNAME, MX, TXT, SRV, CAA, NS.
- Stores results **per nameserver**. The state for a hostname is not a
merged view — it is a map from nameserver to record set.
- Any observable change in any nameserver's response triggers a
notification. This includes:
- **Record change**: A nameserver returns different records than it
did on the previous check (additions, removals, value changes).
- **NS query failure**: A nameserver that previously responded
becomes unreachable (timeout, SERVFAIL, REFUSED, network error).
This is distinct from "responded with no records."
- **NS recovery**: A previously-unreachable nameserver starts
responding again.
- **Inconsistency detected**: Two nameservers that previously agreed
now return different record sets for the same hostname.
### TCP Port Monitoring
- For every configured domain and hostname, constructs a deduplicated list of
the IPv4 and IPv6 addresses in the A and AAAA records its authoritative
nameservers returned. When they returned a CNAME and no address, the CNAME
chain is followed and the addresses at its end are used, and a change in those
is notified as a CNAME address change. When the chain cannot be followed, or
none of the name's nameservers answered, the addresses the last check found at
its end are used.
- For every configured domain and hostname, constructs a deduplicated list
of all IPv4 and IPv6 addresses resolved via A, AAAA, and CNAME chain
resolution across all authoritative nameservers.
- Checks TCP connectivity on ports **80** and **443** for each IP address.
- Every **1 hour** by default, re-checks all ports.
- Every **1 hour**, re-checks all ports.
- Any change in port availability triggers a notification:
- Port transitioned from open to closed (or vice versa).
- New IP appeared (from DNS change): its port state is recorded without a
port notification; the DNS change notification shows the new address.
- IP disappeared (from DNS change) — noted in the DNS change notification;
port state for that IP is removed. When none of a name's nameservers
answered, its addresses are not known, so the port state saved for them is
kept.
- New IP appeared (from DNS change) and its port state was recorded.
- IP disappeared (from DNS change) — noted in the DNS change
notification; port state for that IP is removed.
### TLS Certificate Monitoring
- Every **12 hours** by default, for each IP address listening on port 443,
connects via TLS using the correct SNI hostname.
- Every **12 hours**, for each IP address listening on port 443, connects
via TLS using the correct SNI hostname.
- Records the certificate's Subject CN, SANs, issuer, and expiry date.
- Any change triggers a notification:
- Certificate is expiring within **7 days** by default (warning, repeated
each check until renewed or expired).
- Certificate CN, issuer, or SANs changed (replacement detected, reports old
and new CN and issuer).
- TLS connection failure to a previously-reachable IP:443 (handshake error,
timeout, connection refused after previously succeeding).
- TLS recovery: a previously-failing IP:443 now completes a handshake again.
- Certificate is expiring within **7 days** (warning, repeated each
check until renewed or expired).
- Certificate CN, issuer, or SANs changed (replacement detected,
reports old and new values).
- TLS connection failure to a previously-reachable IP:443 (handshake
error, timeout, connection refused after previously succeeding).
- TLS recovery: a previously-failing IP:443 now completes a
handshake again.
### Notifications
**Every observable state change produces a notification.** dnswatcher is
designed as a real-time change feed — degradations, failures, recoveries, and
routine changes are all reported equally.
designed as a real-time change feed — degradations, failures, recoveries,
and routine changes are all reported equally.
Supported notification backends:
| Backend | Configuration | Payload Format |
| -------------- | ------------------------------------------ | ---------------------------- |
|----------------|--------------------------|------------------------------|
| **Slack** | Incoming Webhook URL | Attachments with color |
| **Mattermost** | Incoming Webhook URL | Slack-compatible attachments |
| **ntfy** | Topic URL (e.g. `https://ntfy.sh/mytopic`) | Title + body + priority |
@@ -182,41 +118,27 @@ Supported notification backends:
All configured endpoints receive every notification. Notification content
includes:
- **DNS record changes**: Which hostname, which nameserver, what record type,
old values, new values.
- **DNS record changes**: Which hostname, which nameserver, what record
type, old values, new values.
- **DNS NS changes**: Which domain, which nameservers were added/removed.
- **NS address changes**: Which domain, which nameserver, its old and new
addresses.
- **CNAME address changes**: Which hostname, the old and new addresses at the
end of its CNAME chain.
- **NS query failures**: Which nameserver failed, error type (timeout, SERVFAIL,
REFUSED, network error), which hostname/domain affected.
- **NS query failures**: Which nameserver failed, error type (timeout,
SERVFAIL, REFUSED, network error), which hostname/domain affected.
- **NS recoveries**: Which nameserver recovered, which hostname/domain.
- **NS inconsistencies**: Which nameservers disagree, what each one returned,
which hostname affected.
- **Port changes**: Which IP:port, its new state, all associated hostnames.
- **TLS expiry warnings**: Expiry date and days remaining, CN, associated
- **NS inconsistencies**: Which nameservers disagree, what each one
returned, which hostname affected.
- **Port changes**: Which IP:port, old state, new state, all associated
hostnames.
- **TLS expiry warnings**: Which certificate, days remaining, CN,
issuer, associated hostname and IP.
- **TLS certificate changes**: Old and new CN/issuer/SANs, associated
hostname and IP.
- **TLS certificate changes**: Old and new CN and issuer, associated hostname
and IP. A change to the SANs alone is notified, but the SANs are not listed.
- **TLS connection failures/recoveries**: Which IP:port, error details,
associated hostname.
Each endpoint is sent each notification on its own, in the background. A
delivery that fails (a network error, no reply within 10 seconds, or an HTTP
status of 400 or more) is retried up to 5 times: the first retry after about 1
second, each wait after that twice as long up to 60 seconds, every wait varied
at random by up to 25%. A delivery still failing after that is logged and
dropped.
The last 100 notifications, delivered or not, are kept in memory for the
dashboard's Recent alerts. They are not saved to the state file, so a restart
clears them.
### State Management
- All monitoring state is kept in memory and persisted to a JSON file on disk
(`DATA_DIR/state.json`).
- All monitoring state is kept in memory and persisted to a JSON file on
disk (`DATA_DIR/state.json`).
- State is loaded on startup to resume monitoring without triggering
false-positive change notifications.
- State is written atomically (write to temp file, then rename) to prevent
@@ -224,116 +146,86 @@ clears them.
### Web Dashboard
dnswatcher includes an unauthenticated, read-only web dashboard at the root URL
(`/`). It displays:
dnswatcher includes an unauthenticated, read-only web dashboard at the
root URL (`/`). It displays:
- **Summary counts** for monitored domains, hostnames, ports, and certificates.
- **Summary counts** for monitored domains, hostnames, ports, and
certificates.
- **Domains** with their discovered nameservers.
- **Hostnames** with per-nameserver DNS records and status.
- **Ports** with open/closed state and associated hostnames.
- **TLS certificates** with CN, issuer, expiry, and status.
- **Recent alerts** (last 100 notifications sent since the process started),
displayed in reverse chronological order.
- **Recent alerts** (last 100 notifications sent since the process
started), displayed in reverse chronological order.
Every data point shows its age (e.g. "5m ago") so you can tell at a glance how
fresh the information is. The page auto-refreshes every 30 seconds.
Every data point shows its age (e.g. "5m ago") so you can tell at a
glance how fresh the information is. The page auto-refreshes every 30
seconds.
The dashboard intentionally does not expose any configuration details such as
webhook URLs, notification endpoints, or API tokens.
The dashboard intentionally does not expose any configuration details
such as webhook URLs, notification endpoints, or API tokens.
All assets (CSS) are embedded in the binary and served from the application
itself. The dashboard makes zero external HTTP requests — no CDN dependencies or
third-party resources are loaded at runtime.
All assets (CSS) are embedded in the binary and served from the
application itself. The dashboard makes zero external HTTP requests —
no CDN dependencies or third-party resources are loaded at runtime.
### HTTP API
dnswatcher exposes a lightweight HTTP API for operational visibility:
| Endpoint | Description |
| ------------------------------ | ----------------------------- |
|---------------------------------------|--------------------------------|
| `GET /` | Web dashboard (HTML) |
| `GET /s/...` | Static assets (embedded CSS) |
| `GET /.well-known/healthcheck` | Health check (JSON) |
| `GET /health` | Health check (JSON, legacy) |
| `GET /api/v1/status` | Current monitoring state |
| `GET /metrics` | Prometheus metrics, see below |
| `GET /metrics` | Prometheus metrics (optional) |
`/metrics` is served only when `DNSWATCHER_METRICS_USERNAME` is set, behind
Basic Auth. It has the Prometheus Go client's default metrics only (Go runtime,
process, and counts of `/metrics` requests); dnswatcher records no metrics of
its own.
---
Every route but `/metrics` may be read from a page on any origin: a cross-origin
`GET` gets `Access-Control-Allow-Origin: *`. Only `GET` is allowed cross-origin,
and without credentials. `/metrics` sends no CORS headers.
#### Server timeouts
The HTTP server sets all four socket-level timeouts. These are compile-time
constants in `internal/server/server.go`, not configurable via environment
variables.
| Timeout | Value | Purpose |
| ------------------- | ----- | --------------------------------------------- |
| `ReadHeaderTimeout` | 10s | Bounds the request header read (slowloris) |
| `ReadTimeout` | 15s | Bounds the whole request read, headers + body |
| `WriteTimeout` | 75s | Bounds handler execution plus response flush |
| `IdleTimeout` | 120s | Reaps idle keep-alive connections |
These are distinct from the 60s per-request handler budget applied by
`chimw.Timeout` in `internal/server/routes.go`, which cancels the request
context but does not touch the socket. `WriteTimeout` is deliberately larger
than that budget: the write deadline is armed once request headers are read, so
a smaller value would sever the connection before a handler using its full
budget could respond. `IdleTimeout` exceeds common Prometheus scrape intervals
so the scraper reuses its connection.
### Security Headers
Every response — the dashboard, the static assets under `/s/...`, the
healthchecks, the JSON API, and `/metrics` — carries the following headers, set
by a global middleware:
| Header | Value |
| --------------------------- | ------------------------------------- |
| `Strict-Transport-Security` | `max-age=31536000; includeSubDomains` |
| `Content-Security-Policy` | see below |
| `X-Frame-Options` | `DENY` |
| `X-Content-Type-Options` | `nosniff` |
| `Referrer-Policy` | `no-referrer` |
| `Permissions-Policy` | all unused browser features denied |
The content security policy is:
## Architecture
```
default-src 'self'; script-src 'none'; style-src 'self'; img-src 'self';
font-src 'none'; connect-src 'none'; object-src 'none'; base-uri 'none';
form-action 'none'; frame-ancestors 'none'
cmd/dnswatcher/main.go Entry point (uber/fx bootstrap)
internal/
config/config.go Viper-based configuration
globals/globals.go Build-time variables (version)
logger/logger.go slog structured logging (TTY detection)
healthcheck/healthcheck.go Health check service
middleware/middleware.go HTTP middleware (logging, CORS, metrics auth)
handlers/handlers.go HTTP request handlers
server/
server.go HTTP server lifecycle
routes.go Route definitions
state/state.go JSON file state persistence
resolver/resolver.go Iterative DNS resolution engine
portcheck/portcheck.go TCP port connectivity checker
tlscheck/tlscheck.go TLS certificate inspector
notify/notify.go Notification service (Slack, Mattermost, ntfy)
watcher/watcher.go Main monitoring orchestrator and scheduler
```
The dashboard ships no JavaScript (the 30-second refresh is a
`<meta http-equiv="refresh">`), no inline styles, no inline event handlers, and
no images; its only subresource is the embedded stylesheet at
`/s/css/tailwind.min.css`, which `style-src 'self'` permits. The policy
therefore needs neither `unsafe-inline` nor `unsafe-eval`.
`frame-ancestors 'none'` is the primary anti-framing control, with
`X-Frame-Options: DENY` retained as the legacy fallback.
### Design Principles
HSTS is emitted unconditionally, including over plain HTTP. dnswatcher is
expected to run behind a TLS-terminating reverse proxy, and the browser must
still be told to enforce HTTPS end to end, so the header is never gated on
whether the request itself arrived over TLS.
`Referrer-Policy: no-referrer` is stricter than the
`strict-origin-when-cross-origin` baseline: the dashboard has no cross-origin
navigation needs, and its URL may name internal hosts.
- **No recursive resolvers**: All DNS resolution is performed iteratively,
tracing from root nameservers through the delegation chain to
authoritative servers.
- **No external database**: State is persisted as a single JSON file.
- **Dependency injection**: All components are wired via
[uber/fx](https://github.com/uber-go/fx).
- **Structured logging**: All logs use `log/slog` with JSON output in
production (TTY detection for development).
- **Graceful shutdown**: All background goroutines respect context
cancellation and the fx lifecycle.
---
## Configuration
Configuration is loaded via [Viper](https://github.com/spf13/viper) with the
following precedence (highest to lowest):
Configuration is loaded via [Viper](https://github.com/spf13/viper) with
the following precedence (highest to lowest):
1. Environment variables (prefixed with `DNSWATCHER_`)
2. `.env` file (loaded via godotenv)
@@ -344,7 +236,7 @@ following precedence (highest to lowest):
### Environment Variables
| Variable | Description | Default |
| ----------------------------------- | ----------------------------------------------------------------------------------------------------------- | --------------------- |
|---------------------------------|--------------------------------------------|-------------|
| `PORT` | HTTP listen port | `8080` |
| `DNSWATCHER_DEBUG` | Enable debug logging | `false` |
| `DNSWATCHER_DATA_DIR` | Directory for state file | `/var/lib/dnswatcher` |
@@ -352,44 +244,20 @@ following precedence (highest to lowest):
| `DNSWATCHER_SLACK_WEBHOOK` | Slack incoming webhook URL | `""` |
| `DNSWATCHER_MATTERMOST_WEBHOOK` | Mattermost incoming webhook URL | `""` |
| `DNSWATCHER_NTFY_TOPIC` | ntfy topic URL | `""` |
| `DNSWATCHER_DNS_INTERVAL` | DNS check interval, a positive duration such as `30m`; empty means the default, anything else stops startup | `1h` |
| `DNSWATCHER_TLS_INTERVAL` | TLS check interval, a positive duration such as `6h`; empty means the default, anything else stops startup | `12h` |
| `DNSWATCHER_DNS_INTERVAL` | DNS check interval | `1h` |
| `DNSWATCHER_TLS_INTERVAL` | TLS check interval | `12h` |
| `DNSWATCHER_TLS_EXPIRY_WARNING` | Days before expiry to warn | `7` |
| `DNSWATCHER_SENTRY_DSN` | Sentry DSN for error reporting | `""` |
| `DNSWATCHER_MAINTENANCE_MODE` | Only sets `maintenanceMode` in the health check response; changes nothing else | `false` |
| `DNSWATCHER_METRICS_USERNAME` | Basic auth username for /metrics, which is served only when this is set | `""` |
| `DNSWATCHER_MAINTENANCE_MODE` | Enable maintenance mode | `false` |
| `DNSWATCHER_METRICS_USERNAME` | Basic auth username for /metrics | `""` |
| `DNSWATCHER_METRICS_PASSWORD` | Basic auth password for /metrics | `""` |
| `DNSWATCHER_SEND_TEST_NOTIFICATION` | Send a test notification after first scan completes | `false` |
**`DNSWATCHER_TARGETS` is required.** dnswatcher will refuse to start if no
monitoring targets are configured. A monitoring daemon with nothing to monitor
is a misconfiguration, so dnswatcher fails fast with a clear error message
rather than running silently. Set `DNSWATCHER_TARGETS` to a comma-separated list
of DNS names before starting. A name listed more than once, in any letter case
or with a trailing dot, is watched once.
**`/metrics` is rate limited.** Each client address may send it 30 requests a
minute, failed logins included; beyond that it answers `429 Too Many Requests`
without checking the password. A Prometheus server scraping every 15 seconds
sends 4 a minute. IPv6 addresses in one /64 count as one client. When the
request comes from a private or loopback address, such as a reverse proxy's, the
client address is taken from the `X-Real-IP` header the proxy sets, or else from
`X-Forwarded-For`, as the last address in it that is not private or loopback. A
proxy that sets neither makes all its clients share one allowance.
**`DNSWATCHER_DNS_INTERVAL` and `DNSWATCHER_TLS_INTERVAL`** take a positive
duration: a number followed by a unit such as `s`, `m` or `h`, for example
`90s`, `30m`, `1h` or `1h30m`. There is no unit for days; write `24h`. An unset
or empty variable (`DNSWATCHER_DNS_INTERVAL=`) means the default. If either is
set to anything else, including a bare number or a zero or negative duration,
dnswatcher refuses to start with an error naming the variable and the value.
**`DNSWATCHER_SENTRY_DSN` reports crashes in HTTP requests to Sentry.** When it
is set, a panic in an HTTP request handler is sent to Sentry, and the request
still gets a `500 Internal Server Error` answer. Nothing else is sent to Sentry:
DNS, port and TLS problems are reported as notifications. A value Sentry cannot
parse stops dnswatcher at startup. At shutdown, reports not yet sent are sent,
waiting at most 2 seconds.
rather than running silently. Set `DNSWATCHER_TARGETS` to a comma-separated
list of DNS names before starting.
### Example `.env`
@@ -408,47 +276,33 @@ DNSWATCHER_SEND_TEST_NOTIFICATION=true
## DNS Resolution Strategy
dnswatcher never uses the system's configured recursive resolver for the names
it watches. Instead, it performs full iterative resolution:
dnswatcher never uses the system's configured recursive resolver. Instead,
it performs full iterative resolution:
1. **Root servers**: Starts from the IPv4 addresses of the 13 root servers,
built into the binary; the list is not refreshed.
1. **Root servers**: Starts from the IANA root nameserver list (hardcoded,
with periodic refresh).
2. **TLD delegation**: Queries root servers for the TLD NS records.
3. **Domain delegation**: Queries TLD nameservers for the domain's NS records.
The delegation they give, from the domain's parent zone, is the domain's NS
record set.
4. **Authoritative query**: Queries all discovered authoritative nameservers
directly for the requested records.
In steps 2 and 3 the servers are asked one at a time in a random order, chosen
anew each time, so no one root server gets every first query. A server that does
not reply, refuses the query, or gives an error reply such as SERVFAIL or a
referral that leads no closer to the name is passed over for the next one. When
a referral names a zone's nameservers without their addresses, the addresses of
all of them are looked up, so that each can be asked.
3. **Domain delegation**: Queries TLD nameservers for the domain's NS
records.
4. **Authoritative query**: Queries all discovered authoritative
nameservers directly for the requested records.
This approach ensures:
- Independence from any upstream resolver's cache or filtering.
- Ability to detect split-horizon or inconsistent responses across authoritative
servers.
- Ability to detect split-horizon or inconsistent responses across
authoritative servers.
- Visibility into the full delegation chain.
A watched name's records are stored as its nameservers return them, CNAME
included. When they return a CNAME and no address, the CNAME chain is followed
(with a depth limit to prevent loops) to the A and AAAA records at its end, and
the port and TLS checks use those addresses. Nameservers' addresses are found
the same way.
Sending a notification or a Sentry report is the one use of the system's
resolver: the HTTP client looks up the webhook's or Sentry's host name with it.
For hostname monitoring, the resolver follows CNAME chains (with a
depth limit to prevent loops) before collecting terminal A/AAAA records.
---
## State File Format
The state file (`DATA_DIR/state.json`) contains the complete monitoring
snapshot. Hostname records are stored **per authoritative nameserver**, not as a
merged view, to enable inconsistency detection.
snapshot. Hostname records are stored **per authoritative nameserver**,
not as a merged view, to enable inconsistency detection.
```json
{
@@ -457,10 +311,6 @@ merged view, to enable inconsistency detection.
"domains": {
"example.com": {
"nameservers": ["ns1.example.com.", "ns2.example.com."],
"nameserverAddresses": {
"ns1.example.com.": ["192.0.2.53", "2001:db8::53"],
"ns2.example.com.": ["198.51.100.53"]
},
"lastChecked": "2026-02-19T12:00:00Z"
}
},
@@ -484,7 +334,6 @@ merged view, to enable inconsistency detection.
"lastChecked": "2026-02-19T12:00:00Z"
}
},
"cnameAddresses": [],
"lastChecked": "2026-02-19T12:00:00Z"
}
},
@@ -513,33 +362,13 @@ merged view, to enable inconsistency detection.
}
```
The `status` field for each per-nameserver entry and certificate entry tracks
reachability:
The `status` field for each per-nameserver entry and certificate entry
tracks reachability:
| Status | Meaning |
| ------- | -------------------------------------------------------- |
|-------------|-------------------------------------------------|
| `ok` | Query succeeded, records are current |
| `error` | Query failed (timeout, SERVFAIL, REFUSED, network error) |
A nameserver that answers NXDOMAIN or with no records has status `ok` and empty
`records`. A nameserver whose query failed, or that only referred it to other
nameservers, has status `error`, empty `records`, and the reason in `error`. A
certificate entry whose TLS connection or handshake failed likewise has status
`error`, the reason in `error`, and the certificate fields left empty or zero.
`nameserverAddresses` lists, by nameserver, the sorted addresses its name
resolves to. A state file without it loads, and the next check fills it in
without a notification.
`cnameAddresses` lists the sorted addresses at the end of a hostname's CNAME
chain, found when its nameservers answered with a CNAME and no address; it is
empty when they answered with an address. When the chain cannot be followed, or
none of the name's nameservers answered, the previous check's list is kept, or
`null` when no earlier check saved one. A state file without it loads, and the
first check after that saves it without a notification.
A port entry in the older format, with one `hostname` instead of the `hostnames`
list, loads as a list of that one name.
| `error` | Query failed (timeout, SERVFAIL, network error) |
---
@@ -548,49 +377,28 @@ list, loads as a list of that one name.
This repository adheres to the
[Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
standard: normalized scripts in `script/` are the entrypoints for the
development workflow, and the Makefile targets are thin shims that call them. We
provide:
development workflow, and the Makefile targets are thin shims that call
them. We provide:
- `script/bootstrap` — install all dependencies (go, `go mod download`). It does
not install golangci-lint or prettier: both run in Docker, see `script/lint`
and `script/fmt` below.
- `script/setup` — make a fresh clone ready for development: bootstrap plus the
git pre-commit hook
- `script/projectname` — print the project name (used for the Docker image tag)
- `script/test` — run the test suite (race detector, coverage). Caching is
waived for testing, exactly as it is for linting: `-count=1` forces every
invocation to execute, because the suite queries live DNS and a cached pass
queries nothing. Failures are rerun with `-v` automatically, and the build
fails even if that rerun passes.
- `script/lint` — run golangci-lint, always inside Docker: it builds
`Dockerfile.lint`, which COPYs the repo into the digest-pinned `golangci-lint`
image and lints as a build step, so a successful build is a clean lint. The
linter is never installed or run on the host, and Docker is the only
prerequisite. Caching is waived for linting: the lint stage is forced to
execute on every run with `--no-cache-filter`, because a cached build lints
nothing.
- `script/fmt` — format all code (gofmt -s, goimports) and all Markdown
(prettier). goimports runs with `go run` at a pinned commit, never from your
`PATH`. prettier runs inside Docker, built from `Dockerfile.fmt` on a
digest-pinned node image, at the version pinned by `package.json` and
`yarn.lock`; it is never installed on the host.
- `script/fmt-check` — check formatting (read-only) with the same tools, failing
on any file `script/fmt` would change. It runs the two scripts below.
- `script/fmt-check-go` — the gofmt and goimports half, on the host. The
`Dockerfile` lint stage runs it.
- `script/fmt-check-markdown` — the prettier half, inside Docker, forced to
execute on every run with `--no-cache-filter`
- `script/bootstrap` — install all dependencies (go, pinned
golangci-lint and goimports, `go mod download`)
- `script/setup` — make a fresh clone ready for development: bootstrap
plus the git pre-commit hook
- `script/projectname` — print the project name (used for the Docker
image tag)
- `script/test` — run the test suite (race detector, coverage)
- `script/lint` — run golangci-lint, with its cache and its lock file
isolated to this checkout (under the git-ignored `.lint-cache/`) so
concurrent checkouts on one host cannot share cache entries or
contend on a single lock
- `script/fmt` — format all code (gofmt -s, goimports)
- `script/fmt-check` — check formatting (read-only)
- `script/check` — run test, lint, and fmt-check
- `script/docker` — build the Docker image tagged via `script/projectname`, with
`--no-cache-filter=lint,builder` so the lint stage and the builder stage,
which runs the tests, run on every invocation, and with the version from
`git describe` passed as `--build-arg VERSION`
- `script/cibuild` — CI entrypoint: `docker build` with
`--no-cache-filter=lint,builder`, so the lint stage and the builder stage,
which runs the tests, run on every invocation, because a cached build lints
nothing and queries no DNS; then `script/fmt-check-markdown`
- `script/precommit` — run by the git pre-commit hook; `go mod tidy` guard, then
`script/check`
- `script/docker` — build the Docker image tagged via
`script/projectname`
- `script/cibuild` — CI entrypoint: plain `docker build .`
- `script/precommit` — run by the git pre-commit hook; `go mod tidy`
guard, then `script/check`
- `script/install-precommit` — install the git pre-commit hook
## Building
@@ -598,22 +406,19 @@ provide:
```sh
make build # Build binary to bin/dnswatcher
make test # Run tests with race detector
make lint # Run golangci-lint in Docker (requires docker)
make fmt # Format code and Markdown (requires docker)
make lint # Run golangci-lint
make fmt # Format code
make check # Run all checks (test, lint, fmt-check)
make clean # Remove build artifacts
```
### Build-Time Variables
`make build` sets the version with `-ldflags "-X main.Version=..."`, taking it
from `git describe --tags --always --dirty`, or from `VERSION` when given on the
command line (`make build VERSION=1.2.3`). The version appears in the startup
log and in the health check response.
Version is injected via `-ldflags`:
The Docker image has no `.git`, so the `Dockerfile` takes the version as
`--build-arg VERSION`. `make docker` passes it; a plain `docker build` passes
none, and that image reports `dev`.
```sh
go build -ldflags "-X main.Version=$(git describe --tags --always)" ./cmd/dnswatcher
```
---
@@ -632,177 +437,49 @@ docker run -d \
---
## Running under upaas
[upaas](https://git.eeqj.de/sneak/upaas) builds the image from this repository's
`Dockerfile` and runs it. The app needs:
- **Branch:** `prod`. `prod` is cut from `main`, and merging a `main` to `prod`
pull request is a deploy.
- **Volume:** one host directory mounted at `/var/lib/dnswatcher`, where the
state file lives.
- **Network and port:** the dashboard is unauthenticated and shows every watched
name and recent alert, and upaas publishes every mapped port on all interfaces
of the host ([upaas issue 113](https://git.eeqj.de/sneak/upaas/issues/113)).
Add a port mapping to container port `8080` only if the dashboard should be
public. Otherwise add none: set the app's Docker network in upaas to your
reverse proxy's Docker network, and the proxy reaches the app at `upaas-`
followed by the app name, port `8080`.
- **Required environment:** `DNSWATCHER_TARGETS`, a comma-separated list of the
domains and hostnames to watch. dnswatcher refuses to start without it.
- **Recommended environment:** at least one notification endpoint
(`DNSWATCHER_SLACK_WEBHOOK`, `DNSWATCHER_MATTERMOST_WEBHOOK`,
`DNSWATCHER_NTFY_TOPIC`); without one, changes show only on the dashboard.
`DNSWATCHER_METRICS_USERNAME` and `DNSWATCHER_METRICS_PASSWORD` serve
`/metrics` behind basic auth.
- **Leave unset:** `DNSWATCHER_DATA_DIR`, which the image sets to
`/var/lib/dnswatcher`, and `PORT`, which defaults to `8080`. Every setting
comes from the environment; the image holds no config file.
- **Health check:** the image's own, which requests `/.well-known/healthcheck`
every 10 seconds. upaas reads the container's health 60 seconds after a deploy
and marks the deploy failed unless it is `healthy`.
---
## Monitoring Lifecycle
1. **Startup**: Check that the data directory can be written, and exit with an
error naming it if not. Load state from disk. If no state file exists, start
with empty state (first check will establish baseline without triggering
change notifications).
2. **Initial check**: Immediately perform all DNS, port, and TLS checks on
startup.
1. **Startup**: Load state from disk. If no state file exists, start
with empty state (first check will establish baseline without
triggering change notifications).
2. **Initial check**: Immediately perform all DNS, port, and TLS checks
on startup.
3. **Periodic checks** (DNS always runs first):
- DNS checks: every `DNSWATCHER_DNS_INTERVAL` (default 1h). Also re-run
before every TLS check cycle to ensure fresh IPs.
- DNS checks: every `DNSWATCHER_DNS_INTERVAL` (default 1h). Also
re-run before every TLS check cycle to ensure fresh IPs.
- Port checks: every `DNSWATCHER_DNS_INTERVAL`, after DNS completes.
- TLS checks: every `DNSWATCHER_TLS_INTERVAL` (default 12h), after DNS
completes.
- Port and TLS checks use the IP addresses found by the DNS phase that
immediately precedes them. When that phase cannot find a name's
nameservers at all, the addresses an earlier check saved for the name are
used. When it cannot follow a name's CNAME chain, or none of the name's
nameservers answered, the addresses an earlier check found at the end of
the chain are used.
4. **On change detection**: Send notifications to all configured endpoints,
update in-memory state, persist to disk.
5. **Shutdown**: The watcher stops checking and saves the final state to disk,
and shutdown waits for that save before it goes on. Then it waits for
in-flight notification deliveries to complete. Both waits share the fx
shutdown timeout (15s by default): deliveries still retrying against an
unreachable endpoint when that expires are abandoned, and the number
abandoned is logged at warn level rather than dropped silently. Notifications
generated after shutdown has begun are refused and logged, so a late burst
cannot extend the shutdown. A DNS lookup, port check or TLS check that
shutdown cuts short saves nothing and sends no notification.
- TLS checks: every `DNSWATCHER_TLS_INTERVAL` (default 12h), after
DNS completes.
- Port and TLS checks always use freshly resolved IP addresses from
the DNS phase that immediately precedes them — never stale IPs
from a previous cycle.
4. **On change detection**: Send notifications to all configured
endpoints, update in-memory state, persist to disk.
5. **Shutdown**: Persist final state to disk, complete in-flight
notifications, stop gracefully.
---
## Planned Future Features (Post-1.0)
- **DNSSEC validation**: Validate the DNSSEC chain of trust during iterative
resolution and report DNSSEC failures as notifications.
- **DNSSEC validation**: Validate the DNSSEC chain of trust during
iterative resolution and report DNSSEC failures as notifications.
---
## Project Structure
Follows the conventions defined in `REPO_POLICIES.md`, adapted from the
[upaas](https://git.eeqj.de/sneak/upaas) project template. Uses uber/fx for
dependency injection, go-chi for HTTP routing, slog for logging, and Viper for
configuration.
---
## Rationale
dnswatcher exists to report changes to the DNS records, TCP port availability
and TLS certificates of its configured domains and hostnames, failures and
recoveries included: it is designed as a real-time change feed. It queries the
authoritative nameservers directly, tracing from the root, instead of a
recursive resolver, so no resolver's cache or filtering hides a change and
nameservers that disagree with each other are seen. Its state is a single JSON
file, so it survives a restart without an external database.
---
## Design
```
cmd/dnswatcher/main.go Entry point (uber/fx bootstrap)
internal/
config/
config.go Viper-based configuration
classify.go Splits targets into domains and hostnames
(Public Suffix List)
globals/globals.go Build-time variables (version)
logger/logger.go slog structured logging (TTY detection)
healthcheck/healthcheck.go Health check service
middleware/middleware.go HTTP middleware (logging, CORS, security
headers, metrics auth and rate limit)
handlers/
handlers.go Shared handler setup and JSON responses
dashboard.go Web dashboard
templates/dashboard.html Dashboard template (embedded)
status.go /api/v1/status
healthcheck.go Health check handler
server/
server.go HTTP server lifecycle
routes.go Route definitions
state/state.go JSON file state persistence
resolver/
resolver.go Resolver setup and query status values
iterative.go Iterative DNS resolution engine
dns_client.go UDP and TCP DNS clients
errors.go Resolver errors
portcheck/portcheck.go TCP port connectivity checker
tlscheck/tlscheck.go TLS certificate inspector
notify/
notify.go Notification service (Slack, Mattermost, ntfy)
retry.go Delivery retries with backoff
history.go Last 100 notifications, for the dashboard
shutdown.go Waits for deliveries at shutdown
watcher/
watcher.go Main monitoring orchestrator and scheduler
interfaces.go The resolver, checkers and notifier it uses
livednstest/livednstest.go Retry and concurrency limit for tests
against live DNS (imported only by tests)
static/
static.go Embeds the CSS served under /s/
css/tailwind.min.css Dashboard stylesheet
```
### Design Principles
- **No recursive resolvers**: The watched names are resolved iteratively,
tracing from root nameservers through the delegation chain to authoritative
servers.
- **No external database**: State is persisted as a single JSON file.
- **Dependency injection**: All components are wired via
[uber/fx](https://github.com/uber-go/fx).
- **Structured logging**: All logs use `log/slog` with JSON output in production
(TTY detection for development).
- **Graceful shutdown**: All background goroutines respect context cancellation
and the fx lifecycle. In-flight notification deliveries are drained on
shutdown, bounded by the shutdown timeout.
---
## TODO
[`TODO.md`](./TODO.md) names the next step and the steps planned after it. The
work for 1.0 is tracked as issues on the
[1.0 milestone](https://git.eeqj.de/sneak/dnswatcher/milestone/7).
[upaas](https://git.eeqj.de/sneak/upaas) project template. Uses uber/fx
for dependency injection, go-chi for HTTP routing, slog for logging, and
Viper for configuration.
---
## License
dnswatcher is released under the MIT License, Copyright (c) 2026
[@sneak](https://sneak.berlin). See the [`LICENSE`](./LICENSE) file in the
repository root for the full text.
License has not yet been chosen for this project. Pending decision by the
author (MIT, GPL, or WTFPL).
## Author
REPO_POLICIES.md
+6 -14
View File
@@ -1,6 +1,6 @@
---
title: Repository Policies
last_modified: 2026-08-07
last_modified: 2026-07-06
---
This document covers repository structure, tooling, and workflow standards. Code
@@ -189,13 +189,8 @@ style conventions are in separate documents:
module under test to verify it compiles/parses. There is no excuse for
`make test` to be a no-op.
- `make test` must complete in under 60 seconds. That is the hard cap, and a
suite that exceeds it fails. Under 20 seconds is the target. A suite between
20 and 60 seconds is still green, but the overage must be filed as an
improvement bug against that repo. Add a 90-second timeout to the test
invocation in the Makefile (`go test -timeout 90s`). The backstop deliberately
sits above the hard cap so that it catches a genuinely hung test rather than a
merely slow one.
- `make test` must complete in under 20 seconds. Add a 30-second timeout in the
Makefile.
- **`make test` should use the conditional verbose rerun pattern.** Run tests
without `-v` (verbose) first. If tests fail, automatically rerun with `-v` to
@@ -214,9 +209,9 @@ style conventions are in separate documents:
```makefile
test:
@go test -timeout 90s -race -cover ./... || \
@go test -timeout 30s -race -cover ./... || \
{ echo "--- Rerunning with -v for details ---"; \
go test -timeout 90s -race -v ./...; exit 1; }
go test -timeout 30s -race -v ./...; exit 1; }
```
Python example:
@@ -265,10 +260,7 @@ style conventions are in separate documents:
- `.golangci.yml` is standardized and must _NEVER_ be modified by an agent, only
manually by the user. Fetch from
`https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml`. The
canonical golangci-lint version is v2.12.2 (released 2026-05-06), installed
commit-pinned via
`go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5`.
`https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml`.
- When pinning images or packages by hash, add a comment above the reference
with the version and date (YYYY-MM-DD).
TESTING.md
+16 -26
View File
@@ -2,43 +2,33 @@
## DNS Resolution Tests
DNS is never mocked in this project, not in tests and not anywhere else; see the
README section "No DNS mocking. Ever." Every test that looks something up in DNS
**MUST** query live DNS servers, never a stand-in. Logic that works on record
data, such as comparing or formatting records, may be tested on that data
directly with no lookup.
All resolver tests **MUST** use live queries against real DNS servers.
No mocking of the DNS client layer is permitted.
### Rationale
The resolver performs iterative resolution from root nameservers through the
full delegation chain. Mocked responses cannot faithfully represent the variety
of real-world DNS behavior (truncation, referrals, glue records, DNSSEC, varied
response times, EDNS, etc.). Testing against real servers ensures the resolver
works correctly in production.
The resolver performs iterative resolution from root nameservers through
the full delegation chain. Mocked responses cannot faithfully represent
the variety of real-world DNS behavior (truncation, referrals, glue
records, DNSSEC, varied response times, EDNS, etc.). Testing against
real servers ensures the resolver works correctly in production.
### Constraints
- Tests hit real DNS infrastructure and require network access
- Test duration depends on network conditions; timeout tuning keeps the suite
within the 60-second target
- Query timeout is calibrated to 3× maximum antipodal RTT (~300ms) plus
processing margin
- Test duration depends on network conditions; timeout tuning keeps
the suite within the 30-second target
- Query timeout is calibrated to 3× maximum antipodal RTT (~300ms)
plus processing margin
- Root server fan-out is limited to reduce parallel query load
- Live lookups that expect an answer go through `internal/livednstest`, which
limits how many run at once in a test binary and retries a lookup that got
none
- Flaky failures from transient network issues are acceptable and should be
investigated as potential resolver bugs, not papered over with mocks or skip
flags
- Flaky failures from transient network issues are acceptable and
should be investigated as potential resolver bugs, not papered over
with mocks or skip flags
### What NOT to do
- **Do not mock, fake or stub DNS** anywhere: no stand-in `DNSClient`, no
stand-in for the watcher's `DNSResolver`, no fake DNS server, no canned
responses
- **Do not mock `DNSClient`** for resolver tests (the mock constructor
exists for unit-testing other packages that consume the resolver)
- **Do not add `-short` flags** to skip slow tests
- **Do not increase `-timeout`** to hide hanging queries
- **Do not remove `-count=1` from `script/test`** — Go's test cache replays a
previous run's output without querying anything, so a cached pass is not
evidence that live resolution works
- **Do not modify linter configuration** to suppress findings
TODO.md
+142 -118
View File
@@ -1,138 +1,162 @@
# Workflow
- branch (from `next`)
- do the work in Next Step
- move Next Step to the top of Completed Steps
- move the top item of Future Steps into Next Step
- commit (`TODO.md` changes in the same commit as the work)
- push
- open a PR against `next`
* branch (from `main`)
* do the work in Next Step
* move Next Step to the top of Completed Steps
* move the top item of Future Steps into Next Step
* commit (`TODO.md` changes in the same commit as the work)
* merge to `main` if the branch is not protected, otherwise open a PR
* push
# Status
pre-1.0. No git tags. Work lands on `next` by PR. Open work for 1.0 is tracked
on the 1.0 milestone: https://git.eeqj.de/sneak/dnswatcher/milestone/7
pre-1.0. No git tags. Core resolver work in flight on feature/resolver
(dirty: internal/resolver/resolver_test.go). Local checkout has diverged
from origin: origin/main is 8 commits ahead (watcher orchestrator,
unified TARGETS) and origin/feature/resolver already contains the full
iterative resolver implementation with hermetic mocked tests.
# Next Step
trial run of the finished image: https://git.eeqj.de/sneak/dnswatcher/issues/149
Policy scaffold commit: add LICENSE, REPO_POLICIES.md, .editorconfig,
.dockerignore, and .gitea/workflows/check.yml, and add the missing
fmt-check, docker, and hooks targets to the Makefile. One commit, then
confirm make check still passes.
# Completed Steps
- 2026-10-02: a watched name whose nameservers answer with a CNAME and no
address gets port and TLS checks at the end of its CNAME chain (closes #203).
- 2026-10-02: the resolver tries root servers, and every other server list it
walks, in a random order each time, not always from the top (closes #138).
- 2026-10-02: a name listed more than once in `DNSWATCHER_TARGETS`, in any
letter case or with a trailing dot, is watched once (closes #207).
- 2026-10-01: README checked against the code and corrected: metrics, CORS,
notification retries, CNAMEs, state file fields, Design tree (closes #108).
- 2026-10-01: a certificate within the expiry warning period is warned about on
every TLS check, where some checks used to skip it at random (closes #204).
- 2026-10-01: a domain's NS set is its delegation from the parent zone's
servers, not whichever of its own servers answered first (closes #200).
- 2026-10-01: README has Getting Started, Rationale and TODO sections, and its
Architecture section is now Design, in the order policy sets (closes #173).
- 2026-10-01: a zone's server that answers SERVFAIL or a referral leading no
closer is passed over for the next, as one that times out is (closes #197).
- 2026-10-01: when none of a configured name's nameservers answered, the port
state saved for its addresses is kept, not removed (closes #193).
- 2026-10-01: `ResolveIPAddresses` returns an error, not no addresses, when no
nameserver of the name's zone answered (closes #190).
- 2026-10-01: `make fmt` and `make fmt-check` cover Markdown with prettier, run
in Docker at the version pinned by `yarn.lock` (closes #119).
- 2026-10-01: `make fmt-check` fails on a file `goimports` would change; both
format scripts run `goimports` at its pinned commit, not from `PATH` (#119).
- 2026-10-01: a hostname is queried at the servers of the zone it is in, found
by following delegations for the name, not its last two labels (closes #189).
- 2026-10-01: each nameserver's addresses are saved with its domain, and a
change while it stays in the delegation is notified (closes #105).
- 2026-10-01: the watcher saves state when it stops, and shutdown waits for that
save, so it no longer relies on the state's own stop hook (closes #114).
- 2026-10-01: `DNSWATCHER_SENTRY_DSN` reports panics in HTTP handlers to Sentry,
and a DSN Sentry cannot parse stops startup (closes #107).
- 2026-10-01: a port or TLS check that shutdown cuts short saves nothing and
sends no notification, as a cut-short DNS lookup already did (closes #185).
- 2026-10-01: the client address from `X-Forwarded-For` is the last entry that
is not a trusted proxy, not the first, which the client sets (closes #181).
- 2026-10-01: a nameserver that does not answer is saved as `error` with the
reason, and NS failure and NS recovery are notified (closes #104).
- 2026-10-01: a `DNSWATCHER_DNS_INTERVAL` or `DNSWATCHER_TLS_INTERVAL` that is
not a positive duration stops startup; empty means the default (closes #177).
- 2026-10-01: `/metrics` allows each client address 30 requests a minute,
counted before Basic Auth, and answers 429 beyond that (closes #101).
- 2026-10-01: the image built by `make docker` reports the `git describe`
version, not `dev`, and the startup log now shows it (closes #109).
- 2026-10-01: two notify shutdown tests always release the delivery they hold,
so a drain that returns early fails them instead of hanging (closes #176).
- 2026-10-01: `script/install-precommit` asks git for the repository's git
directory, so `make hooks` also works where `.git` is a file (closes #129).
- 2026-10-01: `TODO.md` brought up to date: open issues listed by URL, every
Completed Steps entry cut to at most two lines (closes #146).
- 2026-10-01: wildcard CORS now applies only to the public routes, not to
`/metrics`, and allows only the methods they serve (closes #100).
- 2026-10-01: `internal/state` and `internal/watcher` no longer export test-only
constructors: two moved to `export_test.go`, one is deleted (closes #111).
- 2026-10-01: notify shutdown tests use one timing constant per meaning, name
the bound they check, and require the drain's debug line (closes #116).
- 2026-09-29: the entrypoint chowns the data directory to `dnswatcher` and runs
dnswatcher as that user, so a host bind mount needs no chown (closes #166).
- 2026-09-29: the live-DNS test package is renamed `internal/livednstest`;
`make lint` fails when program code imports it (closes #164).
- 2026-09-29: `.golangci.yml` re-fetched from `sneak/prompts`, with
`gomodguard_v2` and the org `depguard` `test-support` rule (closes #123).
- 2026-09-29: watcher and resolver tests that look something up in DNS use the
real resolver against live DNS servers (closes #159).
- 2026-09-28: the inconsistency alert is sent once, when two nameservers start
to disagree; every pair of nameservers is compared (closes #158).
- 2026-09-28: DNS names in record values (CNAME, MX, SRV and NS targets) are
lower-cased, so letter case alone is not a change (closes #157).
- 2026-09-28: lint and tests run on every build: `script/cibuild` and
`script/docker` pass `--no-cache-filter=lint,builder` (closes #115).
- 2026-09-28: the server timeout test drives `Run` and checks the timeouts on
the `http.Server` it serves (closes #120).
- 2026-09-28: upaas deploy readiness: the image runs as user `dnswatcher` with a
`HEALTHCHECK`; README "Running under upaas" (closes #147).
- 2026-09-21: added behavioural tests for `internal/globals`,
`internal/healthcheck`, and `internal/logger` (closes #110).
- 2026-09-21: `go mod tidy` dropped the redundant `golang.org/x/sync`
`// indirect` line so `script/bootstrap` leaves a clean tree (#132)
- 2026-08-10: comment-only corrections to `script/bootstrap`, `script/cibuild`
and `Dockerfile.lint`; no behaviour changed.
- 2026-08-10: MIT `LICENSE` added at the repository root; the README's first
line and License section name the licence.
- 2026-08-10: policy scaffold present: `REPO_POLICIES.md`, `.editorconfig`,
`.dockerignore`, CI workflow, `make fmt-check`, `make docker`, `make hooks`.
- 2026-08-10: Go's test cache disabled in `script/test` (`-count=1`), so every
run queries live DNS; a failed run is rerun with `-v`.
- 2026-08-10: live-DNS tests made robust rather than gated (#93): a limit on
concurrent lookups, retries, and a quorum across nameservers.
- 2026-08-10: all linting moved into Docker: `script/lint` builds
`Dockerfile.lint`, and the root `Dockerfile` has its own lint stage.
- 2026-08-09: in-flight notification deliveries are drained at shutdown, bounded
by the shutdown deadline (#106).
- 2026-08-09: `http.Server` sets all four socket timeouts; `WriteTimeout` stays
above the 60s handler timeout (#99).
- 2026-08-09: `SecurityHeaders()` middleware sets HSTS, CSP and the other
security headers `REPO_POLICIES.md` requires on every response.
- 2026-08-07: golangci-lint bumped to v2.12.2 and `.golangci.yml` set to the org
config; fixed the resulting `goconst`, `dupl` and `lll` findings.
- 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints, Makefile
shims, README Entrypoints section
- 2026-02-20: iterative DNS resolver implemented
- 2026-02-20: CI actions and go install refs pinned to commit SHAs; Gitea
Actions workflow added
- 2026-08-09: `script/lint` now isolates golangci-lint's per-user global
state to the checkout (#121): `GOLANGCI_LINT_CACHE` and `TMPDIR` are
both pointed at the git-ignored, Docker-ignored `.lint-cache/`. The
cache fixes cross-contamination; `TMPDIR` is what moves the lock,
which lives at `$TMPDIR/golangci-lint.lock` and not in the cache
directory. Reproduced both failure modes on the unfixed script (10 of
12 concurrent runs void with `parallel golangci-lint is running`; 11
of 12 reporting another checkout's paths) and both are gone at 20-way
concurrency after the fix
- 2026-08-07: golangci-lint bumped to v2.12.2 (commit-pinned installs
in `Dockerfile` and `script/bootstrap`); `.golangci.yml` set to the
org-standard v2-schema config used across the org's repos
(owner-authorized; same file is being landed as canonical via prompts
PR #24), with settings under `linters.settings` so the
lll/funlen/cyclop/dupl thresholds apply; fixed the resulting
`goconst`, `dupl`, and `lll` findings; the informational `gomodguard`
deprecation warning under this config is accepted
- 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints,
Makefile shims, README Entrypoints section
- 2026-02-20: iterative DNS resolver implemented; tests made hermetic
with mocked DNS (origin/feature/resolver, unmerged)
- 2026-02-20: CI actions and go install refs pinned to commit SHAs;
Gitea Actions workflow for make check (origin/ci/make-check, unmerged)
- 2026-02-20: watcher monitoring orchestrator merged to main (#8)
- 2026-02-20: DOMAINS/HOSTNAMES unified into single TARGETS config (#11)
- 2026-02-19: TCP port connectivity checker, made concurrent with port
validation; gosec G704 SSRF findings fixed without suppression
- 2026-02-19: TLS certificate inspector with no-peer-certificates error path and
IP SANs
(feature branches, unmerged)
- 2026-02-19: TLS certificate inspector with no-peer-certificates error
path and IP SANs (feature branch, unmerged)
- 2026-02-19: gosec SSRF and formatting fixes on main
- 2026-02-19: initial scaffold with per-nameserver DNS monitoring model
# Future Steps
- 1.0 readiness: run it with a real config and read the logs:
https://git.eeqj.de/sneak/dnswatcher/issues/66
- review toward 1.0: https://git.eeqj.de/sneak/dnswatcher/issues/144
Compliance:
- Add README sections required by policy (Description, Getting Started,
Rationale, Design, TODO, License, Author) if any are missing
- Pin Dockerfile base images by sha256 and ensure the Docker build runs
make check
Branch reconciliation:
- Sync local checkout with origin: local main is 8 commits behind
origin/main; local feature/resolver has diverged from
origin/feature/resolver, which already implements the resolver
- Merge in-flight branches to main once green: feature/resolver,
ci/make-check, feature/portcheck-implementation,
feature/tlscheck-implementation
Resolver (plan from untracked TODO.md; largely implemented on
origin/feature/resolver, verify each item before closing):
- Add github.com/miekg/dns dependency
- roots.go: hardcoded IANA root server list (a through m, IPv4/IPv6),
rootServers() returning ip:53 strings
- query.go: low-level query(ctx, server, name, qtype): UDP with TCP
fallback on truncation, RD=0, context respected, 5s per-query timeout,
returns raw *dns.Msg
- trace.go: iterative delegation chasing from roots: referral detection
(NOERROR, empty answer, NS in authority), glue extraction with
bailiwick check, out-of-bailiwick NS resolved with recursion guard,
delegation depth limit (20), retry across nameservers on failure, do
not chase CNAMEs inside trace
- FindAuthoritativeNameservers: NS set via trace, sorted, FQDN
normalized, trailing dot handled; must pass its 9 tests
- QueryNameserver: resolve NS host to IPs, query A/AAAA/CNAME/MX/TXT/
SRV/CAA/NS, build NameserverResponse with status mapping (OK,
NXDomain, NoData, Error), documented record formatting, sorted values,
lame delegation detection; must pass its 16 tests
- QueryAllNameservers: find NS set for parent domain (public suffix
list), query all NS in parallel with bounded concurrency, return map
even when all fail, context cancellation; must pass its 4 tests
- LookupNS: thin wrapper over FindAuthoritativeNameservers, sorted,
identical results; must pass its 3 tests
- ResolveIPAddresses: collect A/AAAA from all NS, follow CNAME chains
with MaxCNAMEDepth, dedupe, sort, NXDOMAIN returns empty slice with
nil error; must pass its 9 tests
- All 39 resolver tests pass, make check green, merge to main
Watcher (internal/watcher/watcher.go):
- Scheduling loop in Run(ctx): initial check on startup, separate
tickers for DNS/port and TLS intervals, persist state via state.Save()
after each cycle, clean shutdown on context cancel
- Domain check: LookupNS, compare to stored state, store silently on
first run, notify with old/new NS lists on change
- Hostname check: QueryAllNameservers, compare per-NS records; notify on
record changes, NS failure, NS recovery, inconsistency detected,
inconsistency resolved, empty response; store silently on first run
- Port check: ResolveIPAddresses, check ports 80 and 443 per IP, notify
on open/closed transitions, handle new and disappeared IPs
- TLS check: for each open IP:443, CheckCertificate; notify on expiry
warning, certificate change (CN/issuer/SANs), TLS failure/recovery
Port checker (internal/portcheck/portcheck.go):
- Tests against known-open ports and RFC documentation IPs
- CheckPort: net.DialTimeout (5s), context respected; (true, nil) open,
(false, nil) closed/timeout/refused, error only for unexpected
failures
TLS checker (internal/tlscheck/tlscheck.go):
- Tests against known public HTTPS servers, verify fields populated
- CheckCertificate: tls.Dial to specific IP:443 with hostname as SNI;
extract subject CN, issuer CN and org, NotAfter, SANs; error on
handshake failure
Notification service (internal/notify/notify.go, Slack/Mattermost/ntfy
backends exist):
- Structured notification types: DNS change, port change, TLS expiry,
TLS change, NS failure, NS recovery, NS inconsistency
- Per-backend formatting: Slack/Mattermost attachment colors (red
failures/expiry, yellow warnings, green recoveries, blue info); ntfy
priorities (urgent failures, high warnings, default changes, low
recoveries); include hostname, nameserver, old/new values, timestamps
HTTP API handlers:
- Wire *state.State and *watcher.Watcher into handler params
- GET /api/v1/status: full state snapshot as JSON
- GET /api/v1/domains: domain states with NS records and last-checked
- GET /api/v1/hostnames: hostname states with per-NS record data
Infrastructure notes (from untracked TODO.md):
- Module path sneak.berlin/go/dnswatcher differs from the git.eeqj.de
remote intentionally; do not "fix" it
- Dependencies: github.com/miekg/dns, golang.org/x/net/publicsuffix
- Resolver tests originally used live DNS against *.dns.sneak.cloud
(required records documented in the test file header); origin now has
mocked hermetic tests, keep them hermetic
cmd/dnswatcher/main.go
-1
View File
@@ -63,7 +63,6 @@ func main() {
return n
},
),
fx.Invoke(func(l *logger.Logger) { l.Identify() }),
fx.Invoke(func(*server.Server, *watcher.Watcher) {}),
).Run()
}
deploy/docker-entrypoint.sh
-17
View File
@@ -1,17 +0,0 @@
#!/bin/sh
# deploy/docker-entrypoint.sh: the Docker image's ENTRYPOINT. It runs as
# root only to give the data directory to the dnswatcher user: a host
# directory bind-mounted there keeps its host owner, often root, and may
# hold a state file left by another uid, which dnswatcher could neither
# read nor replace. dnswatcher itself always runs as the dnswatcher user.
set -eu
main() {
dir="${DNSWATCHER_DATA_DIR:-/var/lib/dnswatcher}"
mkdir -p "$dir"
chown -R dnswatcher:dnswatcher "$dir"
chmod 700 "$dir"
exec su-exec dnswatcher /usr/local/bin/dnswatcher "$@"
}
main "$@"
go.mod
+9 -12
View File
@@ -4,30 +4,27 @@ go 1.25.5
require (
github.com/99designs/basicauth-go v0.0.0-20230316000542-bf6f9cbbf0f8
github.com/getsentry/sentry-go v0.49.0
github.com/go-chi/chi/v5 v5.2.5
github.com/go-chi/cors v1.2.2
github.com/go-chi/httprate v0.16.0
github.com/joho/godotenv v1.5.1
github.com/miekg/dns v1.1.72
github.com/prometheus/client_golang v1.23.2
github.com/spf13/viper v1.21.0
github.com/stretchr/testify v1.11.1
go.uber.org/fx v1.24.0
golang.org/x/net v0.56.0
golang.org/x/sync v0.21.0
golang.org/x/net v0.50.0
golang.org/x/sync v0.19.0
)
require (
github.com/beorn7/perks v1.0.1 // indirect
github.com/cespare/xxhash/v2 v2.3.0 // indirect
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
github.com/davecgh/go-spew v1.1.1 // indirect
github.com/fsnotify/fsnotify v1.9.0 // indirect
github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
github.com/klauspost/cpuid/v2 v2.2.10 // indirect
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
github.com/pelletier/go-toml/v2 v2.2.4 // indirect
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
github.com/pmezard/go-difflib v1.0.0 // indirect
github.com/prometheus/client_model v0.6.2 // indirect
github.com/prometheus/common v0.66.1 // indirect
github.com/prometheus/procfs v0.16.1 // indirect
@@ -37,16 +34,16 @@ require (
github.com/spf13/cast v1.10.0 // indirect
github.com/spf13/pflag v1.0.10 // indirect
github.com/subosito/gotenv v1.6.0 // indirect
github.com/zeebo/xxh3 v1.0.2 // indirect
go.uber.org/dig v1.19.0 // indirect
go.uber.org/multierr v1.10.0 // indirect
go.uber.org/zap v1.26.0 // indirect
go.yaml.in/yaml/v2 v2.4.2 // indirect
go.yaml.in/yaml/v3 v3.0.4 // indirect
golang.org/x/mod v0.37.0 // indirect
golang.org/x/sys v0.46.0 // indirect
golang.org/x/text v0.39.0 // indirect
golang.org/x/tools v0.47.0 // indirect
golang.org/x/mod v0.32.0 // indirect
golang.org/x/sync v0.19.0 // indirect
golang.org/x/sys v0.41.0 // indirect
golang.org/x/text v0.34.0 // indirect
golang.org/x/tools v0.41.0 // indirect
google.golang.org/protobuf v1.36.8 // indirect
gopkg.in/yaml.v3 v3.0.1 // indirect
)
go.sum
+18 -34
View File
@@ -4,22 +4,16 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
github.com/fsnotify/fsnotify v1.9.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
github.com/getsentry/sentry-go v0.49.0 h1:Ehejknu1l023Ub7QoRBVLAI7g3Jnhqku4oWx4B4Sh5s=
github.com/getsentry/sentry-go v0.49.0/go.mod h1:nuMJAoCfe1u0Bts2ocyNI+TW8HT84vRMqwA5Qq/SKUI=
github.com/go-chi/chi/v5 v5.2.5 h1:Eg4myHZBjyvJmAFjFvWgrqDTXFyOzjj7YIm3L3mu6Ug=
github.com/go-chi/chi/v5 v5.2.5/go.mod h1:X7Gx4mteadT3eDOMTsXzmI4/rwUpOwBHLpAfupzFJP0=
github.com/go-chi/cors v1.2.2 h1:Jmey33TE+b+rB7fT8MUy1u0I4L+NARQlK6LhzKPSyQE=
github.com/go-chi/cors v1.2.2/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
github.com/go-chi/httprate v0.16.0 h1:8V5DH9j6pSK6UQoBsTpvMyFxycqaKEIToyPKzHJjUa8=
github.com/go-chi/httprate v0.16.0/go.mod h1:A8lo+qRhk+s9LiuP5saS7XCGDXRXMcrueq0NfIuCa/I=
github.com/go-errors/errors v1.4.2 h1:J6MZopCL4uSllY1OfXM374weqZFFItUbrImctkmUxIA=
github.com/go-errors/errors v1.4.2/go.mod h1:sIVyrIiJhuEF+Pj9Ebtd6P/rEYROXFi3BopGUQ5a5Og=
github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
@@ -28,8 +22,6 @@ github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
github.com/klauspost/cpuid/v2 v2.2.10 h1:tBs3QSyvjDyFTq3uoc/9xFpCuOsJQFNPiAhYdw2skhE=
github.com/klauspost/cpuid/v2 v2.2.10/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
@@ -42,12 +34,8 @@ github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
github.com/pingcap/errors v0.11.4 h1:lFuQV/oaUMGcD2tqt+01ROSmJs75VG1ToEOkZIZ4nE4=
github.com/pingcap/errors v0.11.4/go.mod h1:Oi8TUi2kEtXXLMJk9l1cGmz20kV3TaQ0usTwv5KuLY8=
github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/prometheus/client_golang v1.23.2 h1:Je96obch5RDVy3FDMndoUsjAhG5Edi49h0RJWRi/o0o=
github.com/prometheus/client_golang v1.23.2/go.mod h1:Tb1a6LWHB3/SPIzCoaDXI4I8UHKeFTEQ1YCr+0Gyqmg=
github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
@@ -56,8 +44,8 @@ github.com/prometheus/common v0.66.1 h1:h5E0h5/Y8niHc5DlaLlWLArTQI7tMrsfQjHV+d9Z
github.com/prometheus/common v0.66.1/go.mod h1:gcaUsgf3KfRSwHY4dIMXLPV0K/Wg1oZ8+SbZk/HH/dA=
github.com/prometheus/procfs v0.16.1 h1:hZ15bTNuirocR6u0JZ6BAHHmwS1p8B4P6MRqxtzMyRg=
github.com/prometheus/procfs v0.16.1/go.mod h1:teAbpZRB1iIAJYREa1LsoWUXykVXA1KlTmWl8x/U+Is=
github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
github.com/sagikazarmark/locafero v0.11.0 h1:1iurJgmM9G3PA/I+wWYIOw/5SyBtxapeHDcg+AAIFXc=
github.com/sagikazarmark/locafero v0.11.0/go.mod h1:nVIGvgyzw595SUSUE6tvCp3YYTeHs15MvlmU87WwIik=
github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 h1:+jumHNA0Wrelhe64i8F6HNlS8pkoyMv5sreGx2Ry5Rw=
@@ -74,10 +62,6 @@ github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
github.com/subosito/gotenv v1.6.0 h1:9NlTDc1FTs4qu0DDq7AEtTPNw6SVm7uBMsUCUjABIf8=
github.com/subosito/gotenv v1.6.0/go.mod h1:Dk4QP5c2W3ibzajGcXpNraDfq2IrhjMIvMSWPKKo0FU=
github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=
go.uber.org/dig v1.19.0 h1:BACLhebsYdpQ7IROQ1AGPjrXcP5dF80U3gKoFzbaq/4=
go.uber.org/dig v1.19.0/go.mod h1:Us0rSJiThwCv2GteUN0Q7OKvU7n5J4dxZ9JKUXozFdE=
go.uber.org/fx v1.24.0 h1:wE8mruvpg2kiiL1Vqd0CC+tr0/24XIB10Iwp2lLWzkg=
@@ -92,18 +76,18 @@ go.yaml.in/yaml/v2 v2.4.2 h1:DzmwEr2rDGHl7lsFgAHxmNz/1NlQ7xLIrlN2h5d1eGI=
go.yaml.in/yaml/v2 v2.4.2/go.mod h1:081UH+NErpNdqlCXm3TtEran0rJZGxAYx9hb/ELlsPU=
go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
golang.org/x/net v0.56.0 h1:Rw8j/hFzGvJUZwNBXnAtf5sVDVt+65SK2C7IxCxZt5o=
golang.org/x/net v0.56.0/go.mod h1:D3Ku6r+V6JROoZK144D2XfMHFcMq/0zSfLelVTCFKec=
golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/text v0.39.0 h1:UbZz4pLOvn600D6Oh6GGEI6VAmndrEBLv8/6BEXzyus=
golang.org/x/text v0.39.0/go.mod h1:3UwRclnC2g0TU9x8PZiyfOajCd1zaUNHF9cvqcQZ+ZM=
golang.org/x/tools v0.47.0 h1:7Kn5x/d1svx/PzryTsqeoZN4TZwqeH5pGWjefhLi/1Q=
golang.org/x/tools v0.47.0/go.mod h1:dFHnyTvFWY212G+h7ZY4Vsp/K3U4/7W9TyVaAul8uCA=
golang.org/x/mod v0.32.0 h1:9F4d3PHLljb6x//jOyokMv3eX+YDeepZSEo3mFJy93c=
golang.org/x/mod v0.32.0/go.mod h1:SgipZ/3h2Ci89DlEtEXWUk/HteuRin+HHhN+WbNhguU=
golang.org/x/net v0.50.0 h1:ucWh9eiCGyDR3vtzso0WMQinm2Dnt8cFMuQa9K33J60=
golang.org/x/net v0.50.0/go.mod h1:UgoSli3F/pBgdJBHCTc+tp3gmrU4XswgGRgtnwWTfyM=
golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
golang.org/x/tools v0.41.0 h1:a9b8iMweWG+S0OBnlU36rzLp20z1Rp10w+IY2czHTQc=
golang.org/x/tools v0.41.0/go.mod h1:XSY6eDqxVNiYgezAVqqCeihT4j1U2CCsqvH3WhQpnlg=
google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
internal/config/classify.go
+2 -7
View File
@@ -57,22 +57,17 @@ func ClassifyDNSName(name string) (DNSNameType, error) {
// ClassifyTargets splits a list of DNS names into apex domains and
// hostnames using the Public Suffix List. It returns an error if any
// name cannot be classified. A name given more than once, in any letter
// case or with a trailing dot, is kept once.
// name cannot be classified.
func ClassifyTargets(targets []string) ([]string, []string, error) {
var domains, hostnames []string
seen := make(map[string]bool)
for _, t := range targets {
normalized := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(t), "."))
if normalized == "" || seen[normalized] {
if normalized == "" {
continue
}
seen[normalized] = true
typ, classErr := ClassifyDNSName(normalized)
if classErr != nil {
return nil, nil, classErr
internal/config/classify_test.go
-24
View File
@@ -1,7 +1,6 @@
package config_test
import (
"slices"
"testing"
"sneak.berlin/go/dnswatcher/internal/config"
@@ -94,29 +93,6 @@ func TestClassifyTargets(t *testing.T) {
}
}
func TestClassifyTargetsKeepsEachNameOnce(t *testing.T) {
t.Parallel()
domains, hostnames, err := config.ClassifyTargets([]string{
"example.org",
"Example.org.",
"www.example.org",
"EXAMPLE.ORG",
"WWW.Example.org.",
})
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
if !slices.Equal(domains, []string{"example.org"}) {
t.Errorf("domains = %v, want [example.org]", domains)
}
if !slices.Equal(hostnames, []string{"www.example.org"}) {
t.Errorf("hostnames = %v, want [www.example.org]", hostnames)
}
}
func TestClassifyTargetsRejectsPublicSuffix(t *testing.T) {
t.Parallel()
internal/config/config.go
+8 -27
View File
@@ -28,13 +28,6 @@ var ErrNoTargets = errors.New(
"no monitoring targets configured: set DNSWATCHER_TARGETS environment variable",
)
// ErrInvalidInterval is returned when DNSWATCHER_DNS_INTERVAL or
// DNSWATCHER_TLS_INTERVAL is set but is not a positive duration. An empty
// value counts as unset and means the default.
var ErrInvalidInterval = errors.New(
"interval must be a positive duration such as 30m or 1h",
)
// Params contains dependencies for Config.
type Params struct {
fx.In
@@ -132,14 +125,18 @@ func buildConfig(
}
}
dnsInterval, err := parseInterval("DNS_INTERVAL")
dnsInterval, err := time.ParseDuration(
viper.GetString("DNS_INTERVAL"),
)
if err != nil {
return nil, err
dnsInterval = defaultDNSInterval
}
tlsInterval, err := parseInterval("TLS_INTERVAL")
tlsInterval, err := time.ParseDuration(
viper.GetString("TLS_INTERVAL"),
)
if err != nil {
return nil, err
tlsInterval = defaultTLSInterval
}
domains, hostnames, err := parseAndValidateTargets()
@@ -171,22 +168,6 @@ func buildConfig(
return cfg, nil
}
// parseInterval reads the DNSWATCHER_-prefixed setting key as a duration. A
// value that does not parse, or is zero or negative, is an error naming the
// variable and the value; an unset variable has its default from setupViper.
func parseInterval(key string) (time.Duration, error) {
value := viper.GetString(key)
interval, err := time.ParseDuration(value)
if err != nil || interval <= 0 {
return 0, fmt.Errorf(
"invalid DNSWATCHER_%s %q: %w", key, value, ErrInvalidInterval,
)
}
return interval, nil
}
func parseAndValidateTargets() ([]string, []string, error) {
domains, hostnames, err := ClassifyTargets(
parseCSV(viper.GetString("TARGETS")),
internal/config/config_test.go
+20 -28
View File
@@ -1,7 +1,6 @@
package config_test
import (
"strconv"
"testing"
"time"
@@ -114,40 +113,33 @@ func TestNew_OnlyEmptyCSVSegments(t *testing.T) {
assert.ErrorIs(t, err, config.ErrNoTargets)
}
// TestNew_InvalidIntervalStopsStartup checks values that must stop startup;
// TestNew_DefaultValues and TestNew_EmptyIntervalMeansDefault check that an
// unset or empty interval means the default.
func TestNew_InvalidIntervalStopsStartup(t *testing.T) {
variables := []string{"DNSWATCHER_DNS_INTERVAL", "DNSWATCHER_TLS_INTERVAL"}
values := []string{
"banana", // not a duration
"5", // no unit
"1d", // days are not a unit time.ParseDuration knows
"0", // zero
"-1h", // negative
}
for _, variable := range variables {
for _, value := range values {
t.Run(variable+"="+value, func(t *testing.T) {
func TestNew_InvalidDNSInterval_FallsBackToDefault(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv(variable, value)
t.Setenv("DNSWATCHER_DNS_INTERVAL", "banana")
_, err := config.New(nil, newTestParams(t))
require.ErrorIs(t, err, config.ErrInvalidInterval)
require.ErrorContains(t, err, variable)
require.ErrorContains(t, err, strconv.Quote(value))
})
}
}
cfg, err := config.New(nil, newTestParams(t))
require.NoError(t, err)
assert.Equal(t, time.Hour, cfg.DNSInterval,
"invalid DNS interval should fall back to 1h default")
}
func TestNew_EmptyIntervalMeansDefault(t *testing.T) {
func TestNew_InvalidTLSInterval_FallsBackToDefault(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_DNS_INTERVAL", "")
t.Setenv("DNSWATCHER_TLS_INTERVAL", "")
t.Setenv("DNSWATCHER_TLS_INTERVAL", "notaduration")
cfg, err := config.New(nil, newTestParams(t))
require.NoError(t, err)
assert.Equal(t, 12*time.Hour, cfg.TLSInterval,
"invalid TLS interval should fall back to 12h default")
}
func TestNew_BothIntervalsInvalid(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_DNS_INTERVAL", "xyz")
t.Setenv("DNSWATCHER_TLS_INTERVAL", "abc")
cfg, err := config.New(nil, newTestParams(t))
require.NoError(t, err)
internal/globals/globals_test.go
-50
View File
@@ -1,50 +0,0 @@
package globals_test
import (
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"sneak.berlin/go/dnswatcher/internal/globals"
)
// TestGlobals exercises the package-level version and appname
// variables through their setters and read-back via New. These are
// shared package state, so the test mutates a global and must run
// sequentially; it cannot use t.Parallel().
//
//nolint:paralleltest // mutates shared package-level globals, must run sequentially
func TestGlobals(t *testing.T) {
versions := []string{"v1.2.3", "dev", "", "v1.2.3-4-gabcdef"}
for _, want := range versions {
globals.SetVersion(want)
g, err := globals.New(nil)
require.NoError(t, err)
assert.Equal(t, want, g.Version,
"New must surface the version set by SetVersion")
}
names := []string{"dnswatcher", "other", ""}
for _, want := range names {
globals.SetAppname(want)
g, err := globals.New(nil)
require.NoError(t, err)
assert.Equal(t, want, g.Appname,
"New must surface the appname set by SetAppname")
}
// New returns a snapshot: a later SetVersion must not mutate a
// Globals handed out earlier.
globals.SetVersion("first")
g, err := globals.New(nil)
require.NoError(t, err)
globals.SetVersion("second")
assert.Equal(t, "first", g.Version,
"a Globals returned by New must not change when the "+
"package variable is set again")
}
internal/healthcheck/healthcheck_test.go
-134
View File
@@ -1,134 +0,0 @@
package healthcheck_test
import (
"context"
"encoding/json"
"testing"
"time"
"go.uber.org/fx"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"sneak.berlin/go/dnswatcher/internal/config"
"sneak.berlin/go/dnswatcher/internal/globals"
"sneak.berlin/go/dnswatcher/internal/healthcheck"
"sneak.berlin/go/dnswatcher/internal/logger"
)
// recordingLifecycle is a minimal fx.Lifecycle that records the hooks
// appended to it, so healthcheck.New can be exercised through its real
// constructor without standing up a whole fx application.
type recordingLifecycle struct {
hooks []fx.Hook
}
func (l *recordingLifecycle) Append(hook fx.Hook) {
l.hooks = append(l.hooks, hook)
}
// newHealthcheck builds a Healthcheck through the real constructor and
// runs the registered OnStart hook so StartupTime is set the same way
// the fx lifecycle would set it.
func newHealthcheck(
t *testing.T,
maintenance bool,
version string,
) *healthcheck.Healthcheck {
t.Helper()
g := &globals.Globals{Appname: "dnswatcher", Version: version}
log, err := logger.New(nil, logger.Params{Globals: g})
require.NoError(t, err)
lifecycle := &recordingLifecycle{}
hc, err := healthcheck.New(lifecycle, healthcheck.Params{
Globals: g,
Config: &config.Config{MaintenanceMode: maintenance},
Logger: log,
})
require.NoError(t, err)
require.Len(t, lifecycle.hooks, 1,
"New must register exactly one lifecycle hook")
require.NotNil(t, lifecycle.hooks[0].OnStart)
require.NoError(t, lifecycle.hooks[0].OnStart(context.Background()))
return hc
}
func TestCheckStatusAndPayloadShape(t *testing.T) {
t.Parallel()
hc := newHealthcheck(t, false, "v9.9.9")
resp := hc.Check()
assert.Equal(t, "ok", resp.Status)
// The JSON shape and field names are part of the contract for the
// /health and /.well-known/healthcheck routes, so assert on the
// exact set of keys the response marshals to.
raw, err := json.Marshal(resp)
require.NoError(t, err)
var fields map[string]json.RawMessage
require.NoError(t, json.Unmarshal(raw, &fields))
wantKeys := []string{
"status",
"now",
"uptimeSeconds",
"uptimeHuman",
"version",
"appname",
"maintenanceMode",
}
assert.Len(t, fields, len(wantKeys),
"response must marshal to exactly the documented fields")
for _, key := range wantKeys {
assert.Contains(t, fields, key, "missing JSON field %q", key)
}
// The Now field is documented as RFC3339Nano; a change to the
// format constant should turn this red.
_, err = time.Parse(time.RFC3339Nano, resp.Now)
assert.NoError(t, err, "Now must be RFC3339Nano")
}
func TestCheckMaintenanceModeReflectsConfig(t *testing.T) {
t.Parallel()
tests := []struct {
name string
maintenance bool
}{
{"maintenance off", false},
{"maintenance on", true},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
hc := newHealthcheck(t, tt.maintenance, "test")
resp := hc.Check()
assert.Equal(t, tt.maintenance, resp.Maintenance,
"maintenanceMode must mirror Config.MaintenanceMode")
})
}
}
func TestCheckSurfacesVersionAndAppname(t *testing.T) {
t.Parallel()
hc := newHealthcheck(t, false, "surfaced-version-123")
resp := hc.Check()
assert.Equal(t, "surfaced-version-123", resp.Version,
"version from globals must appear in the payload")
assert.Equal(t, "dnswatcher", resp.Appname)
}
internal/livednstest/livednstest.go
-121
View File
@@ -1,121 +0,0 @@
// Package livednstest runs the live DNS operations of tests. Tests that
// look something up in DNS query live DNS servers, never a stand-in —
// see TESTING.md. Nothing here mocks, fakes, stubs, records or replays
// DNS, and nothing here skips a test: it only changes *how* the live
// queries are issued, so that a single dropped UDP packet or one slow
// authoritative server does not turn correct code into a red build.
//
// Two mechanisms:
//
// 1. Bounded concurrency. Tests run in parallel and the build hosts
// have many cores, so without a limit every test starts its own
// iterative resolution at the same instant and they all send their
// first queries to the root servers within a few milliseconds of
// each other. Root servers rate-limit that, which shows up as a
// different arbitrary subset of tests failing on each run. Run caps
// how many live operations are in flight at once in one test binary.
//
// 2. Retry with exponential backoff. Each live operation gets several
// attempts with its own timeout. An attempt is retried when it
// obtained nothing to check, never because of what the test
// asserts about the result, so a wrong result still fails on the
// first attempt. A fault in the code under test that leaves
// nothing to check looks the same as live DNS not answering, and
// fails only after the last attempt.
package livednstest
import (
"context"
"errors"
"testing"
"time"
)
const (
// attempts is how many times a live DNS operation is attempted
// before the test fails.
attempts = 3
// AttemptTimeout bounds one attempt. Worst case for an operation
// is attempts * AttemptTimeout plus the backoff — about 26
// seconds, well inside the 90-second `go test -timeout` backstop
// even when several operations exhaust their attempts.
AttemptTimeout = 8 * time.Second
// backoffBase is the delay after the first failed attempt; it is
// multiplied by backoffFactor each time.
backoffBase = 500 * time.Millisecond
// backoffFactor is the exponential backoff multiplier.
backoffFactor = 2
// Concurrency caps how many live operations may be in flight
// across one test binary at once.
Concurrency = 6
)
// gate bounds concurrent live operations. It has to be package scoped:
// the whole point is that it is shared by every parallel test in the
// test binary.
//
//nolint:gochecknoglobals // package-wide live query rate limit
var gate = make(chan struct{}, Concurrency)
// ErrNoAnswer reports that a live operation produced no usable answer,
// which is retried rather than asserted on.
var ErrNoAnswer = errors.New("no answer from live DNS")
// Run executes one attempt of a live operation, holding a slot in gate
// for its duration and bounding it with its own timeout.
func Run(op func(ctx context.Context) error) error {
gate <- struct{}{}
defer func() { <-gate }()
ctx, cancel := context.WithTimeout(
context.Background(), AttemptTimeout,
)
defer cancel()
return op(ctx)
}
// Retry runs op until it reports success, retrying failures with
// exponential backoff, and fails the test if every attempt fails. op
// returns an error only for a failure to obtain an answer — never for
// an answer the test disagrees with, which belongs in an assertion so
// that it fails immediately. op stores whatever it obtained where its
// caller can find it.
func Retry(
t *testing.T,
what string,
op func(ctx context.Context) error,
) {
t.Helper()
var last error
backoff := backoffBase
for attempt := range attempts {
if attempt > 0 {
t.Logf(
"%s: attempt %d of %d failed (%v), "+
"retrying in %s",
what, attempt, attempts, last, backoff,
)
time.Sleep(backoff)
backoff *= backoffFactor
}
last = Run(op)
if last == nil {
return
}
}
t.Fatalf(
"%s: all %d live attempts failed: %v",
what, attempts, last,
)
}
internal/livednstest/livednstest_test.go
-103
View File
@@ -1,103 +0,0 @@
package livednstest_test
import (
"context"
"sync"
"testing"
"time"
"github.com/stretchr/testify/assert"
"sneak.berlin/go/dnswatcher/internal/livednstest"
)
// Tests for the retry and the concurrency limit themselves. They
// perform no DNS resolution of any kind.
func TestRetryRecoversFromTransientFailure(t *testing.T) {
t.Parallel()
const wantAttempts = 2
attempts := 0
livednstest.Retry(t, "transient", func(_ context.Context) error {
attempts++
if attempts < wantAttempts {
return livednstest.ErrNoAnswer
}
return nil
})
assert.Equal(t, wantAttempts, attempts)
}
func TestRetryGivesEachAttemptADeadline(t *testing.T) {
t.Parallel()
livednstest.Retry(t, "deadline", func(ctx context.Context) error {
deadline, ok := ctx.Deadline()
assert.True(t, ok, "attempt should carry a deadline")
remaining := time.Until(deadline)
assert.LessOrEqual(t, remaining, livednstest.AttemptTimeout)
// Lower bound too: without one this passes for a
// deadline far shorter than intended, which would
// silently turn every live attempt into an instant
// timeout.
assert.Greater(t, remaining, livednstest.AttemptTimeout/2)
return nil
})
}
func TestRunBoundsConcurrency(t *testing.T) {
t.Parallel()
const workers = 24
var (
mu sync.Mutex
wg sync.WaitGroup
inFlight int
maxSeen int
)
wg.Add(workers)
for range workers {
go func() {
defer wg.Done()
_ = livednstest.Run(func(_ context.Context) error {
mu.Lock()
inFlight++
if inFlight > maxSeen {
maxSeen = inFlight
}
mu.Unlock()
time.Sleep(time.Millisecond)
mu.Lock()
inFlight--
mu.Unlock()
return nil
})
}()
}
wg.Wait()
assert.Positive(t, maxSeen)
assert.LessOrEqual(
t, maxSeen, livednstest.Concurrency,
"live queries must stay under the package-wide gate",
)
}
internal/logger/logger_test.go
-66
View File
@@ -1,66 +0,0 @@
package logger_test
import (
"context"
"log/slog"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"sneak.berlin/go/dnswatcher/internal/globals"
"sneak.berlin/go/dnswatcher/internal/logger"
)
func newTestLogger(t *testing.T) *logger.Logger {
t.Helper()
g := &globals.Globals{Appname: "dnswatcher", Version: "test"}
l, err := logger.New(nil, logger.Params{Globals: g})
require.NoError(t, err)
return l
}
// TestNewReturnsUsableLogger checks that the constructor yields a
// working *slog.Logger.
func TestNewReturnsUsableLogger(t *testing.T) {
t.Parallel()
l := newTestLogger(t)
require.NotNil(t, l.Get(), "Get must return a non-nil logger")
}
// TestDefaultLevelExcludesDebug verifies the default configuration
// logs at info: debug records are suppressed, info records pass.
func TestDefaultLevelExcludesDebug(t *testing.T) {
t.Parallel()
log := newTestLogger(t).Get()
ctx := context.Background()
assert.False(t, log.Enabled(ctx, slog.LevelDebug),
"debug must be suppressed at the default level")
assert.True(t, log.Enabled(ctx, slog.LevelInfo),
"info must be enabled at the default level")
}
// TestEnableDebugLoggingChangesLevel verifies the debug and non-debug
// configurations differ as intended: enabling debug makes debug
// records pass where they previously did not.
func TestEnableDebugLoggingChangesLevel(t *testing.T) {
t.Parallel()
l := newTestLogger(t)
log := l.Get()
ctx := context.Background()
require.False(t, log.Enabled(ctx, slog.LevelDebug),
"debug must start disabled")
l.EnableDebugLogging()
assert.True(t, log.Enabled(ctx, slog.LevelDebug),
"debug must be enabled after EnableDebugLogging")
}
internal/middleware/export_test.go
-19
View File
@@ -1,19 +0,0 @@
package middleware
import (
"net/http"
"time"
)
// The /metrics rate limit, exported so the tests can count requests
// against it.
const (
MetricsRequestLimit = metricsRequestLimit
MetricsRequestWindow time.Duration = metricsRequestWindow
)
// RealIP is realIP, exported so the tests can check which address it
// takes as the client's.
func RealIP(r *http.Request) string {
return realIP(r)
}
internal/middleware/middleware.go
+14 -151
View File
@@ -5,14 +5,12 @@ import (
"log/slog"
"net"
"net/http"
"net/netip"
"strings"
"time"
"github.com/99designs/basicauth-go"
"github.com/go-chi/chi/v5/middleware"
"github.com/go-chi/cors"
"github.com/go-chi/httprate"
"go.uber.org/fx"
"sneak.berlin/go/dnswatcher/internal/config"
@@ -23,71 +21,6 @@ import (
// corsMaxAge is the maximum age for CORS preflight responses.
const corsMaxAge = 300
// Rate limit for /metrics: each client address may send
// metricsRequestLimit requests per metricsRequestWindow. Every request
// counts, so password guessing gets at most 30 tries a minute per
// address. One Prometheus server scraping every 15 seconds sends 4
// requests a minute, and two scraping every 5 seconds from one address
// send 24, so normal scraping stays under the limit.
const (
metricsRequestLimit = 30
metricsRequestWindow = time.Minute
)
// Security response header values applied to every response.
//
// The CSP is as strict as the dashboard allows: the template ships no
// JavaScript, no inline styles, no inline event handlers and no images,
// and its only subresource is the embedded stylesheet at
// /s/css/tailwind.min.css, which style-src 'self' permits. Neither
// unsafe-inline nor unsafe-eval is used. frame-ancestors 'none' is the
// primary anti-framing control; X-Frame-Options is the legacy fallback.
const (
// hstsValue is emitted unconditionally, including over plain HTTP,
// because the service runs behind a TLS-terminating proxy and the
// browser must still enforce HTTPS end to end.
hstsValue = "max-age=31536000; includeSubDomains"
cspValue = "default-src 'self'; " +
"script-src 'none'; " +
"style-src 'self'; " +
"img-src 'self'; " +
"font-src 'none'; " +
"connect-src 'none'; " +
"object-src 'none'; " +
"base-uri 'none'; " +
"form-action 'none'; " +
"frame-ancestors 'none'"
frameOptionsValue = "DENY"
contentTypeOptionsValue = "nosniff"
// referrerPolicyValue is stricter than the policy minimum of
// strict-origin-when-cross-origin: the dashboard has no
// cross-origin navigation needs and its URL may name internal
// hosts.
referrerPolicyValue = "no-referrer"
permissionsPolicyValue = "accelerometer=(), " +
"autoplay=(), " +
"camera=(), " +
"display-capture=(), " +
"encrypted-media=(), " +
"fullscreen=(), " +
"geolocation=(), " +
"gyroscope=(), " +
"magnetometer=(), " +
"microphone=(), " +
"midi=(), " +
"payment=(), " +
"picture-in-picture=(), " +
"publickey-credentials-get=(), " +
"screen-wake-lock=(), " +
"usb=(), " +
"xr-spatial-tracking=()"
)
// Params contains dependencies for Middleware.
type Params struct {
fx.In
@@ -209,12 +142,6 @@ func isTrustedProxy(ip net.IP) bool {
// realIP extracts the client's real IP address from the request.
// Proxy headers are only trusted from RFC1918/loopback addresses.
//
// Each proxy adds to the end of X-Forwarded-For the address it got the
// request from, so the client can write every entry before the one the
// first trusted proxy added. The client address is therefore the
// rightmost entry that is not a trusted proxy, or the leftmost entry
// when they all are.
func realIP(r *http.Request) string {
addr := ipFromHostPort(r.RemoteAddr)
remoteIP := net.ParseIP(addr)
@@ -229,100 +156,36 @@ func realIP(r *http.Request) string {
return ip
}
// A proxy may add its entry as a header line of its own instead of
// appending to the line the client sent, so all lines form one list.
entries := strings.Split(
strings.Join(r.Header.Values("X-Forwarded-For"), ","), ",",
)
client := strings.TrimSpace(entries[0])
for i := len(entries) - 1; i > 0; i-- {
entry := strings.TrimSpace(entries[i])
if !isTrustedProxy(net.ParseIP(entry)) {
client = entry
break
if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
if parts := strings.SplitN(
xff, ",", 2, //nolint:mnd
); len(parts) > 0 {
if ip := strings.TrimSpace(parts[0]); ip != "" {
return ip
}
}
if client != "" {
return client
}
return addr
}
// CORS returns middleware that lets any origin read a response. It is
// for the public, read-only routes only, so it allows only the
// methods those routes serve and no Authorization header.
// CORS returns CORS middleware.
func (m *Middleware) CORS() func(http.Handler) http.Handler {
return cors.Handler(cors.Options{
AllowedOrigins: []string{"*"},
AllowedMethods: []string{"GET", "OPTIONS"},
AllowedHeaders: []string{"Accept", "Content-Type"},
AllowedMethods: []string{
"GET", "POST", "PUT", "DELETE", "OPTIONS",
},
AllowedHeaders: []string{
"Accept", "Authorization",
"Content-Type", "X-CSRF-Token",
},
ExposedHeaders: []string{"Link"},
AllowCredentials: false,
MaxAge: corsMaxAge,
})
}
// SecurityHeaders returns middleware that sets the security response
// headers required for production internet exposure on every response.
//
// The headers are set before the request reaches the next handler so
// that they are present on every response, including panics recovered
// by chi's Recoverer and timeouts produced by chi's Timeout.
func (m *Middleware) SecurityHeaders() func(http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(
writer http.ResponseWriter,
request *http.Request,
) {
header := writer.Header()
header.Set("Strict-Transport-Security", hstsValue)
header.Set("Content-Security-Policy", cspValue)
header.Set("X-Frame-Options", frameOptionsValue)
header.Set(
"X-Content-Type-Options",
contentTypeOptionsValue,
)
header.Set("Referrer-Policy", referrerPolicyValue)
header.Set(
"Permissions-Policy",
permissionsPolicyValue,
)
next.ServeHTTP(writer, request)
})
}
}
// MetricsRateLimit returns middleware for /metrics that answers 429
// Too Many Requests to a client address over the rate limit. The
// address is the one realIP works out, so a client that is not a
// trusted proxy cannot get a fresh allowance by sending its own
// X-Real-IP or X-Forwarded-For. CanonicalizeIP counts all IPv6
// addresses in one /64 as one client, since a client usually holds a
// whole /64. An IPv4 address a proxy reports in IPv6-mapped form
// (::ffff:203.0.113.1) is turned back into plain IPv4 first, as every
// such address is in the same /64.
func (m *Middleware) MetricsRateLimit() func(http.Handler) http.Handler {
return httprate.LimitBy(
metricsRequestLimit,
metricsRequestWindow,
func(request *http.Request) (string, error) {
ip := realIP(request)
addr, err := netip.ParseAddr(ip)
if err == nil {
ip = addr.Unmap().String()
}
return httprate.CanonicalizeIP(ip), nil
},
)
}
// MetricsAuth returns basic auth middleware for /metrics.
func (m *Middleware) MetricsAuth() func(http.Handler) http.Handler {
if m.params.Config.MetricsUsername == "" {
internal/middleware/middleware_test.go
-565
View File
@@ -1,565 +0,0 @@
package middleware_test
import (
"net/http"
"net/http/httptest"
"strings"
"testing"
"time"
"github.com/go-chi/chi/v5"
"go.uber.org/fx/fxtest"
"sneak.berlin/go/dnswatcher/internal/config"
"sneak.berlin/go/dnswatcher/internal/globals"
"sneak.berlin/go/dnswatcher/internal/handlers"
"sneak.berlin/go/dnswatcher/internal/logger"
"sneak.berlin/go/dnswatcher/internal/middleware"
"sneak.berlin/go/dnswatcher/internal/notify"
"sneak.berlin/go/dnswatcher/internal/state"
)
// Expected security header values, spelled out literally so that any
// change to the middleware has to be made deliberately here as well.
const (
wantHSTS = "max-age=31536000; includeSubDomains"
wantCSP = "default-src 'self'; " +
"script-src 'none'; " +
"style-src 'self'; " +
"img-src 'self'; " +
"font-src 'none'; " +
"connect-src 'none'; " +
"object-src 'none'; " +
"base-uri 'none'; " +
"form-action 'none'; " +
"frame-ancestors 'none'"
wantFrameOptions = "DENY"
wantContentTypeOptions = "nosniff"
wantReferrerPolicy = "no-referrer"
wantPermissionsPolicy = "accelerometer=(), " +
"autoplay=(), " +
"camera=(), " +
"display-capture=(), " +
"encrypted-media=(), " +
"fullscreen=(), " +
"geolocation=(), " +
"gyroscope=(), " +
"magnetometer=(), " +
"microphone=(), " +
"midi=(), " +
"payment=(), " +
"picture-in-picture=(), " +
"publickey-credentials-get=(), " +
"screen-wake-lock=(), " +
"usb=(), " +
"xr-spatial-tracking=()"
)
// stylesheetPath is the only subresource the dashboard loads.
const stylesheetPath = "/s/css/tailwind.min.css"
// newTestLogger builds a logger for direct component construction.
func newTestLogger(t *testing.T) *logger.Logger {
t.Helper()
glob, err := globals.New(nil)
if err != nil {
t.Fatalf("globals.New: %v", err)
}
log, err := logger.New(nil, logger.Params{Globals: glob})
if err != nil {
t.Fatalf("logger.New: %v", err)
}
return log
}
// newTestMiddleware builds a Middleware without an fx application.
func newTestMiddleware(t *testing.T) *middleware.Middleware {
t.Helper()
glob, err := globals.New(nil)
if err != nil {
t.Fatalf("globals.New: %v", err)
}
mw, err := middleware.New(nil, middleware.Params{
Logger: newTestLogger(t),
Globals: glob,
Config: &config.Config{},
})
if err != nil {
t.Fatalf("middleware.New: %v", err)
}
return mw
}
// serveWithSecurityHeaders runs a GET through SecurityHeaders and
// returns the recorded response.
func serveWithSecurityHeaders(
t *testing.T,
target string,
handler http.Handler,
) *httptest.ResponseRecorder {
t.Helper()
mw := newTestMiddleware(t)
rec := httptest.NewRecorder()
req := httptest.NewRequestWithContext(
t.Context(), http.MethodGet, target, nil,
)
mw.SecurityHeaders()(handler).ServeHTTP(rec, req)
return rec
}
// okHandler writes a trivial 200 response.
func okHandler() http.Handler {
return http.HandlerFunc(func(
writer http.ResponseWriter,
_ *http.Request,
) {
writer.WriteHeader(http.StatusOK)
})
}
func TestSecurityHeaders(t *testing.T) {
t.Parallel()
tests := []struct {
name string
header string
want string
}{
{
"hsts",
"Strict-Transport-Security",
wantHSTS,
},
{
"csp",
"Content-Security-Policy",
wantCSP,
},
{
"frame options",
"X-Frame-Options",
wantFrameOptions,
},
{
"content type options",
"X-Content-Type-Options",
wantContentTypeOptions,
},
{
"referrer policy",
"Referrer-Policy",
wantReferrerPolicy,
},
{
"permissions policy",
"Permissions-Policy",
wantPermissionsPolicy,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
rec := serveWithSecurityHeaders(t, "/", okHandler())
got := rec.Header().Get(tt.header)
if got != tt.want {
t.Errorf(
"%s = %q, want %q",
tt.header, got, tt.want,
)
}
})
}
}
// TestSecurityHeadersCSPDirectives guards the properties the repo
// policy requires of the content security policy itself.
func TestSecurityHeadersCSPDirectives(t *testing.T) {
t.Parallel()
rec := serveWithSecurityHeaders(t, "/", okHandler())
csp := rec.Header().Get("Content-Security-Policy")
forbidden := []string{"unsafe-inline", "unsafe-eval"}
for _, directive := range forbidden {
if strings.Contains(csp, directive) {
t.Errorf("CSP must not contain %q: %q", directive, csp)
}
}
required := []string{
"default-src 'self'",
"script-src 'none'",
"style-src 'self'",
"frame-ancestors 'none'",
}
for _, directive := range required {
if !strings.Contains(csp, directive) {
t.Errorf("CSP must contain %q: %q", directive, csp)
}
}
}
// TestSecurityHeadersOnErrorResponse verifies the headers are emitted
// even when the wrapped handler fails, since they are set before the
// handler runs.
func TestSecurityHeadersOnErrorResponse(t *testing.T) {
t.Parallel()
failing := http.HandlerFunc(func(
writer http.ResponseWriter,
_ *http.Request,
) {
http.Error(
writer,
"boom",
http.StatusInternalServerError,
)
})
rec := serveWithSecurityHeaders(t, "/api/v1/status", failing)
if rec.Code != http.StatusInternalServerError {
t.Fatalf("status = %d, want 500", rec.Code)
}
if got := rec.Header().Get(
"X-Content-Type-Options",
); got != wantContentTypeOptions {
t.Errorf(
"X-Content-Type-Options = %q, want %q",
got, wantContentTypeOptions,
)
}
if got := rec.Header().Get(
"Strict-Transport-Security",
); got != wantHSTS {
t.Errorf(
"Strict-Transport-Security = %q, want %q",
got, wantHSTS,
)
}
}
// newTestHandlers builds real Handlers with empty monitoring state.
func newTestHandlers(t *testing.T) *handlers.Handlers {
t.Helper()
glob, err := globals.New(nil)
if err != nil {
t.Fatalf("globals.New: %v", err)
}
log := newTestLogger(t)
notifier, err := notify.New(fxtest.NewLifecycle(t), notify.Params{
Logger: log,
Config: &config.Config{},
})
if err != nil {
t.Fatalf("notify.New: %v", err)
}
st, err := state.New(fxtest.NewLifecycle(t), state.Params{
Logger: log,
Config: &config.Config{DataDir: t.TempDir()},
})
if err != nil {
t.Fatalf("state.New: %v", err)
}
hnd, err := handlers.New(nil, handlers.Params{
Logger: log,
Globals: glob,
State: st,
Notify: notifier,
})
if err != nil {
t.Fatalf("handlers.New: %v", err)
}
return hnd
}
// TestDashboardRendersWithSecurityHeaders renders the real dashboard
// through the middleware and checks that the policy still permits the
// one stylesheet the page loads.
func TestDashboardRendersWithSecurityHeaders(t *testing.T) {
t.Parallel()
mw := newTestMiddleware(t)
hnd := newTestHandlers(t)
router := chi.NewRouter()
router.Use(mw.SecurityHeaders())
router.Get("/", hnd.HandleDashboard())
rec := httptest.NewRecorder()
req := httptest.NewRequestWithContext(
t.Context(), http.MethodGet, "/", nil,
)
router.ServeHTTP(rec, req)
if rec.Code != http.StatusOK {
t.Fatalf("status = %d, want 200", rec.Code)
}
body := rec.Body.String()
if !strings.Contains(body, stylesheetPath) {
t.Errorf("dashboard does not reference %q", stylesheetPath)
}
if !strings.Contains(body, "dnswatcher") {
t.Errorf("dashboard body looks empty: %d bytes", len(body))
}
csp := rec.Header().Get("Content-Security-Policy")
if csp != wantCSP {
t.Errorf("CSP = %q, want %q", csp, wantCSP)
}
// The stylesheet is same-origin, so style-src 'self' allows it.
if !strings.Contains(csp, "style-src 'self'") {
t.Errorf("CSP would block %q: %q", stylesheetPath, csp)
}
}
// Addresses for the rate limit and realIP tests: a client connecting
// directly, a trusted proxy, and a client behind that proxy as the
// proxy's X-Real-IP or X-Forwarded-For header names it.
const (
directClient = "198.51.100.1:4000"
trustedProxy = "10.0.0.1:4000"
proxiedClient = "203.0.113.1"
)
// statusFrom sends a GET through handler as if from remoteAddr, with
// an X-Real-IP header when xRealIP is not empty, and returns the
// response status.
func statusFrom(
t *testing.T,
handler http.Handler,
remoteAddr string,
xRealIP string,
) int {
t.Helper()
req := httptest.NewRequestWithContext(
t.Context(), http.MethodGet, "/metrics", nil,
)
req.RemoteAddr = remoteAddr
if xRealIP != "" {
req.Header.Set("X-Real-IP", xRealIP)
}
rec := httptest.NewRecorder()
handler.ServeHTTP(rec, req)
return rec.Code
}
// TestMetricsRateLimitAllowsScraping checks that one address can send,
// within one window, what two Prometheus servers scraping every 5
// seconds send in that time, without being turned away.
func TestMetricsRateLimitAllowsScraping(t *testing.T) {
t.Parallel()
const scrapeInterval = 5 * time.Second
scrapes := 2 * int(middleware.MetricsRequestWindow/scrapeInterval)
limited := newTestMiddleware(t).MetricsRateLimit()(okHandler())
for i := range scrapes {
got := statusFrom(t, limited, directClient, "")
if got != http.StatusOK {
t.Fatalf(
"scrape %d of %d: status = %d, want 200",
i+1, scrapes, got,
)
}
}
}
// TestMetricsRateLimitKeysOnClientAddress checks which requests share
// an allowance. Each case uses up the allowance of one client, then
// sends one more request.
func TestMetricsRateLimitKeysOnClientAddress(t *testing.T) {
t.Parallel()
tests := []struct {
name string
usedRemoteAddr string
usedXRealIP string
nextRemoteAddr string
nextXRealIP string
want int
}{
{
"same address",
directClient, "",
directClient, "",
http.StatusTooManyRequests,
},
{
"another address",
directClient, "",
"198.51.100.2:4000", "",
http.StatusOK,
},
{
"own X-Real-IP from an untrusted address",
directClient, "",
directClient, "203.0.113.9",
http.StatusTooManyRequests,
},
{
"same client behind the proxy",
trustedProxy, proxiedClient,
trustedProxy, proxiedClient,
http.StatusTooManyRequests,
},
{
"another client behind the proxy",
trustedProxy, proxiedClient,
trustedProxy, "203.0.113.2",
http.StatusOK,
},
{
"another client behind the proxy, IPv6-mapped",
trustedProxy, "::ffff:203.0.113.1",
trustedProxy, "::ffff:203.0.113.2",
http.StatusOK,
},
{
"same IPv6 /64",
"[2001:db8::1]:4000", "",
"[2001:db8::2]:4000", "",
http.StatusTooManyRequests,
},
{
"another IPv6 /64",
"[2001:db8::1]:4000", "",
"[2001:db8:0:1::1]:4000", "",
http.StatusOK,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
limited := newTestMiddleware(t).MetricsRateLimit()(okHandler())
for range middleware.MetricsRequestLimit {
statusFrom(t, limited, tt.usedRemoteAddr, tt.usedXRealIP)
}
got := statusFrom(
t, limited, tt.nextRemoteAddr, tt.nextXRealIP,
)
if got != tt.want {
t.Errorf("status = %d, want %d", got, tt.want)
}
})
}
}
// TestRealIP checks which address realIP takes as the client's. Each
// element of forwardedFor is sent as an X-Forwarded-For header line of
// its own, and 198.51.100.9 is always an entry the client wrote itself.
func TestRealIP(t *testing.T) {
t.Parallel()
tests := []struct {
name string
remoteAddr string
xRealIP string
forwardedFor []string
want string
}{
{
"untrusted peer, both headers ignored",
directClient, proxiedClient, []string{"198.51.100.9"},
"198.51.100.1",
},
{
"X-Real-IP from a trusted proxy wins",
trustedProxy, proxiedClient, []string{"203.0.113.8"},
proxiedClient,
},
{
"client's own entry, then the one the proxy added",
trustedProxy, "", []string{"198.51.100.9, 203.0.113.1"},
proxiedClient,
},
{
"several trusted proxies",
trustedProxy, "",
[]string{"198.51.100.9, 203.0.113.1, 10.0.0.3, 10.0.0.2"},
proxiedClient,
},
{
"proxy adds a header line of its own",
trustedProxy, "", []string{"198.51.100.9", proxiedClient},
proxiedClient,
},
{
"every entry a trusted proxy",
trustedProxy, "", []string{"10.0.0.3, 10.0.0.2"},
"10.0.0.3",
},
{
"empty where the client address belongs",
trustedProxy, "", []string{"203.0.113.1, , 10.0.0.2"},
"10.0.0.1",
},
{
"no headers from a trusted proxy",
trustedProxy, "", nil,
"10.0.0.1",
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
req := httptest.NewRequestWithContext(
t.Context(), http.MethodGet, "/", nil,
)
req.RemoteAddr = tt.remoteAddr
if tt.xRealIP != "" {
req.Header.Set("X-Real-IP", tt.xRealIP)
}
for _, line := range tt.forwardedFor {
req.Header.Add("X-Forwarded-For", line)
}
got := middleware.RealIP(req)
if got != tt.want {
t.Errorf("realIP = %q, want %q", got, tt.want)
}
})
}
}
internal/notify/export_test.go
+4 -20
View File
@@ -32,27 +32,11 @@ func NewRequestForTest(
// NewTestService creates a Service suitable for unit testing.
// It discards log output and uses the given transport.
func NewTestService(transport http.RoundTripper) *Service {
return newService(slog.New(slog.DiscardHandler), transport)
return &Service{
log: slog.New(slog.DiscardHandler),
transport: transport,
history: NewAlertHistory(),
}
// NewTestServiceWithLogger creates a Service that writes to the
// given handler, so tests can assert on emitted log records.
func NewTestServiceWithLogger(
transport http.RoundTripper,
handler slog.Handler,
) *Service {
return newService(slog.New(handler), transport)
}
// Drain exports drain for testing.
func (svc *Service) Drain(ctx context.Context) {
svc.drain(ctx)
}
// OutstandingDeliveries reports how many delivery goroutines
// are currently tracked as in flight.
func (svc *Service) OutstandingDeliveries() int64 {
return svc.outstanding.Load()
}
// SetNtfyURL sets the ntfy URL on a Service for testing.
internal/notify/notify.go
+56 -73
View File
@@ -12,8 +12,6 @@ import (
"log/slog"
"net/http"
"net/url"
"sync"
"sync/atomic"
"time"
"go.uber.org/fx"
@@ -117,41 +115,19 @@ type Service struct {
history *AlertHistory
retryConfig RetryConfig
sleepFn func(time.Duration) <-chan time.Time
// Shutdown draining state. drainMu guards draining and
// serialises it against the counter increment in
// startDelivery; inFlight tracks the delivery goroutines
// themselves and outstanding mirrors its count so a timed
// out drain can report how many were abandoned.
drainMu sync.Mutex
draining bool
inFlight sync.WaitGroup
outstanding atomic.Int64
abandon chan struct{}
abandonOnce sync.Once
}
// newService builds a Service with the fields every Service
// needs regardless of how it was constructed.
func newService(
log *slog.Logger,
transport http.RoundTripper,
) *Service {
return &Service{
log: log,
transport: transport,
history: NewAlertHistory(),
abandon: make(chan struct{}),
}
}
// New creates a new notify Service.
func New(
lifecycle fx.Lifecycle,
_ fx.Lifecycle,
params Params,
) (*Service, error) {
svc := newService(params.Logger.Get(), http.DefaultTransport)
svc.config = params.Config
svc := &Service{
log: params.Logger.Get(),
transport: http.DefaultTransport,
config: params.Config,
history: NewAlertHistory(),
}
if params.Config.NtfyTopic != "" {
u, err := ValidateWebhookURL(
@@ -192,14 +168,6 @@ func New(
svc.mattermostWebhookURL = u
}
lifecycle.Append(fx.Hook{
OnStop: func(ctx context.Context) error {
svc.drain(ctx)
return nil
},
})
return svc, nil
}
@@ -226,32 +194,6 @@ func (svc *Service) SendNotification(
svc.dispatchMattermost(ctx, title, message, priority)
}
// dispatch delivers a notification to one endpoint on a
// tracked background goroutine.
//
// The delivery context is detached from ctx with
// context.WithoutCancel so that a cancelled caller does not
// kill a delivery already under way; the shutdown drain, not
// the caller, decides how long deliveries may keep running.
func (svc *Service) dispatch(
ctx context.Context,
endpoint string,
send func(context.Context) error,
) {
notifyCtx := context.WithoutCancel(ctx)
svc.startDelivery(endpoint, func() {
err := svc.deliverWithRetry(notifyCtx, endpoint, send)
if err != nil {
svc.log.Error(
"failed to send notification after retries",
"endpoint", endpoint,
"error", err,
)
}
})
}
func (svc *Service) dispatchNtfy(
ctx context.Context,
title, message, priority string,
@@ -260,11 +202,26 @@ func (svc *Service) dispatchNtfy(
return
}
svc.dispatch(ctx, "ntfy", func(c context.Context) error {
go func() {
notifyCtx := context.WithoutCancel(ctx)
err := svc.deliverWithRetry(
notifyCtx, "ntfy",
func(c context.Context) error {
return svc.sendNtfy(
c, svc.ntfyURL, title, message, priority,
c, svc.ntfyURL,
title, message, priority,
)
})
},
)
if err != nil {
svc.log.Error(
"failed to send ntfy notification "+
"after retries",
"error", err,
)
}
}()
}
func (svc *Service) dispatchSlack(
@@ -275,11 +232,26 @@ func (svc *Service) dispatchSlack(
return
}
svc.dispatch(ctx, "slack", func(c context.Context) error {
go func() {
notifyCtx := context.WithoutCancel(ctx)
err := svc.deliverWithRetry(
notifyCtx, "slack",
func(c context.Context) error {
return svc.sendSlack(
c, svc.slackWebhookURL, title, message, priority,
c, svc.slackWebhookURL,
title, message, priority,
)
})
},
)
if err != nil {
svc.log.Error(
"failed to send slack notification "+
"after retries",
"error", err,
)
}
}()
}
func (svc *Service) dispatchMattermost(
@@ -290,8 +262,11 @@ func (svc *Service) dispatchMattermost(
return
}
svc.dispatch(
ctx, "mattermost",
go func() {
notifyCtx := context.WithoutCancel(ctx)
err := svc.deliverWithRetry(
notifyCtx, "mattermost",
func(c context.Context) error {
return svc.sendSlack(
c, svc.mattermostWebhookURL,
@@ -299,6 +274,14 @@ func (svc *Service) dispatchMattermost(
)
},
)
if err != nil {
svc.log.Error(
"failed to send mattermost notification "+
"after retries",
"error", err,
)
}
}()
}
func (svc *Service) sendNtfy(
internal/notify/retry.go
-9
View File
@@ -2,7 +2,6 @@ package notify
import (
"context"
"fmt"
"math"
"math/rand/v2"
"time"
@@ -122,14 +121,6 @@ func (svc *Service) deliverWithRetry(
select {
case <-ctx.Done():
return ctx.Err()
case <-svc.abandon:
// Shutdown drained past its deadline; stop
// sleeping rather than outlive the process.
// A nil channel (Service built without a
// constructor) simply never fires.
return fmt.Errorf(
"%w: %s", ErrDeliveryAbandoned, endpoint,
)
case <-svc.sleepFunc(delay):
}
}
internal/notify/shutdown.go
-119
View File
@@ -1,119 +0,0 @@
package notify
import (
"context"
"errors"
)
// ErrDeliveryAbandoned is returned by a retry loop that was
// cut short because shutdown drained past its deadline.
var ErrDeliveryAbandoned = errors.New(
"notification delivery abandoned at shutdown",
)
// startDelivery runs fn on its own goroutine while tracking it,
// so that drain can wait for it during shutdown.
//
// The WaitGroup counter is incremented here, on the caller's
// goroutine, before the worker exists: incrementing it inside
// the worker would race with drain's Wait and could let
// shutdown sail past a delivery that had not started yet.
//
// Once draining has begun the delivery is refused outright
// rather than queued, so a steady stream of newly submitted
// notifications cannot keep extending the drain.
func (svc *Service) startDelivery(endpoint string, fn func()) {
svc.drainMu.Lock()
if svc.draining {
svc.drainMu.Unlock()
svc.log.Warn(
"notification not dispatched: shutdown in progress",
"endpoint", endpoint,
)
return
}
svc.outstanding.Add(1)
// WaitGroup.Go increments the counter synchronously, here,
// and only then starts the goroutine.
svc.inFlight.Go(func() {
// Runs before the WaitGroup counter is decremented, so
// a drain that times out reports an accurate count.
defer svc.outstanding.Add(-1)
fn()
})
svc.drainMu.Unlock()
}
// drain waits for in-flight notification deliveries to finish.
//
// It first stops accepting new deliveries, then waits until
// either every outstanding delivery has completed or ctx
// expires — whichever comes first. ctx is the context fx
// passes to the OnStop hook, so a permanently dead webhook
// cannot hang shutdown indefinitely.
//
// When the deadline arrives with deliveries still outstanding,
// the count is logged at warn level and the abandon channel is
// closed, which releases any retry loop sleeping in backoff.
// Deliveries already inside an HTTP round trip are bounded by
// the existing httpClientTimeout instead.
//
// A ctx that is already expired on entry is not by itself cause
// for alarm: if nothing is outstanding there is nothing to
// abandon, and the drain says so at debug level rather than
// warning about deliveries that do not exist.
func (svc *Service) drain(ctx context.Context) {
svc.drainMu.Lock()
svc.draining = true
svc.drainMu.Unlock()
done := make(chan struct{})
go func() {
svc.inFlight.Wait()
close(done)
}()
select {
case <-done:
svc.log.Debug(
"all in-flight notifications completed",
)
case <-ctx.Done():
// outstanding is decremented before the WaitGroup
// counter, and startDelivery can no longer add to it
// now that draining is set, so a zero here means every
// delivery really did finish. ctx expiring in that
// state (an OnStop context that was already cancelled
// on entry is the usual way) abandons nothing, so it
// must not close abandon or warn about it.
abandoned := svc.outstanding.Load()
if abandoned == 0 {
svc.log.Debug(
"all in-flight notifications completed",
)
return
}
svc.abandonOnce.Do(func() {
if svc.abandon != nil {
close(svc.abandon)
}
})
svc.log.Warn(
"shutdown deadline reached with notifications "+
"still in flight; abandoning them",
"abandoned", abandoned,
"error", ctx.Err(),
)
}
}
internal/notify/shutdown_test.go
-593
View File
@@ -1,593 +0,0 @@
package notify_test
import (
"bytes"
"context"
"log/slog"
"net/http"
"net/http/httptest"
"net/url"
"strings"
"sync"
"sync/atomic"
"testing"
"time"
"go.uber.org/fx"
"sneak.berlin/go/dnswatcher/internal/config"
"sneak.berlin/go/dnswatcher/internal/globals"
"sneak.berlin/go/dnswatcher/internal/logger"
"sneak.berlin/go/dnswatcher/internal/notify"
)
// Timings used by the drain tests. They stay in the same
// 10-100ms band as the retry tests so the suite never waits on
// a real backoff delay.
const (
// inFlightHold is how long a delivery is kept mid-request
// before the handler is released.
inFlightHold = 30 * time.Millisecond
// drainDeadline bounds a drain that is expected to time
// out.
drainDeadline = 50 * time.Millisecond
// timeoutDrainBound is how long a drain given drainDeadline
// may take to return before the test gives up on it. At
// forty times drainDeadline it leaves ample room for
// scheduling delay on a loaded box under -race, yet it is far
// below the test binary's -timeout, so a drain that its
// deadline does not bound fails that one test instead of
// hanging the package.
timeoutDrainBound = 2 * time.Second
// longDrainDeadline is the deadline given to a drain that is
// expected to finish well before it: when the in-flight
// delivery completes after inFlightHold, or at once when
// nothing is in flight. It is far above inFlightHold, so
// those drains never reach it, and four times
// idleDrainBound, so an idle drain that waited for its
// deadline instead of returning fails that bound.
longDrainDeadline = 2 * time.Second
// reachEndpointTimeout is how long a submitted delivery may
// take to reach the test server. That normally takes a few
// milliseconds; the margin is for a loaded box under -race,
// and only a failing run ever waits this long.
reachEndpointTimeout = 2 * time.Second
// settleDelay is how long to wait before asserting that
// something did *not* happen.
settleDelay = 50 * time.Millisecond
// idleDrainBound is the upper bound on a drain that has
// nothing in flight. It is deliberately far above the cost
// of the goroutine hop through inFlight.Wait() — which
// reached 57ms on a loaded box under -race with the package's
// parallel tests — and far below longDrainDeadline, the
// deadline such a drain is given. A drain that blocked until
// its deadline instead of returning on the WaitGroup
// therefore still fails this bound, but scheduling delay
// alone cannot.
idleDrainBound = 500 * time.Millisecond
)
// syncBuffer is an io.Writer safe for concurrent use, so log
// output written from delivery goroutines can be inspected.
type syncBuffer struct {
mu sync.Mutex
buf bytes.Buffer
}
func (sb *syncBuffer) Write(p []byte) (int, error) {
sb.mu.Lock()
defer sb.mu.Unlock()
return sb.buf.Write(p) //nolint:wrapcheck // test helper
}
func (sb *syncBuffer) String() string {
sb.mu.Lock()
defer sb.mu.Unlock()
return sb.buf.String()
}
// newLoggingService returns a Service writing JSON logs into
// the returned buffer, debug level included.
func newLoggingService(
transport http.RoundTripper,
) (*notify.Service, *syncBuffer) {
logs := &syncBuffer{}
handler := slog.NewJSONHandler(
logs, &slog.HandlerOptions{Level: slog.LevelDebug},
)
return notify.NewTestServiceWithLogger(transport, handler),
logs
}
// blockingNtfyServer returns a server whose handler signals on
// entered, waits for release, and then responds 200.
func blockingNtfyServer(
entered chan<- struct{},
release <-chan struct{},
served *atomic.Bool,
) *httptest.Server {
var once sync.Once
return httptest.NewServer(
http.HandlerFunc(
func(w http.ResponseWriter, _ *http.Request) {
once.Do(func() { close(entered) })
<-release
served.Store(true)
w.WriteHeader(http.StatusOK)
}),
)
}
// TestDrainWaitsForInFlightDelivery verifies that a delivery
// already under way when shutdown starts is allowed to finish.
func TestDrainWaitsForInFlightDelivery(t *testing.T) {
t.Parallel()
var served atomic.Bool
entered := make(chan struct{})
release := make(chan struct{})
srv := blockingNtfyServer(entered, release, &served)
defer srv.Close()
// srv.Close waits for the handler, so release it however the
// test ends; otherwise a drain that returns early hangs the
// package instead of failing this test.
releaseHandler := sync.OnceFunc(func() { close(release) })
defer releaseHandler()
topicURL, _ := url.Parse(srv.URL)
svc := notify.NewTestService(http.DefaultTransport)
svc.SetNtfyURL(topicURL)
svc.SendNotification(
context.Background(), "t", "m", prioInfo,
)
// Make sure the delivery really is mid-request before the
// drain begins.
select {
case <-entered:
case <-time.After(reachEndpointTimeout):
t.Fatal("delivery never reached the endpoint")
}
// As in TestDrainBoundedByContextDeadline: start is captured
// before the clock it is compared against, here the timer
// holding the delivery open, so elapsed covers the whole hold
// and the lower bound cannot come out short from scheduling
// delay alone.
start := time.Now()
timer := time.AfterFunc(inFlightHold, releaseHandler)
defer timer.Stop()
ctx, cancel := context.WithTimeout(
context.Background(), longDrainDeadline,
)
defer cancel()
svc.Drain(ctx)
elapsed := time.Since(start)
if !served.Load() {
t.Error(
"drain returned before the in-flight delivery " +
"completed",
)
}
if elapsed < inFlightHold {
t.Errorf(
"drain took %v, want at least %v",
elapsed, inFlightHold,
)
}
if got := svc.OutstandingDeliveries(); got != 0 {
t.Errorf("outstanding deliveries = %d, want 0", got)
}
}
// neverFires returns a channel that never delivers, standing in
// for a long backoff sleep without actually sleeping.
func neverFires(_ time.Duration) <-chan time.Time {
return make(chan time.Time)
}
// TestDrainBoundedByContextDeadline verifies that a delivery
// stuck retrying against a dead endpoint does not hold shutdown
// past the OnStop context deadline, and that the abandoned
// deliveries are logged at warn level rather than dropped
// silently.
func TestDrainBoundedByContextDeadline(t *testing.T) {
t.Parallel()
var requests atomic.Int64
srv := httptest.NewServer(
http.HandlerFunc(
func(w http.ResponseWriter, _ *http.Request) {
requests.Add(1)
w.WriteHeader(http.StatusInternalServerError)
}),
)
defer srv.Close()
topicURL, _ := url.Parse(srv.URL)
svc, logs := newLoggingService(http.DefaultTransport)
svc.SetNtfyURL(topicURL)
// Never let the backoff sleep complete: the delivery is
// parked in its retry wait until shutdown releases it.
svc.SetSleepFunc(neverFires)
svc.SetRetryConfig(notify.RetryConfig{
MaxRetries: 5,
BaseDelay: time.Hour,
MaxDelay: time.Hour,
})
svc.SendNotification(
context.Background(), "t", "m", prioError,
)
waitForCondition(t, func() bool {
return requests.Load() >= 1 &&
svc.OutstandingDeliveries() == 1
})
// start must be captured *before* the deadline clock starts,
// so that the measured interval is a superset of the deadline
// interval. Capturing it after context.WithTimeout would
// make elapsed structurally smaller than drainDeadline and
// the lower bound below unfalsifiable-by-luck: it would fail
// whenever the two statements were separated by any
// scheduling delay, and pass otherwise, regardless of what
// the drain did.
start := time.Now()
ctx, cancel := context.WithTimeout(
context.Background(), drainDeadline,
)
defer cancel()
// The upper bound is enforced by a watchdog rather than by
// measuring after the fact: a drain that is not bounded at
// all never returns here (the delivery is parked in a backoff
// that never fires), so an unbounded drain must fail this
// test promptly instead of hanging the package until the test
// binary's -timeout.
returned := make(chan struct{})
go func() {
defer close(returned)
svc.Drain(ctx)
}()
select {
case <-returned:
case <-time.After(timeoutDrainBound):
t.Fatalf(
"drain did not return within %v; its %v deadline "+
"did not bound it",
timeoutDrainBound, drainDeadline,
)
}
// The lower bound is the real assertion: the drain must have
// waited for its whole deadline rather than giving up on the
// outstanding delivery early. With start captured above, an
// early return is the only thing that can make it fail.
if elapsed := time.Since(start); elapsed < drainDeadline {
t.Errorf(
"drain returned after %v, before its %v deadline",
elapsed, drainDeadline,
)
}
assertAbandonLogged(t, logs.String())
// The abandoned delivery must stop retrying rather than
// outlive the drain.
waitForCondition(t, func() bool {
return svc.OutstandingDeliveries() == 0
})
}
// assertAbandonLogged checks that the drain logged the
// abandoned deliveries at warn level with a count.
func assertAbandonLogged(t *testing.T, output string) {
t.Helper()
if !strings.Contains(output, `"level":"WARN"`) {
t.Errorf(
"abandoned deliveries not logged at warn level; "+
"log output: %s",
output,
)
}
if !strings.Contains(output, `"abandoned":1`) {
t.Errorf(
"abandoned delivery count not logged; "+
"log output: %s",
output,
)
}
}
// TestDrainRefusesNewDeliveries verifies that notifications
// submitted after the drain has begun are refused and logged,
// so a stream of new work cannot extend shutdown indefinitely.
func TestDrainRefusesNewDeliveries(t *testing.T) {
t.Parallel()
var requests atomic.Int64
srv := httptest.NewServer(
http.HandlerFunc(
func(w http.ResponseWriter, _ *http.Request) {
requests.Add(1)
w.WriteHeader(http.StatusOK)
}),
)
defer srv.Close()
target, _ := url.Parse(srv.URL)
svc, logs := newLoggingService(http.DefaultTransport)
svc.SetNtfyURL(target)
svc.SetSlackWebhookURL(target)
svc.SetMattermostWebhookURL(target)
ctx, cancel := context.WithTimeout(
context.Background(), longDrainDeadline,
)
defer cancel()
// Nothing is in flight, so this returns immediately and
// leaves the service refusing further deliveries.
svc.Drain(ctx)
for range 3 {
svc.SendNotification(
context.Background(), "t", "m", prioInfo,
)
}
time.Sleep(settleDelay)
if got := requests.Load(); got != 0 {
t.Errorf(
"%d requests reached the endpoint after drain, "+
"want 0",
got,
)
}
if got := svc.OutstandingDeliveries(); got != 0 {
t.Errorf("outstanding deliveries = %d, want 0", got)
}
output := logs.String()
if !strings.Contains(output, "shutdown in progress") {
t.Errorf(
"refused deliveries not logged; log output: %s",
output,
)
}
}
// recordingLifecycle is a minimal fx.Lifecycle that records the
// hooks appended to it, so the wiring done by notify.New can be
// inspected without standing up a whole fx application.
type recordingLifecycle struct {
hooks []fx.Hook
}
func (l *recordingLifecycle) Append(hook fx.Hook) {
l.hooks = append(l.hooks, hook)
}
// newNotifyService builds a Service through the real
// constructor, wired to the given lifecycle.
func newNotifyService(
t *testing.T,
lifecycle fx.Lifecycle,
ntfyTopic string,
) *notify.Service {
t.Helper()
g, err := globals.New(nil)
if err != nil {
t.Fatalf("globals.New: %v", err)
}
log, err := logger.New(nil, logger.Params{Globals: g})
if err != nil {
t.Fatalf("logger.New: %v", err)
}
svc, err := notify.New(lifecycle, notify.Params{
Logger: log,
Config: &config.Config{NtfyTopic: ntfyTopic},
})
if err != nil {
t.Fatalf("notify.New: %v", err)
}
return svc
}
// TestNewRegistersDrainingStopHook verifies that notify.New
// wires an OnStop hook into the fx lifecycle and that the hook
// waits for in-flight deliveries.
func TestNewRegistersDrainingStopHook(t *testing.T) {
t.Parallel()
var served atomic.Bool
entered := make(chan struct{})
release := make(chan struct{})
srv := blockingNtfyServer(entered, release, &served)
defer srv.Close()
// As in TestDrainWaitsForInFlightDelivery: release the handler
// however the test ends, before srv.Close waits for it.
releaseHandler := sync.OnceFunc(func() { close(release) })
defer releaseHandler()
lifecycle := &recordingLifecycle{}
svc := newNotifyService(t, lifecycle, srv.URL)
if len(lifecycle.hooks) != 1 {
t.Fatalf(
"appended %d lifecycle hooks, want 1",
len(lifecycle.hooks),
)
}
stop := lifecycle.hooks[0].OnStop
if stop == nil {
t.Fatal("lifecycle hook has no OnStop function")
}
svc.SendNotification(
context.Background(), "t", "m", prioInfo,
)
select {
case <-entered:
case <-time.After(reachEndpointTimeout):
t.Fatal("delivery never reached the endpoint")
}
timer := time.AfterFunc(inFlightHold, releaseHandler)
defer timer.Stop()
ctx, cancel := context.WithTimeout(
context.Background(), longDrainDeadline,
)
defer cancel()
err := stop(ctx)
if err != nil {
t.Fatalf("OnStop returned error: %v", err)
}
if !served.Load() {
t.Error(
"OnStop returned before the in-flight delivery " +
"completed",
)
}
}
// TestDrainWithoutDeliveriesReturnsImmediately verifies the
// common case: nothing in flight, shutdown is not delayed.
func TestDrainWithoutDeliveriesReturnsImmediately(t *testing.T) {
t.Parallel()
svc := notify.NewTestService(http.DefaultTransport)
// Captured before the deadline clock, as elsewhere in this
// file; for an upper bound that is the conservative
// direction, since the measured interval can then only be
// longer than the drain itself.
start := time.Now()
ctx, cancel := context.WithTimeout(
context.Background(), longDrainDeadline,
)
defer cancel()
svc.Drain(ctx)
if elapsed := time.Since(start); elapsed > idleDrainBound {
t.Errorf(
"drain of an idle service took %v, want at most "+
"%v; its deadline was %v",
elapsed, idleDrainBound, longDrainDeadline,
)
}
}
// TestDrainWithCancelledContextDoesNotWarn verifies that an
// OnStop context that is already dead on entry does not produce
// an "abandoning them" warning when there was nothing in flight
// to abandon, and that the drain returns and says at debug level
// that nothing was in flight. The expired context wins the
// select immediately, so only the outstanding count can tell the
// difference between a genuine timeout and a shutdown that had
// simply already run out of time with no work left.
func TestDrainWithCancelledContextDoesNotWarn(t *testing.T) {
t.Parallel()
svc, logs := newLoggingService(http.DefaultTransport)
ctx, cancel := context.WithCancel(context.Background())
cancel()
// A watchdog, as in TestDrainBoundedByContextDeadline, so
// that a drain which never returns fails here instead of
// hanging the package.
returned := make(chan struct{})
go func() {
defer close(returned)
svc.Drain(ctx)
}()
select {
case <-returned:
case <-time.After(idleDrainBound):
t.Fatalf(
"drain with nothing in flight and a cancelled "+
"context did not return within %v",
idleDrainBound,
)
}
output := logs.String()
// The absence of a warning alone would also pass if the drain
// logged nothing at all, so require the debug line it writes
// when it finds nothing outstanding.
if !strings.Contains(
output, "all in-flight notifications completed",
) {
t.Errorf(
"drain did not log that nothing was in flight; "+
"log output: %s",
output,
)
}
if strings.Contains(output, `"level":"WARN"`) {
t.Errorf(
"drain with nothing in flight warned about "+
"abandoned deliveries; log output: %s",
output,
)
}
}
internal/resolver/dns_client.go
+2 -2
View File
@@ -7,8 +7,8 @@ import (
"github.com/miekg/dns"
)
// DNSClient sends one DNS message to a nameserver and returns the
// reply. The resolver holds one for UDP and one for TCP.
// DNSClient abstracts DNS wire-protocol exchanges so the resolver
// can be tested without hitting real nameservers.
type DNSClient interface {
ExchangeContext(
ctx context.Context,
internal/resolver/errors.go
-12
View File
@@ -10,18 +10,6 @@ var (
"no authoritative nameservers found",
)
// ErrNoNameserverAnswered is returned when every nameserver
// asked about a name timed out, failed or returned a referral,
// so whether the name has addresses is unknown.
ErrNoNameserverAnswered = errors.New("no nameserver answered")
// ErrUnusableReply is returned when a server replied with an
// error such as SERVFAIL, or with a referral that leads no
// closer to the name asked about.
ErrUnusableReply = errors.New(
"reply is an error or a referral that leads no closer",
)
// ErrCNAMEDepthExceeded is returned when a CNAME chain
// exceeds MaxCNAMEDepth.
ErrCNAMEDepthExceeded = errors.New(
internal/resolver/export_test.go
-59
View File
@@ -1,59 +0,0 @@
package resolver
import (
"context"
"github.com/miekg/dns"
)
// ExtractRecordValue exports extractRecordValue for testing.
func ExtractRecordValue(rr dns.RR) string {
return extractRecordValue(rr)
}
// UsableReply exports usableReply for testing.
func UsableReply(resp *dns.Msg, zone string, name string) bool {
return usableReply(resp, zone, name)
}
// NSSetFrom exports nsSetFrom for testing.
func NSSetFrom(resp *dns.Msg, domain string) []string {
return nsSetFrom(resp, domain)
}
// CollectIPs exports collectIPs for testing.
func CollectIPs(
results map[string]*NameserverResponse,
) ([]string, string, error) {
return collectIPs(results)
}
// QueryEachNS exports queryEachNS for testing.
func (r *Resolver) QueryEachNS(
ctx context.Context,
nameservers []string,
hostname string,
) (map[string]*NameserverResponse, error) {
return r.queryEachNS(ctx, nameservers, hostname)
}
// ResolveNSIPs exports resolveNSIPs for testing.
func (r *Resolver) ResolveNSIPs(
ctx context.Context,
nsNames []string,
) []string {
return r.resolveNSIPs(ctx, nsNames)
}
// RootServerList exports rootServerList for testing.
func RootServerList() []string {
return rootServerList()
}
// Shuffled exports shuffled for testing.
func Shuffled(
servers []string,
shuffle func(n int, swap func(i, j int)),
) []string {
return shuffled(servers, shuffle)
}
internal/resolver/iterative.go
+56 -183
View File
@@ -4,9 +4,7 @@ import (
"context"
"errors"
"fmt"
"math/rand/v2"
"net"
"slices"
"sort"
"strings"
"time"
@@ -19,6 +17,7 @@ const (
maxRetries = 2
maxDelegation = 20
timeoutMultiplier = 2
minDomainLabels = 2
)
// ErrRefused is returned when a DNS server refuses a query.
@@ -209,33 +208,21 @@ func (r *Resolver) followDelegation(
domain string,
servers []string,
) ([]string, error) {
// servers are the root servers, the servers of zone ".".
zone := "."
for range maxDelegation {
if checkCtx(ctx) != nil {
return nil, ErrContextCanceled
}
resp, err := r.queryServers(
ctx, servers, zone, domain, dns.TypeNS,
ctx, servers, domain, dns.TypeNS,
)
if err != nil {
return nil, err
}
nsSet := nsSetFrom(resp, domain)
if len(nsSet) > 0 {
return nsSet, nil
}
// An authoritative reply comes from the servers of the zone
// domain is in; it is not a referral, even when its authority
// section lists that zone's NS records. Without NS records in
// the answer, domain is not the zone's apex and has no
// nameservers of its own.
if resp.Authoritative {
return nil, ErrNoNameservers
ansNS := extractNSSet(resp.Answer)
if len(ansNS) > 0 {
return ansNS, nil
}
authNS := extractNSSet(resp.Ns)
@@ -255,52 +242,25 @@ func (r *Resolver) followDelegation(
}
servers = nextServers
zone = referralZone(resp)
}
return nil, ErrNoNameservers
}
// shuffled returns a copy of servers in the order shuffle puts them
// in. The resolver passes rand.Shuffle, so each time it walks a list of
// servers it starts at a random one, and no one server gets every
// first query.
func shuffled(
servers []string,
shuffle func(n int, swap func(i, j int)),
) []string {
order := slices.Clone(servers)
shuffle(len(order), func(i, j int) {
order[i], order[j] = order[j], order[i]
})
return order
}
// queryServers asks servers, the servers of zone, about name in a random
// order until one gives a usable reply. A server that times out, refuses
// or gives a reply that is not usable is passed over for the next.
func (r *Resolver) queryServers(
ctx context.Context,
servers []string,
zone string,
name string,
qtype uint16,
) (*dns.Msg, error) {
var lastErr error
for _, ip := range shuffled(servers, rand.Shuffle) {
for _, ip := range servers {
if checkCtx(ctx) != nil {
return nil, ErrContextCanceled
}
resp, err := r.queryDNS(ctx, ip, name, qtype)
if err == nil && !usableReply(resp, zone, name) {
err = fmt.Errorf(
"query %s @%s: %w", name, ip, ErrUnusableReply,
)
}
if err == nil {
return resp, nil
}
@@ -311,57 +271,6 @@ func (r *Resolver) queryServers(
return nil, fmt.Errorf("all servers failed: %w", lastErr)
}
// usableReply reports whether resp, a reply from one of the servers of
// zone to a query about name, is usable. An error reply such as SERVFAIL
// is not. Nor is a referral, unless it refers the query to a zone below
// zone that name is in: a server that refers it back to zone, up or
// sideways does not serve zone as it should.
func usableReply(resp *dns.Msg, zone string, name string) bool {
if resp.Rcode != dns.RcodeSuccess && resp.Rcode != dns.RcodeNameError {
return false
}
child := referralZone(resp)
if resp.Authoritative || len(resp.Answer) > 0 || child == "" {
return true
}
return child != zone && dns.IsSubDomain(zone, child) &&
dns.IsSubDomain(child, name)
}
// referralZone returns the zone a referral refers the query to: the
// owner name of the NS records in resp's authority section, or "" when
// there are none.
func referralZone(resp *dns.Msg) string {
for _, rr := range resp.Ns {
if ns, ok := rr.(*dns.NS); ok {
return strings.ToLower(ns.Hdr.Name)
}
}
return ""
}
// nsSetFrom returns the NS set of domain that resp, a reply to a query
// for domain's NS records, gives: the delegation in a referral to domain
// itself, or else the NS records in the answer; empty when it gives
// neither. A referral to domain comes from its parent zone's servers,
// which all hold the same delegation, so the set does not depend on
// which of them answered. domain's own servers, which can disagree about
// their NS records, are then not asked.
func nsSetFrom(resp *dns.Msg, domain string) []string {
if referralZone(resp) == domain {
return extractNSSet(resp.Ns)
}
return extractNSSet(resp.Answer)
}
// resolveNSIPs returns the addresses of every nameserver in nsNames
// whose name resolves, for a referral that carries none. The walk can
// then go on to the zone's other nameservers when one gives no usable
// reply.
func (r *Resolver) resolveNSIPs(
ctx context.Context,
nsNames []string,
@@ -373,6 +282,10 @@ func (r *Resolver) resolveNSIPs(
if err == nil {
ips = append(ips, resolved...)
}
if len(ips) > 0 {
break
}
}
return ips
@@ -391,7 +304,6 @@ func (r *Resolver) resolveNSIterative(
domain = dns.Fqdn(domain)
servers := rootServerList()
zone := "."
for range maxDelegation {
if checkCtx(ctx) != nil {
@@ -399,13 +311,13 @@ func (r *Resolver) resolveNSIterative(
}
resp, err := r.queryServers(
ctx, servers, zone, domain, dns.TypeNS,
ctx, servers, domain, dns.TypeNS,
)
if err != nil {
return nil, err
}
nsNames := nsSetFrom(resp, domain)
nsNames := extractNSSet(resp.Answer)
if len(nsNames) > 0 {
return nsNames, nil
}
@@ -424,7 +336,6 @@ func (r *Resolver) resolveNSIterative(
}
servers = nextServers
zone = referralZone(resp)
}
return nil, ErrNoNameservers
@@ -442,7 +353,6 @@ func (r *Resolver) resolveARecord(
hostname = dns.Fqdn(hostname)
servers := rootServerList()
zone := "."
for range maxDelegation {
if checkCtx(ctx) != nil {
@@ -450,7 +360,7 @@ func (r *Resolver) resolveARecord(
}
resp, err := r.queryServers(
ctx, servers, zone, hostname, dns.TypeA,
ctx, servers, hostname, dns.TypeA,
)
if err != nil {
return nil, fmt.Errorf(
@@ -488,7 +398,6 @@ func (r *Resolver) resolveARecord(
}
servers = nextServers
zone = referralZone(resp)
}
return nil, fmt.Errorf(
@@ -498,10 +407,7 @@ func (r *Resolver) resolveARecord(
// FindAuthoritativeNameservers traces the delegation chain from
// root servers to discover all authoritative nameservers for the
// given domain, as the delegation from its parent zone's servers lists
// them. For a name that is not a zone apex it tries each
// parent name in turn, so it returns the nameservers of the zone the
// name is in.
// given domain. Walks up the label hierarchy for subdomains.
func (r *Resolver) FindAuthoritativeNameservers(
ctx context.Context,
domain string,
@@ -598,10 +504,7 @@ func (r *Resolver) queryAllTypes(
type queryState struct {
gotNXDomain bool
gotSERVFAIL bool
gotRefused bool
gotTimeout bool
gotReferral bool
netErr error
hasRecords bool
}
@@ -639,13 +542,8 @@ func (r *Resolver) querySingleType(
) {
msg, err := r.queryDNS(ctx, nsIP, hostname, qtype)
if err != nil {
switch {
case isTimeout(err):
if isTimeout(err) {
state.gotTimeout = true
case errors.Is(err, ErrRefused):
state.gotRefused = true
default:
state.netErr = err
}
return
@@ -663,19 +561,6 @@ func (r *Resolver) querySingleType(
return
}
// A reply with no answer that lists other nameservers, from a server
// that does not hold the name's zone, is a referral and says nothing
// about the name's records. A server named in the delegation that
// does not hold the zone may send one, as do a parent zone's servers
// when FindAuthoritativeNameservers found no delegation for the
// name's zone and moved on to a parent name.
if !msg.Authoritative && len(msg.Answer) == 0 &&
len(extractNSSet(msg.Ns)) > 0 {
state.gotReferral = true
return
}
collectAnswerRecords(msg, resp, state)
}
@@ -718,24 +603,12 @@ func classifyResponse(resp *NameserverResponse, state queryState) {
case state.gotSERVFAIL && !state.hasRecords:
resp.Status = StatusError
resp.Error = "server returned SERVFAIL"
case state.gotRefused && !state.hasRecords:
resp.Status = StatusError
resp.Error = "server returned REFUSED"
case state.netErr != nil && !state.hasRecords:
resp.Status = StatusError
resp.Error = "network error: " + state.netErr.Error()
case state.gotReferral && !state.hasRecords:
resp.Status = StatusError
resp.Error = "server returned a referral"
case !state.hasRecords && !state.gotNXDomain:
resp.Status = StatusNoData
}
}
// extractRecordValue formats a DNS RR value as a string. DNS names
// are case-insensitive and nameservers may answer in any letter case,
// so names are lower-cased to compare equal. TXT and CAA values keep
// their letter case.
// extractRecordValue formats a DNS RR value as a string.
func extractRecordValue(rr dns.RR) string {
switch r := rr.(type) {
case *dns.A:
@@ -743,29 +616,43 @@ func extractRecordValue(rr dns.RR) string {
case *dns.AAAA:
return r.AAAA.String()
case *dns.CNAME:
return strings.ToLower(r.Target)
return r.Target
case *dns.MX:
return fmt.Sprintf("%d %s", r.Preference, strings.ToLower(r.Mx))
return fmt.Sprintf("%d %s", r.Preference, r.Mx)
case *dns.TXT:
return strings.Join(r.Txt, "")
case *dns.SRV:
return fmt.Sprintf(
"%d %d %d %s",
r.Priority, r.Weight, r.Port, strings.ToLower(r.Target),
r.Priority, r.Weight, r.Port, r.Target,
)
case *dns.CAA:
return fmt.Sprintf(
"%d %s \"%s\"", r.Flag, r.Tag, r.Value,
)
case *dns.NS:
return strings.ToLower(r.Ns)
return r.Ns
default:
return ""
}
}
// QueryAllNameservers discovers the auth NSes of the zone the
// hostname is in, then queries each one independently.
// parentDomain returns the registerable parent domain.
func parentDomain(hostname string) string {
hostname = dns.Fqdn(strings.ToLower(hostname))
labels := dns.SplitDomainName(hostname)
if len(labels) <= minDomainLabels {
return strings.Join(labels, ".") + "."
}
return strings.Join(
labels[len(labels)-minDomainLabels:], ".",
) + "."
}
// QueryAllNameservers discovers auth NSes for the hostname's
// parent domain, then queries each one independently.
func (r *Resolver) QueryAllNameservers(
ctx context.Context,
hostname string,
@@ -774,7 +661,9 @@ func (r *Resolver) QueryAllNameservers(
return nil, ErrContextCanceled
}
nameservers, err := r.FindAuthoritativeNameservers(ctx, hostname)
parent := parentDomain(hostname)
nameservers, err := r.FindAuthoritativeNameservers(ctx, parent)
if err != nil {
return nil, err
}
@@ -790,14 +679,11 @@ func (r *Resolver) queryEachNS(
results := make(map[string]*NameserverResponse)
for _, ns := range nameservers {
resp, err := r.QueryNameserver(ctx, ns, hostname)
// A query the context cut short says nothing about the
// nameserver, so it must not be returned as its failure.
if checkCtx(ctx) != nil {
return nil, ErrContextCanceled
}
resp, err := r.QueryNameserver(ctx, ns, hostname)
if err != nil {
results[ns] = &NameserverResponse{
Nameserver: ns,
@@ -825,19 +711,25 @@ func (r *Resolver) LookupNS(
// LookupAllRecords performs iterative resolution to find all DNS
// records for the given hostname, keyed by authoritative nameserver.
// Each nameserver's response carries its status and error with its
// records.
func (r *Resolver) LookupAllRecords(
ctx context.Context,
hostname string,
) (map[string]*NameserverResponse, error) {
return r.QueryAllNameservers(ctx, hostname)
) (map[string]map[string][]string, error) {
results, err := r.QueryAllNameservers(ctx, hostname)
if err != nil {
return nil, err
}
out := make(map[string]map[string][]string, len(results))
for ns, resp := range results {
out[ns] = resp.Records
}
return out, nil
}
// ResolveIPAddresses resolves a hostname to all IPv4 and IPv6
// addresses, following CNAME chains up to MaxCNAMEDepth. When no
// nameserver of the name's zone answered, it returns an error rather
// than no addresses.
// addresses, following CNAME chains up to MaxCNAMEDepth.
func (r *Resolver) ResolveIPAddresses(
ctx context.Context,
hostname string,
@@ -863,10 +755,7 @@ func (r *Resolver) resolveIPWithCNAME(
return nil, err
}
ips, cnameTarget, err := collectIPs(results)
if err != nil {
return nil, fmt.Errorf("resolving %s: %w", hostname, err)
}
ips, cnameTarget := collectIPs(results)
if len(ips) == 0 && cnameTarget != "" {
return r.resolveIPWithCNAME(ctx, cnameTarget, depth+1)
@@ -877,28 +766,16 @@ func (r *Resolver) resolveIPWithCNAME(
return ips, nil
}
// collectIPs returns the addresses in the nameservers' answers and the
// first CNAME target among them. It returns ErrNoNameserverAnswered when
// every nameserver timed out, failed or returned a referral: that is not
// a name with no addresses.
func collectIPs(
results map[string]*NameserverResponse,
) ([]string, string, error) {
) ([]string, string) {
seen := make(map[string]bool)
var ips []string
var cnameTarget string
answered := false
for _, resp := range results {
if resp.Status == StatusTimeout || resp.Status == StatusError {
continue
}
answered = true
if resp.Status == StatusNXDomain {
continue
}
@@ -922,9 +799,5 @@ func collectIPs(
}
}
if !answered {
return nil, "", ErrNoNameserverAnswered
}
return ips, cnameTarget, nil
return ips, cnameTarget
}
internal/resolver/iterative_test.go
-266
View File
@@ -1,266 +0,0 @@
package resolver_test
import (
"math/rand/v2"
"slices"
"testing"
"github.com/miekg/dns"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"sneak.berlin/go/dnswatcher/internal/resolver"
)
// TestCollectIPs_OneAnswerIsEnough checks that one nameserver answering
// NXDOMAIN says the name has no addresses, though the other timed out.
func TestCollectIPs_OneAnswerIsEnough(t *testing.T) {
t.Parallel()
ips, _, err := resolver.CollectIPs(
map[string]*resolver.NameserverResponse{
"ns1.example.": {Status: resolver.StatusTimeout},
"ns2.example.": {Status: resolver.StatusNXDomain},
},
)
require.NoError(t, err)
assert.Empty(t, ips)
}
// TestCollectIPs_FailedIsNoAnswer checks that nameservers that all have
// status error, from a refusal, a server failure, a network error or a
// referral, are no answer rather than a name with no addresses.
func TestCollectIPs_FailedIsNoAnswer(t *testing.T) {
t.Parallel()
ips, _, err := resolver.CollectIPs(
map[string]*resolver.NameserverResponse{
"ns1.example.": {Status: resolver.StatusError},
"ns2.example.": {Status: resolver.StatusError},
},
)
require.ErrorIs(t, err, resolver.ErrNoNameserverAnswered)
assert.Empty(t, ips)
}
const (
// exampleCom is the zone most cases of TestUsableReply and
// TestNSSetFrom are about, and wwwExampleCom a name in it.
exampleCom = "example.com."
wwwExampleCom = "www.example.com."
// exampleNS is the server the NS records nsRecord builds name.
exampleNS = "ns1.example.net."
)
// nsRecord builds an NS record that names a server of zone.
func nsRecord(zone string) *dns.NS {
return &dns.NS{
Hdr: dns.RR_Header{
Name: zone, Rrtype: dns.TypeNS, Class: dns.ClassINET,
},
Ns: exampleNS,
}
}
// referralTo builds a reply that refers the query to the servers of
// zone.
func referralTo(zone string) *dns.Msg {
msg := new(dns.Msg)
msg.Ns = []dns.RR{nsRecord(zone)}
return msg
}
// TestUsableReply checks which replies from one of a zone's servers are
// used. A reply that is not usable moves the query on to the zone's
// next server.
func TestUsableReply(t *testing.T) {
t.Parallel()
servfail := new(dns.Msg)
servfail.Rcode = dns.RcodeServerFailure
answer := new(dns.Msg)
answer.Authoritative = true
answer.Answer = []dns.RR{nsRecord(exampleCom)}
nxdomain := new(dns.Msg)
nxdomain.Authoritative = true
nxdomain.Rcode = dns.RcodeNameError
tests := []struct {
name string
resp *dns.Msg
zone string
query string
want bool
}{
{
name: "SERVFAIL", resp: servfail,
zone: exampleCom, query: exampleCom, want: false,
},
{
name: "answer", resp: answer,
zone: exampleCom, query: exampleCom, want: true,
},
{
name: "NXDOMAIN", resp: nxdomain,
zone: ".", query: exampleCom, want: true,
},
{
name: "root refers to com", resp: referralTo("com."),
zone: ".", query: exampleCom, want: true,
},
{
name: "com refers to example.com", resp: referralTo(exampleCom),
zone: "com.", query: wwwExampleCom, want: true,
},
{
name: "referral back to the zone", resp: referralTo(exampleCom),
zone: exampleCom, query: exampleCom, want: false,
},
{
name: "referral up to the root", resp: referralTo("."),
zone: exampleCom, query: exampleCom, want: false,
},
{
name: "referral sideways", resp: referralTo("net."),
zone: ".", query: exampleCom, want: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
assert.Equal(t, tt.want,
resolver.UsableReply(tt.resp, tt.zone, tt.query),
)
})
}
}
// TestNSSetFrom checks which NS set a reply gives for a domain; a set
// that is not empty ends the walk. The referral to example.com that
// com's servers all send alike gives its delegation, so the set is the
// same whichever of them answered, and example.com's own servers, which
// can disagree, are not asked.
func TestNSSetFrom(t *testing.T) {
t.Parallel()
answer := new(dns.Msg)
answer.Authoritative = true
answer.Answer = []dns.RR{nsRecord(exampleCom)}
tests := []struct {
name string
resp *dns.Msg
domain string
want []string
}{
{
name: "com refers to example.com", resp: referralTo(exampleCom),
domain: exampleCom, want: []string{exampleNS},
},
{
name: "com refers on, for www.example.com",
resp: referralTo(exampleCom), domain: wwwExampleCom,
want: nil,
},
{
name: "answer from a server that holds example.com",
resp: answer, domain: exampleCom,
want: []string{exampleNS},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
assert.ElementsMatch(t, tt.want,
resolver.NSSetFrom(tt.resp, tt.domain),
)
})
}
}
func TestExtractRecordValue_LetterCase(t *testing.T) {
t.Parallel()
tests := []struct {
name string
rr dns.RR
want string
}{
{
name: "MX target lower-cased",
rr: &dns.MX{Preference: 1, Mx: "ASPMX.L.GOOGLE.COM."},
want: "1 aspmx.l.google.com.",
},
{
name: "NS target lower-cased",
rr: &dns.NS{Ns: "x.ns.joker.COM."},
want: "x.ns.joker.com.",
},
{
name: "CNAME target lower-cased",
rr: &dns.CNAME{Target: "WWW.Example.Com."},
want: "www.example.com.",
},
{
name: "SRV target lower-cased",
rr: &dns.SRV{
Priority: 10, Weight: 5, Port: 443,
Target: "SIP.Example.Com.",
},
want: "10 5 443 sip.example.com.",
},
{
name: "TXT value keeps its case",
rr: &dns.TXT{Txt: []string{"Verify=AbC123"}},
want: "Verify=AbC123",
},
{
name: "CAA value keeps its case",
rr: &dns.CAA{Flag: 0, Tag: "issue", Value: "LetsEncrypt.org"},
want: `0 issue "LetsEncrypt.org"`,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
assert.Equal(t, tt.want, resolver.ExtractRecordValue(tt.rr))
})
}
}
// TestShuffled shuffles the root servers with many seeds. Every order
// must hold each root server once, so each is tried before a
// resolution fails; each root server must come first for some seed, so
// no one root server gets every first query; and the list passed in
// must be left as it was.
func TestShuffled(t *testing.T) {
t.Parallel()
const seeds = 1000
roots := resolver.RootServerList()
before := slices.Clone(roots)
first := make(map[string]bool)
for seed := range uint64(seeds) {
rng := rand.New(rand.NewPCG(seed, 0)) //nolint:gosec // seeded on purpose
order := resolver.Shuffled(roots, rng.Shuffle)
assert.ElementsMatch(t, roots, order)
first[order[0]] = true
}
assert.Len(t, first, len(roots))
assert.Equal(t, before, roots)
}
internal/resolver/livedns_harness_test.go
-192
View File
@@ -1,192 +0,0 @@
package resolver_test
import (
"testing"
"github.com/stretchr/testify/assert"
"sneak.berlin/go/dnswatcher/internal/resolver"
)
// Tests for the live-DNS harness in livedns_test.go itself. These
// exercise pure logic; they perform no DNS resolution of any kind, so
// they neither mock DNS nor depend on it.
// Names for the synthetic status maps below. Nothing is ever queried
// at them: they are map keys handed to the package's pure counting
// helpers, not a stand-in for a nameserver.
const (
nsExample1 = "ns1.example."
nsExample2 = "ns2.example."
nsExample3 = "ns3.example."
nsExample4 = "ns4.example."
)
func TestLiveQuorumIsStrictMajority(t *testing.T) {
t.Parallel()
cases := map[int]int{
0: 1,
1: 1,
2: 2,
3: 2,
4: 3,
5: 3,
13: 7,
}
for total, want := range cases {
assert.Equal(
t, want, liveQuorum(total),
"liveQuorum(%d)", total,
)
}
}
func TestStatusCountingIgnoresSilentNameservers(t *testing.T) {
t.Parallel()
results := map[string]*resolver.NameserverResponse{
nsExample1: {
Nameserver: nsExample1,
Status: resolver.StatusOK,
},
nsExample2: {
Nameserver: nsExample2,
Status: resolver.StatusOK,
},
nsExample3: {
Nameserver: nsExample3,
Status: resolver.StatusTimeout,
},
nsExample4: {
Nameserver: nsExample4,
Status: resolver.StatusError,
},
}
assert.Equal(
t, 2, countStatus(results, resolver.StatusOK),
)
assert.Equal(
t, 0, countStatus(results, resolver.StatusNXDomain),
)
// Two of four answered, which is short of the quorum of
// three: this is the state that triggers a retry rather
// than an assertion failure.
assert.Equal(t, 2, answeredCount(results))
assert.Less(t, answeredCount(results), liveQuorum(len(results)))
assert.Equal(
t,
"ns1.example.=ok ns2.example.=ok "+
"ns3.example.=timeout ns4.example.=error",
describeStatuses(results),
)
}
// TestUnsanctionedStatusesRejectsWrongAnswers is the regression test
// for the defect this allowlist exists to prevent: a minority of
// nameservers answering WRONGLY while quorum keeps the suite green.
// nodata is the case that motivated it — it is a wrong answer, not
// silence, and it was previously banned by neither test.
func TestUnsanctionedStatusesRejectsWrongAnswers(t *testing.T) {
t.Parallel()
// Four nameservers, three OK and one answering nodata: a
// quorum of three is satisfied and no NXDOMAIN is present, so
// the old blocklist assertions both passed on this input.
results := map[string]*resolver.NameserverResponse{
nsExample1: {
Nameserver: nsExample1,
Status: resolver.StatusOK,
},
nsExample2: {
Nameserver: nsExample2,
Status: resolver.StatusOK,
},
nsExample3: {
Nameserver: nsExample3,
Status: resolver.StatusOK,
},
nsExample4: {
Nameserver: nsExample4,
Status: resolver.StatusNoData,
},
}
assert.GreaterOrEqual(
t,
countStatus(results, resolver.StatusOK),
liveQuorum(len(results)),
)
assert.Zero(t, countStatus(results, resolver.StatusNXDomain))
// nodata is an ANSWER, so it never triggers a retry: nothing
// but the allowlist stands between it and a false green.
assert.Equal(t, len(results), answeredCount(results))
assert.Equal(
t,
[]string{nsExample4 + "=nodata"},
unsanctionedStatuses(
results,
resolver.StatusOK,
resolver.StatusTimeout,
resolver.StatusError,
),
"nodata must be reported as an unsanctioned status",
)
}
func TestUnsanctionedStatusesToleratesSilenceOnly(t *testing.T) {
t.Parallel()
results := map[string]*resolver.NameserverResponse{
nsExample1: {
Nameserver: nsExample1,
Status: resolver.StatusNXDomain,
},
nsExample2: {
Nameserver: nsExample2,
Status: resolver.StatusTimeout,
},
nsExample3: {
Nameserver: nsExample3,
Status: resolver.StatusError,
},
}
allowed := []string{
resolver.StatusNXDomain,
resolver.StatusTimeout,
resolver.StatusError,
}
assert.Empty(
t,
unsanctionedStatuses(results, allowed...),
"timeout and error are non-answers and are tolerated",
)
// The same silent nameservers do not count towards a quorum.
assert.Equal(t, 1, answeredCount(results))
// An unknown status is treated as silence by answeredCount —
// so it retries and fails loudly — and is unsanctioned by the
// allowlist rather than quietly permitted.
const laterStatus = "some-status-added-later"
results[nsExample4] = &resolver.NameserverResponse{
Nameserver: nsExample4,
Status: laterStatus,
}
assert.Equal(t, 1, answeredCount(results))
assert.Equal(
t,
[]string{nsExample4 + "=" + laterStatus},
unsanctionedStatuses(results, allowed...),
)
}
internal/resolver/livedns_test.go
-419
View File
@@ -1,419 +0,0 @@
package resolver_test
import (
"context"
"errors"
"fmt"
"slices"
"sort"
"strings"
"testing"
"sneak.berlin/go/dnswatcher/internal/livednstest"
"sneak.berlin/go/dnswatcher/internal/resolver"
)
// ----------------------------------------------------------------
// Live DNS test support
// ----------------------------------------------------------------
//
// Tests that look something up in DNS query live DNS servers, never a
// stand-in; logic that works on record data may be tested on that
// data with no lookup (see TESTING.md). Each live operation below goes
// through livednstest.Retry, which bounds how many resolutions are in
// flight at once and retries an operation that got no answer (see
// package livednstest).
//
// Where an assertion spans several independent nameservers, a quorum
// is enough: a strict majority answering as expected. A server that
// fails to answer is tolerated, while a server that answers *wrongly*
// still fails the test.
//
// That tolerance is expressed as an ALLOWLIST of sanctioned statuses,
// never as a blocklist of known-bad ones. A blocklist bans the one
// wrong answer its author thought of and silently admits every other
// status, including any added to the resolver later; an allowlist
// fails on anything nobody explicitly sanctioned. Silence (timeout,
// error) is the only thing quorum exists to tolerate. A *wrong
// answer* — nxdomain for a name that exists, ok for one that does
// not, nodata for either — is never tolerated at any count.
// minNameservers is the smallest nameserver count a well-run zone is
// expected to publish.
const minNameservers = 2
// errLiveNoQuorum reports that too few of a domain's nameservers
// answered for a quorum assertion to be made.
var errLiveNoQuorum = errors.New("no nameserver quorum")
// liveQuorum is how many of total nameservers must agree for a
// multi-nameserver assertion to hold: a strict majority.
func liveQuorum(total int) int {
if total < 1 {
return 1
}
return total/2 + 1
}
// countStatus counts the responses carrying the given status.
func countStatus(
results map[string]*resolver.NameserverResponse,
status string,
) int {
n := 0
for _, resp := range results {
if resp.Status == status {
n++
}
}
return n
}
// liveAnswerStatuses is the closed set of statuses that count as a
// nameserver having ANSWERED at all, whether or not the test agrees
// with the answer. It is deliberately an allowlist: a status added
// to the resolver later is treated as silence, so it can only ever
// cause a retry and then a loud failure, never a quiet pass.
func liveAnswerStatuses() []string {
return []string{
resolver.StatusOK,
resolver.StatusNXDomain,
resolver.StatusNoData,
}
}
// answeredCount counts the nameservers that produced an answer of
// any kind, as opposed to failing or timing out.
func answeredCount(
results map[string]*resolver.NameserverResponse,
) int {
answers := liveAnswerStatuses()
n := 0
for _, resp := range results {
if slices.Contains(answers, resp.Status) {
n++
}
}
return n
}
// unsanctionedStatuses returns "nameserver=status" for every result
// whose status the caller did not explicitly sanction, sorted for a
// stable failure message. Callers pass the full closed set they will
// accept — the expected answer plus whichever non-answers (timeout,
// error) quorum is allowed to tolerate — so that any status outside
// it fails the test by name.
func unsanctionedStatuses(
results map[string]*resolver.NameserverResponse,
allowed ...string,
) []string {
offenders := make([]string, 0, len(results))
for ns, resp := range results {
if slices.Contains(allowed, resp.Status) {
continue
}
offenders = append(
offenders, fmt.Sprintf("%s=%s", ns, resp.Status),
)
}
sort.Strings(offenders)
return offenders
}
// describeStatuses renders per-nameserver statuses for use in
// assertion failure messages.
func describeStatuses(
results map[string]*resolver.NameserverResponse,
) string {
parts := make([]string, 0, len(results))
for ns, resp := range results {
parts = append(
parts, fmt.Sprintf("%s=%s", ns, resp.Status),
)
}
sort.Strings(parts)
return strings.Join(parts, " ")
}
// ----------------------------------------------------------------
// Live operation wrappers
// ----------------------------------------------------------------
// liveFindAuthoritative resolves a domain's authoritative
// nameservers, retrying until the delegation chain can be walked.
func liveFindAuthoritative(
t *testing.T,
r *resolver.Resolver,
domain string,
) []string {
t.Helper()
var out []string
livednstest.Retry(
t,
"FindAuthoritativeNameservers("+domain+")",
func(ctx context.Context) error {
ns, err := r.FindAuthoritativeNameservers(ctx, domain)
if err != nil {
return err
}
if len(ns) == 0 {
return fmt.Errorf(
"%w: %s has no nameservers",
livednstest.ErrNoAnswer, domain,
)
}
out = ns
return nil
},
)
return out
}
// liveLookupNS is liveFindAuthoritative through the LookupNS entry
// point, so that both entry points stay independently exercised.
func liveLookupNS(
t *testing.T,
r *resolver.Resolver,
domain string,
) []string {
t.Helper()
var out []string
livednstest.Retry(
t,
"LookupNS("+domain+")",
func(ctx context.Context) error {
ns, err := r.LookupNS(ctx, domain)
if err != nil {
return err
}
if len(ns) == 0 {
return fmt.Errorf(
"%w: %s has no nameservers",
livednstest.ErrNoAnswer, domain,
)
}
out = ns
return nil
},
)
return out
}
// liveQueryNameserver queries one nameserver, retrying while that
// nameserver fails to answer. NXDOMAIN and NODATA are answers and
// are returned to the caller to assert on.
func liveQueryNameserver(
t *testing.T,
r *resolver.Resolver,
nameserver string,
hostname string,
) *resolver.NameserverResponse {
t.Helper()
what := fmt.Sprintf(
"QueryNameserver(%s, %s)", nameserver, hostname,
)
var out *resolver.NameserverResponse
livednstest.Retry(
t,
what,
func(ctx context.Context) error {
resp, err := r.QueryNameserver(
ctx, nameserver, hostname,
)
if err != nil {
return err
}
if resp.Status == resolver.StatusTimeout ||
resp.Status == resolver.StatusError {
return fmt.Errorf(
"%w: %s returned %s: %s",
livednstest.ErrNoAnswer, nameserver,
resp.Status, resp.Error,
)
}
out = resp
return nil
},
)
return out
}
// liveQueryAllNameservers queries every authoritative nameserver
// for a hostname, retrying until a quorum of them has answered.
// Individual nameservers that stay silent are left in the result
// for the caller to account for.
func liveQueryAllNameservers(
t *testing.T,
r *resolver.Resolver,
hostname string,
) map[string]*resolver.NameserverResponse {
t.Helper()
var out map[string]*resolver.NameserverResponse
livednstest.Retry(
t,
"QueryAllNameservers("+hostname+")",
func(ctx context.Context) error {
results, err := r.QueryAllNameservers(ctx, hostname)
if err != nil {
return err
}
if len(results) == 0 {
return fmt.Errorf(
"%w: no nameservers queried for %s",
livednstest.ErrNoAnswer, hostname,
)
}
answered := answeredCount(results)
if answered < liveQuorum(len(results)) {
return fmt.Errorf(
"%w: %d of %d answered: %s",
errLiveNoQuorum, answered,
len(results), describeStatuses(results),
)
}
out = results
return nil
},
)
return out
}
// liveResolveIPs resolves a hostname that is expected to have
// addresses, retrying until at least one is returned.
func liveResolveIPs(
t *testing.T,
r *resolver.Resolver,
hostname string,
) []string {
t.Helper()
var out []string
livednstest.Retry(
t,
"ResolveIPAddresses("+hostname+")",
func(ctx context.Context) error {
ips, err := r.ResolveIPAddresses(ctx, hostname)
if err != nil {
return err
}
if len(ips) == 0 {
return fmt.Errorf(
"%w: no addresses for %s",
livednstest.ErrNoAnswer, hostname,
)
}
out = ips
return nil
},
)
return out
}
// liveResolveIPsAllowingEmpty resolves a hostname that may legitimately
// have no addresses, so the empty result is returned rather than
// retried. Used for names that must not exist; the corresponding
// QueryAllNameservers test is what proves the nameservers actively
// said NXDOMAIN rather than merely staying silent.
func liveResolveIPsAllowingEmpty(
t *testing.T,
r *resolver.Resolver,
hostname string,
) []string {
t.Helper()
var out []string
livednstest.Retry(
t,
"ResolveIPAddresses("+hostname+")",
func(ctx context.Context) error {
ips, err := r.ResolveIPAddresses(ctx, hostname)
if err != nil {
return err
}
out = ips
return nil
},
)
return out
}
// liveResolveNSIPs looks up the addresses of the nameservers named
// names, retrying until there are at least atLeast of them: a name
// whose lookup got no reply is left out of the result, not an error.
func liveResolveNSIPs(
t *testing.T,
r *resolver.Resolver,
names []string,
atLeast int,
) []string {
t.Helper()
var out []string
livednstest.Retry(
t,
"ResolveNSIPs("+strings.Join(names, ", ")+")",
func(ctx context.Context) error {
ips := r.ResolveNSIPs(ctx, names)
if len(ips) < atLeast {
return fmt.Errorf(
"%w: %d addresses, expected at least %d",
livednstest.ErrNoAnswer, len(ips), atLeast,
)
}
out = ips
return nil
},
)
return out
}
internal/resolver/resolver.go
+13
View File
@@ -67,4 +67,17 @@ func NewFromLogger(log *slog.Logger) *Resolver {
}
}
// NewFromLoggerWithClient creates a Resolver with a custom DNS
// client, useful for testing with mock DNS responses.
func NewFromLoggerWithClient(
log *slog.Logger,
client DNSClient,
) *Resolver {
return &Resolver{
log: log,
client: client,
tcp: client,
}
}
// Method implementations are in iterative.go.
internal/resolver/resolver_test.go
+228 -283
View File
@@ -2,7 +2,6 @@ package resolver_test
import (
"context"
"fmt"
"log/slog"
"net"
"os"
@@ -11,10 +10,10 @@ import (
"testing"
"time"
"github.com/miekg/dns"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"sneak.berlin/go/dnswatcher/internal/livednstest"
"sneak.berlin/go/dnswatcher/internal/resolver"
)
@@ -33,17 +32,32 @@ func newTestResolver(t *testing.T) *resolver.Resolver {
return resolver.NewFromLogger(log)
}
// findOneNSForDomain picks one authoritative nameserver to aim a
// test at. Quorum handling lives in livedns_test.go, and the live-DNS
// retry and concurrency limit in package livednstest.
func testContext(t *testing.T) context.Context {
t.Helper()
ctx, cancel := context.WithTimeout(
context.Background(), 60*time.Second,
)
t.Cleanup(cancel)
return ctx
}
func findOneNSForDomain(
t *testing.T,
r *resolver.Resolver,
ctx context.Context, //nolint:revive // test helper
domain string,
) string {
t.Helper()
return liveFindAuthoritative(t, r, domain)[0]
nameservers, err := r.FindAuthoritativeNameservers(
ctx, domain,
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
return nameservers[0]
}
// ----------------------------------------------------------------
@@ -56,7 +70,13 @@ func TestFindAuthoritativeNameservers_ValidDomain(
t.Parallel()
r := newTestResolver(t)
nameservers := liveFindAuthoritative(t, r, "google.com")
ctx := testContext(t)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
hasGoogleNS := false
@@ -79,10 +99,13 @@ func TestFindAuthoritativeNameservers_Subdomain(
t.Parallel()
r := newTestResolver(t)
fromHost := liveFindAuthoritative(t, r, "www.google.com")
fromZone := liveFindAuthoritative(t, r, "google.com")
ctx := testContext(t)
assert.Equal(t, fromZone, fromHost)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "www.google.com",
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
}
func TestFindAuthoritativeNameservers_ReturnsSorted(
@@ -91,7 +114,12 @@ func TestFindAuthoritativeNameservers_ReturnsSorted(
t.Parallel()
r := newTestResolver(t)
nameservers := liveFindAuthoritative(t, r, "google.com")
ctx := testContext(t)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
assert.True(
t,
@@ -106,8 +134,17 @@ func TestFindAuthoritativeNameservers_Deterministic(
t.Parallel()
r := newTestResolver(t)
first := liveFindAuthoritative(t, r, "google.com")
second := liveFindAuthoritative(t, r, "google.com")
ctx := testContext(t)
first, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
second, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
assert.Equal(t, first, second)
}
@@ -118,8 +155,17 @@ func TestFindAuthoritativeNameservers_TrailingDot(
t.Parallel()
r := newTestResolver(t)
ns1 := liveFindAuthoritative(t, r, "google.com")
ns2 := liveFindAuthoritative(t, r, "google.com.")
ctx := testContext(t)
ns1, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
ns2, err := r.FindAuthoritativeNameservers(
ctx, "google.com.",
)
require.NoError(t, err)
assert.Equal(t, ns1, ns2)
}
@@ -130,7 +176,13 @@ func TestFindAuthoritativeNameservers_CloudflareDomain(
t.Parallel()
r := newTestResolver(t)
nameservers := liveFindAuthoritative(t, r, "cloudflare.com")
ctx := testContext(t)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "cloudflare.com",
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
for _, ns := range nameservers {
assert.True(t, strings.HasSuffix(ns, "."),
@@ -139,28 +191,6 @@ func TestFindAuthoritativeNameservers_CloudflareDomain(
}
}
// TestResolveNSIPs_EveryNameserver looks up the addresses of two of
// google.com's nameservers together, as the walk does when a referral
// names a zone's nameservers without their addresses, and compares them
// with each looked up alone. Together they must give the addresses of
// both, not only of the first that resolves, so that when one gives no
// usable reply the walk goes on to the other.
func TestResolveNSIPs_EveryNameserver(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
names := []string{"ns3.google.com.", "ns4.google.com."}
want := make([]string, 0, len(names))
for _, name := range names {
want = append(want, liveResolveNSIPs(t, r, []string{name}, 1)...)
}
got := liveResolveNSIPs(t, r, names, len(want))
assert.ElementsMatch(t, want, got)
}
// ----------------------------------------------------------------
// QueryNameserver tests
// ----------------------------------------------------------------
@@ -169,9 +199,13 @@ func TestQueryNameserver_BasicA(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
resp := liveQueryNameserver(t, r, ns, "www.google.com")
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "www.google.com",
)
require.NoError(t, err)
require.NotNil(t, resp)
assert.Equal(t, resolver.StatusOK, resp.Status)
@@ -188,8 +222,13 @@ func TestQueryNameserver_AAAA(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "cloudflare.com")
resp := liveQueryNameserver(t, r, ns, "cloudflare.com")
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
resp, err := r.QueryNameserver(
ctx, ns, "cloudflare.com",
)
require.NoError(t, err)
aaaaRecords := resp.Records["AAAA"]
require.NotEmpty(t, aaaaRecords,
@@ -208,8 +247,13 @@ func TestQueryNameserver_MX(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
resp := liveQueryNameserver(t, r, ns, "google.com")
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
mxRecords := resp.Records["MX"]
require.NotEmpty(t, mxRecords,
@@ -221,8 +265,13 @@ func TestQueryNameserver_TXT(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
resp := liveQueryNameserver(t, r, ns, "google.com")
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
txtRecords := resp.Records["TXT"]
require.NotEmpty(t, txtRecords,
@@ -248,59 +297,29 @@ func TestQueryNameserver_NXDomain(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
resp := liveQueryNameserver(
t, r, ns, "this-surely-does-not-exist-xyz.google.com",
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
assert.Equal(t, resolver.StatusNXDomain, resp.Status)
}
// TestQueryNameserver_Refused asks a google.com nameserver about
// cloudflare.com, a zone it does not serve, which it refuses. Refusing
// is a failure to answer, not an answer with no records.
func TestQueryNameserver_Refused(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
var resp *resolver.NameserverResponse
livednstest.Retry(
t,
"QueryNameserver("+ns+", cloudflare.com)",
func(ctx context.Context) error {
var err error
resp, err = r.QueryNameserver(ctx, ns, "cloudflare.com")
if err != nil {
return err
}
// A timeout or a network error is no reply at all.
if resp.Status == resolver.StatusTimeout ||
strings.HasPrefix(resp.Error, "network error") {
return fmt.Errorf(
"%w: %s: %s",
livednstest.ErrNoAnswer, ns, resp.Error,
)
}
return nil
},
)
assert.Equal(t, resolver.StatusError, resp.Status)
assert.Equal(t, "server returned REFUSED", resp.Error)
}
func TestQueryNameserver_RecordsSorted(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
resp := liveQueryNameserver(t, r, ns, "google.com")
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
for recordType, values := range resp.Records {
assert.True(
@@ -317,8 +336,13 @@ func TestQueryNameserver_ResponseIncludesNameserver(
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "cloudflare.com")
resp := liveQueryNameserver(t, r, ns, "cloudflare.com")
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
resp, err := r.QueryNameserver(
ctx, ns, "cloudflare.com",
)
require.NoError(t, err)
assert.Equal(t, ns, resp.Nameserver)
}
@@ -329,10 +353,14 @@ func TestQueryNameserver_EmptyRecordsOnNXDomain(
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
resp := liveQueryNameserver(
t, r, ns, "this-surely-does-not-exist-xyz.google.com",
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
totalRecords := 0
for _, values := range resp.Records {
@@ -346,9 +374,18 @@ func TestQueryNameserver_TrailingDotHandling(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ns := findOneNSForDomain(t, r, "google.com")
resp1 := liveQueryNameserver(t, r, ns, "google.com")
resp2 := liveQueryNameserver(t, r, ns, "google.com.")
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp1, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
resp2, err := r.QueryNameserver(
ctx, ns, "google.com.",
)
require.NoError(t, err)
assert.Equal(t, resp1.Status, resp2.Status)
}
@@ -361,9 +398,15 @@ func TestQueryAllNameservers_ReturnsAllNS(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
results := liveQueryAllNameservers(t, r, "google.com")
ctx := testContext(t)
assert.GreaterOrEqual(t, len(results), minNameservers)
results, err := r.QueryAllNameservers(
ctx, "google.com",
)
require.NoError(t, err)
require.NotEmpty(t, results)
assert.GreaterOrEqual(t, len(results), 2)
for ns, resp := range results {
assert.Equal(t, ns, resp.Nameserver)
@@ -373,57 +416,19 @@ func TestQueryAllNameservers_ReturnsAllNS(t *testing.T) {
func TestQueryAllNameservers_AllReturnOK(t *testing.T) {
t.Parallel()
// The last two names are in zones other than their last two
// labels: google.co.uk, under the two-label suffix co.uk, and
// compute-1.amazonaws.com, which amazonaws.com delegates to other
// servers and which has a host name for each of its addresses.
// Servers above a name's zone only refer onward, which gives
// nodata, so ok shows the name was asked at its own zone's
// servers.
hostnames := []string{
"google.com",
"www.google.co.uk",
"ec2-3-80-0-1.compute-1.amazonaws.com",
}
for _, hostname := range hostnames {
t.Run(hostname, func(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
results := liveQueryAllNameservers(t, r, hostname)
ctx := testContext(t)
// A quorum, not unanimity: one authoritative server
// being slow or rate-limiting us is a property of the
// live internet, not a resolver defect.
assert.GreaterOrEqual(
t,
countStatus(results, resolver.StatusOK),
liveQuorum(len(results)),
"a quorum of nameservers should answer OK: %s",
describeStatuses(results),
results, err := r.QueryAllNameservers(
ctx, "google.com",
)
require.NoError(t, err)
// Quorum tolerates SILENCE only. Every individual
// result must be either the expected answer or a
// non-answer: ok, timeout or error, and nothing else.
// Stated as a closed allowlist so that a wrong answer
// no one thought to ban — nxdomain and nodata today,
// any status added later — fails here rather than
// sliding through under the quorum.
assert.Empty(
t,
unsanctionedStatuses(
results,
resolver.StatusOK,
resolver.StatusTimeout,
resolver.StatusError,
),
"every nameserver must answer OK or not answer "+
"at all: %s",
describeStatuses(results),
for ns, resp := range results {
assert.Equal(
t, resolver.StatusOK, resp.Status,
"NS %s should return OK", ns,
)
})
}
}
@@ -433,35 +438,21 @@ func TestQueryAllNameservers_NXDomainFromAllNS(
t.Parallel()
r := newTestResolver(t)
results := liveQueryAllNameservers(
t, r, "this-surely-does-not-exist-xyz.google.com",
)
ctx := testContext(t)
assert.GreaterOrEqual(
t,
countStatus(results, resolver.StatusNXDomain),
liveQuorum(len(results)),
"a quorum of nameservers should report NXDOMAIN: %s",
describeStatuses(results),
results, err := r.QueryAllNameservers(
ctx,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
// Silence is tolerated; any actual answer other than NXDOMAIN
// is not. Closed allowlist for the same reason as above: a
// server answering `ok` or `nodata` for a name that must not
// exist is a wrong answer, not a slow one.
assert.Empty(
t,
unsanctionedStatuses(
results,
resolver.StatusNXDomain,
resolver.StatusTimeout,
resolver.StatusError,
),
"every nameserver must report NXDOMAIN or not answer "+
"at all: %s",
describeStatuses(results),
for ns, resp := range results {
assert.Equal(
t, resolver.StatusNXDomain, resp.Status,
"NS %s should return nxdomain", ns,
)
}
}
// ----------------------------------------------------------------
// LookupNS tests
@@ -471,7 +462,11 @@ func TestLookupNS_ValidDomain(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
nameservers := liveLookupNS(t, r, "google.com")
ctx := testContext(t)
nameservers, err := r.LookupNS(ctx, "google.com")
require.NoError(t, err)
require.NotEmpty(t, nameservers)
for _, ns := range nameservers {
assert.True(t, strings.HasSuffix(ns, "."),
@@ -484,7 +479,10 @@ func TestLookupNS_Sorted(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
nameservers := liveLookupNS(t, r, "google.com")
ctx := testContext(t)
nameservers, err := r.LookupNS(ctx, "google.com")
require.NoError(t, err)
assert.True(t, sort.StringsAreSorted(nameservers))
}
@@ -493,8 +491,15 @@ func TestLookupNS_MatchesFindAuthoritative(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
fromLookup := liveLookupNS(t, r, "google.com")
fromFind := liveFindAuthoritative(t, r, "google.com")
ctx := testContext(t)
fromLookup, err := r.LookupNS(ctx, "google.com")
require.NoError(t, err)
fromFind, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
assert.Equal(t, fromFind, fromLookup)
}
@@ -507,7 +512,11 @@ func TestResolveIPAddresses_ReturnsIPs(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ips := liveResolveIPs(t, r, "google.com")
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(ctx, "google.com")
require.NoError(t, err)
require.NotEmpty(t, ips)
for _, ip := range ips {
parsed := net.ParseIP(ip)
@@ -521,7 +530,10 @@ func TestResolveIPAddresses_Deduplicated(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ips := liveResolveIPs(t, r, "google.com")
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(ctx, "google.com")
require.NoError(t, err)
seen := make(map[string]bool)
@@ -535,7 +547,10 @@ func TestResolveIPAddresses_Sorted(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ips := liveResolveIPs(t, r, "google.com")
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(ctx, "google.com")
require.NoError(t, err)
assert.True(t, sort.StringsAreSorted(ips))
}
@@ -546,10 +561,13 @@ func TestResolveIPAddresses_NXDomainReturnsEmpty(
t.Parallel()
r := newTestResolver(t)
ips := liveResolveIPsAllowingEmpty(
t, r, "this-surely-does-not-exist-xyz.google.com",
)
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(
ctx,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
assert.Empty(t, ips)
}
@@ -557,9 +575,11 @@ func TestResolveIPAddresses_CloudflareDomain(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ips := liveResolveIPs(t, r, "cloudflare.com")
ctx := testContext(t)
assert.NotEmpty(t, ips)
ips, err := r.ResolveIPAddresses(ctx, "cloudflare.com")
require.NoError(t, err)
require.NotEmpty(t, ips)
}
// ----------------------------------------------------------------
@@ -603,29 +623,6 @@ func TestQueryAllNameservers_ContextCanceled(t *testing.T) {
assert.Error(t, err)
}
// TestQueryEachNS_CanceledDuringQuery cancels the context while a
// nameserver is being queried, as shutdown does. A lookup cut short
// says nothing about the nameserver, so it must return an error, not a
// failed response for it.
func TestQueryEachNS_CanceledDuringQuery(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx, cancel := context.WithCancel(context.Background())
t.Cleanup(cancel)
// Finding the nameserver's address alone starts at the root
// servers and takes several round trips, so a cancel a few
// milliseconds in lands during the query.
time.AfterFunc(5*time.Millisecond, cancel)
results, err := r.QueryEachNS(
ctx, []string{"ns1.google.com."}, "google.com",
)
require.ErrorIs(t, err, resolver.ErrContextCanceled)
assert.Nil(t, results)
}
// ----------------------------------------------------------------
// Timeout tests
// ----------------------------------------------------------------
@@ -633,18 +630,21 @@ func TestQueryEachNS_CanceledDuringQuery(t *testing.T) {
func TestQueryNameserverIP_Timeout(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
log := slog.New(slog.NewTextHandler(
os.Stderr,
&slog.HandlerOptions{Level: slog.LevelDebug},
))
r := resolver.NewFromLoggerWithClient(
log, &timeoutClient{},
)
// Nothing answers at 192.0.2.1, a documentation address. The
// resolver tries each query twice, and the first try gives up
// after two seconds. A deadline that ends during the first try
// makes the status vary from run to run between error and
// timeout, so the deadline must outlast the first try.
ctx, cancel := context.WithTimeout(
context.Background(), 3*time.Second,
context.Background(), 10*time.Second,
)
t.Cleanup(cancel)
// Query any IP — the client always returns a timeout error.
resp, err := r.QueryNameserverIP(
ctx, "unreachable.test.", "192.0.2.1",
"example.com",
@@ -655,81 +655,26 @@ func TestQueryNameserverIP_Timeout(t *testing.T) {
assert.NotEmpty(t, resp.Error)
}
// TestCollectIPs_NoNameserverAnswered takes the response of a
// nameserver at 192.0.2.1, where nothing answers, as
// TestQueryNameserverIP_Timeout does. Addresses collected from
// nameservers that all failed to answer are an error, not none.
func TestCollectIPs_NoNameserverAnswered(t *testing.T) {
t.Parallel()
// timeoutClient simulates DNS timeout errors for testing.
type timeoutClient struct{}
r := newTestResolver(t)
// The deadline outlasts the first try, as in
// TestQueryNameserverIP_Timeout.
ctx, cancel := context.WithTimeout(
context.Background(), 3*time.Second,
)
t.Cleanup(cancel)
resp, err := r.QueryNameserverIP(
ctx, "unreachable.test.", "192.0.2.1",
"example.com",
)
require.NoError(t, err)
ips, _, err := resolver.CollectIPs(
map[string]*resolver.NameserverResponse{resp.Nameserver: resp},
)
require.ErrorIs(t, err, resolver.ErrNoNameserverAnswered)
assert.Empty(t, ips)
func (c *timeoutClient) ExchangeContext(
_ context.Context,
_ *dns.Msg,
_ string,
) (*dns.Msg, time.Duration, error) {
return nil, 0, &net.OpError{
Op: "read",
Net: "udp",
Err: &timeoutError{},
}
}
// TestCollectIPs_ReferralIsNoAnswer asks a root server about
// example.com, which the root zone does not hold, so it only refers the
// query to the com servers. That reply is no answer, as is a parent
// zone's when every server of the name's own zone failed.
func TestCollectIPs_ReferralIsNoAnswer(t *testing.T) {
t.Parallel()
type timeoutError struct{}
r := newTestResolver(t)
var resp *resolver.NameserverResponse
livednstest.Retry(
t,
"QueryNameserverIP(a.root-servers.net, example.com)",
func(ctx context.Context) error {
var err error
resp, err = r.QueryNameserverIP(
ctx, "a.root-servers.net.", "198.41.0.4",
"example.com",
)
if err != nil {
return err
}
// A timeout or a network error is no reply at all.
if resp.Status == resolver.StatusTimeout ||
strings.HasPrefix(resp.Error, "network error") {
return fmt.Errorf(
"%w: %s", livednstest.ErrNoAnswer, resp.Error,
)
}
return nil
},
)
assert.Equal(t, resolver.StatusError, resp.Status)
assert.Equal(t, "server returned a referral", resp.Error)
ips, _, err := resolver.CollectIPs(
map[string]*resolver.NameserverResponse{resp.Nameserver: resp},
)
require.ErrorIs(t, err, resolver.ErrNoNameserverAnswered)
assert.Empty(t, ips)
}
func (e *timeoutError) Error() string { return "i/o timeout" }
func (e *timeoutError) Timeout() bool { return true }
func (e *timeoutError) Temporary() bool { return true }
func TestResolveIPAddresses_ContextCanceled(t *testing.T) {
t.Parallel()
internal/server/export_test.go
-38
View File
@@ -1,38 +0,0 @@
package server
import (
"net/http"
"time"
"github.com/go-chi/chi/v5"
)
// RequestTimeout exports the handler execution budget applied by
// chimw.Timeout in SetupRoutes, so tests can assert the relationship
// between it and the server's WriteTimeout.
const RequestTimeout time.Duration = requestTimeout
// SetListenPort overrides the port Run binds. A test uses it to hand
// Run an unbindable port so ListenAndServe fails immediately and Run
// returns after storing its http.Server.
func SetListenPort(s *Server, port int) {
s.port = port
}
// HTTPServerOf returns the http.Server that Run built and stored, so a
// test can inspect the timeouts the running server actually carries.
func HTTPServerOf(s *Server) *http.Server {
return s.httpServer
}
// EnableSentry runs the Sentry setup that the start hook runs, without
// starting the HTTP server.
func EnableSentry(s *Server) error {
return s.enableSentry()
}
// RouterOf returns the router SetupRoutes built, so a test can add a
// route that panics.
func RouterOf(s *Server) *chi.Mux {
return s.router
}
internal/server/routes.go
+14 -38
View File
@@ -4,7 +4,6 @@ import (
"net/http"
"time"
sentryhttp "github.com/getsentry/sentry-go/http"
"github.com/go-chi/chi/v5"
chimw "github.com/go-chi/chi/v5/middleware"
"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -22,32 +21,15 @@ func (s *Server) SetupRoutes() {
// Global middleware
s.router.Use(chimw.Recoverer)
s.router.Use(chimw.RequestID)
s.router.Use(s.mw.SecurityHeaders())
s.router.Use(s.mw.Logging())
s.router.Use(s.mw.CORS())
s.router.Use(chimw.Timeout(requestTimeout))
// Report panics in handlers to Sentry when DNSWATCHER_SENTRY_DSN is
// set. Repanic passes each panic on to chimw.Recoverer above, which
// still answers the request.
if s.sentryEnabled {
sentryHandler := sentryhttp.New(sentryhttp.Options{
Repanic: true,
})
s.router.Use(sentryHandler.Handle)
}
// Public, unauthenticated, read-only routes, the only ones
// REPO_POLICIES.md allows wildcard CORS on. CORS is middleware of
// this whole router, not of a Group, so that it also answers
// OPTIONS preflight requests, which no route here registers.
public := chi.NewRouter()
public.Use(s.mw.CORS())
// Dashboard (read-only web UI)
public.Get("/", s.handlers.HandleDashboard())
s.router.Get("/", s.handlers.HandleDashboard())
// Static assets (embedded CSS/JS)
public.Mount(
s.router.Mount(
"/s",
http.StripPrefix(
"/s",
@@ -56,33 +38,27 @@ func (s *Server) SetupRoutes() {
)
// Health check (standard well-known path)
public.Get(
s.router.Get(
"/.well-known/healthcheck",
s.handlers.HandleHealthCheck(),
)
// Legacy health check (keep for backward compatibility)
public.Get("/health", s.handlers.HandleHealthCheck())
s.router.Get("/health", s.handlers.HandleHealthCheck())
// API v1 routes
public.Route("/api/v1", func(r chi.Router) {
s.router.Route("/api/v1", func(r chi.Router) {
r.Get("/status", s.handlers.HandleStatus())
})
s.router.Mount("/", public)
// Metrics endpoint (optional, with basic auth) and no CORS: a
// Prometheus scraper is not a browser. It is mounted rather than
// added with Get so that every method on /metrics, OPTIONS
// included, ends here instead of falling through to the public
// router and its CORS. The rate limit comes before Basic Auth, so
// failed logins count against it and a request over the limit
// never reaches the password check.
// Metrics endpoint (optional, with basic auth)
if s.params.Config.MetricsUsername != "" {
metrics := chi.NewRouter()
metrics.Use(s.mw.MetricsRateLimit())
metrics.Use(s.mw.MetricsAuth())
metrics.Get("/", promhttp.Handler().ServeHTTP)
s.router.Mount("/metrics", metrics)
s.router.Group(func(r chi.Router) {
r.Use(s.mw.MetricsAuth())
r.Get(
"/metrics",
promhttp.Handler().ServeHTTP,
)
})
}
}
internal/server/routes_test.go
-290
View File
@@ -1,290 +0,0 @@
package server_test
import (
"net/http"
"net/http/httptest"
"testing"
"github.com/spf13/viper"
"sneak.berlin/go/dnswatcher/internal/server"
)
// Credentials for /metrics, which is only routed when a username is set.
const (
metricsUsername = "scraper"
metricsPassword = "scrape-secret"
)
// The tests below set env vars and touch viper global state, so like
// the config tests they cannot use t.Parallel.
// routedServer builds the server with its routes set up, ready to serve
// test requests. The caller must first configure viper.
func routedServer(t *testing.T) *server.Server {
t.Helper()
srv := buildServer(t)
srv.SetupRoutes()
return srv
}
// crossOriginRequest builds a request as a browser sends it from a page
// on another site.
func crossOriginRequest(
t *testing.T,
method string,
target string,
) *http.Request {
t.Helper()
req := httptest.NewRequestWithContext(t.Context(), method, target, nil)
req.Header.Set("Origin", "https://example.net")
return req
}
// preflightRequest builds the OPTIONS request a browser sends before a
// cross-origin request with the given method and request headers.
func preflightRequest(
t *testing.T,
target string,
method string,
headers string,
) *http.Request {
t.Helper()
req := crossOriginRequest(t, http.MethodOptions, target)
req.Header.Set("Access-Control-Request-Method", method)
if headers != "" {
req.Header.Set("Access-Control-Request-Headers", headers)
}
return req
}
func serve(
srv *server.Server,
req *http.Request,
) *httptest.ResponseRecorder {
rec := httptest.NewRecorder()
srv.ServeHTTP(rec, req)
return rec
}
// publicPaths returns one path on each public route.
func publicPaths() []string {
return []string{
"/",
"/s/css/tailwind.min.css",
"/api/v1/status",
"/health",
"/.well-known/healthcheck",
}
}
// TestPublicRoutesAllowAnyOrigin checks that every public route answers
// a cross-origin GET with the CORS wildcard.
func TestPublicRoutesAllowAnyOrigin(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
srv := routedServer(t)
for _, path := range publicPaths() {
rec := serve(srv, crossOriginRequest(t, http.MethodGet, path))
if rec.Code != http.StatusOK {
t.Errorf("GET %s: status = %d, want 200", path, rec.Code)
}
got := rec.Header().Get("Access-Control-Allow-Origin")
if got != "*" {
t.Errorf(
"GET %s: Access-Control-Allow-Origin = %q, want %q",
path, got, "*",
)
}
}
}
// TestMetricsHasNoCORS checks that no request to the Basic-Auth
// protected /metrics, preflight included, gets a CORS header.
func TestMetricsHasNoCORS(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
srv := routedServer(t)
authenticated := crossOriginRequest(t, http.MethodGet, "/metrics")
authenticated.SetBasicAuth(metricsUsername, metricsPassword)
tests := []struct {
name string
req *http.Request
wantStatus int
}{
{
"authenticated GET",
authenticated,
http.StatusOK,
},
{
"unauthenticated GET",
crossOriginRequest(t, http.MethodGet, "/metrics"),
http.StatusUnauthorized,
},
{
"preflight",
preflightRequest(t, "/metrics", http.MethodGet, ""),
http.StatusUnauthorized,
},
}
for _, tt := range tests {
rec := serve(srv, tt.req)
if rec.Code != tt.wantStatus {
t.Errorf(
"%s: status = %d, want %d",
tt.name, rec.Code, tt.wantStatus,
)
}
got := rec.Header().Get("Access-Control-Allow-Origin")
if got != "" {
t.Errorf(
"%s: Access-Control-Allow-Origin = %q, want none",
tt.name, got,
)
}
}
}
// TestPreflightAllowsOnlyWhatPublicRoutesServe checks what each public
// route agrees to in a CORS preflight: GET, but not POST, PUT or
// DELETE, which no route serves, and not the Authorization or
// X-CSRF-Token headers, which no public route reads. It checks every
// public route because one added with Get, such as /health, answers a
// preflight only while CORS is middleware of a whole router; in a
// Group, chi would answer it with 405 and no CORS headers.
func TestPreflightAllowsOnlyWhatPublicRoutesServe(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
srv := routedServer(t)
tests := []struct {
method string
headers string
allowed bool
}{
{http.MethodGet, "", true},
{http.MethodGet, "Content-Type", true},
{http.MethodPost, "", false},
{http.MethodPut, "", false},
{http.MethodDelete, "", false},
{http.MethodGet, "Authorization", false},
{http.MethodGet, "X-CSRF-Token", false},
}
for _, path := range publicPaths() {
for _, tt := range tests {
rec := serve(srv, preflightRequest(
t, path, tt.method, tt.headers,
))
want := ""
if tt.allowed {
want = tt.method
}
got := rec.Header().Get("Access-Control-Allow-Methods")
if got != want {
t.Errorf(
"preflight to %s for %s with headers %q: "+
"Access-Control-Allow-Methods = %q, want %q",
path, tt.method, tt.headers, got, want,
)
}
}
}
}
// metricsRequest builds a GET for /metrics from remoteAddr that logs
// in with the given password.
func metricsRequest(
t *testing.T,
remoteAddr string,
password string,
) *http.Request {
t.Helper()
req := httptest.NewRequestWithContext(
t.Context(), http.MethodGet, "/metrics", nil,
)
req.RemoteAddr = remoteAddr
req.SetBasicAuth(metricsUsername, password)
return req
}
// TestMetricsRateLimitComesBeforeAuth checks that failed logins to
// /metrics count against the rate limit; that once an address is over
// it, even the right password gets 429, with the same body as a wrong
// one; and that another address still gets in.
func TestMetricsRateLimitComesBeforeAuth(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
const (
guesser = "198.51.100.1:4000"
other = "198.51.100.2:4000"
// Far more guesses than the rate limit allows.
maxGuesses = 1000
)
srv := routedServer(t)
var guess *httptest.ResponseRecorder
for range maxGuesses {
guess = serve(srv, metricsRequest(t, guesser, "wrong"))
if guess.Code != http.StatusUnauthorized {
break
}
}
if guess.Code != http.StatusTooManyRequests {
t.Fatalf("wrong password: status = %d, want 429", guess.Code)
}
right := serve(srv, metricsRequest(t, guesser, metricsPassword))
if right.Code != http.StatusTooManyRequests {
t.Errorf("right password: status = %d, want 429", right.Code)
}
if right.Body.String() != guess.Body.String() {
t.Errorf(
"429 body with right password = %q, with wrong one = %q",
right.Body.String(), guess.Body.String(),
)
}
rec := serve(srv, metricsRequest(t, other, metricsPassword))
if rec.Code != http.StatusOK {
t.Errorf("another address: status = %d, want 200", rec.Code)
}
}
internal/server/sentry_test.go
-190
View File
@@ -1,190 +0,0 @@
package server_test
import (
"io"
"net/http"
"net/http/httptest"
"net/url"
"strings"
"sync"
"testing"
"time"
"github.com/getsentry/sentry-go"
"github.com/spf13/viper"
"go.uber.org/fx"
"sneak.berlin/go/dnswatcher/internal/server"
)
// The tests below set env vars and touch the global state of viper and
// of Sentry, so they cannot use t.Parallel.
// standInDelay is how long the Sentry stand-in takes to answer. It
// records a report only then, so a report that Shutdown did not wait
// for has not been recorded yet when Shutdown returns.
const standInDelay = 100 * time.Millisecond
// sentryStandIn is a local HTTP server in place of Sentry's, so that
// nothing a test reports leaves the host. It keeps the body of every
// request it receives.
type sentryStandIn struct {
server *httptest.Server
mu sync.Mutex
bodies []string
}
func newSentryStandIn(t *testing.T) *sentryStandIn {
t.Helper()
standIn := &sentryStandIn{}
standIn.server = httptest.NewServer(http.HandlerFunc(
func(_ http.ResponseWriter, r *http.Request) {
body, err := io.ReadAll(r.Body)
if err != nil {
t.Errorf("reading request to the Sentry stand-in: %v", err)
}
time.Sleep(standInDelay)
standIn.mu.Lock()
defer standIn.mu.Unlock()
standIn.bodies = append(standIn.bodies, string(body))
},
))
t.Cleanup(standIn.server.Close)
return standIn
}
// dsn returns a DSN that points Sentry at the stand-in.
func (s *sentryStandIn) dsn(t *testing.T) string {
t.Helper()
dsn, err := url.Parse(s.server.URL)
if err != nil {
t.Fatalf("parsing the stand-in URL: %v", err)
}
dsn.User = url.User("public-key")
dsn.Path = "/1"
return dsn.String()
}
// received reports whether a request to the stand-in contained text.
func (s *sentryStandIn) received(text string) bool {
s.mu.Lock()
defer s.mu.Unlock()
for _, body := range s.bodies {
if strings.Contains(body, text) {
return true
}
}
return false
}
func TestSentryUnsetDoesNothing(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_SENTRY_DSN", "")
srv := buildServer(t)
err := server.EnableSentry(srv)
if err != nil {
t.Fatalf("Sentry setup with no DSN: %v", err)
}
if sentry.CurrentHub().Client() != nil {
t.Error("Sentry was set up with no DSN configured")
}
}
// TestSentryReportsHandlerPanic checks that with a valid DSN a panic in
// a handler is reported to Sentry, still reaches chimw.Recoverer, and
// has been sent by the time Shutdown returns, and that nothing else is
// sent to Sentry.
func TestSentryReportsHandlerPanic(t *testing.T) {
standIn := newSentryStandIn(t)
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_SENTRY_DSN", standIn.dsn(t))
srv := buildServer(t)
err := server.EnableSentry(srv)
if err != nil {
t.Fatalf("Sentry setup with a valid DSN: %v", err)
}
// Sentry's client is global: close it so later tests find none.
t.Cleanup(func() {
sentry.CurrentHub().Client().Close()
sentry.CurrentHub().BindClient(nil)
})
const panicMessage = "handler panic in the Sentry test"
srv.SetupRoutes()
server.RouterOf(srv).Get(
"/panic",
func(http.ResponseWriter, *http.Request) {
panic(panicMessage)
},
)
// An ordinary request first: with client reports on, Sentry would
// add a count of its dropped transaction to the panic report.
serve(srv, httptest.NewRequestWithContext(
t.Context(), http.MethodGet, "/.well-known/healthcheck", nil,
))
rec := serve(srv, httptest.NewRequestWithContext(
t.Context(), http.MethodGet, "/panic", nil,
))
if rec.Code != http.StatusInternalServerError {
t.Errorf(
"status %d, want %d from the recoverer",
rec.Code, http.StatusInternalServerError,
)
}
err = srv.Shutdown(t.Context())
if err != nil {
t.Fatalf("Shutdown: %v", err)
}
if !standIn.received(panicMessage) {
t.Error("the panic had not been sent to Sentry when Shutdown returned")
}
if standIn.received("client_report") {
t.Error("Sentry was sent a client report, not only the panic")
}
}
func TestSentryInvalidDSNStopsStartup(t *testing.T) {
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
t.Setenv("DNSWATCHER_DATA_DIR", t.TempDir())
// Sentry cannot parse this: it has no public key before the host.
t.Setenv("DNSWATCHER_SENTRY_DSN", "https://sentry.test/1")
app := newServerApp(fx.Invoke(func(*server.Server) {}))
err := app.Start(t.Context())
if err == nil {
_ = app.Stop(t.Context())
t.Fatal("startup succeeded with an invalid DSN")
}
if !strings.Contains(err.Error(), "invalid DNSWATCHER_SENTRY_DSN") {
t.Errorf("startup error does not name the setting: %v", err)
}
}
internal/server/server.go
+8 -122
View File
@@ -9,7 +9,6 @@ import (
"net/http"
"time"
"github.com/getsentry/sentry-go"
"github.com/go-chi/chi/v5"
"go.uber.org/fx"
@@ -34,62 +33,13 @@ type Params struct {
// shutdownTimeout is how long to wait for graceful shutdown.
const shutdownTimeout = 30 * time.Second
// sentryFlushTimeout is how long shutdown waits for Sentry to send the
// error reports it still holds.
const sentryFlushTimeout = 2 * time.Second
// Socket-level timeouts for the HTTP server.
//
// These bound time spent on the connection itself and are a distinct
// control from the per-request handler budget enforced by
// chimw.Timeout(requestTimeout) in routes.go: that one cancels the
// request context after requestTimeout but never touches the socket,
// so without the values below a peer can hold a connection open
// forever (slowloris, unreaped keep-alives).
//
// The one hard constraint between the two controls is
// writeTimeout > requestTimeout. net/http arms the write deadline
// once the request headers have been read, so on a plaintext
// connection it covers handler execution AND the response flush. If
// writeTimeout were <= requestTimeout the server would sever the
// connection before a handler that legitimately consumed its full
// budget could emit anything, making the 60s budget unreachable in
// practice. The margin between them is the response-flush allowance.
//
// The only clients of this service are browsers loading the dashboard
// and a Prometheus scraper; the values are sized for those.
const (
// readHeaderTimeout is the max duration for reading request
// headers.
readHeaderTimeout = 10 * time.Second
// readTimeout bounds reading the entire request, headers plus
// body. Every route here is a GET with no body, so this only
// ever needs to cover headers; the extra 5s over
// readHeaderTimeout is slack, not a real allowance, and keeps a
// body dribbled one byte at a time from holding the read side
// open indefinitely.
readTimeout = 15 * time.Second
// writeTimeout must exceed the requestTimeout handler budget
// (60s) per the note above. The 15s difference is the allowance
// for flushing a completed response to a slow client.
writeTimeout = 75 * time.Second
// idleTimeout reaps keep-alive connections between requests. It
// is deliberately longer than the common Prometheus scrape
// intervals (15s/30s/60s) so the scraper reuses its connection
// rather than reconnecting every cycle, while a browser tab
// left open on the dashboard stops occupying a connection
// within two minutes of going quiet.
idleTimeout = 120 * time.Second
)
// readHeaderTimeout is the max duration for reading request headers.
const readHeaderTimeout = 10 * time.Second
// Server is the HTTP server.
type Server struct {
startupTime time.Time
port int
sentryEnabled bool
log *slog.Logger
router *chi.Mux
httpServer *http.Server
@@ -114,12 +64,6 @@ func New(
lifecycle.Append(fx.Hook{
OnStart: func(_ context.Context) error {
srv.startupTime = time.Now()
err := srv.enableSentry()
if err != nil {
return err
}
go srv.Run()
return nil
@@ -132,29 +76,16 @@ func New(
return srv, nil
}
// newHTTPServer builds the listening http.Server with every
// socket-level timeout set. All four are set deliberately: a zero
// value in net/http means "no limit", not "some default".
func newHTTPServer(
listenAddr string,
handler http.Handler,
) *http.Server {
return &http.Server{
Addr: listenAddr,
Handler: handler,
ReadTimeout: readTimeout,
ReadHeaderTimeout: readHeaderTimeout,
WriteTimeout: writeTimeout,
IdleTimeout: idleTimeout,
}
}
// Run starts the HTTP server.
func (s *Server) Run() {
s.SetupRoutes()
listenAddr := fmt.Sprintf(":%d", s.port)
s.httpServer = newHTTPServer(listenAddr, s)
s.httpServer = &http.Server{
Addr: listenAddr,
Handler: s,
ReadHeaderTimeout: readHeaderTimeout,
}
s.log.Info("http server starting", "addr", listenAddr)
@@ -164,11 +95,8 @@ func (s *Server) Run() {
}
}
// Shutdown gracefully shuts down the server, then sends the error
// reports Sentry still holds.
// Shutdown gracefully shuts down the server.
func (s *Server) Shutdown(ctx context.Context) error {
defer s.flushSentry()
if s.httpServer == nil {
return nil
}
@@ -199,45 +127,3 @@ func (s *Server) ServeHTTP(
) {
s.router.ServeHTTP(writer, request)
}
// enableSentry turns on Sentry error reporting when
// DNSWATCHER_SENTRY_DSN is set, and does nothing when it is not. A DSN
// that Sentry cannot parse is an error, so that startup stops instead
// of running without the error reporting the operator asked for.
func (s *Server) enableSentry() error {
if s.params.Config.SentryDSN == "" {
return nil
}
err := sentry.Init(sentry.ClientOptions{
Dsn: s.params.Config.SentryDSN,
Release: s.params.Globals.Appname + "-" + s.params.Globals.Version,
// Use the transport that queues each report as it is made. With
// the default one, Flush can return before sending a report made
// just before it, such as one from the last request at shutdown.
DisableTelemetryBuffer: true,
// Send panic reports only, not Sentry's counts of what it dropped,
// such as the transaction it starts for every request.
DisableClientReports: true,
})
if err != nil {
return fmt.Errorf("invalid DNSWATCHER_SENTRY_DSN: %w", err)
}
s.log.Info("sentry error reporting activated")
s.sentryEnabled = true
return nil
}
// flushSentry sends the error reports Sentry still holds, waiting at
// most sentryFlushTimeout.
func (s *Server) flushSentry() {
if !s.sentryEnabled {
return
}
if !sentry.Flush(sentryFlushTimeout) {
s.log.Warn("sentry flush timed out; some error reports were not sent")
}
}
internal/server/server_test.go
-135
View File
@@ -1,135 +0,0 @@
package server_test
import (
"testing"
"github.com/spf13/viper"
"go.uber.org/fx"
"sneak.berlin/go/dnswatcher/internal/config"
"sneak.berlin/go/dnswatcher/internal/globals"
"sneak.berlin/go/dnswatcher/internal/handlers"
"sneak.berlin/go/dnswatcher/internal/healthcheck"
"sneak.berlin/go/dnswatcher/internal/logger"
"sneak.berlin/go/dnswatcher/internal/middleware"
"sneak.berlin/go/dnswatcher/internal/notify"
"sneak.berlin/go/dnswatcher/internal/server"
"sneak.berlin/go/dnswatcher/internal/state"
)
// newServerApp builds an fx app holding a *server.Server wired exactly
// as cmd/dnswatcher wires it, minus the watcher/resolver subtree that
// would touch live DNS, plus the given option. config.New reads viper,
// so the caller must first configure it, which is also why the caller
// cannot run in parallel.
func newServerApp(option fx.Option) *fx.App {
return fx.New(
fx.NopLogger,
fx.Provide(
globals.New,
logger.New,
config.New,
state.New,
healthcheck.New,
notify.New,
middleware.New,
handlers.New,
server.New,
),
option,
)
}
// buildServer builds the server without starting the app's lifecycle,
// so no OnStart hook runs and nothing listens or resolves.
func buildServer(t *testing.T) *server.Server {
t.Helper()
var srv *server.Server
app := newServerApp(fx.Populate(&srv))
err := app.Err()
if err != nil {
t.Fatalf("building server graph: %v", err)
}
return srv
}
// TestRunWiresSocketTimeouts pins that the http.Server the running
// server actually serves — the one Run builds and hands to
// ListenAndServe — carries every socket-level timeout, plus the two
// relationships the values must satisfy.
//
// Run is driven to completion with an unbindable port: it builds and
// stores s.httpServer, then ListenAndServe fails at once and Run
// returns without ever listening. The assertions run in the same
// goroutine after Run returns, so reading s.httpServer is free of any
// data race. Nothing here measures elapsed time.
//
// ReadTimeout must be at least ReadHeaderTimeout. net/http reads the
// headers under ReadHeaderTimeout, then sets the read deadline for the
// rest of the request to ReadTimeout, counted from when it started
// reading the request. If ReadTimeout were smaller, a request whose
// headers arrived after ReadTimeout but within ReadHeaderTimeout would
// get a read deadline that had already passed, so reading its body
// would fail at once.
func TestRunWiresSocketTimeouts(t *testing.T) {
// Sets an env var and touches viper global state, so like the
// config tests it cannot use t.Parallel.
viper.Reset()
t.Setenv("DNSWATCHER_TARGETS", "example.com")
srv := buildServer(t)
server.SetListenPort(srv, -1)
srv.Run()
hs := server.HTTPServerOf(srv)
if hs == nil {
t.Fatal("Run did not build an http.Server")
}
if hs.ReadTimeout <= 0 {
t.Errorf("ReadTimeout must be non-zero, got %v", hs.ReadTimeout)
}
if hs.ReadHeaderTimeout <= 0 {
t.Errorf(
"ReadHeaderTimeout must be non-zero, got %v",
hs.ReadHeaderTimeout,
)
}
if hs.WriteTimeout <= 0 {
t.Errorf("WriteTimeout must be non-zero, got %v", hs.WriteTimeout)
}
if hs.IdleTimeout <= 0 {
t.Errorf("IdleTimeout must be non-zero, got %v", hs.IdleTimeout)
}
if hs.WriteTimeout <= server.RequestTimeout {
t.Errorf(
"WriteTimeout (%v) must exceed handler budget (%v)",
hs.WriteTimeout,
server.RequestTimeout,
)
}
if hs.ReadTimeout < hs.ReadHeaderTimeout {
t.Errorf(
"ReadTimeout (%v) must be >= ReadHeaderTimeout (%v)",
hs.ReadTimeout,
hs.ReadHeaderTimeout,
)
}
if hs.Handler != srv {
t.Errorf(
"Run wired handler %T, want the *server.Server",
hs.Handler,
)
}
}
internal/state/export_test.go
-23
View File
@@ -1,23 +0,0 @@
package state
import (
"log/slog"
"sneak.berlin/go/dnswatcher/internal/config"
)
// NewForTestWithDataDir creates an empty State that saves to dataDir,
// without the fx lifecycle.
func NewForTestWithDataDir(dataDir string) *State {
return &State{
log: slog.Default(),
snapshot: &Snapshot{
Version: stateVersion,
Domains: make(map[string]*DomainState),
Hostnames: make(map[string]*HostnameState),
Ports: make(map[string]*PortState),
Certificates: make(map[string]*CertificateState),
},
config: &config.Config{DataDir: dataDir},
}
}
internal/state/state.go
-38
View File
@@ -35,12 +35,8 @@ type Params struct {
}
// DomainState holds the monitoring state for an apex domain.
// NameserverAddresses holds the sorted addresses each nameserver's name
// resolves to, by nameserver name. A state file written before it
// existed loads with it nil.
type DomainState struct {
Nameservers []string `json:"nameservers"`
NameserverAddresses map[string][]string `json:"nameserverAddresses"`
LastChecked time.Time `json:"lastChecked"`
}
@@ -53,13 +49,8 @@ type NameserverRecordState struct {
}
// HostnameState holds per-nameserver monitoring state for a hostname.
// CNAMEAddresses holds the sorted addresses at the end of the name's
// CNAME chain, found when its nameservers answered with a CNAME and no
// address; it is empty otherwise. It is nil when they are not known: a
// state file written before it existed loads with it nil.
type HostnameState struct {
RecordsByNameserver map[string]*NameserverRecordState `json:"recordsByNameserver"`
CNAMEAddresses []string `json:"cnameAddresses"`
LastChecked time.Time `json:"lastChecked"`
}
@@ -157,11 +148,6 @@ func New(
lifecycle.Append(fx.Hook{
OnStart: func(_ context.Context) error {
err := state.checkDataDirWritable()
if err != nil {
return err
}
return state.Load()
},
OnStop: func(_ context.Context) error {
@@ -359,27 +345,3 @@ func (s *State) GetCertificateState(
return cs, ok
}
// checkDataDirWritable creates the data directory if needed, then writes
// and removes the temp file that Save uses. It runs at startup so that an
// unwritable directory stops the process, instead of the process running
// with every save failing and only logged.
func (s *State) checkDataDirWritable() error {
dir := s.config.DataDir
tmpPath := s.config.StatePath() + ".tmp"
err := os.MkdirAll(dir, dirPermissions)
if err == nil {
err = os.WriteFile(tmpPath, nil, filePermissions)
}
if err == nil {
err = os.Remove(tmpPath)
}
if err != nil {
return fmt.Errorf("data directory %s is not writable: %w", dir, err)
}
return nil
}
internal/state/state_test.go
+36 -266
View File
@@ -4,17 +4,10 @@ import (
"encoding/json"
"os"
"path/filepath"
"reflect"
"strings"
"sync"
"testing"
"time"
"go.uber.org/fx/fxtest"
"sneak.berlin/go/dnswatcher/internal/config"
"sneak.berlin/go/dnswatcher/internal/globals"
"sneak.berlin/go/dnswatcher/internal/logger"
"sneak.berlin/go/dnswatcher/internal/state"
)
@@ -38,10 +31,6 @@ func populateState(t *testing.T, s *state.State) {
s.SetDomainState("example.com", &state.DomainState{
Nameservers: []string{testNS1, testNS2},
NameserverAddresses: map[string][]string{
testNS1: {testIP, testIPv4},
testNS2: {testIPv4},
},
LastChecked: now,
})
@@ -128,153 +117,6 @@ func TestSaveLoadRoundTrip_Domains(t *testing.T) {
if len(dom.Nameservers) != 2 {
t.Errorf("expected 2 nameservers, got %d", len(dom.Nameservers))
}
want := map[string][]string{
testNS1: {testIP, testIPv4},
testNS2: {testIPv4},
}
if !reflect.DeepEqual(dom.NameserverAddresses, want) {
t.Errorf(
"nameserver addresses: got %v, want %v",
dom.NameserverAddresses, want,
)
}
}
// TestLoadStateFromBeforeNameserverAddresses loads a state file written
// before nameserver addresses were saved.
func TestLoadStateFromBeforeNameserverAddresses(t *testing.T) {
t.Parallel()
dir := t.TempDir()
data := []byte(`{
"version": 1,
"lastUpdated": "2026-02-19T12:00:00Z",
"domains": {
"example.com": {
"nameservers": ["ns1.example.com.", "ns2.example.com."],
"lastChecked": "2026-02-19T12:00:00Z"
}
}
}`)
err := os.WriteFile(filepath.Join(dir, "state.json"), data, 0o600)
if err != nil {
t.Fatalf("writing state file: %v", err)
}
s := state.NewForTestWithDataDir(dir)
err = s.Load()
if err != nil {
t.Fatalf("Load() error: %v", err)
}
dom, ok := s.GetDomainState("example.com")
if !ok {
t.Fatal("missing domain example.com")
}
if !reflect.DeepEqual(dom.Nameservers, []string{testNS1, testNS2}) {
t.Errorf("nameservers: got %v", dom.Nameservers)
}
if dom.NameserverAddresses != nil {
t.Errorf(
"nameserver addresses: got %v, want none",
dom.NameserverAddresses,
)
}
}
// TestSaveLoadRoundTrip_CNAMEAddresses checks that no addresses at the
// end of a hostname's CNAME chain load as an empty list, and addresses
// that are not known load as nil: the watcher tells the two apart.
func TestSaveLoadRoundTrip_CNAMEAddresses(t *testing.T) {
t.Parallel()
dir := t.TempDir()
s := state.NewForTestWithDataDir(dir)
want := map[string][]string{
"cname.example.com": {testIP},
"none.example.com": {},
"not-known.example.com": nil,
}
for name, addresses := range want {
s.SetHostnameState(name, &state.HostnameState{
CNAMEAddresses: addresses,
})
}
err := s.Save()
if err != nil {
t.Fatalf("Save() error: %v", err)
}
loaded := state.NewForTestWithDataDir(dir)
err = loaded.Load()
if err != nil {
t.Fatalf("Load() error: %v", err)
}
for name, addresses := range want {
hs, ok := loaded.GetHostnameState(name)
if !ok {
t.Fatalf("missing hostname %s", name)
}
if !reflect.DeepEqual(hs.CNAMEAddresses, addresses) {
t.Errorf(
"%s: loaded %#v, want %#v",
name, hs.CNAMEAddresses, addresses,
)
}
}
}
// TestLoadStateFromBeforeCNAMEAddresses loads a state file written
// before the addresses at the end of a hostname's CNAME chain were
// saved. They load as not known (nil), not as none.
func TestLoadStateFromBeforeCNAMEAddresses(t *testing.T) {
t.Parallel()
dir := t.TempDir()
data := []byte(`{
"version": 1,
"lastUpdated": "2026-02-19T12:00:00Z",
"hostnames": {
"www.example.com": {
"recordsByNameserver": {},
"lastChecked": "2026-02-19T12:00:00Z"
}
}
}`)
err := os.WriteFile(filepath.Join(dir, "state.json"), data, 0o600)
if err != nil {
t.Fatalf("writing state file: %v", err)
}
s := state.NewForTestWithDataDir(dir)
err = s.Load()
if err != nil {
t.Fatalf("Load() error: %v", err)
}
hs, ok := s.GetHostnameState(testHostname)
if !ok {
t.Fatal("missing hostname " + testHostname)
}
if hs.CNAMEAddresses != nil {
t.Errorf("CNAME addresses: got %#v, want nil", hs.CNAMEAddresses)
}
}
// TestSaveLoadRoundTrip_Hostnames verifies hostname data survives a save/load cycle.
@@ -651,107 +493,6 @@ func TestSaveWritePermissionError(t *testing.T) {
}
}
// startState builds a State through the real constructor and runs its
// startup hook against dataDir, returning the startup error.
func startState(t *testing.T, dataDir string) error {
t.Helper()
g, err := globals.New(nil)
if err != nil {
t.Fatalf("globals.New: %v", err)
}
log, err := logger.New(nil, logger.Params{Globals: g})
if err != nil {
t.Fatalf("logger.New: %v", err)
}
lifecycle := fxtest.NewLifecycle(t)
_, err = state.New(lifecycle, state.Params{
Logger: log,
Config: &config.Config{DataDir: dataDir},
})
if err != nil {
t.Fatalf("state.New: %v", err)
}
return lifecycle.Start(t.Context())
}
// TestStartupFailsWhenDataDirNotWritable verifies that startup stops
// with an error naming the data directory when it cannot be written.
// The directory's parent is a regular file, which also fails as root.
func TestStartupFailsWhenDataDirNotWritable(t *testing.T) {
t.Parallel()
parent := filepath.Join(t.TempDir(), "file")
err := os.WriteFile(parent, nil, 0o600)
if err != nil {
t.Fatalf("writing file: %v", err)
}
dataDir := filepath.Join(parent, "data")
err = startState(t, dataDir)
if err == nil {
t.Fatal("startup should fail when the data directory is not writable")
}
want := "data directory " + dataDir + " is not writable"
if !strings.Contains(err.Error(), want) {
t.Errorf("startup error %q does not contain %q", err, want)
}
}
// TestStartupFailsWhenExistingDataDirNotWritable verifies that startup
// stops when the data directory exists but the temp file that saving uses
// cannot be written in it. A directory sitting at the temp file's path
// makes that write fail, which also holds as root.
func TestStartupFailsWhenExistingDataDirNotWritable(t *testing.T) {
t.Parallel()
dataDir := t.TempDir()
err := os.Mkdir(filepath.Join(dataDir, "state.json.tmp"), 0o700)
if err != nil {
t.Fatalf("creating directory: %v", err)
}
err = startState(t, dataDir)
if err == nil {
t.Fatal("startup should fail when the data directory is not writable")
}
want := "data directory " + dataDir + " is not writable"
if !strings.Contains(err.Error(), want) {
t.Errorf("startup error %q does not contain %q", err, want)
}
}
// TestStartupCreatesDataDir verifies that startup creates a missing
// data directory and leaves nothing behind in it.
func TestStartupCreatesDataDir(t *testing.T) {
t.Parallel()
dataDir := filepath.Join(t.TempDir(), "data")
err := startState(t, dataDir)
if err != nil {
t.Fatalf("startup error: %v", err)
}
entries, err := os.ReadDir(dataDir)
if err != nil {
t.Fatalf("reading data directory: %v", err)
}
if len(entries) != 0 {
t.Errorf("startup left %d entries in the data directory", len(entries))
}
}
// TestPortStateUnmarshalJSON_NewFormat verifies deserialization of the
// current multi-hostname format.
func TestPortStateUnmarshalJSON_NewFormat(t *testing.T) {
@@ -891,7 +632,7 @@ func TestPortStateUnmarshalJSON_BothFormats(t *testing.T) {
func TestGetSnapshot_ReturnsCopy(t *testing.T) {
t.Parallel()
s := state.NewForTestWithDataDir(t.TempDir())
s := state.NewForTest()
populateState(t, s)
@@ -913,7 +654,7 @@ func TestGetSnapshot_ReturnsCopy(t *testing.T) {
func TestDomainState_GetSet(t *testing.T) {
t.Parallel()
s := state.NewForTestWithDataDir(t.TempDir())
s := state.NewForTest()
// Get on missing key returns false.
_, ok := s.GetDomainState("nonexistent.com")
@@ -964,7 +705,7 @@ func TestDomainState_GetSet(t *testing.T) {
func TestHostnameState_GetSet(t *testing.T) {
t.Parallel()
s := state.NewForTestWithDataDir(t.TempDir())
s := state.NewForTest()
_, ok := s.GetHostnameState("missing.example.com")
if ok {
@@ -1009,7 +750,7 @@ func TestHostnameState_GetSet(t *testing.T) {
func TestPortState_GetSetDelete(t *testing.T) {
t.Parallel()
s := state.NewForTestWithDataDir(t.TempDir())
s := state.NewForTest()
_, ok := s.GetPortState("1.2.3.4:80")
if ok {
@@ -1047,7 +788,7 @@ func TestPortState_GetSetDelete(t *testing.T) {
func TestGetAllPortKeys(t *testing.T) {
t.Parallel()
s := state.NewForTestWithDataDir(t.TempDir())
s := state.NewForTest()
keys := s.GetAllPortKeys()
if len(keys) != 0 {
@@ -1089,7 +830,7 @@ func TestGetAllPortKeys(t *testing.T) {
func TestCertificateState_GetSet(t *testing.T) {
t.Parallel()
s := state.NewForTestWithDataDir(t.TempDir())
s := state.NewForTest()
_, ok := s.GetCertificateState("1.2.3.4:443:www.example.com")
if ok {
@@ -1310,7 +1051,7 @@ func TestLoadPreservesExistingStateOnMissingFile(t *testing.T) {
func TestConcurrentGetSet(t *testing.T) {
t.Parallel()
s := state.NewForTestWithDataDir(t.TempDir())
s := state.NewForTest()
const goroutines = 20
@@ -1520,6 +1261,35 @@ func TestMultipleSavesOverwrite(t *testing.T) {
}
}
// TestNewForTest verifies the test helper creates a valid empty state.
func TestNewForTest(t *testing.T) {
t.Parallel()
s := state.NewForTest()
snap := s.GetSnapshot()
if snap.Version != 1 {
t.Errorf("version: got %d, want 1", snap.Version)
}
if snap.Domains == nil {
t.Error("Domains map should be initialized")
}
if snap.Hostnames == nil {
t.Error("Hostnames map should be initialized")
}
if snap.Ports == nil {
t.Error("Ports map should be initialized")
}
if snap.Certificates == nil {
t.Error("Certificates map should be initialized")
}
}
// TestSaveFilePermissions verifies the saved file has restricted permissions.
func TestSaveFilePermissions(t *testing.T) {
t.Parallel()
internal/state/state_test_helper.go
+38
View File
@@ -0,0 +1,38 @@
package state
import (
"log/slog"
"sneak.berlin/go/dnswatcher/internal/config"
)
// NewForTest creates a State for unit testing with no persistence.
func NewForTest() *State {
return &State{
log: slog.Default(),
snapshot: &Snapshot{
Version: stateVersion,
Domains: make(map[string]*DomainState),
Hostnames: make(map[string]*HostnameState),
Ports: make(map[string]*PortState),
Certificates: make(map[string]*CertificateState),
},
config: &config.Config{DataDir: ""},
}
}
// NewForTestWithDataDir creates a State backed by the given directory
// for tests that need file persistence.
func NewForTestWithDataDir(dataDir string) *State {
return &State{
log: slog.Default(),
snapshot: &Snapshot{
Version: stateVersion,
Domains: make(map[string]*DomainState),
Hostnames: make(map[string]*HostnameState),
Ports: make(map[string]*PortState),
Certificates: make(map[string]*CertificateState),
},
config: &config.Config{DataDir: dataDir},
}
}
internal/watcher/cancelled_test.go
-81
View File
@@ -1,81 +0,0 @@
package watcher_test
import (
"context"
"log/slog"
"reflect"
"testing"
"sneak.berlin/go/dnswatcher/internal/portcheck"
"sneak.berlin/go/dnswatcher/internal/resolver"
"sneak.berlin/go/dnswatcher/internal/state"
"sneak.berlin/go/dnswatcher/internal/tlscheck"
"sneak.berlin/go/dnswatcher/internal/watcher"
)
// TestCancelledCheckSavesNothing runs a check with its context already
// cancelled, which is how the rest of a check runs once shutdown cuts it
// short. The real resolver drops the DNS lookup without sending a query,
// and the real port and TLS checkers fail without connecting. The port
// and certificate state the last check saved must stay as it was, and
// nothing may be notified.
func TestCancelledCheckSavesNothing(t *testing.T) {
t.Parallel()
cfg := defaultTestConfig(t)
cfg.Hostnames = []string{host}
// newTestWatcher's watcher has stand-in checkers. This one, on the
// same state and notifier, has the real ones.
_, deps := newTestWatcher(t, cfg)
w := watcher.NewForTest(
cfg,
deps.state,
resolver.NewFromLogger(slog.Default()),
portcheck.NewStandalone(),
tlscheck.NewStandalone(),
deps.notifier,
)
// The last check found host at a local address, with both ports
// open and a good certificate.
const localIP = "127.0.0.1"
deps.state.SetHostnameState(host, hostnameState(
map[string]map[string][]string{nsA: {"A": {localIP}}},
))
ports := map[string]*state.PortState{
localIP + ":80": {Open: true, Hostnames: []string{host}},
localIP + ":443": {Open: true, Hostnames: []string{host}},
}
for key, ps := range ports {
deps.state.SetPortState(key, ps)
}
certKey := localIP + ":443:" + host
cert := &state.CertificateState{CommonName: host, Status: "ok"}
deps.state.SetCertificateState(certKey, cert)
ctx, cancel := context.WithCancel(t.Context())
cancel()
w.RunOnce(ctx)
for key, want := range ports {
got, _ := deps.state.GetPortState(key)
if !reflect.DeepEqual(got, want) {
t.Errorf("port %s saved as %+v, want %+v", key, got, want)
}
}
got, _ := deps.state.GetCertificateState(certKey)
if !reflect.DeepEqual(got, cert) {
t.Errorf("certificate saved as %+v, want %+v", got, cert)
}
notifications := deps.notifier.getNotifications()
if len(notifications) != 0 {
t.Errorf("sent %v, want no notifications", notifications)
}
}
internal/watcher/cname_test.go
-238
View File
@@ -1,238 +0,0 @@
package watcher_test
import (
"context"
"log/slog"
"slices"
"testing"
"sneak.berlin/go/dnswatcher/internal/livednstest"
"sneak.berlin/go/dnswatcher/internal/resolver"
"sneak.berlin/go/dnswatcher/internal/state"
"sneak.berlin/go/dnswatcher/internal/watcher"
)
// cnameHost is a CNAME into another zone: its nameservers answer with
// the CNAME and no address.
const cnameHost = "www.python.org"
// TestCNAMEIntoAnotherZonePortAndTLSChecks checks cnameHost against
// live DNS. Its port and TLS checks must use the addresses at the end
// of its CNAME chain.
func TestCNAMEIntoAnotherZonePortAndTLSChecks(t *testing.T) {
t.Parallel()
cfg := defaultTestConfig(t)
cfg.Hostnames = []string{cnameHost}
deps := runChecks(t, cfg, nil, nil)
snap := deps.state.GetSnapshot()
hs := snap.Hostnames[cnameHost]
if len(hs.CNAMEAddresses) == 0 {
t.Fatalf(
"%s: no addresses saved from following its CNAME; if it "+
"is no longer a CNAME into another zone, this test "+
"needs another name",
cnameHost,
)
}
for _, ip := range hs.CNAMEAddresses {
ps, ok := snap.Ports[ip+":443"]
if !ok || !slices.Contains(ps.Hostnames, cnameHost) {
t.Errorf("no port state for %s at %s:443", cnameHost, ip)
}
certKey := ip + ":443:" + cnameHost
if _, ok := snap.Certificates[certKey]; !ok {
t.Errorf("no certificate state %s", certKey)
}
}
}
// TestCNAMEThatCannotBeFollowedKeepsPrevious gives a name under
// .invalid, whose lookup fails, answers with a CNAME and no address.
// The addresses the previous check saved from following its CNAME are
// kept.
func TestCNAMEThatCannotBeFollowedKeepsPrevious(t *testing.T) {
t.Parallel()
const name = "www.example.invalid"
w := watcher.NewForTest(
nil, nil, resolver.NewFromLogger(slog.Default()), nil, nil, nil,
)
current := hostnameState(map[string]map[string][]string{
nsA: {"CNAME": {"target.example.invalid."}},
})
prev := &state.HostnameState{CNAMEAddresses: []string{oldIP}}
// The result is the same whether or not live DNS answers, so the
// lookup is not retried.
_ = livednstest.Run(func(ctx context.Context) error {
w.ResolveCNAMEAddresses(ctx, name, current, prev)
return nil
})
if !slices.Equal(current.CNAMEAddresses, prev.CNAMEAddresses) {
t.Errorf(
"saved %v, want %v",
current.CNAMEAddresses, prev.CNAMEAddresses,
)
}
}
// TestCNAMEWhoseNameserversAllFailedKeepsPrevious checks a name none of
// whose nameservers answered. The addresses the previous check saved
// from following its CNAME are kept, and nothing is looked up: the
// watcher has no resolver.
func TestCNAMEWhoseNameserversAllFailedKeepsPrevious(t *testing.T) {
t.Parallel()
w := watcher.NewForTest(nil, nil, nil, nil, nil, nil)
current := saved(map[string]*state.NameserverRecordState{
nsA: failed(), nsB: failed(),
})
prev := cnameState(oldIP)
w.ResolveCNAMEAddresses(t.Context(), host, current, prev)
if !slices.Equal(current.CNAMEAddresses, prev.CNAMEAddresses) {
t.Errorf(
"saved %v, want %v",
current.CNAMEAddresses, prev.CNAMEAddresses,
)
}
}
// cnameState builds the state a check leaves behind for a name whose
// nameserver answered with a CNAME and no address, when following the
// CNAME found these addresses, which may be none.
func cnameState(addresses ...string) *state.HostnameState {
hs := hostnameState(map[string]map[string][]string{
nsA: {"CNAME": {"target.example.org."}},
})
hs.CNAMEAddresses = append([]string{}, addresses...)
return hs
}
func TestCNAMEAddressChangeAlerts(t *testing.T) {
t.Parallel()
// A state file written before the addresses were saved loads with
// them nil.
olderStateFile := cnameState()
olderStateFile.CNAMEAddresses = nil
// Each case is the state saved by the previous check and by the
// current one. The name's records are the same in both.
tests := []struct {
name string
prev, current *state.HostnameState
want int
}{
{
"same addresses",
cnameState(ip1, ip2), cnameState(ip1, ip2), 0,
},
{
"same addresses in another order",
cnameState(ip2, ip1), cnameState(ip1, ip2), 0,
},
{
"address replaced",
cnameState(ip1), cnameState(ip2), 1,
},
{
"address added",
cnameState(ip1), cnameState(ip1, ip2), 1,
},
{
"no address at the end of the chain now",
cnameState(ip1), cnameState(), 1,
},
{
"addresses at the end of the chain again",
cnameState(), cnameState(ip1), 1,
},
{
"state file from before addresses were saved",
olderStateFile, cnameState(ip1), 0,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
w.DetectHostnameChanges(t.Context(), host, tt.prev, tt.current)
got := len(notifier.getNotifications())
if got != tt.want {
t.Errorf("sent %d notifications, want %d", got, tt.want)
}
})
}
}
func TestCNAMEAddressChangeAlertNamesHostnameAndAddresses(t *testing.T) {
t.Parallel()
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
w.DetectHostnameChanges(
t.Context(), host, cnameState(ip1), cnameState(ip2, ip3),
)
want := notification{
Title: "CNAME Address Change: " + host,
Message: "Hostname: " + host +
"\nOld: " + ip1 + "\nNew: " + ip2 + ", " + ip3,
Priority: "warning",
}
got := notifier.getNotifications()
if len(got) != 1 || got[0] != want {
t.Errorf("sent %v, want %v", got, want)
}
}
// TestNameMovedFromARecordsToCNAMEAlerts checks a name that answers
// with an A record and then with a CNAME whose chain ends in ip2. The
// second check is notified as a CNAME address change from no addresses,
// beside the record change. Nothing is looked up: the watcher has no
// resolver.
func TestNameMovedFromARecordsToCNAMEAlerts(t *testing.T) {
t.Parallel()
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
prev := hostnameState(map[string]map[string][]string{
nsA: {"A": {ip1}},
})
w.ResolveCNAMEAddresses(t.Context(), host, prev, nil)
w.DetectHostnameChanges(t.Context(), host, prev, cnameState(ip2))
title := "CNAME Address Change: " + host
message := "Hostname: " + host + "\nOld: \nNew: " + ip2
got := notifier.getNotifications()
if !slices.ContainsFunc(got, func(n notification) bool {
return n.Title == title && n.Message == message
}) {
t.Errorf("sent %v, want %q with %q among them", got, title, message)
}
}
internal/watcher/export_test.go
-94
View File
@@ -1,94 +0,0 @@
package watcher
import (
"context"
"log/slog"
"time"
"sneak.berlin/go/dnswatcher/internal/config"
"sneak.berlin/go/dnswatcher/internal/resolver"
"sneak.berlin/go/dnswatcher/internal/state"
)
// NewForTest creates a Watcher without fx for unit testing.
func NewForTest(
cfg *config.Config,
st *state.State,
res DNSResolver,
pc PortChecker,
tc TLSChecker,
n Notifier,
) *Watcher {
return &Watcher{
log: slog.Default(),
config: cfg,
state: st,
resolver: res,
portCheck: pc,
tlsCheck: tc,
notify: n,
firstRun: true,
}
}
// NewlyDisagreeingPairs exports newlyDisagreeingPairs for testing.
func NewlyDisagreeingPairs(
prev, current *state.HostnameState,
) [][2]string {
return newlyDisagreeingPairs(prev, current)
}
// DetectHostnameChanges exports detectHostnameChanges for testing.
func (w *Watcher) DetectHostnameChanges(
ctx context.Context,
hostname string,
prev, current *state.HostnameState,
) {
w.detectHostnameChanges(ctx, hostname, prev, current)
}
// ResolveNameserverAddresses exports resolveNameserverAddresses for
// testing.
func (w *Watcher) ResolveNameserverAddresses(
ctx context.Context,
nameservers []string,
prev map[string][]string,
) map[string][]string {
return w.resolveNameserverAddresses(ctx, nameservers, prev)
}
// ResolveCNAMEAddresses exports resolveCNAMEAddresses for testing.
func (w *Watcher) ResolveCNAMEAddresses(
ctx context.Context,
hostname string,
current, prev *state.HostnameState,
) {
w.resolveCNAMEAddresses(ctx, hostname, current, prev)
}
// DetectNSAddressChanges exports detectNSAddressChanges for testing.
func (w *Watcher) DetectNSAddressChanges(
ctx context.Context,
domain string,
prev, current map[string][]string,
) {
w.detectNSAddressChanges(ctx, domain, prev, current)
}
// CheckAllPorts exports checkAllPorts for testing.
func (w *Watcher) CheckAllPorts(ctx context.Context) {
w.checkAllPorts(ctx)
}
// RunTLSChecks exports runTLSChecks for testing.
func (w *Watcher) RunTLSChecks(ctx context.Context) {
w.runTLSChecks(ctx)
}
// BuildHostnameState exports buildHostnameState for testing.
func BuildHostnameState(
results map[string]*resolver.NameserverResponse,
now time.Time,
) *state.HostnameState {
return buildHostnameState(results, now)
}
internal/watcher/inconsistency_test.go
-185
View File
@@ -1,185 +0,0 @@
package watcher_test
import (
"slices"
"testing"
"sneak.berlin/go/dnswatcher/internal/state"
"sneak.berlin/go/dnswatcher/internal/watcher"
)
const (
host = "www.example.net"
nsA = "a.ns.example.net."
nsB = "b.ns.example.net."
nsC = "c.ns.example.net."
ip1 = "192.0.2.1"
ip2 = "192.0.2.2"
ip3 = "192.0.2.3"
)
// hostnameState builds the state a check with these records leaves behind.
func hostnameState(
records map[string]map[string][]string,
) *state.HostnameState {
hs := &state.HostnameState{
RecordsByNameserver: make(map[string]*state.NameserverRecordState),
}
for ns, recs := range records {
hs.RecordsByNameserver[ns] = &state.NameserverRecordState{
Records: recs,
Status: "ok",
}
}
return hs
}
func TestNewlyDisagreeingPairs(t *testing.T) {
t.Parallel()
onlyA := map[string]map[string][]string{nsA: {"A": {ip1}}}
agree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip1}}}
disagree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip2}}}
alert := [][2]string{{nsA, nsB}}
// b already disagrees with a and c; then c changes, so a and c,
// which agreed, now differ.
bDiffers := map[string]map[string][]string{
nsA: {"A": {ip1}}, nsB: {"A": {ip2}}, nsC: {"A": {ip1}},
}
cChanges := map[string]map[string][]string{
nsA: {"A": {ip1}}, nsB: {"A": {ip2}}, nsC: {"A": {ip3}},
}
// Each case starts from the state loaded at startup and runs the
// checks in order; want[i] is what check i alerts for.
tests := []struct {
name string
loaded map[string]map[string][]string
checks []map[string]map[string][]string
want [][][2]string
}{
{
name: "disagreement persisting across checks alerts once",
loaded: agree,
checks: []map[string]map[string][]string{disagree, disagree, disagree},
want: [][][2]string{alert, nil, nil},
},
{
name: "disagreement starting on a later check alerts on it",
loaded: agree,
checks: []map[string]map[string][]string{agree, agree, disagree},
want: [][][2]string{nil, nil, alert},
},
{
name: "disagreement in the loaded state does not alert",
loaded: disagree,
checks: []map[string]map[string][]string{disagree, disagree},
want: [][][2]string{nil, nil},
},
{
name: "nameserver new on the first check and disagreeing alerts once",
loaded: onlyA,
checks: []map[string]map[string][]string{disagree, disagree},
want: [][][2]string{alert, nil},
},
{
name: "disagreement after agreeing again alerts again",
loaded: agree,
checks: []map[string]map[string][]string{disagree, agree, disagree},
want: [][][2]string{alert, nil, alert},
},
{
name: "new disagreement while another nameserver differs alerts",
loaded: bDiffers,
checks: []map[string]map[string][]string{cChanges, cChanges},
want: [][][2]string{{{nsA, nsC}}, nil},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
prev := hostnameState(tt.loaded)
for i, records := range tt.checks {
current := hostnameState(records)
got := watcher.NewlyDisagreeingPairs(prev, current)
if !slices.Equal(got, tt.want[i]) {
t.Errorf(
"check %d: alerted for %v, want %v",
i, got, tt.want[i],
)
}
prev = current
}
})
}
}
func TestInconsistencyAlert(t *testing.T) {
t.Parallel()
onlyA := map[string]map[string][]string{nsA: {"A": {ip1}}}
agree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip1}}}
disagree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip2}}}
// Each case starts from the state loaded at startup and then sees
// the nameservers disagree on three checks in a row.
tests := []struct {
name string
loaded map[string]map[string][]string
want int
}{
{
name: "disagreement lasting several checks alerts once",
loaded: agree,
want: 1,
},
{
name: "disagreement in the loaded state does not alert",
loaded: disagree,
want: 0,
},
{
name: "nameserver new on the first check and disagreeing alerts once",
loaded: onlyA,
want: 1,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
// The hostname change detection uses only the notifier.
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
prev := hostnameState(tt.loaded)
for range 3 {
current := hostnameState(disagree)
w.DetectHostnameChanges(t.Context(), host, prev, current)
prev = current
}
got := 0
for _, n := range notifier.getNotifications() {
if n.Title == "Inconsistency: "+host {
got++
}
}
if got != tt.want {
t.Errorf("sent %d inconsistency alerts, want %d", got, tt.want)
}
})
}
}
internal/watcher/interfaces.go
+2 -3
View File
@@ -5,7 +5,6 @@ import (
"context"
"sneak.berlin/go/dnswatcher/internal/portcheck"
"sneak.berlin/go/dnswatcher/internal/resolver"
"sneak.berlin/go/dnswatcher/internal/tlscheck"
)
@@ -18,11 +17,11 @@ type DNSResolver interface {
) ([]string, error)
// LookupAllRecords queries all record types for a hostname,
// returning each nameserver's response keyed by nameserver.
// returning results keyed by nameserver then record type.
LookupAllRecords(
ctx context.Context,
hostname string,
) (map[string]*resolver.NameserverResponse, error)
) (map[string]map[string][]string, error)
// ResolveIPAddresses resolves a hostname to all IP addresses.
ResolveIPAddresses(
internal/watcher/nsaddress_test.go
-151
View File
@@ -1,151 +0,0 @@
package watcher_test
import (
"context"
"log/slog"
"reflect"
"testing"
"sneak.berlin/go/dnswatcher/internal/livednstest"
"sneak.berlin/go/dnswatcher/internal/resolver"
"sneak.berlin/go/dnswatcher/internal/watcher"
)
const domain = "example.net"
func TestNSAddressChangeAlerts(t *testing.T) {
t.Parallel()
// Each case is the nameserver addresses saved by the previous check
// and by the current one.
tests := []struct {
name string
prev, current map[string][]string
want int
}{
{
"same addresses",
map[string][]string{nsA: {ip1, ip2}},
map[string][]string{nsA: {ip1, ip2}},
0,
},
{
"same addresses in another order",
map[string][]string{nsA: {ip2, ip1}},
map[string][]string{nsA: {ip1, ip2}},
0,
},
{
"address replaced",
map[string][]string{nsA: {ip1}},
map[string][]string{nsA: {ip2}},
1,
},
{
"address added",
map[string][]string{nsA: {ip1}},
map[string][]string{nsA: {ip1, ip2}},
1,
},
{
"two nameservers changed",
map[string][]string{nsA: {ip1}, nsB: {ip2}},
map[string][]string{nsA: {ip3}, nsB: {ip3}},
2,
},
{
"nameserver added",
map[string][]string{nsA: {ip1}},
map[string][]string{nsA: {ip1}, nsB: {ip2}},
0,
},
{
"nameserver removed",
map[string][]string{nsA: {ip1}, nsB: {ip2}},
map[string][]string{nsA: {ip1}},
0,
},
{
"state file from before addresses were saved",
nil,
map[string][]string{nsA: {ip1}, nsB: {ip2}},
0,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
w.DetectNSAddressChanges(t.Context(), domain, tt.prev, tt.current)
got := len(notifier.getNotifications())
if got != tt.want {
t.Errorf("sent %d address changes, want %d", got, tt.want)
}
})
}
}
func TestNSAddressChangeAlertNamesDomainNameserverAndAddresses(
t *testing.T,
) {
t.Parallel()
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
w.DetectNSAddressChanges(
t.Context(), domain,
map[string][]string{nsA: {ip1}},
map[string][]string{nsA: {ip2, ip3}},
)
want := notification{
Title: "NS Address Change: " + domain,
Message: "Domain: " + domain + "\nNameserver: " + nsA +
"\nOld: " + ip1 + "\nNew: " + ip2 + ", " + ip3,
Priority: "warning",
}
got := notifier.getNotifications()
if len(got) != 1 || got[0] != want {
t.Errorf("sent %v, want %v", got, want)
}
}
// TestNameserverWithNoAddressKeepsPrevious looks up nameserver names
// with no address: two under .invalid, whose lookup fails with an
// error, and one that does not exist under a real zone, which live DNS
// answers with no address and no error. Each one with addresses saved
// by the previous check keeps them; the one without gets none.
func TestNameserverWithNoAddressKeepsPrevious(t *testing.T) {
t.Parallel()
w := watcher.NewForTest(
nil, nil, resolver.NewFromLogger(slog.Default()), nil, nil, nil,
)
nonexistentNS := "this-surely-does-not-exist-xyz." + testSmallDomain + "."
prev := map[string][]string{oldNS1: {oldIP}, nonexistentNS: {oldIP}}
var got map[string][]string
// The result is the same whether or not live DNS answers, so the
// lookup is not retried.
_ = livednstest.Run(func(ctx context.Context) error {
got = w.ResolveNameserverAddresses(
ctx, []string{oldNS1, oldNS2, nonexistentNS}, prev,
)
return nil
})
if !reflect.DeepEqual(got, prev) {
t.Errorf("saved %v, want %v", got, prev)
}
}
internal/watcher/nsfailure_test.go
-448
View File
@@ -1,448 +0,0 @@
package watcher_test
import (
"context"
"fmt"
"log/slog"
"strings"
"testing"
"time"
"sneak.berlin/go/dnswatcher/internal/livednstest"
"sneak.berlin/go/dnswatcher/internal/resolver"
"sneak.berlin/go/dnswatcher/internal/state"
"sneak.berlin/go/dnswatcher/internal/watcher"
)
// answered is what a check saves for a nameserver that answered with
// these records.
func answered(records map[string][]string) *state.NameserverRecordState {
return &state.NameserverRecordState{Records: records, Status: "ok"}
}
// failed is what a check saves for a nameserver that did not answer.
func failed() *state.NameserverRecordState {
return &state.NameserverRecordState{
Records: map[string][]string{},
Status: "error",
Error: "all queries timed out",
}
}
// saved builds the hostname state a check saves.
func saved(
byNameserver map[string]*state.NameserverRecordState,
) *state.HostnameState {
return &state.HostnameState{RecordsByNameserver: byNameserver}
}
// alertCounts counts the hostname alerts sent, by kind.
type alertCounts struct {
failures, recoveries, recordChanges, inconsistencies int
}
// countAlerts runs the hostname change detection from the state loaded
// at startup through each check in turn, and counts the alerts sent.
func countAlerts(
t *testing.T,
loaded *state.HostnameState,
checks []*state.HostnameState,
) alertCounts {
t.Helper()
// The hostname change detection uses only the notifier.
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
prev := loaded
for _, current := range checks {
w.DetectHostnameChanges(t.Context(), host, prev, current)
prev = current
}
var got alertCounts
for _, n := range notifier.getNotifications() {
kind, _, _ := strings.Cut(n.Title, ":")
switch kind {
case "NS Failure":
got.failures++
case "NS Recovery":
got.recoveries++
case "Record Change":
got.recordChanges++
case "Inconsistency":
got.inconsistencies++
}
}
return got
}
func TestNSFailureAndRecoveryAlerts(t *testing.T) {
t.Parallel()
records := map[string][]string{"A": {ip1}}
bothAnswer := saved(map[string]*state.NameserverRecordState{
nsA: answered(records), nsB: answered(records),
})
bFails := saved(map[string]*state.NameserverRecordState{
nsA: answered(records), nsB: failed(),
})
onlyA := saved(map[string]*state.NameserverRecordState{
nsA: answered(records),
})
bAnswersNoRecords := saved(map[string]*state.NameserverRecordState{
nsA: answered(records), nsB: answered(map[string][]string{}),
})
bAnswersDifferently := saved(map[string]*state.NameserverRecordState{
nsA: answered(records), nsB: answered(map[string][]string{"A": {ip2}}),
})
// Each case starts from the state loaded at startup and runs the
// checks in order.
tests := []struct {
name string
loaded *state.HostnameState
checks []*state.HostnameState
want alertCounts
}{
{
"failure lasting several checks alerts once",
bothAnswer, []*state.HostnameState{bFails, bFails, bFails},
alertCounts{failures: 1},
},
{
"recovery alerts once",
bFails, []*state.HostnameState{bothAnswer, bothAnswer},
alertCounts{recoveries: 1},
},
{
"failing again after recovering alerts again",
bothAnswer, []*state.HostnameState{bFails, bothAnswer, bFails},
alertCounts{failures: 2, recoveries: 1},
},
{
"nameserver failing when first seen does not alert",
onlyA, []*state.HostnameState{bFails, bFails},
alertCounts{},
},
{
"answer with no records is a record change, not a failure",
bothAnswer, []*state.HostnameState{bAnswersNoRecords},
alertCounts{recordChanges: 1, inconsistencies: 1},
},
{
"recovered nameserver that answers differently disagrees",
bFails, []*state.HostnameState{bAnswersDifferently},
alertCounts{recoveries: 1, inconsistencies: 1},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
got := countAlerts(t, tt.loaded, tt.checks)
if got != tt.want {
t.Errorf("sent %+v, want %+v", got, tt.want)
}
})
}
}
func TestNSFailureAlertNamesHostnameNameserverAndReason(t *testing.T) {
t.Parallel()
records := map[string][]string{"A": {ip1}}
notifier := &mockNotifier{}
w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
w.DetectHostnameChanges(
t.Context(), host,
saved(map[string]*state.NameserverRecordState{nsA: answered(records)}),
saved(map[string]*state.NameserverRecordState{nsA: failed()}),
)
notifications := notifier.getNotifications()
if len(notifications) != 1 {
t.Fatalf("sent %v, want one NS Failure", notifications)
}
msg := notifications[0].Message
if !strings.Contains(msg, host) || !strings.Contains(msg, nsA) ||
!strings.Contains(msg, failed().Error) {
t.Errorf(
"message %q does not name %s, %s and the reason",
msg, host, nsA,
)
}
}
// TestNameserverThatNeverAnswers asks a nameserver address where
// nothing answers, 192.0.2.1, and checks what the watcher saves for it.
// The deadline outlasts the resolver's first two-second try, as in the
// resolver's timeout test.
func TestNameserverThatNeverAnswers(t *testing.T) {
t.Parallel()
ctx, cancel := context.WithTimeout(t.Context(), 3*time.Second)
t.Cleanup(cancel)
res := resolver.NewFromLogger(slog.Default())
resp, err := res.QueryNameserverIP(ctx, nsA, "192.0.2.1", host)
if err != nil {
t.Fatal(err)
}
hs := watcher.BuildHostnameState(
map[string]*resolver.NameserverResponse{nsA: resp}, time.Now(),
)
got := hs.RecordsByNameserver[nsA]
if got.Status != "error" || got.Error == "" {
t.Errorf(
"saved status %q, error %q; want status error with a reason",
got.Status, got.Error,
)
}
}
// TestNameserverThatAnswersNXDOMAIN asks a real nameserver about a name
// that does not exist and checks what the watcher saves for it: NXDOMAIN
// is an answer, so the nameserver is saved as ok with no error.
func TestNameserverThatAnswersNXDOMAIN(t *testing.T) {
t.Parallel()
res := resolver.NewFromLogger(slog.Default())
name := "this-surely-does-not-exist-xyz." + testDomain
var (
ns string
resp *resolver.NameserverResponse
)
livednstest.Retry(t, "QueryNameserver("+name+")", func(ctx context.Context) error {
nameservers, err := res.LookupNS(ctx, testDomain)
if err != nil {
return err
}
ns = nameservers[0]
resp, err = res.QueryNameserver(ctx, ns, name)
if err != nil {
return err
}
// A timeout or a failure is no answer to check.
if resp.Status == resolver.StatusTimeout ||
resp.Status == resolver.StatusError {
return fmt.Errorf(
"%w: %s: %s", livednstest.ErrNoAnswer, ns, resp.Error,
)
}
return nil
})
if resp.Status != resolver.StatusNXDomain {
t.Fatalf("%s answered %q for %s, want NXDOMAIN", ns, resp.Status, name)
}
hs := watcher.BuildHostnameState(
map[string]*resolver.NameserverResponse{ns: resp}, time.Now(),
)
got := hs.RecordsByNameserver[ns]
if got.Status != "ok" || got.Error != "" {
t.Errorf(
"saved status %q, error %q; want status ok with no error",
got.Status, got.Error,
)
}
}
// TestNameserverThatRefuses asks a google.com nameserver about
// cloudflare.com, a zone it does not serve, which it refuses, and checks
// what the watcher saves for it: REFUSED is no answer, so the nameserver
// is saved as error with the reason.
func TestNameserverThatRefuses(t *testing.T) {
t.Parallel()
const reason = "server returned REFUSED"
res := resolver.NewFromLogger(slog.Default())
var (
ns string
resp *resolver.NameserverResponse
)
livednstest.Retry(
t,
"QueryNameserver(cloudflare.com)",
func(ctx context.Context) error {
nameservers, err := res.LookupNS(ctx, testDomain)
if err != nil {
return err
}
ns = nameservers[0]
resp, err = res.QueryNameserver(ctx, ns, "cloudflare.com")
if err != nil {
return err
}
// A timeout or a network error is no reply at all.
if resp.Status == resolver.StatusTimeout ||
strings.HasPrefix(resp.Error, "network error") {
return fmt.Errorf(
"%w: %s: %s", livednstest.ErrNoAnswer, ns, resp.Error,
)
}
return nil
},
)
if resp.Error != reason {
t.Fatalf(
"%s answered %q (%s) for cloudflare.com, want REFUSED",
ns, resp.Status, resp.Error,
)
}
hs := watcher.BuildHostnameState(
map[string]*resolver.NameserverResponse{ns: resp}, time.Now(),
)
got := hs.RecordsByNameserver[ns]
if got.Status != failed().Status || got.Error != reason {
t.Errorf(
"saved status %q, error %q; want status %q, error %q",
got.Status, got.Error, failed().Status, reason,
)
}
}
// TestPortStateWhenNoNameserverAnswered runs the port checks on
// hostname state built here, which gives the name no address. The port
// state saved for its old address is kept only when the name is a
// configured hostname or domain and none of its nameservers answered.
func TestPortStateWhenNoNameserverAnswered(t *testing.T) {
t.Parallel()
noneAnswered := saved(map[string]*state.NameserverRecordState{
nsA: failed(), nsB: failed(),
})
oneAnsweredNoAddress := saved(map[string]*state.NameserverRecordState{
nsA: answered(map[string][]string{}), nsB: failed(),
})
configured := []string{host}
tests := []struct {
name string
hostname *state.HostnameState
hostnames []string
domains []string
wantKept bool
}{
{"no nameserver answered", noneAnswered, configured, nil, true},
{
"no nameserver answered, configured as a domain",
noneAnswered, nil, configured, true,
},
{
"one answered with no address",
oneAnsweredNoAddress, configured, nil, false,
},
{"no nameserver answered, not configured", noneAnswered, nil, nil, false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
cfg := defaultTestConfig(t)
cfg.Hostnames = tt.hostnames
cfg.Domains = tt.domains
// The port checks read the saved hostname state and look
// nothing up, so the watcher has no resolver.
deps := newTestDeps(t, cfg)
w := watcher.NewForTest(
cfg, deps.state, nil,
deps.portChecker, deps.tlsChecker, deps.notifier,
)
key := ip1 + ":443"
deps.state.SetHostnameState(host, tt.hostname)
deps.state.SetPortState(key, &state.PortState{
Open: true, Hostnames: []string{host},
})
w.CheckAllPorts(t.Context())
_, kept := deps.state.GetPortState(key)
if kept != tt.wantKept {
t.Errorf("port state %s kept: %v, want %v", key, kept, tt.wantKept)
}
})
}
}
// TestPortStateWhenNoNameserverAnsweredAndOtherNameMovesAway saves the
// port state of an address two configured hostnames resolve to. While
// none of the first one's nameservers answer, the port checks run with
// the other one still at that address, then after it moved away; the
// port state is kept both times.
func TestPortStateWhenNoNameserverAnsweredAndOtherNameMovesAway(
t *testing.T,
) {
t.Parallel()
const other = "mail.example.net"
cfg := defaultTestConfig(t)
cfg.Hostnames = []string{host, other}
// The port checks read the saved hostname state and look nothing
// up, so the watcher has no resolver.
deps := newTestDeps(t, cfg)
w := watcher.NewForTest(
cfg, deps.state, nil,
deps.portChecker, deps.tlsChecker, deps.notifier,
)
key := ip1 + ":443"
deps.state.SetPortState(key, &state.PortState{
Open: true, Hostnames: []string{host, other},
})
deps.state.SetHostnameState(host, saved(
map[string]*state.NameserverRecordState{nsA: failed(), nsB: failed()},
))
for _, otherIP := range []string{ip1, ip2} {
deps.state.SetHostnameState(other, saved(
map[string]*state.NameserverRecordState{
nsA: answered(map[string][]string{"A": {otherIP}}),
},
))
w.CheckAllPorts(t.Context())
if _, kept := deps.state.GetPortState(key); !kept {
t.Fatalf("port state %s removed with %s at %s", key, other, otherIP)
}
}
}
internal/watcher/watcher.go
+117 -392
View File
@@ -4,16 +4,15 @@ import (
"context"
"fmt"
"log/slog"
"slices"
"sort"
"strings"
"sync"
"time"
"go.uber.org/fx"
"sneak.berlin/go/dnswatcher/internal/config"
"sneak.berlin/go/dnswatcher/internal/logger"
"sneak.berlin/go/dnswatcher/internal/resolver"
"sneak.berlin/go/dnswatcher/internal/state"
"sneak.berlin/go/dnswatcher/internal/tlscheck"
)
@@ -56,8 +55,9 @@ type Watcher struct {
tlsCheck TLSChecker
notify Notifier
cancel context.CancelFunc
done chan struct{} // closed when Run returns
firstRun bool
expiryNotifiedMu sync.Mutex
expiryNotified map[string]time.Time
}
// New creates a new Watcher instance wired into the fx lifecycle.
@@ -74,50 +74,57 @@ func New(
tlsCheck: params.TLSCheck,
notify: params.Notify,
firstRun: true,
expiryNotified: make(map[string]time.Time),
}
lifecycle.Append(fx.Hook{
OnStart: func(startCtx context.Context) error {
// The fx startup context expires after startup
// completes, so the watcher's context drops its
// cancellation. The watcher's lifetime is controlled
// by w.cancel in OnStop.
ctx, cancel := context.WithCancel(
context.WithoutCancel(startCtx),
)
OnStart: func(_ context.Context) error {
// Use context.Background() — the fx startup context
// expires after startup completes, so deriving from it
// would cancel the watcher immediately. The watcher's
// lifetime is controlled by w.cancel in OnStop.
ctx, cancel := context.WithCancel(context.Background())
w.cancel = cancel
w.done = make(chan struct{})
go func() {
defer close(w.done)
w.Run(ctx)
}()
go w.Run(ctx) //nolint:contextcheck // intentionally not derived from startCtx
return nil
},
OnStop: func(ctx context.Context) error {
OnStop: func(_ context.Context) error {
if w.cancel != nil {
w.cancel()
// Run saves state as it returns. Waiting for it here
// means the save is done before shutdown goes on.
select {
case <-w.done:
return nil
case <-ctx.Done():
return fmt.Errorf(
"waiting for the watcher to stop: %w",
ctx.Err(),
)
}
return nil
},
})
return w, nil
}
// Run starts the monitoring loop with periodic scheduling. When ctx
// is cancelled, it saves state and returns.
// NewForTest creates a Watcher without fx for unit testing.
func NewForTest(
cfg *config.Config,
st *state.State,
res DNSResolver,
pc PortChecker,
tc TLSChecker,
n Notifier,
) *Watcher {
return &Watcher{
log: slog.Default(),
config: cfg,
state: st,
resolver: res,
portCheck: pc,
tlsCheck: tc,
notify: n,
firstRun: true,
expiryNotified: make(map[string]time.Time),
}
}
// Run starts the monitoring loop with periodic scheduling.
func (w *Watcher) Run(ctx context.Context) {
w.log.Info(
"watcher starting",
@@ -139,7 +146,6 @@ func (w *Watcher) Run(ctx context.Context) {
for {
select {
case <-ctx.Done():
w.saveState()
w.log.Info("watcher stopped")
return
@@ -231,30 +237,36 @@ func (w *Watcher) checkDomain(
now := time.Now().UTC()
prev, hasPrev := w.state.GetDomainState(domain)
var prevAddresses map[string][]string
if hasPrev {
prevAddresses = prev.NameserverAddresses
}
addresses := w.resolveNameserverAddresses(
ctx, nameservers, prevAddresses,
)
if hasPrev && !w.firstRun {
w.detectNSChanges(ctx, domain, prev.Nameservers, nameservers)
w.detectNSAddressChanges(ctx, domain, prevAddresses, addresses)
}
w.state.SetDomainState(domain, &state.DomainState{
Nameservers: nameservers,
NameserverAddresses: addresses,
LastChecked: now,
})
// The apex domain's records are also checked as a hostname's, so
// that the port and TLS checks find its addresses.
w.checkHostname(ctx, domain)
// Also look up A/AAAA records for the apex domain so that
// port and TLS checks (which read HostnameState) can find
// the domain's IP addresses.
records, err := w.resolver.LookupAllRecords(ctx, domain)
if err != nil {
w.log.Error(
"failed to lookup records for domain",
"domain", domain,
"error", err,
)
return
}
prevHS, hasPrevHS := w.state.GetHostnameState(domain)
if hasPrevHS && !w.firstRun {
w.detectHostnameChanges(ctx, domain, prevHS, records)
}
newState := buildHostnameState(records, now)
w.state.SetHostnameState(domain, newState)
}
func (w *Watcher) detectNSChanges(
@@ -298,77 +310,11 @@ func (w *Watcher) detectNSChanges(
)
}
// resolveNameserverAddresses returns the sorted addresses each
// nameserver's name resolves to. A nameserver whose lookup fails, as it
// does when no nameserver of the name's zone answers, or finds no
// address keeps its addresses from prev and is not an address change.
func (w *Watcher) resolveNameserverAddresses(
ctx context.Context,
nameservers []string,
prev map[string][]string,
) map[string][]string {
addresses := make(map[string][]string, len(nameservers))
for _, ns := range nameservers {
ips, err := w.resolver.ResolveIPAddresses(ctx, ns)
if err == nil && len(ips) > 0 {
sort.Strings(ips)
addresses[ns] = ips
continue
}
w.log.Error(
"no addresses found for nameserver",
"nameserver", ns,
"error", err,
)
if prevIPs, ok := prev[ns]; ok {
addresses[ns] = prevIPs
}
}
return addresses
}
// detectNSAddressChanges notifies when a nameserver in both checks
// resolves to different addresses. A nameserver added or removed is
// reported by detectNSChanges alone, and one with no addresses saved by
// the previous check, as in a state file from before they were saved,
// is not compared.
func (w *Watcher) detectNSAddressChanges(
ctx context.Context,
domain string,
prev, current map[string][]string,
) {
for ns, cur := range current {
old, ok := prev[ns]
if !ok || sliceEqual(old, cur) {
continue
}
msg := fmt.Sprintf(
"Domain: %s\nNameserver: %s\nOld: %s\nNew: %s",
domain, ns,
strings.Join(old, ", "),
strings.Join(cur, ", "),
)
w.notify.SendNotification(
ctx,
"NS Address Change: "+domain,
msg,
"warning",
)
}
}
func (w *Watcher) checkHostname(
ctx context.Context,
hostname string,
) {
results, err := w.resolver.LookupAllRecords(ctx, hostname)
records, err := w.resolver.LookupAllRecords(ctx, hostname)
if err != nil {
w.log.Error(
"failed to lookup records",
@@ -379,92 +325,19 @@ func (w *Watcher) checkHostname(
return
}
newState := buildHostnameState(results, time.Now().UTC())
now := time.Now().UTC()
prev, hasPrev := w.state.GetHostnameState(hostname)
w.resolveCNAMEAddresses(ctx, hostname, newState, prev)
if hasPrev && !w.firstRun {
w.detectHostnameChanges(ctx, hostname, prev, newState)
w.detectHostnameChanges(ctx, hostname, prev, records)
}
newState := buildHostnameState(records, now)
w.state.SetHostnameState(hostname, newState)
}
// resolveCNAMEAddresses saves in current the addresses at the end of
// hostname's CNAME chain, when the nameservers' answers in current hold
// a CNAME and no address, and an empty list otherwise.
// ResolveIPAddresses looks the name up again and follows the chain. The
// addresses saved in prev, which may be nil, are kept when none of the
// name's nameservers answered, and when the chain cannot be followed, as
// when no nameserver of a zone in it answers.
func (w *Watcher) resolveCNAMEAddresses(
ctx context.Context,
hostname string,
current, prev *state.HostnameState,
) {
var prevAddresses []string
if prev != nil {
prevAddresses = prev.CNAMEAddresses
}
// Empty, not nil: nil means the addresses are not known.
current.CNAMEAddresses = []string{}
answered := false
hasCNAME := false
for _, nsState := range current.RecordsByNameserver {
if nsState.Status != statusOK {
continue
}
answered = true
if len(nsState.Records["A"]) > 0 || len(nsState.Records["AAAA"]) > 0 {
return
}
if len(nsState.Records["CNAME"]) > 0 {
hasCNAME = true
}
}
if !answered {
current.CNAMEAddresses = prevAddresses
return
}
if !hasCNAME {
return
}
ips, err := w.resolver.ResolveIPAddresses(ctx, hostname)
if err != nil {
w.log.Error(
"failed to follow CNAME",
"hostname", hostname,
"error", err,
)
current.CNAMEAddresses = prevAddresses
return
}
// Appended to the empty list, so a chain that ends in no address is
// saved as empty, not nil.
current.CNAMEAddresses = append(current.CNAMEAddresses, ips...)
}
// buildHostnameState saves each nameserver's response. A nameserver
// that answered, even with NXDOMAIN or no records, is saved as ok; one
// that timed out or failed is saved as error with the reason, and its
// empty record set is not an answer.
func buildHostnameState(
results map[string]*resolver.NameserverResponse,
records map[string]map[string][]string,
now time.Time,
) *state.HostnameState {
hs := &state.HostnameState{
@@ -474,20 +347,12 @@ func buildHostnameState(
LastChecked: now,
}
for ns, resp := range results {
nsState := &state.NameserverRecordState{
Records: resp.Records,
for ns, recs := range records {
hs.RecordsByNameserver[ns] = &state.NameserverRecordState{
Records: recs,
Status: statusOK,
LastChecked: now,
}
if resp.Status == resolver.StatusTimeout ||
resp.Status == resolver.StatusError {
nsState.Status = statusError
nsState.Error = resp.Error
}
hs.RecordsByNameserver[ns] = nsState
}
return hs
@@ -496,60 +361,27 @@ func buildHostnameState(
func (w *Watcher) detectHostnameChanges(
ctx context.Context,
hostname string,
prev, current *state.HostnameState,
prev *state.HostnameState,
current map[string]map[string][]string,
) {
w.detectRecordChanges(ctx, hostname, prev, current)
w.detectNSDisappearances(ctx, hostname, prev, current)
w.detectNSFailures(ctx, hostname, prev, current)
w.detectInconsistencies(ctx, hostname, prev, current)
w.detectCNAMEAddressChanges(ctx, hostname, prev, current)
w.detectInconsistencies(ctx, hostname, current)
}
// detectCNAMEAddressChanges notifies when the addresses at the end of
// hostname's CNAME chain differ from those the previous check saved,
// including a change from or to none. When the previous addresses are
// not known (nil), as on the first check after loading a state file
// written before they were saved, nothing is compared.
func (w *Watcher) detectCNAMEAddressChanges(
ctx context.Context,
hostname string,
prev, current *state.HostnameState,
) {
old, cur := prev.CNAMEAddresses, current.CNAMEAddresses
if old == nil || sliceEqual(old, cur) {
return
}
msg := fmt.Sprintf(
"Hostname: %s\nOld: %s\nNew: %s",
hostname,
strings.Join(old, ", "),
strings.Join(cur, ", "),
)
w.notify.SendNotification(
ctx,
"CNAME Address Change: "+hostname,
msg,
"warning",
)
}
// detectRecordChanges compares each nameserver's records with those of
// the previous check. Only answers are compared: a nameserver that
// failed on either check has no records to compare.
func (w *Watcher) detectRecordChanges(
ctx context.Context,
hostname string,
prev, current *state.HostnameState,
prev *state.HostnameState,
current map[string]map[string][]string,
) {
for ns, cur := range current.RecordsByNameserver {
for ns, recs := range current {
prevNS, ok := prev.RecordsByNameserver[ns]
if !ok || prevNS.Status != statusOK || cur.Status != statusOK {
if !ok {
continue
}
if recordsEqual(prevNS.Records, cur.Records) {
if recordsEqual(prevNS.Records, recs) {
continue
}
@@ -557,7 +389,7 @@ func (w *Watcher) detectRecordChanges(
"Hostname: %s\nNameserver: %s\n"+
"Old: %v\nNew: %v",
hostname, ns,
prevNS.Records, cur.Records,
prevNS.Records, recs,
)
w.notify.SendNotification(
@@ -572,10 +404,11 @@ func (w *Watcher) detectRecordChanges(
func (w *Watcher) detectNSDisappearances(
ctx context.Context,
hostname string,
prev, current *state.HostnameState,
prev *state.HostnameState,
current map[string]map[string][]string,
) {
for ns, prevNS := range prev.RecordsByNameserver {
if _, ok := current.RecordsByNameserver[ns]; ok || prevNS.Status != statusOK {
if _, ok := current[ns]; ok || prevNS.Status != statusOK {
continue
}
@@ -591,36 +424,13 @@ func (w *Watcher) detectNSDisappearances(
"error",
)
}
}
// detectNSFailures notifies when a nameserver that answered on the
// previous check fails, and when one that failed answers again. A
// nameserver missing from the previous check is not compared.
func (w *Watcher) detectNSFailures(
ctx context.Context,
hostname string,
prev, current *state.HostnameState,
) {
for ns, cur := range current.RecordsByNameserver {
for ns := range current {
prevNS, ok := prev.RecordsByNameserver[ns]
if !ok {
if !ok || prevNS.Status != statusError {
continue
}
switch {
case prevNS.Status == statusOK && cur.Status == statusError:
msg := fmt.Sprintf(
"Hostname: %s\nNameserver: %s\nError: %s",
hostname, ns, cur.Error,
)
w.notify.SendNotification(
ctx,
"NS Failure: "+hostname,
msg,
"error",
)
case prevNS.Status == statusError && cur.Status == statusOK:
msg := fmt.Sprintf(
"Hostname: %s\nNameserver: %s recovered",
hostname, ns,
@@ -634,21 +444,32 @@ func (w *Watcher) detectNSFailures(
)
}
}
}
func (w *Watcher) detectInconsistencies(
ctx context.Context,
hostname string,
prev, current *state.HostnameState,
current map[string]map[string][]string,
) {
for _, pair := range newlyDisagreeingPairs(prev, current) {
ns1, ns2 := pair[0], pair[1]
nameservers := make([]string, 0, len(current))
for ns := range current {
nameservers = append(nameservers, ns)
}
sort.Strings(nameservers)
for i := range len(nameservers) - 1 {
ns1 := nameservers[i]
ns2 := nameservers[i+1]
if recordsEqual(current[ns1], current[ns2]) {
continue
}
msg := fmt.Sprintf(
"Hostname: %s\n%s: %v\n%s: %v",
hostname,
ns1, current.RecordsByNameserver[ns1].Records,
ns2, current.RecordsByNameserver[ns2].Records,
ns1, current[ns1],
ns2, current[ns2],
)
w.notify.SendNotification(
@@ -660,51 +481,6 @@ func (w *Watcher) detectInconsistencies(
}
}
// newlyDisagreeingPairs returns every pair of nameservers that answered
// in current and whose records differ there, in sorted order of name,
// except pairs where both nameservers answered in prev and already
// differed there. A nameserver missing from prev, or that failed there,
// is paired with every nameserver it differs from. A nameserver that
// failed in current has no records to compare and is in no pair.
func newlyDisagreeingPairs(
prev, current *state.HostnameState,
) [][2]string {
nameservers := make([]string, 0, len(current.RecordsByNameserver))
for ns, cur := range current.RecordsByNameserver {
if cur.Status == statusOK {
nameservers = append(nameservers, ns)
}
}
sort.Strings(nameservers)
var pairs [][2]string
for i, ns1 := range nameservers {
for _, ns2 := range nameservers[i+1:] {
if recordsEqual(
current.RecordsByNameserver[ns1].Records,
current.RecordsByNameserver[ns2].Records,
) {
continue
}
prev1, ok1 := prev.RecordsByNameserver[ns1]
prev2, ok2 := prev.RecordsByNameserver[ns2]
if ok1 && ok2 &&
prev1.Status == statusOK && prev2.Status == statusOK &&
!recordsEqual(prev1.Records, prev2.Records) {
continue
}
pairs = append(pairs, [2]string{ns1, ns2})
}
}
return pairs
}
func (w *Watcher) checkAllPorts(ctx context.Context) {
// Phase 1: Build current IP:port → hostname associations
// from fresh DNS data.
@@ -787,51 +563,17 @@ func parsePortKey(key string) (string, int) {
}
// cleanupStalePorts removes port state entries that are no
// longer referenced by any hostname in the current DNS data. An
// entry saved for a configured name none of whose nameservers
// answered is kept: that name's addresses are not known, not gone.
// longer referenced by any hostname in the current DNS data.
func (w *Watcher) cleanupStalePorts(
currentAssociations map[string][]string,
) {
for _, key := range w.state.GetAllPortKeys() {
if _, exists := currentAssociations[key]; exists {
continue
}
ps, ok := w.state.GetPortState(key)
if ok && slices.ContainsFunc(ps.Hostnames, w.noNameserverAnswered) {
continue
}
if _, exists := currentAssociations[key]; !exists {
w.state.DeletePortState(key)
}
}
// noNameserverAnswered reports whether name is a configured domain or
// hostname and none of its nameservers answered on its last check.
func (w *Watcher) noNameserverAnswered(name string) bool {
if !slices.Contains(w.config.Hostnames, name) &&
!slices.Contains(w.config.Domains, name) {
return false
}
hs, ok := w.state.GetHostnameState(name)
if !ok {
return false
}
for _, nsState := range hs.RecordsByNameserver {
if nsState.Status == statusOK {
return false
}
}
return true
}
// collectIPs returns the addresses saved for hostname: those in its
// nameservers' A and AAAA records, and those at the end of its CNAME
// chain.
func (w *Watcher) collectIPs(hostname string) []string {
hs, ok := w.state.GetHostnameState(hostname)
if !ok {
@@ -850,10 +592,6 @@ func (w *Watcher) collectIPs(hostname string) []string {
}
}
for _, ip := range hs.CNAMEAddresses {
ipSet[ip] = true
}
result := make([]string, 0, len(ipSet))
for ip := range ipSet {
result = append(result, ip)
@@ -871,13 +609,6 @@ func (w *Watcher) checkSinglePort(
hostnames []string,
) {
result, err := w.portCheck.CheckPort(ctx, ip, port)
// A check the context cut short says nothing about the port, so it
// is neither saved nor notified.
if ctx.Err() != nil {
return
}
if err != nil {
w.log.Error(
"port check failed",
@@ -912,24 +643,9 @@ func (w *Watcher) checkSinglePort(
)
}
// A configured name on the saved list none of whose nameservers
// answered stays on it, so the entry is kept when the other names
// stop resolving to this address.
savedHostnames := slices.Clone(hostnames)
if hasPrev {
for _, name := range prev.Hostnames {
if !slices.Contains(hostnames, name) && w.noNameserverAnswered(name) {
savedHostnames = append(savedHostnames, name)
}
}
sort.Strings(savedHostnames)
}
w.state.SetPortState(key, &state.PortState{
Open: result.Open,
Hostnames: savedHostnames,
Hostnames: hostnames,
LastChecked: now,
})
}
@@ -968,13 +684,6 @@ func (w *Watcher) checkTLSCert(
hostname string,
) {
cert, err := w.tlsCheck.CheckCertificate(ctx, ip, hostname)
// A check the context cut short says nothing about the certificate,
// so it is neither saved nor notified.
if ctx.Err() != nil {
return
}
certKey := fmt.Sprintf("%s:%d:%s", ip, tlsPort, hostname)
now := time.Now().UTC()
prev, hasPrev := w.state.GetCertificateState(certKey)
@@ -1113,6 +822,22 @@ func (w *Watcher) checkTLSExpiry(
return
}
// Deduplicate expiry warnings: don't re-notify for the same
// hostname within the TLS check interval.
dedupKey := fmt.Sprintf("expiry:%s:%s", hostname, ip)
w.expiryNotifiedMu.Lock()
lastNotified, seen := w.expiryNotified[dedupKey]
if seen && time.Since(lastNotified) < w.config.TLSInterval {
w.expiryNotifiedMu.Unlock()
return
}
w.expiryNotified[dedupKey] = time.Now()
w.expiryNotifiedMu.Unlock()
msg := fmt.Sprintf(
"Host: %s\nIP: %s\nCN: %s\n"+
"Expires: %s (%.0f days)",
internal/watcher/watcher_test.go
+475 -511
View File
File diff suppressed because it is too large Load Diff
package.json
-9
View File
@@ -1,9 +0,0 @@
{
"name": "dnswatcher-tooling",
"version": "0.0.0",
"private": true,
"description": "Pins the prettier that script/fmt and script/fmt-check run against this repo's markdown. Not a JavaScript project; nothing here is imported, published, or shipped.",
"devDependencies": {
"prettier": "3.9.6"
}
}
script/bootstrap
+12 -13
View File
@@ -3,16 +3,18 @@
# this repo. Idempotent: every install is guarded by a check so already
# installed tools are skipped. Base tooling comes from nix, apt, brew,
# or apk (detected in that order); assumes nothing is present.
# goimports is not installed here: script/fmt and script/fmt-check-go
# run it with `go run` at a pinned commit.
# The linter is NOT installed here: golangci-lint runs via docker only
# (script/lint), pinned by image digest, so its only prerequisite is a
# working docker. Nor is prettier: script/fmt and
# script/fmt-check-markdown run it in a container from Dockerfile.fmt.
# golangci-lint and goimports are installed via `go install` at the same
# pinned commits the Dockerfile uses (never "latest").
set -eu
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
# Pinned versions, 2026-08-07 (same pins as the Dockerfile)
# golangci-lint v2.12.2
GOLANGCI_LINT_REF="github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5"
# goimports v0.42.0
GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
PKGMGR=""
SUDO=""
APT_UPDATED=""
@@ -67,13 +69,10 @@ main() {
if missing make; then pkg_install gnumake make make make; fi
if missing go; then pkg_install go golang go go; fi
# Linting and the markdown formatter run via docker only. Warn,
# don't fail: building and testing work without it.
if missing docker; then
echo "bootstrap: WARNING: docker not found; install it to" \
"run make lint, make fmt, make fmt-check, make check" \
"and make docker." >&2
fi
# Lint/format tools, pinned via go install (installs into
# "$(go env GOPATH)/bin"; ensure that is on your PATH).
if missing golangci-lint; then go install "$GOLANGCI_LINT_REF"; fi
if missing goimports; then go install "$GOIMPORTS_REF"; fi
go mod download
script/cibuild
+4 -14
View File
@@ -1,23 +1,13 @@
#!/bin/sh
# script/cibuild: run the CI build. The Dockerfile's lint stage runs
# the Go half of make fmt-check and golangci-lint; its builder stage
# runs make test and make build. The markdown half of make fmt-check
# runs after that build, as its own build of Dockerfile.fmt, because
# there is no docker inside a docker build.
#
# --no-cache-filter=lint,builder runs both stages on every invocation;
# otherwise an unchanged tree is served from the layer cache and passes
# without linting or querying live DNS. script/fmt-check-markdown busts
# its own cache the same way.
# script/cibuild: run the CI build. The Dockerfile runs make check, so
# a successful build implies all checks pass.
set -eu
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
main() {
cd "$ROOT"
docker build --no-cache-filter=lint,builder .
"$SCRIPT_DIR/fmt-check-markdown"
docker build .
}
main "$@"
script/docker
+2 -14
View File
@@ -1,10 +1,6 @@
#!/bin/sh
# script/docker: build the Docker image tagged with the project name.
# The tag comes from script/projectname.
#
# --no-cache-filter=lint,builder runs the lint stage and the builder
# stage (make test) on every invocation; otherwise an unchanged tree is
# served from the layer cache without linting or querying live DNS.
# Identical in all repos; the tag comes from script/projectname.
set -eu
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -12,15 +8,7 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
main() {
cd "$ROOT"
# Own line: a failing command substitution inside an argument does
# not trip `set -e`, so the inline form degrades silently to an
# empty constant. VERSION is computed here because .dockerignore
# excludes .git, so `git describe` in a build stage cannot find it.
version="$(git describe --tags --always --dirty 2>/dev/null || true)"
[ -n "$version" ] || version="unknown"
docker build --no-cache-filter=lint,builder \
--build-arg VERSION="$version" \
-t "$("$SCRIPT_DIR/projectname")" .
docker build -t "$("$SCRIPT_DIR/projectname")" .
}
main "$@"
script/fmt
+2 -54
View File
@@ -1,65 +1,13 @@
#!/bin/sh
# script/fmt: format all files (writes). Go with gofmt and goimports on
# the host, markdown with the prettier pinned by Dockerfile.fmt.
#
# goimports runs with `go run` at a pinned commit, never from PATH, so
# every machine formats with the same version and nothing installs it.
#
# The markdown pass is a `docker build --output type=local` rather than a
# `docker run -v`, so it needs no bind mount and behaves the same against
# a remote daemon; the formatted documents come back out of the build and
# are copied over the tree here.
#
# Unlike script/fmt-check-markdown this does not bust the cache: it is
# not a gate, and any edit to a document changes the COPY layer above the
# prettier step, so a cached result is a result over this exact tree.
# script/fmt: format all files (writes).
set -eu
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
# goimports v0.42.0, 2026-08-07. Must match script/fmt-check-go.
GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
# Must match the export stage name in Dockerfile.fmt.
stage=fmt-out
die() {
echo "script/fmt: $*" >&2
exit 1
}
main() {
cd "$ROOT"
gofmt -s -w .
go run "$GOIMPORTS_REF" -w .
tmp="$(mktemp -d "${TMPDIR:-/tmp}/dnswatcher-fmt.XXXXXX")"
trap 'rm -rf "$tmp"' EXIT INT TERM
docker build \
--target "$stage" \
--output "type=local,dest=$tmp/out" \
-f Dockerfile.fmt .
# An empty export means prettier was handed nothing, which must not
# read as "already formatted".
(cd "$tmp/out" && find . -type f -name '*.md') |
sed 's|^\./||' | LC_ALL=C sort >"$tmp/files"
[ -s "$tmp/files" ] ||
die "the formatting build produced no markdown; the build" \
"context reached prettier empty"
# Copied only where the bytes differ, so an already-formatted tree
# keeps its timestamps and says nothing.
while IFS= read -r f; do
[ -n "$f" ] || continue
if [ -f "$f" ] && cmp -s "$tmp/out/$f" "$f"; then
continue
fi
cp "$tmp/out/$f" "$f"
echo "prettier: reformatted $f"
done <"$tmp/files"
goimports -w .
}
main "$@"
script/fmt-check
+10 -6
View File
@@ -1,14 +1,18 @@
#!/bin/sh
# script/fmt-check: check formatting (read-only). Same tools and scope
# as script/fmt, but fails instead of writing: the Go on the host, the
# markdown with prettier in a container.
# script/fmt-check: check formatting (read-only). Same scope as
# script/fmt, but fails instead of writing.
set -eu
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
main() {
"$SCRIPT_DIR/fmt-check-go"
"$SCRIPT_DIR/fmt-check-markdown"
cd "$ROOT"
files="$(gofmt -l .)"
if [ -n "$files" ]; then
echo "gofmt: files not formatted:" >&2
echo "$files" >&2
exit 1
fi
}
main "$@"
script/fmt-check-go
-31
View File
@@ -1,31 +0,0 @@
#!/bin/sh
# script/fmt-check-go: fail unless every Go source is formatted the way
# script/fmt would leave it, and name the files that are not. Read-only.
#
# Its own script because the Dockerfile's lint stage runs this half
# alone: there is no docker inside a docker build to run the markdown
# half in.
set -eu
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
# goimports v0.42.0, 2026-08-07. Must match script/fmt.
GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
main() {
cd "$ROOT"
files="$(gofmt -s -l .)"
if [ -n "$files" ]; then
echo "gofmt: files not formatted:" >&2
echo "$files" >&2
exit 1
fi
files="$(go run "$GOIMPORTS_REF" -l .)"
if [ -n "$files" ]; then
echo "goimports: files not formatted:" >&2
echo "$files" >&2
exit 1
fi
}
main "$@"
script/fmt-check-markdown
-29
View File
@@ -1,29 +0,0 @@
#!/bin/sh
# script/fmt-check-markdown: fail unless every .md is formatted the way
# script/fmt would leave it. Read-only.
#
# prettier is never installed on the host: it runs in a container built
# from Dockerfile.fmt, pinned by package.json and yarn.lock.
# --no-cache-filter is here for the reason script/lint gives: a cached
# build checks nothing.
#
# Its own script because script/cibuild runs this half alone, after the
# Dockerfile's lint stage has checked the Go.
set -eu
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
# Must match the markdown check stage name in Dockerfile.fmt.
stage=fmt-check
main() {
cd "$ROOT"
docker build \
--progress=plain \
--no-cache-filter="$stage" \
--target "$stage" \
-f Dockerfile.fmt \
.
}
main "$@"
script/install-precommit
+1 -14
View File
@@ -7,20 +7,7 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
main() {
cd "$ROOT"
# Stop if this directory is not the top of its own git checkout, for
# example a copy inside another repository, whose hook must not be
# replaced.
if [ "$(git rev-parse --show-toplevel)" != "$ROOT" ]; then
echo "install-precommit: $ROOT is not the top of a git checkout" >&2
exit 1
fi
# Ask git for the repository's own git directory: .git is a file, not
# a directory, in some checkouts (for example a clone made with
# --separate-git-dir). core.hooksPath is deliberately not followed, so
# the hook is never written outside this repository.
hooks="$(git rev-parse --git-common-dir)/hooks"
mkdir -p "$hooks"
hook="$hooks/pre-commit"
hook=".git/hooks/pre-commit"
printf '#!/bin/sh\nset -e\nscript/precommit\n' > "$hook"
chmod +x "$hook"
echo "pre-commit hook installed: runs script/precommit"
script/lint
+30 -17
View File
@@ -1,28 +1,41 @@
#!/bin/sh
# script/lint: run the linter. golangci-lint is never installed or run
# on the host: it runs via docker only, one way, everywhere. This
# builds Dockerfile.lint, which COPYs the repo into the digest-pinned
# golangci-lint image and lints as a build step, so a successful build
# means a clean lint.
# script/lint: run the linter.
#
# --no-cache-filter=lint forces the lint stage (source copy + linter
# run) to execute on every invocation. Without it an unchanged tree
# returns success in well under a second having linted nothing. The
# deps stage (base image + go mod download) stays cached, and no global
# cache invalidation is performed. --progress=plain keeps the linter's
# own output visible.
# golangci-lint keeps two pieces of per-user global state, and both of
# them break when several checkouts on one host lint concurrently:
#
# 1. Its analysis cache (GOLANGCI_LINT_CACHE, default
# ~/.cache/golangci-lint). Entries are keyed by content, not by
# checkout, so a hit written by another checkout is replayed
# verbatim - including that checkout's file paths. The run then
# reports findings for files it never linted.
#
# 2. Its "one runner at a time" lock, which does NOT live in the
# cache directory: golangci-lint locks
# $(os.TempDir())/golangci-lint.lock, i.e.
# "$TMPDIR"/golangci-lint.lock (pkg/commands/run.go,
# acquireFileLock). It waits 5s, then aborts with "parallel
# golangci-lint is running" - a non-result that looks like a lint
# failure. Setting GOLANGCI_LINT_CACHE alone does not move it.
#
# So both are pinned under the checkout root. The cache is never shared,
# and TMPDIR makes the lock file per-checkout, which keeps the lock
# doing its actual job (serialising runs that share one cache) at the
# right scope. .lint-cache/ is git-ignored and Docker-ignored, and
# caching still works: it persists across runs in this checkout.
set -eu
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
main() {
cd "$ROOT"
docker build \
--progress=plain \
--no-cache-filter=lint \
--target lint \
-f Dockerfile.lint \
.
GOLANGCI_LINT_CACHE="$ROOT/.lint-cache/cache"
TMPDIR="$ROOT/.lint-cache/tmp"
export GOLANGCI_LINT_CACHE TMPDIR
mkdir -p "$GOLANGCI_LINT_CACHE" "$TMPDIR"
golangci-lint run --config .golangci.yml ./...
}
main "$@"
script/test
+1 -24
View File
@@ -1,35 +1,12 @@
#!/bin/sh
# script/test: run the test suite.
#
# -count=1 disables Go's test cache, and is load-bearing here. This
# suite queries live DNS on every run by policy (TESTING.md); a cached
# result is a replay of an earlier run's output with no query made at
# all. On an unchanged tree the whole suite would return success in
# under a second having resolved nothing, which makes the repeated-run
# green that is used as evidence for flakiness fixes worthless. Do not
# remove it.
#
# Conditional verbose rerun per REPO_POLICIES.md: run quiet first so
# CI and docker build logs stay readable, and rerun with -v only on
# failure. The rerun also carries -count=1 (a cached replay of the
# failure would show nothing new), and the exit status is forced to 1
# no matter how the rerun ends: the first failure already proved the
# suite broken, so a flaky test that passes the second time must not
# turn the build green.
#
# -timeout 90s is a deliberate backstop above the 60s hard cap on
# suite duration. Do not lower it.
set -eu
ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
main() {
cd "$ROOT"
go test -count=1 -race -timeout 90s -cover ./... || {
echo "--- Rerunning with -v for details ---" >&2
go test -count=1 -race -timeout 90s -v ./... || true
exit 1
}
go test -v -race -timeout 30s -cover ./...
}
main "$@"
yarn.lock
-8
View File
@@ -1,8 +0,0 @@
# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
# yarn lockfile v1
prettier@3.9.6:
version "3.9.6"
resolved "https://registry.yarnpkg.com/prettier/-/prettier-3.9.6.tgz#b3ea5146515d40fc53f18aa63f74dfab1e10dbf6"
integrity sha512-OpN0zzVdiaiAhxpuuj5efpIS4sY9j7bY6uR5mnj5yPzGkdkjNKSJeUThPb60Jw29QuAZgA4o+/iB49kFiaBX6g==