build: always install pinned lint tools in script/bootstrap (closes #117)

`script/bootstrap` guarded its pinned `go install` calls with
`missing()`, which only tests whether a binary is on `PATH`. On any
machine that already had some `golangci-lint`, the install was skipped
and the commit pin had no effect: a v1.x binary cannot parse this
repo's v2-schema `.golangci.yml`, and a different v2.x can silently
disagree with CI. The same reasoning made the v2.12.2 pin bump inert
on every already-provisioned machine.

Install both pinned tools unconditionally. `go install` at a fixed
commit ref is idempotent and cheap with a warm module cache, so
skipping it saved nothing. The `missing()` presence check is kept for
`git`, `make`, and `go`, which really are system-package presence
checks.

Also warn when `PATH` resolves either tool somewhere other than the
directory `go install` writes to, since a shadowing copy earlier on
`PATH` is what `make lint` and `make fmt` would actually run. This is
a warning, not a failure: the remedy is the user's `PATH`.

The pins themselves are unchanged and still match the Dockerfile.

.gitea/workflows/check.yml

@@ -6,4 +6,4 @@ jobs:
         steps:
             # actions/checkout v4.2.2, 2026-02-28
             - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-            - run: docker build .
+            - run: script/cibuild

.golangci.yml

@@ -1,5 +1,9 @@
 version: "2"
 
+# Config schema uses the golangci-lint v2 layout (settings live under
+# linters.settings, not top-level linters-settings) so that the
+# thresholds below are actually applied by golangci-lint >= v2.
+
 run:
   timeout: 5m
   modules-download-mode: readonly
@@ -14,8 +18,7 @@ linters:
     - wsl              # Deprecated, replaced by wsl_v5
     - wrapcheck        # Too verbose for internal packages
     - varnamelen       # Short names like db, id are idiomatic Go
-
+  settings:
-linters-settings:
     lll:
       line-length: 88
     funlen:
@@ -27,6 +30,5 @@ linters-settings:
       threshold: 100
 
 issues:
-  exclude-use-default: false
   max-issues-per-linter: 0
   max-same-issues: 0

Dockerfile

@@ -4,8 +4,8 @@ FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4
 
 RUN apk add --no-cache git make gcc musl-dev binutils-gold
 
-# golangci-lint v2.10.1
+# golangci-lint v2.12.2, 2026-08-07
-RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@5d1e709b7be35cb2025444e19de266b056b7b7ee
+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
 

Makefile

@@ -1,48 +1,44 @@
-.PHONY: all build lint fmt fmt-check test check clean hooks docker
+.PHONY: all bootstrap setup build lint fmt fmt-check test check clean hooks docker
 
 BINARY := dnswatcher
 VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
 LDFLAGS := -X main.Version=$(VERSION)
 
+# Standard targets are thin shims; the implementations live in script/
+# per the scripts-to-rule-them-all pattern (see the Entrypoints section
+# of README.md).
+
 all: check build
 
+bootstrap:
+	@script/bootstrap
+
+setup:
+	@script/setup
+
 build:
 	go build -ldflags "$(LDFLAGS)" -o bin/$(BINARY) ./cmd/dnswatcher
 
+test:
+	@script/test
+
 lint:
-	golangci-lint run --config .golangci.yml ./...
+	@script/lint
 
 fmt:
-	gofmt -s -w .
+	@script/fmt
-	goimports -w .
 
 fmt-check:
-	@test -z "$$(gofmt -l .)" || (echo "gofmt: files not formatted:" && gofmt -l . && exit 1)
+	@script/fmt-check
 
-test:
-	go test -v -race -timeout 30s -cover ./...
-
-# Check runs all validation without making changes
-# Used by CI and Docker build - fails if anything is wrong
 check:
-	@echo "==> Checking formatting..."
+	@script/check
-	@test -z "$$(gofmt -l .)" || (echo "Files not formatted:" && gofmt -l . && exit 1)
+
-	@echo "==> Running linter..."
+docker:
-	golangci-lint run --config .golangci.yml ./...
+	@script/docker
-	@echo "==> Running tests..."
+
-	go test -v -race -timeout 30s ./...
+hooks:
-	@echo "==> Building..."
+	@script/install-precommit
-	go build -ldflags "$(LDFLAGS)" -o /dev/null ./cmd/dnswatcher
-	@echo "==> All checks passed!"
 
 clean:
 	rm -rf bin/
-
-hooks:
-	@echo '#!/bin/sh' > .git/hooks/pre-commit
-	@echo 'make check' >> .git/hooks/pre-commit
-	@chmod +x .git/hooks/pre-commit
-	@echo "Pre-commit hook installed."
-
-docker:
-	docker build .

README.md

@@ -17,6 +17,26 @@ 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.
+
+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.
+
+Contributions that introduce mocked, faked, or stubbed DNS will be
+rejected.
+
+---
+
 ## Features
 
 ### DNS Domain Monitoring (Apex Domains)
@@ -352,6 +372,32 @@ tracks reachability:
 
 ---
 
+## Entrypoints
+
+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:
+
+- `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
+- `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`
+- `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
 
 ```sh
@@ -359,7 +405,7 @@ make build      # Build binary to bin/dnswatcher
 make test       # Run tests with race detector
 make lint       # Run golangci-lint
 make fmt        # Format code
-make check      # Run all checks (format, lint, test, build)
+make check      # Run all checks (test, lint, fmt-check)
 make clean      # Remove build artifacts
 ```
 

REPO_POLICIES.md

@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-02-22
+last_modified: 2026-07-06
 ---
 
 This document covers repository structure, tooling, and workflow standards. Code
@@ -34,10 +34,46 @@ style conventions are in separate documents:
   every file before committing. There are zero exceptions to this rule.
 
 - Every repo with software must have a root `Makefile` with these targets:
-  `make test`, `make lint`, `make fmt` (writes), `make fmt-check` (read-only),
+  `make bootstrap`, `make setup`, `make test`, `make lint`, `make fmt` (writes),
-  `make check` (prereqs: `test`, `lint`, `fmt-check`), `make docker`, and
+  `make fmt-check` (read-only), `make check` (runs `test`, `lint`, `fmt-check`),
-  `make hooks` (installs pre-commit hook). A model Makefile is at
+  `make docker`, and `make hooks` (installs pre-commit hook). A model Makefile
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/Makefile`.
+  is at `https://git.eeqj.de/sneak/prompts/raw/branch/main/Makefile`.
+
+- Repos follow the
+  [Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
+  pattern: the implementation of each Makefile target lives in an executable
+  script in `script/` (`script/bootstrap`, `script/setup`, `script/test`,
+  `script/lint`, `script/fmt`, `script/fmt-check`, `script/check`,
+  `script/docker`), and the Makefile targets are thin shims that call them. The
+  scripts must be POSIX sh (`#!/bin/sh`, `set -eu`, no bashisms) so they run in
+  minimal containers (e.g. alpine images have no bash); locate the repo root
+  with `$(cd "$(dirname "$0")/.." && pwd -P)` and `cd` there before acting. From
+  the standard's canonical set we use `bootstrap`, `setup` (make the repo ready
+  for development after a fresh clone: runs `bootstrap`, then
+  `install-precommit`, plus any repo-specific initialization), `test`, and
+  `cibuild`. `script/bootstrap` installs all dependencies idempotently and
+  assumes nothing is present: base tools come from nix, apt, brew, or apk
+  (detected in that order; apt runs noninteractive). For node it uses the
+  installed node if present; otherwise it installs a PINNED node version via
+  nvm, first installing nvm itself if missing — from a hash-verified GitHub
+  release archive (never `curl | sh`), with bash installed as an explicit
+  prerequisite since nvm requires bash. yarn is then pinned via
+  `corepack prepare yarn@<version> --activate`. Never install "latest" or "lts";
+  always exact versions. `script/cibuild` runs the CI build: it changes to the
+  repo root and runs `docker build .`; the Gitea workflow calls it. Four further
+  scripts are our own extensions to the standard: `script/check` runs
+  `script/test`, `script/lint`, and `script/fmt-check`; `script/precommit` is
+  what the git pre-commit hook runs, and it calls `script/check`;
+  `script/install-precommit` installs the git pre-commit hook (the `make hooks`
+  target shims to it); and `script/projectname` (literally that filename) simply
+  outputs the project's name. Scripts that need the name call
+  `script/projectname` — e.g. `script/docker` assembles its image tag from it —
+  so those scripts stay byte-identical across all repos. Repo-type-specific
+  pre-commit extras (e.g. `go mod tidy` verification in Go repos) belong in
+  `script/precommit`, not in the hook itself. Model scripts are at
+  `https://git.eeqj.de/sneak/prompts/raw/branch/main/script/<name>`. The README
+  must document the provided scripts in an **Entrypoints** section (see the
+  README requirements below).
 
 - Always use Makefile targets (`make fmt`, `make test`, `make lint`, etc.)
   instead of invoking the underlying tools directly. The Makefile is the single
@@ -57,11 +93,83 @@ style conventions are in separate documents:
   as a build step so the build fails if the branch is not green. For non-server
   repos, the Dockerfile should bring up a development environment and run
   `make check`. For server repos, `make check` should run as an early build
-  stage before the final image is assembled.
+  stage before the final image is assembled. Dockerfiles install development
+  prerequisites by running `script/bootstrap` rather than duplicating installs
+  inline; COPY `script/` and the dependency manifests (`package.json` +
+  `yarn.lock`, `go.mod` + `go.sum`, etc.) before running it so the bootstrap
+  layer stays cached until dependencies change.
+
+- **Dockerfiles must use a separate lint stage for fail-fast feedback.** Go
+  repos use a multistage build where linting runs in an independent stage based
+  on the `golangci/golangci-lint` image (pinned by hash). This stage runs
+  `make fmt-check` and `make lint` before the full build begins. The build stage
+  then declares an explicit dependency on the lint stage via
+  `COPY --from=lint /src/go.sum /dev/null`, which forces BuildKit to complete
+  linting before proceeding to compilation and tests. This ensures lint failures
+  surface in seconds rather than minutes, without blocking on dependency
+  download or compilation in the build stage.
+
+    The standard pattern for a Go repo Dockerfile is:
+
+    ```dockerfile
+    # Lint stage — fast feedback on formatting and lint issues
+    # golangci/golangci-lint:v2.x.x, YYYY-MM-DD
+    FROM golangci/golangci-lint@sha256:... AS lint
+    WORKDIR /src
+    COPY go.mod go.sum ./
+    RUN go mod download
+    COPY . .
+    RUN make fmt-check
+    RUN make lint
+
+    # Build stage
+    # golang:1.x-alpine, YYYY-MM-DD
+    FROM golang@sha256:... AS builder
+    WORKDIR /src
+
+    # Force BuildKit to run the lint stage before proceeding
+    COPY --from=lint /src/go.sum /dev/null
+
+    COPY go.mod go.sum ./
+    RUN go mod download
+    COPY . .
+    RUN make test
+
+    ARG VERSION=dev
+    RUN CGO_ENABLED=0 go build -trimpath \
+        -ldflags="-s -w -X main.Version=${VERSION}" \
+        -o /app ./cmd/app/
+
+    # Runtime stage
+    FROM alpine@sha256:...
+    COPY --from=builder /app /usr/local/bin/app
+    ENTRYPOINT ["app"]
+    ```
+
+    Key points:
+    - The lint stage uses the `golangci/golangci-lint` image directly (it
+      includes both Go and the linter), so there is no need to install the
+      linter separately.
+    - `COPY --from=lint /src/go.sum /dev/null` is a no-op file copy that creates
+      a stage dependency. BuildKit runs stages in parallel by default; without
+      this line, the build stage would not wait for lint to finish and a lint
+      failure might not fail the overall build.
+    - If the project uses `//go:embed` directives that reference build artifacts
+      (e.g. a web frontend compiled in a separate stage), the lint stage must
+      create placeholder files so the embed directives resolve. Example:
+      `RUN mkdir -p web/dist && touch web/dist/index.html web/dist/style.css`.
+      The lint stage should not depend on the actual build output — it exists to
+      fail fast.
+    - If the project requires CGO or system libraries for linting (e.g.
+      `vips-dev`), install them in the lint stage with `apk add`.
+    - The build stage runs `make test` after compilation setup. Tests run in the
+      build stage, not the lint stage, because they may require compiled
+      artifacts or heavier dependencies.
 
 - Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
-  runs `docker build .` on push. Since the Dockerfile already runs `make check`,
+  runs `script/cibuild` (which runs `docker build .`) on push. Since the
-  a successful build implies all checks pass.
+  Dockerfile already runs `make check`, a successful build implies all checks
+  pass.
 
 - Use platform-standard formatters: `black` for Python, `prettier` for
   JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
@@ -69,9 +177,11 @@ style conventions are in separate documents:
   Markdown (hard-wrap at 80 columns). Documentation and writing repos (Markdown,
   HTML, CSS) should also have `.prettierrc` and `.prettierignore`.
 
-- Pre-commit hook: `make check` if local testing is possible, otherwise
+- Pre-commit hook: runs `script/precommit`, which calls `script/check`. If local
-  `make lint && make fmt-check`. The Makefile should provide a `make hooks`
+  testing is not possible in the repo, `script/precommit` may skip `script/test`
-  target to install the pre-commit hook.
+  and run only `script/lint` and `script/fmt-check`. The hook is installed by
+  `script/install-precommit`; the Makefile must provide a `make hooks` target
+  that shims to it.
 
 - All repos with software must have tests that run via the platform-standard
   test framework (`go test`, `pytest`, `jest`/`vitest`, etc.). If no meaningful
@@ -82,6 +192,42 @@ style conventions are in separate documents:
 - `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
+  show full output. This keeps CI logs and `docker build` output clean on
+  success (just package/suite summaries) while providing full diagnostic detail
+  on failure (every test case, every assertion). The general shell pattern:
+
+    ```makefile
+    test:
+    	@<test-command> || \
+    		{ echo "--- Rerunning with -v for details ---"; \
+    		  <test-command-with-v>; exit 1; }
+    ```
+
+    Go example:
+
+    ```makefile
+    test:
+    	@go test -timeout 30s -race -cover ./... || \
+    		{ echo "--- Rerunning with -v for details ---"; \
+    		  go test -timeout 30s -race -v ./...; exit 1; }
+    ```
+
+    Python example:
+
+    ```makefile
+    test:
+    	@python -m pytest || \
+    		{ echo "--- Rerunning with -v for details ---"; \
+    		  python -m pytest -v; exit 1; }
+    ```
+
+    The `exit 1` ensures the target always fails after a rerun — the first run
+    already proved the tests are broken, so the build must not pass even if a
+    flaky test happens to succeed on the second attempt. The rerun exists solely
+    for diagnostic output.
+
 - Docker builds must complete in under 5 minutes.
 
 - `make check` must not modify any files in the repo. Tests may use temporary
@@ -98,6 +244,13 @@ style conventions are in separate documents:
   `https://git.eeqj.de/sneak/prompts/raw/branch/main/.gitignore` when setting up
   a new repo.
 
+- **No build artifacts in version control.** Code-derived data (compiled
+  bundles, minified output, generated assets) must never be committed to the
+  repository if it can be avoided. The build process (e.g. Dockerfile, Makefile)
+  should generate these at build time. Notable exception: Go protobuf generated
+  files (`.pb.go`) ARE committed because repos need to work with `go get`, which
+  downloads code but does not execute code generation.
+
 - Never use `git add -A` or `git add .`. Always stage files explicitly by name.
 
 - Never force-push to `main`.
@@ -121,12 +274,76 @@ style conventions are in separate documents:
 - Dockerized web services listen on port 8080 by default, overridable with
   `PORT`.
 
+- **HTTP/web services must be hardened for production internet exposure before
+  tagging 1.0.** This means full compliance with security best practices
+  including, without limitation, all of the following:
+    - **Security headers** on every response:
+        - `Strict-Transport-Security` (HSTS) with `max-age` of at least one year
+          and `includeSubDomains`.
+        - `Content-Security-Policy` (CSP) with a restrictive default policy
+          (`default-src 'self'` as a baseline, tightened per-resource as
+          needed). Never use `unsafe-inline` or `unsafe-eval` unless
+          unavoidable, and document the reason.
+        - `X-Frame-Options: DENY` (or `SAMEORIGIN` if framing is required).
+          Prefer the `frame-ancestors` CSP directive as the primary control.
+        - `X-Content-Type-Options: nosniff`.
+        - `Referrer-Policy: strict-origin-when-cross-origin` (or stricter).
+        - `Permissions-Policy` restricting access to browser features the
+          application does not use (camera, microphone, geolocation, etc.).
+    - **Request and response limits:**
+        - Maximum request body size enforced on all endpoints (e.g. Go
+          `http.MaxBytesReader`). Choose a sane default per-route; never accept
+          unbounded input.
+        - Maximum response body size where applicable (e.g. paginated APIs).
+        - `ReadTimeout` and `ReadHeaderTimeout` on the `http.Server` to defend
+          against slowloris attacks.
+        - `WriteTimeout` on the `http.Server`.
+        - `IdleTimeout` on the `http.Server`.
+        - Per-handler execution time limits via `context.WithTimeout` or
+          chi/stdlib `middleware.Timeout`.
+    - **Authentication and session security:**
+        - Rate limiting on password-based authentication endpoints. API keys are
+          high-entropy and not susceptible to brute force, so they are exempt.
+        - CSRF tokens on all state-mutating HTML forms. API endpoints
+          authenticated via `Authorization` header (Bearer token, API key) are
+          exempt because the browser does not attach these automatically.
+        - Passwords stored using bcrypt, scrypt, or argon2 — never plain-text,
+          MD5, or SHA.
+        - Session cookies set with `HttpOnly`, `Secure`, and `SameSite=Lax` (or
+          `Strict`) attributes.
+    - **Reverse proxy awareness:**
+        - True client IP detection when behind a reverse proxy
+          (`X-Forwarded-For`, `X-Real-IP`). The application must accept
+          forwarded headers only from a configured set of trusted proxy
+          addresses — never trust `X-Forwarded-For` unconditionally.
+    - **CORS:**
+        - Authenticated endpoints must restrict `Access-Control-Allow-Origin` to
+          an explicit allowlist of known origins. Wildcard (`*`) is acceptable
+          only for public, unauthenticated read-only APIs.
+    - **Error handling:**
+        - Internal errors must never leak stack traces, SQL queries, file paths,
+          or other implementation details to the client. Return generic error
+          messages in production; detailed errors only when `DEBUG` is enabled.
+    - **TLS:**
+        - Services never terminate TLS directly. They are always deployed behind
+          a TLS-terminating reverse proxy. The service itself listens on plain
+          HTTP. However, HSTS headers and `Secure` cookie flags must still be
+          set by the application so that the browser enforces HTTPS end-to-end.
+
+    This list is non-exhaustive. Apply defense-in-depth: if a standard security
+    hardening measure exists for HTTP services and is not listed here, it is
+    still expected. When in doubt, harden.
+
 - `README.md` is the primary documentation. Required sections:
     - **Description**: First line must include the project name, purpose,
       category (web server, SPA, CLI tool, etc.), license, and author. Example:
       "µPaaS is an MIT-licensed Go web application by @sneak that receives
       git-frontend webhooks and deploys applications via Docker in realtime."
     - **Getting Started**: Copy-pasteable install/usage code block.
+    - **Entrypoints**: Opens by stating that the repo adheres to the
+      [Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
+      standard (with that link), then documents each provided `script/`
+      entrypoint and its purpose.
     - **Rationale**: Why does this exist?
     - **Design**: How is the program structured?
     - **TODO**: Update meticulously, even between commits. When planning, put
@@ -145,11 +362,11 @@ style conventions are in separate documents:
 
 - Database migrations live in `internal/db/migrations/` and must be embedded in
   the binary.
-  - `000_migration.sql` — contains ONLY the creation of the migrations tracking
+    - `000_migration.sql` — contains ONLY the creation of the migrations
-    table itself. Nothing else.
+      tracking table itself. Nothing else.
     - `001_schema.sql` — the full application schema.
-  - **Pre-1.0.0:** never add additional migration files (002, 003, etc.). There
+    - **Pre-1.0.0:** never add additional migration files (002, 003, etc.).
-    is no installed base to migrate. Edit `001_schema.sql` directly.
+      There is no installed base to migrate. Edit `001_schema.sql` directly.
     - **Post-1.0.0:** add new numbered migration files for each schema change.
       Never edit existing migrations after release.
 
@@ -181,6 +398,9 @@ style conventions are in separate documents:
     - `README.md`, `.git`, `.gitignore`, `.editorconfig`
     - `LICENSE`, `REPO_POLICIES.md` (copy from the `prompts` repo)
     - `Makefile`
+    - `script/` entrypoints (`bootstrap`, `setup`, `projectname`, `test`,
+      `lint`, `fmt`, `fmt-check`, `check`, `docker`, `cibuild`, `precommit`,
+      `install-precommit`)
     - `Dockerfile`, `.dockerignore`
     - `.gitea/workflows/check.yml`
     - Go: `go.mod`, `go.sum`, `.golangci.yml`

TODO.md

@@ -0,0 +1,160 @@
+# Workflow
+
+* 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. 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
+
+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
+
+- 2026-08-09: `script/bootstrap` now installs the pinned `golangci-lint`
+  and `goimports` unconditionally instead of only when the binary is
+  absent from `PATH`, so the commit pins actually take effect on
+  already-provisioned machines; it also warns when `PATH` resolves
+  either tool to a copy outside the directory `go install` writes to.
+  The `missing` presence check is retained for `git`, `make`, and `go`
+  (#117)
+- 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
+  (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
+
+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

internal/config/classify_test.go

@@ -17,13 +17,33 @@ func TestClassifyDNSName(t *testing.T) {
 	}{
 		{name: "apex domain simple", input: "example.com", want: config.DNSNameTypeDomain},
 		{name: "hostname simple", input: "www.example.com", want: config.DNSNameTypeHostname},
-		{name: "apex domain multi-part TLD", input: "example.co.uk", want: config.DNSNameTypeDomain},
+		{
-		{name: "hostname multi-part TLD", input: "api.example.co.uk", want: config.DNSNameTypeHostname},
+			name:  "apex domain multi-part TLD",
+			input: "example.co.uk",
+			want:  config.DNSNameTypeDomain,
+		},
+		{
+			name:  "hostname multi-part TLD",
+			input: "api.example.co.uk",
+			want:  config.DNSNameTypeHostname,
+		},
 		{name: "public suffix itself", input: "co.uk", wantErr: true},
 		{name: "empty string", input: "", wantErr: true},
-		{name: "deeply nested hostname", input: "a.b.c.example.com", want: config.DNSNameTypeHostname},
+		{
-		{name: "trailing dot stripped", input: "example.com.", want: config.DNSNameTypeDomain},
+			name:  "deeply nested hostname",
-		{name: "uppercase normalized", input: "WWW.Example.COM", want: config.DNSNameTypeHostname},
+			input: "a.b.c.example.com",
+			want:  config.DNSNameTypeHostname,
+		},
+		{
+			name:  "trailing dot stripped",
+			input: "example.com.",
+			want:  config.DNSNameTypeDomain,
+		},
+		{
+			name:  "uppercase normalized",
+			input: "WWW.Example.COM",
+			want:  config.DNSNameTypeHostname,
+		},
 	}
 
 	for _, tt := range tests {

internal/notify/delivery_test.go

@@ -25,6 +25,20 @@ const (
 	colorDefault = "#6c757d"
 )
 
+// Priority strings used across multiple tests.
+const (
+	prioError   = "error"
+	prioWarning = "warning"
+	prioSuccess = "success"
+	prioInfo    = "info"
+	prioUnknown = "unknown"
+	prioDefault = "default"
+	prioUrgent  = "urgent"
+)
+
+// testHost is the hostname used in request construction tests.
+const testHost = "example.com"
+
 // errSimulated is a static error for transport failures.
 var errSimulated = errors.New("simulated transport failure")
 
@@ -101,13 +115,13 @@ func TestNtfyPriority(t *testing.T) {
 		input string
 		want  string
 	}{
-		{"error", "urgent"},
+		{prioError, prioUrgent},
-		{"warning", "high"},
+		{prioWarning, "high"},
-		{"success", "default"},
+		{prioSuccess, prioDefault},
-		{"info", "low"},
+		{prioInfo, "low"},
-		{"", "default"},
+		{"", prioDefault},
-		{"unknown", "default"},
+		{prioUnknown, prioDefault},
-		{"critical", "default"},
+		{"critical", prioDefault},
 	}
 
 	for _, tc := range cases {
@@ -134,12 +148,12 @@ func TestSlackColor(t *testing.T) {
 		input string
 		want  string
 	}{
-		{"error", colorError},
+		{prioError, colorError},
-		{"warning", colorWarning},
+		{prioWarning, colorWarning},
-		{"success", colorSuccess},
+		{prioSuccess, colorSuccess},
-		{"info", colorInfo},
+		{prioInfo, colorInfo},
 		{"", colorDefault},
-		{"unknown", colorDefault},
+		{prioUnknown, colorDefault},
 		{"critical", colorDefault},
 	}
 
@@ -165,7 +179,7 @@ func TestNewRequest(t *testing.T) {
 
 	target := &url.URL{
 		Scheme: "https",
-		Host:   "example.com",
+		Host:   testHost,
 		Path:   "/webhook",
 	}
 	body := bytes.NewBufferString("hello")
@@ -187,9 +201,9 @@ func TestNewRequest(t *testing.T) {
 		)
 	}
 
-	if req.Host != "example.com" {
+	if req.Host != testHost {
 		t.Errorf(
-			"Host = %q, want %q", req.Host, "example.com",
+			"Host = %q, want %q", req.Host, testHost,
 		)
 	}
 
@@ -217,7 +231,7 @@ func TestNewRequestPreservesContext(t *testing.T) {
 		ctxKey("k"),
 		"v",
 	)
-	target := &url.URL{Scheme: "https", Host: "example.com"}
+	target := &url.URL{Scheme: "https", Host: testHost}
 
 	req := notify.NewRequestForTest(
 		ctx, http.MethodGet, target, http.NoBody,
@@ -289,10 +303,10 @@ func TestSendNtfyHeaders(t *testing.T) {
 		)
 	}
 
-	if captured.priority != "urgent" {
+	if captured.priority != prioUrgent {
 		t.Errorf(
 			"Priority header = %q, want %q",
-			captured.priority, "urgent",
+			captured.priority, prioUrgent,
 		)
 	}
 
@@ -311,10 +325,10 @@ func TestSendNtfyAllPriorities(t *testing.T) {
 		input string
 		want  string
 	}{
-		{"error", "urgent"},
+		{prioError, prioUrgent},
-		{"warning", "high"},
+		{prioWarning, "high"},
-		{"success", "default"},
+		{prioSuccess, prioDefault},
-		{"info", "low"},
+		{prioInfo, "low"},
 	}
 
 	for _, tc := range priorities {
@@ -356,56 +370,69 @@ func TestSendNtfyAllPriorities(t *testing.T) {
 	}
 }
 
-func TestSendNtfyClientError(t *testing.T) {
+// assertSendStatusError verifies that send returns an error
-	t.Parallel()
+// wrapping wantErr when the server responds with status.
+func assertSendStatusError(
+	t *testing.T,
+	status int,
+	wantErr error,
+	send func(*notify.Service, *url.URL) error,
+) {
+	t.Helper()
 
 	srv := httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
-				w.WriteHeader(http.StatusForbidden)
+				w.WriteHeader(status)
 			}),
 	)
 	defer srv.Close()
 
 	svc := notify.NewTestService(srv.Client().Transport)
-	topicURL, _ := url.Parse(srv.URL)
+	target, _ := url.Parse(srv.URL)
 
-	err := svc.SendNtfy(
+	err := send(svc, target)
-		context.Background(), topicURL, "t", "m", "info",
-	)
 	if err == nil {
-		t.Fatal("expected error for 403 response")
+		t.Fatalf("expected error for %d response", status)
 	}
 
-	if !errors.Is(err, notify.ErrNtfyFailed) {
+	if !errors.Is(err, wantErr) {
-		t.Errorf("error = %v, want ErrNtfyFailed", err)
+		t.Errorf("error = %v, want %v", err, wantErr)
 	}
 }
 
+func sendNtfyInfo(
+	svc *notify.Service, target *url.URL,
+) error {
+	return svc.SendNtfy(
+		context.Background(), target, "t", "m", prioInfo,
+	)
+}
+
+func sendSlackInfo(
+	svc *notify.Service, target *url.URL,
+) error {
+	return svc.SendSlack(
+		context.Background(), target, "t", "m", prioInfo,
+	)
+}
+
+func TestSendNtfyClientError(t *testing.T) {
+	t.Parallel()
+
+	assertSendStatusError(
+		t, http.StatusForbidden,
+		notify.ErrNtfyFailed, sendNtfyInfo,
+	)
+}
+
 func TestSendNtfyServerError(t *testing.T) {
 	t.Parallel()
 
-	srv := httptest.NewServer(
+	assertSendStatusError(
-		http.HandlerFunc(
+		t, http.StatusInternalServerError,
-			func(w http.ResponseWriter, _ *http.Request) {
+		notify.ErrNtfyFailed, sendNtfyInfo,
-				w.WriteHeader(http.StatusInternalServerError)
-			}),
 	)
-	defer srv.Close()
-
-	svc := notify.NewTestService(srv.Client().Transport)
-	topicURL, _ := url.Parse(srv.URL)
-
-	err := svc.SendNtfy(
-		context.Background(), topicURL, "t", "m", "info",
-	)
-	if err == nil {
-		t.Fatal("expected error for 500 response")
-	}
-
-	if !errors.Is(err, notify.ErrNtfyFailed) {
-		t.Errorf("error = %v, want ErrNtfyFailed", err)
-	}
 }
 
 func TestSendNtfySuccess(t *testing.T) {
@@ -550,11 +577,11 @@ func TestSendSlackAllColors(t *testing.T) {
 		priority string
 		want     string
 	}{
-		{"error", colorError},
+		{prioError, colorError},
-		{"warning", colorWarning},
+		{prioWarning, colorWarning},
-		{"success", colorSuccess},
+		{prioSuccess, colorSuccess},
-		{"info", colorInfo},
+		{prioInfo, colorInfo},
-		{"unknown", colorDefault},
+		{prioUnknown, colorDefault},
 	}
 
 	for _, tc := range colors {
@@ -606,53 +633,19 @@ func TestSendSlackAllColors(t *testing.T) {
 func TestSendSlackClientError(t *testing.T) {
 	t.Parallel()
 
-	srv := httptest.NewServer(
+	assertSendStatusError(
-		http.HandlerFunc(
+		t, http.StatusBadRequest,
-			func(w http.ResponseWriter, _ *http.Request) {
+		notify.ErrSlackFailed, sendSlackInfo,
-				w.WriteHeader(http.StatusBadRequest)
-			}),
 	)
-	defer srv.Close()
-
-	svc := notify.NewTestService(srv.Client().Transport)
-	webhookURL, _ := url.Parse(srv.URL)
-
-	err := svc.SendSlack(
-		context.Background(), webhookURL, "t", "m", "info",
-	)
-	if err == nil {
-		t.Fatal("expected error for 400 response")
-	}
-
-	if !errors.Is(err, notify.ErrSlackFailed) {
-		t.Errorf("error = %v, want ErrSlackFailed", err)
-	}
 }
 
 func TestSendSlackServerError(t *testing.T) {
 	t.Parallel()
 
-	srv := httptest.NewServer(
+	assertSendStatusError(
-		http.HandlerFunc(
+		t, http.StatusBadGateway,
-			func(w http.ResponseWriter, _ *http.Request) {
+		notify.ErrSlackFailed, sendSlackInfo,
-				w.WriteHeader(http.StatusBadGateway)
-			}),
 	)
-	defer srv.Close()
-
-	svc := notify.NewTestService(srv.Client().Transport)
-	webhookURL, _ := url.Parse(srv.URL)
-
-	err := svc.SendSlack(
-		context.Background(), webhookURL, "t", "m", "error",
-	)
-	if err == nil {
-		t.Fatal("expected error for 502 response")
-	}
-
-	if !errors.Is(err, notify.ErrSlackFailed) {
-		t.Errorf("error = %v, want ErrSlackFailed", err)
-	}
 }
 
 func TestSendSlackNetworkError(t *testing.T) {
@@ -977,74 +970,62 @@ func TestSendNotificationMattermostOnly(t *testing.T) {
 	}
 }
 
-func TestSendNotificationNtfyError(t *testing.T) {
+// assertSendNotificationTolerates verifies SendNotification
-	t.Parallel()
+// neither panics nor blocks when the endpoint configured by
+// setURL responds with status.
+func assertSendNotificationTolerates(
+	t *testing.T,
+	status int,
+	priority string,
+	setURL func(*notify.Service, *url.URL),
+) {
+	t.Helper()
 
 	srv := httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
-				w.WriteHeader(http.StatusInternalServerError)
+				w.WriteHeader(status)
 			}),
 	)
 	defer srv.Close()
 
-	ntfyURL, _ := url.Parse(srv.URL)
+	target, _ := url.Parse(srv.URL)
 
 	svc := notify.NewTestService(http.DefaultTransport)
-	svc.SetNtfyURL(ntfyURL)
+	setURL(svc, target)
 
-	// Should not panic or block.
 	svc.SendNotification(
-		context.Background(), "t", "m", "error",
+		context.Background(), "t", "m", priority,
 	)
 
 	time.Sleep(100 * time.Millisecond)
 }
 
+func TestSendNotificationNtfyError(t *testing.T) {
+	t.Parallel()
+
+	assertSendNotificationTolerates(
+		t, http.StatusInternalServerError, prioError,
+		(*notify.Service).SetNtfyURL,
+	)
+}
+
 func TestSendNotificationSlackError(t *testing.T) {
 	t.Parallel()
 
-	srv := httptest.NewServer(
+	assertSendNotificationTolerates(
-		http.HandlerFunc(
+		t, http.StatusForbidden, prioError,
-			func(w http.ResponseWriter, _ *http.Request) {
+		(*notify.Service).SetSlackWebhookURL,
-				w.WriteHeader(http.StatusForbidden)
-			}),
 	)
-	defer srv.Close()
-
-	slackURL, _ := url.Parse(srv.URL)
-
-	svc := notify.NewTestService(http.DefaultTransport)
-	svc.SetSlackWebhookURL(slackURL)
-
-	svc.SendNotification(
-		context.Background(), "t", "m", "error",
-	)
-
-	time.Sleep(100 * time.Millisecond)
 }
 
 func TestSendNotificationMattermostError(t *testing.T) {
 	t.Parallel()
 
-	srv := httptest.NewServer(
+	assertSendNotificationTolerates(
-		http.HandlerFunc(
+		t, http.StatusBadGateway, prioWarning,
-			func(w http.ResponseWriter, _ *http.Request) {
+		(*notify.Service).SetMattermostWebhookURL,
-				w.WriteHeader(http.StatusBadGateway)
-			}),
 	)
-	defer srv.Close()
-
-	mmURL, _ := url.Parse(srv.URL)
-
-	svc := notify.NewTestService(http.DefaultTransport)
-	svc.SetMattermostWebhookURL(mmURL)
-
-	svc.SendNotification(
-		context.Background(), "t", "m", "warning",
-	)
-
-	time.Sleep(100 * time.Millisecond)
 }
 
 // ── SlackPayload JSON marshaling ──────────────────────────

internal/notify/history_test.go

@@ -29,14 +29,14 @@ func TestAlertHistoryAddAndRecent(t *testing.T) {
 		Timestamp: now.Add(-2 * time.Minute),
 		Title:     "first",
 		Message:   "msg1",
-		Priority:  "info",
+		Priority:  prioInfo,
 	})
 
 	h.Add(notify.AlertEntry{
 		Timestamp: now.Add(-1 * time.Minute),
 		Title:     "second",
 		Message:   "msg2",
-		Priority:  "warning",
+		Priority:  prioWarning,
 	})
 
 	entries := h.Recent()

internal/notify/retry.go

@@ -69,7 +69,7 @@ func (rc RetryConfig) backoff(attempt int) time.Duration {
 	lo := raw * (1 - jitterFraction)
 	hi := raw * (1 + jitterFraction)
 
-	jittered := lo + rand.Float64()*(hi-lo) //nolint:gosec // jitter does not need crypto/rand
+	jittered := lo + rand.Float64()*(hi-lo) //nolint:gosec // jitter needs no crypto/rand
 
 	return time.Duration(jittered)
 }

internal/state/state_test.go

@@ -13,6 +13,16 @@ import (
 
 const testHostname = "www.example.com"
 
+// Shared fixture values used across tests.
+const (
+	testNS1     = "ns1.example.com."
+	testNS2     = "ns2.example.com."
+	testAltNS1  = "ns1.test.com."
+	testIPv4    = "93.184.216.34"
+	testIP      = "1.2.3.4"
+	statusError = "error"
+)
+
 // populateState fills a State with representative test data across all categories.
 func populateState(t *testing.T, s *state.State) {
 	t.Helper()
@@ -20,7 +30,7 @@ func populateState(t *testing.T, s *state.State) {
 	now := time.Now().UTC().Truncate(time.Second)
 
 	s.SetDomainState("example.com", &state.DomainState{
-		Nameservers: []string{"ns1.example.com.", "ns2.example.com."},
+		Nameservers: []string{testNS1, testNS2},
 		LastChecked: now,
 	})
 
@@ -31,17 +41,17 @@ func populateState(t *testing.T, s *state.State) {
 
 	s.SetHostnameState(testHostname, &state.HostnameState{
 		RecordsByNameserver: map[string]*state.NameserverRecordState{
-			"ns1.example.com.": {
+			testNS1: {
 				Records: map[string][]string{
-					"A":    {"93.184.216.34"},
+					"A":    {testIPv4},
 					"AAAA": {"2606:2800:220:1:248:1893:25c8:1946"},
 				},
 				Status:      "ok",
 				LastChecked: now,
 			},
-			"ns2.example.com.": {
+			testNS2: {
 				Records: map[string][]string{
-					"A": {"93.184.216.34"},
+					"A": {testIPv4},
 				},
 				Status:      "ok",
 				LastChecked: now,
@@ -152,13 +162,13 @@ func TestSaveLoadRoundTrip_Hostnames(t *testing.T) {
 func verifyNS1Records(t *testing.T, hn *state.HostnameState) {
 	t.Helper()
 
-	ns1, ok := hn.RecordsByNameserver["ns1.example.com."]
+	ns1, ok := hn.RecordsByNameserver[testNS1]
 	if !ok {
 		t.Fatal("missing nameserver ns1.example.com.")
 	}
 
 	aRecords := ns1.Records["A"]
-	if len(aRecords) != 1 || aRecords[0] != "93.184.216.34" {
+	if len(aRecords) != 1 || aRecords[0] != testIPv4 {
 		t.Errorf("ns1 A records: got %v", aRecords)
 	}
 
@@ -213,7 +223,8 @@ func TestSaveLoadRoundTrip_Ports(t *testing.T) {
 	}
 }
 
-// TestSaveLoadRoundTrip_Certificates verifies certificate data survives a save/load cycle.
+// TestSaveLoadRoundTrip_Certificates verifies certificate data
+// survives a save/load cycle.
 func TestSaveLoadRoundTrip_Certificates(t *testing.T) {
 	t.Parallel()
 
@@ -653,7 +664,7 @@ func TestDomainState_GetSet(t *testing.T) {
 
 	now := time.Now().UTC().Truncate(time.Second)
 	ds := &state.DomainState{
-		Nameservers: []string{"ns1.test.com."},
+		Nameservers: []string{testAltNS1},
 		LastChecked: now,
 	}
 
@@ -664,7 +675,7 @@ func TestDomainState_GetSet(t *testing.T) {
 		t.Fatal("expected true for existing domain")
 	}
 
-	if len(got.Nameservers) != 1 || got.Nameservers[0] != "ns1.test.com." {
+	if len(got.Nameservers) != 1 || got.Nameservers[0] != testAltNS1 {
 		t.Errorf("nameservers: got %v", got.Nameservers)
 	}
 
@@ -674,7 +685,7 @@ func TestDomainState_GetSet(t *testing.T) {
 
 	// Overwrite.
 	ds2 := &state.DomainState{
-		Nameservers: []string{"ns1.test.com.", "ns2.test.com."},
+		Nameservers: []string{testAltNS1, "ns2.test.com."},
 		LastChecked: now.Add(time.Hour),
 	}
 
@@ -704,8 +715,8 @@ func TestHostnameState_GetSet(t *testing.T) {
 	now := time.Now().UTC().Truncate(time.Second)
 	hs := &state.HostnameState{
 		RecordsByNameserver: map[string]*state.NameserverRecordState{
-			"ns1.example.com.": {
+			testNS1: {
-				Records:     map[string][]string{"A": {"1.2.3.4"}},
+				Records:     map[string][]string{"A": {testIP}},
 				Status:      "ok",
 				LastChecked: now,
 			},
@@ -720,7 +731,7 @@ func TestHostnameState_GetSet(t *testing.T) {
 		t.Fatal("expected true for existing hostname")
 	}
 
-	nsState, ok := got.RecordsByNameserver["ns1.example.com."]
+	nsState, ok := got.RecordsByNameserver[testNS1]
 	if !ok {
 		t.Fatal("missing nameserver entry")
 	}
@@ -730,7 +741,7 @@ func TestHostnameState_GetSet(t *testing.T) {
 	}
 
 	aRecords := nsState.Records["A"]
-	if len(aRecords) != 1 || aRecords[0] != "1.2.3.4" {
+	if len(aRecords) != 1 || aRecords[0] != testIP {
 		t.Errorf("A records: got %v", aRecords)
 	}
 }
@@ -869,7 +880,7 @@ func TestCertificateState_ErrorField(t *testing.T) {
 
 	now := time.Now().UTC().Truncate(time.Second)
 	cs := &state.CertificateState{
-		Status:      "error",
+		Status:      statusError,
 		Error:       "connection refused",
 		LastChecked: now,
 	}
@@ -893,8 +904,8 @@ func TestCertificateState_ErrorField(t *testing.T) {
 		t.Fatal("missing certificate after load")
 	}
 
-	if got.Status != "error" {
+	if got.Status != statusError {
-		t.Errorf("status: got %q, want %q", got.Status, "error")
+		t.Errorf("status: got %q, want %q", got.Status, statusError)
 	}
 
 	if got.Error != "connection refused" {
@@ -912,9 +923,9 @@ func TestHostnameState_ErrorField(t *testing.T) {
 	now := time.Now().UTC().Truncate(time.Second)
 	hs := &state.HostnameState{
 		RecordsByNameserver: map[string]*state.NameserverRecordState{
-			"ns1.example.com.": {
+			testNS1: {
 				Records:     nil,
-				Status:      "error",
+				Status:      statusError,
 				Error:       "SERVFAIL",
 				LastChecked: now,
 			},
@@ -941,9 +952,9 @@ func TestHostnameState_ErrorField(t *testing.T) {
 		t.Fatal("missing hostname after load")
 	}
 
-	nsState := got.RecordsByNameserver["ns1.example.com."]
+	nsState := got.RecordsByNameserver[testNS1]
-	if nsState.Status != "error" {
+	if nsState.Status != statusError {
-		t.Errorf("status: got %q, want %q", nsState.Status, "error")
+		t.Errorf("status: got %q, want %q", nsState.Status, statusError)
 	}
 
 	if nsState.Error != "SERVFAIL" {
@@ -1062,7 +1073,8 @@ func TestConcurrentGetSet(t *testing.T) {
 	wg.Wait()
 }
 
-// runConcurrentOps performs a series of get/set/delete operations for concurrency testing.
+// runConcurrentOps performs a series of get/set/delete
+// operations for concurrency testing.
 func runConcurrentOps(s *state.State, key string, now time.Time) {
 	const iterations = 50
 
@@ -1085,7 +1097,7 @@ func runConcurrentOps(s *state.State, key string, now time.Time) {
 		s.SetHostnameState(key+".example.com", &state.HostnameState{
 			RecordsByNameserver: map[string]*state.NameserverRecordState{
 				"ns1.test.": {
-					Records:     map[string][]string{"A": {"1.2.3.4"}},
+					Records:     map[string][]string{"A": {testIP}},
 					Status:      "ok",
 					LastChecked: now,
 				},

internal/watcher/watcher.go

@@ -26,6 +26,12 @@ const tlsPort = 443
 // hoursPerDay converts days to hours for duration calculations.
 const hoursPerDay = 24
 
+// Status values recorded for nameserver and certificate checks.
+const (
+	statusOK    = "ok"
+	statusError = "error"
+)
+
 // Params contains dependencies for Watcher.
 type Params struct {
 	fx.In
@@ -344,7 +350,7 @@ func buildHostnameState(
 	for ns, recs := range records {
 		hs.RecordsByNameserver[ns] = &state.NameserverRecordState{
 			Records:     recs,
-			Status:      "ok",
+			Status:      statusOK,
 			LastChecked: now,
 		}
 	}
@@ -402,7 +408,7 @@ func (w *Watcher) detectNSDisappearances(
 	current map[string]map[string][]string,
 ) {
 	for ns, prevNS := range prev.RecordsByNameserver {
-		if _, ok := current[ns]; ok || prevNS.Status != "ok" {
+		if _, ok := current[ns]; ok || prevNS.Status != statusOK {
 			continue
 		}
 
@@ -421,7 +427,7 @@ func (w *Watcher) detectNSDisappearances(
 
 	for ns := range current {
 		prevNS, ok := prev.RecordsByNameserver[ns]
-		if !ok || prevNS.Status != "error" {
+		if !ok || prevNS.Status != statusError {
 			continue
 		}
 
@@ -705,7 +711,7 @@ func (w *Watcher) handleTLSError(
 	now time.Time,
 	err error,
 ) {
-	if hasPrev && !w.firstRun && prev.Status == "ok" {
+	if hasPrev && !w.firstRun && prev.Status == statusOK {
 		msg := fmt.Sprintf(
 			"Host: %s\nIP: %s\nError: %s",
 			hostname, ip, err,
@@ -721,7 +727,7 @@ func (w *Watcher) handleTLSError(
 
 	w.state.SetCertificateState(
 		certKey, &state.CertificateState{
-			Status:      "error",
+			Status:      statusError,
 			Error:       err.Error(),
 			LastChecked: now,
 		},
@@ -748,7 +754,7 @@ func (w *Watcher) handleTLSSuccess(
 			Issuer:                  cert.Issuer,
 			NotAfter:                cert.NotAfter,
 			SubjectAlternativeNames: cert.SubjectAlternativeNames,
-			Status:                  "ok",
+			Status:                  statusOK,
 			LastChecked:             now,
 		},
 	)
@@ -760,7 +766,7 @@ func (w *Watcher) detectTLSChanges(
 	prev *state.CertificateState,
 	cert *tlscheck.CertificateInfo,
 ) {
-	if prev.Status == "error" {
+	if prev.Status == statusError {
 		msg := fmt.Sprintf(
 			"Host: %s\nIP: %s\nTLS recovered",
 			hostname, ip,

internal/watcher/watcher_test.go

@@ -18,6 +18,17 @@ import (
 // errNotFound is returned when mock data is missing.
 var errNotFound = errors.New("not found")
 
+// Fixture values shared across tests.
+const (
+	testDomain = "example.com"
+	testHost   = "www.example.com"
+	testNS1    = "ns1.example.com."
+	testNS2    = "ns2.example.com."
+	testIPv4   = "93.184.216.34"
+	testIP     = "1.2.3.4"
+	testIssuer = "DigiCert"
+)
+
 // --- Mock implementations ---
 
 type mockResolver struct {
@@ -256,8 +267,8 @@ func TestFirstRunBaseline(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
+	cfg.Domains = []string{testDomain}
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 
 	w, deps := newTestWatcher(t, cfg)
 	setupBaselineMocks(deps)
@@ -269,37 +280,37 @@ func TestFirstRunBaseline(t *testing.T) {
 }
 
 func setupBaselineMocks(deps *testDeps) {
-	deps.resolver.nsRecords["example.com"] = []string{
+	deps.resolver.nsRecords[testDomain] = []string{
-		"ns1.example.com.",
+		testNS1,
-		"ns2.example.com.",
+		testNS2,
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testDomain] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"93.184.216.34"}},
+		testNS1: {"A": {testIPv4}},
-		"ns2.example.com.": {"A": {"93.184.216.34"}},
+		testNS2: {"A": {testIPv4}},
 	}
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"93.184.216.34"}},
+		testNS1: {"A": {testIPv4}},
-		"ns2.example.com.": {"A": {"93.184.216.34"}},
+		testNS2: {"A": {testIPv4}},
 	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
+	deps.resolver.ipAddresses[testHost] = []string{
-		"93.184.216.34",
+		testIPv4,
 	}
 	deps.portChecker.results["93.184.216.34:80"] = true
 	deps.portChecker.results["93.184.216.34:443"] = true
 	deps.tlsChecker.certs["93.184.216.34:www.example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "www.example.com",
+		CommonName: testHost,
-		Issuer:     "DigiCert",
+		Issuer:     testIssuer,
 		NotAfter:   time.Now().Add(90 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{
-			"www.example.com",
+			testHost,
 		},
 	}
 	deps.tlsChecker.certs["93.184.216.34:example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "example.com",
+		CommonName: testDomain,
-		Issuer:     "DigiCert",
+		Issuer:     testIssuer,
 		NotAfter:   time.Now().Add(90 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{
-			"example.com",
+			testDomain,
 		},
 	}
 }
@@ -348,24 +359,24 @@ func TestDomainPortAndTLSChecks(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
+	cfg.Domains = []string{testDomain}
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.nsRecords["example.com"] = []string{
+	deps.resolver.nsRecords[testDomain] = []string{
-		"ns1.example.com.",
+		testNS1,
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testDomain] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"93.184.216.34"}},
+		testNS1: {"A": {testIPv4}},
 	}
 	deps.portChecker.results["93.184.216.34:80"] = true
 	deps.portChecker.results["93.184.216.34:443"] = true
 	deps.tlsChecker.certs["93.184.216.34:example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "example.com",
+		CommonName: testDomain,
-		Issuer:     "DigiCert",
+		Issuer:     testIssuer,
 		NotAfter:   time.Now().Add(90 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{
-			"example.com",
+			testDomain,
 		},
 	}
 
@@ -406,17 +417,17 @@ func TestNSChangeDetection(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
+	cfg.Domains = []string{testDomain}
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.nsRecords["example.com"] = []string{
+	deps.resolver.nsRecords[testDomain] = []string{
-		"ns1.example.com.",
+		testNS1,
-		"ns2.example.com.",
+		testNS2,
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testDomain] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1: {"A": {testIP}},
-		"ns2.example.com.": {"A": {"1.2.3.4"}},
+		testNS2: {"A": {testIP}},
 	}
 	deps.portChecker.results["1.2.3.4:80"] = false
 	deps.portChecker.results["1.2.3.4:443"] = false
@@ -425,13 +436,13 @@ func TestNSChangeDetection(t *testing.T) {
 	w.RunOnce(ctx)
 
 	deps.resolver.mu.Lock()
-	deps.resolver.nsRecords["example.com"] = []string{
+	deps.resolver.nsRecords[testDomain] = []string{
-		"ns1.example.com.",
+		testNS1,
 		"ns3.example.com.",
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testDomain] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1:            {"A": {testIP}},
-		"ns3.example.com.": {"A": {"1.2.3.4"}},
+		"ns3.example.com.": {"A": {testIP}},
 	}
 	deps.resolver.mu.Unlock()
 
@@ -459,15 +470,15 @@ func TestRecordChangeDetection(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"93.184.216.34"}},
+		testNS1: {"A": {testIPv4}},
 	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
+	deps.resolver.ipAddresses[testHost] = []string{
-		"93.184.216.34",
+		testIPv4,
 	}
 	deps.portChecker.results["93.184.216.34:80"] = false
 	deps.portChecker.results["93.184.216.34:443"] = false
@@ -476,10 +487,10 @@ func TestRecordChangeDetection(t *testing.T) {
 	w.RunOnce(ctx)
 
 	deps.resolver.mu.Lock()
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"93.184.216.35"}},
+		testNS1: {"A": {"93.184.216.35"}},
 	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
+	deps.resolver.ipAddresses[testHost] = []string{
 		"93.184.216.35",
 	}
 	deps.resolver.mu.Unlock()
@@ -501,24 +512,24 @@ func TestPortStateChange(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1: {"A": {testIP}},
 	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
+	deps.resolver.ipAddresses[testHost] = []string{
-		"1.2.3.4",
+		testIP,
 	}
 	deps.portChecker.results["1.2.3.4:80"] = true
 	deps.portChecker.results["1.2.3.4:443"] = true
 	deps.tlsChecker.certs["1.2.3.4:www.example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "www.example.com",
+		CommonName: testHost,
-		Issuer:     "DigiCert",
+		Issuer:     testIssuer,
 		NotAfter:   time.Now().Add(90 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{
-			"www.example.com",
+			testHost,
 		},
 	}
 
@@ -541,24 +552,24 @@ func TestTLSExpiryWarning(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1: {"A": {testIP}},
 	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
+	deps.resolver.ipAddresses[testHost] = []string{
-		"1.2.3.4",
+		testIP,
 	}
 	deps.portChecker.results["1.2.3.4:80"] = true
 	deps.portChecker.results["1.2.3.4:443"] = true
 	deps.tlsChecker.certs["1.2.3.4:www.example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "www.example.com",
+		CommonName: testHost,
-		Issuer:     "DigiCert",
+		Issuer:     testIssuer,
 		NotAfter:   time.Now().Add(3 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{
-			"www.example.com",
+			testHost,
 		},
 	}
 
@@ -592,25 +603,25 @@ func TestTLSExpiryWarningDedup(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 	cfg.TLSInterval = 24 * time.Hour
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1: {"A": {testIP}},
 	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
+	deps.resolver.ipAddresses[testHost] = []string{
-		"1.2.3.4",
+		testIP,
 	}
 	deps.portChecker.results["1.2.3.4:80"] = true
 	deps.portChecker.results["1.2.3.4:443"] = true
 	deps.tlsChecker.certs["1.2.3.4:www.example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "www.example.com",
+		CommonName: testHost,
-		Issuer:     "DigiCert",
+		Issuer:     testIssuer,
 		NotAfter:   time.Now().Add(3 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{
-			"www.example.com",
+			testHost,
 		},
 	}
 
@@ -647,17 +658,17 @@ func TestGracefulShutdown(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
+	cfg.Domains = []string{testDomain}
 	cfg.DNSInterval = 100 * time.Millisecond
 	cfg.TLSInterval = 100 * time.Millisecond
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.nsRecords["example.com"] = []string{
+	deps.resolver.nsRecords[testDomain] = []string{
-		"ns1.example.com.",
+		testNS1,
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testDomain] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1: {"A": {testIP}},
 	}
 	deps.portChecker.results["1.2.3.4:80"] = false
 	deps.portChecker.results["1.2.3.4:443"] = false
@@ -687,13 +698,13 @@ func setupHostnameIP(
 	hostname, ip string,
 ) {
 	deps.resolver.allRecords[hostname] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {ip}},
+		testNS1: {"A": {ip}},
 	}
 	deps.portChecker.results[ip+":80"] = true
 	deps.portChecker.results[ip+":443"] = true
 	deps.tlsChecker.certs[ip+":"+hostname] = &tlscheck.CertificateInfo{
 		CommonName:              hostname,
-		Issuer:                  "DigiCert",
+		Issuer:                  testIssuer,
 		NotAfter:                time.Now().Add(90 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{hostname},
 	}
@@ -702,7 +713,7 @@ func setupHostnameIP(
 func updateHostnameIP(deps *testDeps, hostname, ip string) {
 	deps.resolver.mu.Lock()
 	deps.resolver.allRecords[hostname] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {ip}},
+		testNS1: {"A": {ip}},
 	}
 	deps.resolver.mu.Unlock()
 
@@ -714,7 +725,7 @@ func updateHostnameIP(deps *testDeps, hostname, ip string) {
 	deps.tlsChecker.mu.Lock()
 	deps.tlsChecker.certs[ip+":"+hostname] = &tlscheck.CertificateInfo{
 		CommonName:              hostname,
-		Issuer:                  "DigiCert",
+		Issuer:                  testIssuer,
 		NotAfter:                time.Now().Add(90 * 24 * time.Hour),
 		SubjectAlternativeNames: []string{hostname},
 	}
@@ -725,11 +736,11 @@ func TestDNSRunsBeforePortAndTLSChecks(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 
 	w, deps := newTestWatcher(t, cfg)
 
-	setupHostnameIP(deps, "www.example.com", "10.0.0.1")
+	setupHostnameIP(deps, testHost, "10.0.0.1")
 
 	ctx := t.Context()
 	w.RunOnce(ctx)
@@ -740,7 +751,7 @@ func TestDNSRunsBeforePortAndTLSChecks(t *testing.T) {
 	}
 
 	// DNS changes to a new IP; port and TLS must pick it up.
-	updateHostnameIP(deps, "www.example.com", "10.0.0.2")
+	updateHostnameIP(deps, testHost, "10.0.0.2")
 
 	w.RunOnce(ctx)
 
@@ -760,8 +771,8 @@ func TestSendTestNotification_Enabled(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
+	cfg.Domains = []string{testDomain}
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 	cfg.SendTestNotification = true
 
 	w, deps := newTestWatcher(t, cfg)
@@ -786,8 +797,8 @@ func TestSendTestNotification_ViaRun(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
+	cfg.Domains = []string{testDomain}
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 	cfg.SendTestNotification = true
 	cfg.DNSInterval = 24 * time.Hour
 	cfg.TLSInterval = 24 * time.Hour
@@ -833,8 +844,8 @@ func TestSendTestNotification_Disabled(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
+	cfg.Domains = []string{testDomain}
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 	cfg.SendTestNotification = false
 	cfg.DNSInterval = 24 * time.Hour
 	cfg.TLSInterval = 24 * time.Hour
@@ -871,16 +882,16 @@ func TestNSFailureAndRecovery(t *testing.T) {
 	t.Parallel()
 
 	cfg := defaultTestConfig(t)
-	cfg.Hostnames = []string{"www.example.com"}
+	cfg.Hostnames = []string{testHost}
 
 	w, deps := newTestWatcher(t, cfg)
 
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1: {"A": {testIP}},
-		"ns2.example.com.": {"A": {"1.2.3.4"}},
+		testNS2: {"A": {testIP}},
 	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
+	deps.resolver.ipAddresses[testHost] = []string{
-		"1.2.3.4",
+		testIP,
 	}
 	deps.portChecker.results["1.2.3.4:80"] = false
 	deps.portChecker.results["1.2.3.4:443"] = false
@@ -890,8 +901,8 @@ func TestNSFailureAndRecovery(t *testing.T) {
 	w.RunOnce(ctx)
 
 	deps.resolver.mu.Lock()
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
+	deps.resolver.allRecords[testHost] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
+		testNS1: {"A": {testIP}},
 	}
 	deps.resolver.mu.Unlock()
 

script/bootstrap

@@ -0,0 +1,117 @@
+#!/bin/sh
+# script/bootstrap: install all dependencies needed to build and develop
+# this repo. Base tooling (git, make, go) comes from nix, apt, brew, or
+# apk (detected in that order) and is installed only when absent;
+# assumes nothing is present. golangci-lint and goimports are always
+# (re)installed via `go install` at the same pinned commits the
+# Dockerfile uses (never "latest") -- a presence check cannot tell the
+# pinned build from an arbitrary one already on PATH, so guarding them
+# would make the pins inert. Idempotent either way: running this twice
+# succeeds both times and leaves the same result.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+# Pinned versions, 2026-08-07 (same pins as the Dockerfile)
+# golangci-lint v2.12.2
+GOLANGCI_LINT_REF="github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5"
+# goimports v0.42.0
+GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
+
+PKGMGR=""
+SUDO=""
+APT_UPDATED=""
+
+detect_pkgmgr() {
+    [ -n "$PKGMGR" ] && return 0
+    if command -v nix-env >/dev/null 2>&1; then
+        PKGMGR="nix"
+    elif command -v apt-get >/dev/null 2>&1; then
+        PKGMGR="apt"
+    elif command -v brew >/dev/null 2>&1; then
+        PKGMGR="brew"
+    elif command -v apk >/dev/null 2>&1; then
+        PKGMGR="apk"
+    else
+        echo "bootstrap: no supported package manager (nix, apt, brew, apk)" >&2
+        exit 1
+    fi
+    if [ "$PKGMGR" = "apt" ]; then
+        export DEBIAN_FRONTEND=noninteractive
+        if [ "$(id -u)" != "0" ]; then
+            SUDO="sudo"
+        fi
+    fi
+}
+
+# pkg_install <nix-attr> <apt-pkg> <brew-formula> <apk-pkg>
+pkg_install() {
+    detect_pkgmgr
+    case "$PKGMGR" in
+        nix) nix-env -iA "nixpkgs.$1" ;;
+        apt)
+            if [ -z "$APT_UPDATED" ]; then
+                $SUDO env DEBIAN_FRONTEND=noninteractive apt-get update
+                APT_UPDATED=1
+            fi
+            $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y "$2"
+            ;;
+        brew) brew install "$3" ;;
+        apk) apk add --no-cache "$4" ;;
+    esac
+}
+
+missing() {
+    ! command -v "$1" >/dev/null 2>&1
+}
+
+# go_bin_dir: directory `go install` writes binaries to.
+go_bin_dir() {
+    gobin="$(go env GOBIN)"
+    if [ -n "$gobin" ]; then
+        echo "$gobin"
+    else
+        echo "$(go env GOPATH)/bin"
+    fi
+}
+
+# warn_if_shadowed <tool> <dir>: the pinned build was just installed
+# into <dir>. If PATH resolves <tool> anywhere else, that other copy is
+# what `make lint` and `make fmt` will actually run, and it is not the
+# pinned version. Warn loudly rather than failing, since the fix is the
+# user's PATH and not anything this script can do.
+warn_if_shadowed() {
+    resolved="$(command -v "$1" 2>/dev/null || true)"
+    if [ "$resolved" != "$2/$1" ]; then
+        echo "bootstrap: WARNING: installed pinned $1 to $2/$1, but PATH" >&2
+        echo "bootstrap: WARNING: resolves $1 to ${resolved:-(not on PATH)};" >&2
+        echo "bootstrap: WARNING: put $2 first on PATH or lint results will" >&2
+        echo "bootstrap: WARNING: not match CI." >&2
+    fi
+}
+
+main() {
+    cd "$ROOT"
+
+    if missing git; then pkg_install git git git git; fi
+    if missing make; then pkg_install gnumake make make make; fi
+    if missing go; then pkg_install go golang go go; fi
+
+    # Lint/format tools, pinned via go install. These are installed
+    # unconditionally: `command -v` only proves *some* build is on PATH,
+    # and a wrong golangci-lint either cannot parse our v2-schema
+    # .golangci.yml at all or silently disagrees with CI. Installing at
+    # a fixed commit ref is idempotent and cheap with a warm module
+    # cache, so there is nothing to save by skipping it.
+    GOBIN_DIR="$(go_bin_dir)"
+    go install "$GOLANGCI_LINT_REF"
+    go install "$GOIMPORTS_REF"
+    warn_if_shadowed golangci-lint "$GOBIN_DIR"
+    warn_if_shadowed goimports "$GOBIN_DIR"
+
+    go mod download
+
+    echo "bootstrap complete"
+}
+
+main "$@"

script/check

@@ -0,0 +1,14 @@
+#!/bin/sh
+# script/check: run all checks (test, lint, fmt-check). Our own
+# extension to scripts-to-rule-them-all. Must not modify any files.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+
+main() {
+    "$SCRIPT_DIR/test"
+    "$SCRIPT_DIR/lint"
+    "$SCRIPT_DIR/fmt-check"
+}
+
+main "$@"

script/cibuild

@@ -0,0 +1,13 @@
+#!/bin/sh
+# script/cibuild: run the CI build. The Dockerfile runs make check, so
+# a successful build implies all checks pass.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    docker build .
+}
+
+main "$@"

script/docker

@@ -0,0 +1,14 @@
+#!/bin/sh
+# script/docker: build the Docker image tagged with the project name.
+# Identical in all repos; the tag comes from script/projectname.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    docker build -t "$("$SCRIPT_DIR/projectname")" .
+}
+
+main "$@"

script/fmt

@@ -0,0 +1,13 @@
+#!/bin/sh
+# script/fmt: format all files (writes).
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    gofmt -s -w .
+    goimports -w .
+}
+
+main "$@"

script/fmt-check

@@ -0,0 +1,18 @@
+#!/bin/sh
+# script/fmt-check: check formatting (read-only). Same scope as
+# script/fmt, but fails instead of writing.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    files="$(gofmt -l .)"
+    if [ -n "$files" ]; then
+        echo "gofmt: files not formatted:" >&2
+        echo "$files" >&2
+        exit 1
+    fi
+}
+
+main "$@"

script/install-precommit

@@ -0,0 +1,16 @@
+#!/bin/sh
+# script/install-precommit: install the git pre-commit hook that runs
+# script/precommit. Our own extension to scripts-to-rule-them-all.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    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"
+}
+
+main "$@"

script/lint

@@ -0,0 +1,12 @@
+#!/bin/sh
+# script/lint: run the linter.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    golangci-lint run --config .golangci.yml ./...
+}
+
+main "$@"

script/precommit

@@ -0,0 +1,21 @@
+#!/bin/sh
+# script/precommit: run by the git pre-commit hook; fails the commit if
+# checks fail. Our own extension to scripts-to-rule-them-all. Go extra:
+# go mod tidy must be a no-op before the checks run.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    go mod tidy
+    if ! git diff --exit-code -- go.mod go.sum; then
+        echo "precommit: go mod tidy changed go.mod/go.sum;" \
+            "stage the changes and retry" >&2
+        exit 1
+    fi
+    "$SCRIPT_DIR/check"
+}
+
+main "$@"

script/projectname

@@ -0,0 +1,12 @@
+#!/bin/sh
+# script/projectname: output the name of this project. Our own
+# extension to scripts-to-rule-them-all. Other scripts that need the
+# name (e.g. script/docker) call this, so they can stay identical
+# across all repos.
+set -eu
+
+main() {
+    echo "dnswatcher"
+}
+
+main "$@"

script/setup

@@ -0,0 +1,13 @@
+#!/bin/sh
+# script/setup: set up the repo for development after a fresh clone:
+# installs dependencies and the git pre-commit hook.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+
+main() {
+    "$SCRIPT_DIR/bootstrap"
+    "$SCRIPT_DIR/install-precommit"
+}
+
+main "$@"

script/test

@@ -0,0 +1,12 @@
+#!/bin/sh
+# script/test: run the test suite.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    go test -v -race -timeout 30s -cover ./...
+}
+
+main "$@"