Debug log adds each line instead of drawing the whole panel (closes #131)

With the debug log open, every line written drew the panel again with
up to 1000 lines, and a check that ends while the page draws is timed
only when the drawing is done, so latencies measured with the panel open
read too high. Each line is now appended to the open panel and its first
line dropped once it holds more than maxLogEntries; the whole panel is
drawn only when it is opened. Scrolling to the newest line reads the
panel's height, which lays out all its lines, so it runs once a frame,
with at most one frame request waiting.

Model: opus-5-5

Dockerfile

@@ -5,27 +5,16 @@
 #
 # The lint and test phases are the gates: `make lint` (script/lint)
 # builds the lint stage alone and `make test` (script/test) the test
-# stage alone, and the two build stages, frontend-build and builder,
-# depend on both, so the image cannot be built unless they pass. Each
-# phase covers the frontend as well, through a copy from a node stage.
-# Inside them each tool is invoked directly, never through make or
-# script/, whose lint and test are themselves docker builds.
-#
-# In every stage ARG CACHEBUST comes right after the steps that install
-# system packages and download Go's modules, or right after FROM in a
-# stage with neither, and every step that lints, tests or compiles
-# comes after it, as does yarn install in the node stages. script/
-# passes a new value on every build, which reruns every RUN step after
-# it. Docker keeps the layers above it until the base image, their own
-# lines or go.mod and go.sum change. The steps that compile mount Go's
-# build cache, and golangci-lint run also mounts golangci-lint's; both
-# survive from build to build.
+# stage alone, and the builder stage depends on both, so the image
+# cannot be built unless they pass. Each covers the frontend as well,
+# through a copy from a node stage. Inside them each tool is invoked
+# directly, never through make or script/, whose lint and test are
+# themselves docker builds.
 
 # Frontend lint stage: eslint with the rules in eslint.config.js. The
 # lint phase below runs it.
 # node:22-alpine as of 2026-02-22
 FROM node@sha256:e4bf2a82ad0a4037d28035ae71529873c069b13eb0455466ae0bc13363826e34 AS frontend-lint
-ARG CACHEBUST
 WORKDIR /app
 COPY package.json yarn.lock ./
 RUN yarn install --frozen-lockfile
@@ -40,86 +29,69 @@ FROM golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a924
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
-ARG CACHEBUST
 COPY . .
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    --mount=type=cache,target=/root/.cache/golangci-lint \
-    golangci-lint run --config .golangci.yml ./...
+RUN golangci-lint run --config .golangci.yml ./...
 # Nothing is wanted from frontend-lint; the copy is what makes this
 # phase run it.
 COPY --from=frontend-lint /app/yarn.lock /dev/null
 
-# Frontend test stage: the unit tests in test/unit/. The test phase
-# below runs it, and the frontend-build stage starts from it. The tests
-# print a dot each; if any fails, they run again with every test listed,
-# and the step fails even if that run passes. NODE_OPTIONS chooses the
-# reporter because yarn adds its arguments after the test files, where
-# node would take a reporter option for one more file.
+# Frontend stage: the unit tests in test/unit/, then the production
+# build into dist/, which the runtime stage serves. The test phase below
+# runs it. The tests print a dot each; if any fails, they run again with
+# every test listed, and the step fails even if that run passes.
+# NODE_OPTIONS chooses the reporter because yarn adds its arguments
+# after the test files, where node would take a reporter option for one
+# more file.
 # node:22-alpine as of 2026-02-22
-FROM node@sha256:e4bf2a82ad0a4037d28035ae71529873c069b13eb0455466ae0bc13363826e34 AS frontend-test
-ARG CACHEBUST
+FROM node@sha256:e4bf2a82ad0a4037d28035ae71529873c069b13eb0455466ae0bc13363826e34 AS frontend
 WORKDIR /app
 COPY package.json yarn.lock ./
 RUN yarn install --frozen-lockfile
+# vite.config.js reads the commit for the page's footer with git.
+RUN apk add --no-cache git
 COPY . .
 RUN NODE_OPTIONS=--test-reporter=dot timeout 90 yarn --silent run test || \
     { echo "--- Rerunning with every test listed for details ---"; \
       NODE_OPTIONS=--test-reporter=spec timeout 90 yarn --silent run test; \
       exit 1; }
+RUN yarn build
 
 # Test phase: the backend's tests with the race detector and coverage,
-# and the frontend's through the copy from the frontend-test stage at
-# the end. -race needs cgo and so a C compiler, which the Debian Go image
+# and the frontend's through the copy from the frontend stage at the
+# end. -race needs cgo and so a C compiler, which the Debian Go image
 # ships and the alpine one does not. -timeout 90s is a backstop above
 # the 60-second cap on the suite. The rerun with -v only shows details:
 # the step fails however it ends, because the first run already failed.
-# -count=1 because the mounted cache also holds test results, which go
-# test would otherwise replay.
+# Go's module and build caches are in memory (tmpfs) for the go test
+# step alone, so the image make test tags does not carry them and the
+# build spends no time writing them into it. They start empty on every
+# build, so no stored test result can stand in for a run.
 # golang:1.25.7-trixie, 2026-10-07
 FROM golang@sha256:2b174ffcf56c7ad0c47d30d2630693265639ddf2a5141149c2da34db921791b4 AS test
 WORKDIR /src
-COPY go.mod go.sum ./
-RUN go mod download
-ARG CACHEBUST
 COPY . .
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    go test -count=1 -timeout 90s -race -cover ./... || \
+RUN --mount=type=tmpfs,target=/go/pkg/mod \
+    --mount=type=tmpfs,target=/root/.cache/go-build \
+    go test -timeout 90s -race -cover ./... || \
     { echo "--- Rerunning with -v for details ---"; \
-      go test -count=1 -timeout 90s -race -v ./...; exit 1; }
-# Nothing is wanted from the frontend-test stage; the copy is what makes
+      go test -timeout 90s -race -v ./...; exit 1; }
+# Nothing is wanted from the frontend stage; the copy is what makes
 # this phase run its tests.
-COPY --from=frontend-test /app/yarn.lock /dev/null
-
-# Frontend build stage: the production build into dist/, which the
-# runtime stage serves, on the yarn packages and source of the
-# frontend-test stage. Nothing is wanted from the two phases; the copies
-# are what make BuildKit build them first, so this stage cannot run
-# unless lint and test passed.
-FROM frontend-test AS frontend-build
-COPY --from=lint /src/go.sum /dev/null
-COPY --from=test /src/go.sum /dev/null
-# vite.config.js reads the commit for the page's footer with git. git is
-# installed again on every image build, although it comes above
-# ARG CACHEBUST, because this stage starts from frontend-test, whose
-# steps run again on every build.
-RUN apk add --no-cache git
-ARG CACHEBUST
-RUN yarn build
+COPY --from=frontend /app/yarn.lock /dev/null
 
 # Backend build stage. Nothing is wanted from the two phases; the copies
-# are what make BuildKit build them first, so nothing after them can
-# run unless lint and test passed.
+# are what make BuildKit build them first, so this stage cannot run
+# unless lint and test passed.
 # golang:1.25-alpine (2026-02-27)
 FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
+COPY --from=lint /src/go.sum /dev/null
+COPY --from=test /src/go.sum /dev/null
 RUN apk add --no-cache git
+# A tar-stream context keeps the sender's file owners, which git refuses.
+RUN git config --system --add safe.directory /src
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
-ARG CACHEBUST
-COPY --from=lint /src/go.sum /dev/null
-COPY --from=test /src/go.sum /dev/null
-# A tar-stream context keeps the sender's file owners, which git refuses.
-RUN git config --system --add safe.directory /src
 COPY . .
 
 # The same go build as in script/build, which builds the binary on the
@@ -132,8 +104,7 @@ COPY . .
 # still empty, dev or unknown fails the build: git is missing or could
 # not read the checkout.
 ARG VERSION
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    version="${VERSION:-$(git describe --tags --always)}"; \
+RUN version="${VERSION:-$(git describe --tags --always)}"; \
     if [ -e .git ]; then \
         case "$version" in ""|dev|unknown) \
             echo "version is '$version' although .git is present" >&2; \
@@ -148,7 +119,6 @@ RUN --mount=type=cache,target=/root/.cache/go-build \
 # and the stages it copies from, the two phases included.
 # nginx:stable-alpine as of 2026-02-22
 FROM nginx@sha256:15e96e59aa3b0aada3a121296e3bce117721f42d88f5f64217ef4b18f458c6ab
-ARG CACHEBUST
 
 # netwatch-server runs as this user, which owns the report directory.
 # nginx keeps the image's own arrangement: its main process runs as
@@ -161,7 +131,7 @@ RUN addgroup -g 1000 -S netwatch && \
 RUN rm /etc/nginx/conf.d/default.conf
 COPY configs/nginx.conf /etc/nginx/templates/netwatch.conf.template
 COPY configs/security-headers.conf /etc/nginx/security-headers.conf
-COPY --from=frontend-build /app/dist /usr/share/nginx/html
+COPY --from=frontend /app/dist /usr/share/nginx/html
 COPY --from=builder /src/netwatch-server /usr/local/bin/netwatch-server
 COPY bin/entrypoint.sh /usr/local/bin/entrypoint.sh
 

README.md

@@ -58,11 +58,10 @@ either one is broken. We provide:
   defaults (see [Settings](#settings))
 - `script/clean` — remove what `script/build` writes
 - `script/projectname` — print the project name (used for the Docker image tag)
-- `script/test` — build the `test` phase of `Dockerfile`, writing no image: the
-  frontend's unit tests in its `frontend-test` stage, and the backend's Go tests
-  with the race detector and coverage. The frontend's production build is left
-  to the image build, in the `frontend-build` stage
-- `script/lint` — build the `lint` phase of `Dockerfile`, writing no image:
+- `script/test` — build the `test` phase of `Dockerfile` without the cache: the
+  frontend's unit tests and production build in its `frontend` stage, and the
+  backend's Go tests with the race detector and coverage
+- `script/lint` — build the `lint` phase of `Dockerfile` without the cache:
   eslint in its `frontend-lint` stage, and golangci-lint over the Go packages
 - `script/fmt` — format all files (writes): prettier over the JavaScript, CSS,
   HTML and Markdown, then gofmt over `cmd/` and `internal/`. It runs on the
@@ -79,36 +78,22 @@ either one is broken. We provide:
 - `script/frontend-test` — run the unit tests in `test/unit/` on the host with
   Node's built-in test runner, through the `test` script in `package.json`, and
   if any fails, run them again listing every test, and fail; then the production
-  build. Each test run has a 90-second timeout. `make test` runs the same tests
-  in Docker, without the production build
+  build. Each test run has a 90-second timeout. `make test` runs the same in
+  Docker
 - `script/frontend-fmt` — format the JavaScript, CSS, HTML and Markdown with
   prettier (writes)
 - `script/frontend-fmt-check` — check prettier formatting (read-only)
 - `script/frontend-viewport-test` — responsive-layout verification of the built
   frontend in a containerised headless Chrome (see
-  [test/viewport/README.md](test/viewport/README.md)). Before the browser
-  starts, it checks that the page, and a path that falls back to it, are served
-  with `Cache-Control: no-cache` and `Content-Security-Policy`. Not part of
+  [test/viewport/README.md](test/viewport/README.md)). Not part of
   `script/check`: it takes minutes.
-- `script/docker` — build the image from `Dockerfile`, tagged `netwatch` via
-  `script/projectname`
+- `script/docker` — build the image from `Dockerfile` without the build cache,
+  tagged `netwatch` via `script/projectname`
 - `script/cibuild` — CI entrypoint: runs `script/bootstrap` and `script/check`,
-  then builds the image as `script/docker` does
+  then builds the image as `script/docker` does, without the build cache
 - `script/precommit` — run by the git pre-commit hook; runs `script/check`
 - `script/install-precommit` — install the git pre-commit hook
 
-`script/test`, `script/lint`, `script/docker` and `script/cibuild` each pass a
-new `CACHEBUST` value, so every step in `Dockerfile` that lints, tests or
-compiles runs again even when nothing has changed. Docker keeps the system
-packages and the Go modules from earlier builds until the base image, the step
-that installs them, or `go.mod` and `go.sum` change. The `frontend-build` stage
-is the exception: it installs git again on every image build, because it starts
-from the `frontend-test` stage, whose steps run again on every build. Go's build
-cache and golangci-lint's are kept as well, and each reuses a result only when
-everything it was made from is unchanged. Both `go test` runs carry `-count=1`,
-so no test result is reused. The yarn packages are installed again on every
-build.
-
 ## Responsive layout
 
 The narrow-viewport layout lives in the `max-width: 768px` media block in
@@ -164,29 +149,9 @@ same-origin path `/api/v1/reports`: a random per-browser `clientId` kept in
 `localStorage`, `geo` sent as null, and each host's unreported, non-paused
 samples (timestamp, latency, error). A per-host high-water mark makes every
 report a delta, so only new samples are sent; the mark advances only on a
-delivered report, and while paused nothing is sent. Changing the interval clears
-each host's history on the page; the samples in it not yet reported still go in
-the next report. Delivery failure is quiet — one debug-log line per outage,
-never blocking probing. The report-building step is a pure function of host
-state.
-
-A sample in the history that no report has delivered is sent only as long as the
-history holds it, so after a refused or failed report the next report carries
-the samples the history still has. Samples an interval change cleared from the
-history are kept apart, the last 100 per host, until they are delivered. The
-history keeps each host's last 100 rounds: 100 seconds at the 1-second interval,
-200 seconds at 2 seconds, 5 minutes at the default of 3 seconds and 100 minutes
-at 60 seconds. At 1 second, one refused or failed report loses the oldest 20
-seconds of each host's samples, as the next delivered report comes 2 minutes
-after the last. At 2 seconds and longer one loses nothing; samples are lost from
-the third refused report in a row at 2 seconds, from the fifth at 3 seconds, and
-later still at the longer intervals.
-
-No report is sent while the page is paused, but each paused round still adds an
-entry to the history, so each report due during a pause counts as a refused one.
-A pause longer than the history spans loses the samples in the history recorded
-between the last delivered report and the pause: up to a minute's worth for each
-host if the report before the pause was delivered.
+delivered report, and while paused nothing is sent. Delivery failure is quiet —
+one debug-log line per outage, retried at the next interval, never blocking
+probing. The report-building step is a pure function of host state.
 
 ### Backend
 
@@ -232,32 +197,23 @@ image, `make run` builds it and runs it on port 8080.
 | `DATA_DIR`             | `./data/reports`     | Directory for compressed reports                                                                         |
 | `DATA_DIR_MAX_BYTES`   | `1073741824` (1 GiB) | Most bytes of report files kept in `DATA_DIR`, oldest deleted first; see [Report limits](#report-limits) |
 | `DEBUG`                | `false`              | Enable debug logging                                                                                     |
-| `TRUSTED_PROXIES`      | RFC 1918 ranges      | Comma-separated CIDRs whose `X-Forwarded-For` / `X-Real-IP` headers are trusted for client IP resolution |
+| `TRUSTED_PROXIES`      | loopback + RFC1918   | Comma-separated CIDRs whose `X-Forwarded-For` / `X-Real-IP` headers are trusted for client IP resolution |
 | `REPORTS_PER_MINUTE`   | `60`                 | Reports each client address may send a minute; see [Report limits](#report-limits)                       |
 | `CORS_ALLOWED_ORIGINS` | empty                | Comma-separated origins whose pages may call the API; see [CORS](#cors)                                  |
 | `METRICS_USERNAME`     | empty                | Basic auth user name for `/metrics`; see [Metrics](#metrics)                                             |
 | `METRICS_PASSWORD`     | empty                | Basic auth password for `/metrics`; see [Metrics](#metrics)                                              |
 | `SENTRY_DSN`           | empty                | DSN of the Sentry project to send errors to; see [Sentry](#sentry)                                       |
 
-`TRUSTED_PROXIES` defaults to `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16`. A list
-replaces the default; set and empty, the server trusts no proxy. Loopback is not
-in the default, so a reverse proxy on the same host has to be named, as in
-`TRUSTED_PROXIES=127.0.0.1/32`. A request whose direct peer is outside this set
-has its forwarded headers ignored, and the direct peer is logged and
-rate-limited instead. From a direct peer inside the set, the client address is
-the right-most `X-Forwarded-For` entry that is not in the set: each proxy
-appends the address it took the request from, so the entries further left were
-written by the client and are not used. An entry written as an address with a
-port, such as `198.51.100.7:5000` or `[2001:db8::1]:443`, is read as that
-address. If the search from the right finds only addresses in the set, or meets
-an entry that is not an address at all, such as `unknown`, the direct peer is
-used. `X-Real-IP` is read only when `X-Forwarded-For` is missing or empty. The
-container image does not use this default; see [Deployment](#deployment).
+`TRUSTED_PROXIES` defaults to
+`127.0.0.1/32,::1/128,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16`. The loopback
+entries cover a reverse proxy on the same host. A request whose direct peer is
+outside this set has its forwarded headers ignored, and the direct peer is
+logged and rate-limited instead. The container image does not use this default;
+see [Deployment](#deployment).
 
 A variable set to a value the server cannot use, such as `PORT=abc`,
 `DEBUG=maybe` or a `BIND_ADDRESS` that is not an IP address, stops it from
-starting, with an error naming the variable. An empty variable counts as unset,
-except `TRUSTED_PROXIES`.
+starting, with an error naming the variable. An empty variable counts as unset.
 
 #### Report storage
 
@@ -270,38 +226,12 @@ the numbers: its file, if it was created, is removed. The file stays, counted
 toward `DATA_DIR_MAX_BYTES` from the next start, only if removing it fails too.
 Files are created with `O_EXCL` to prevent overwrites.
 
-The reports of a failed write stay in memory, and the next flush, within a
-minute, tries again to write them. From the failed write until a write succeeds,
-`POST /api/v1/reports` refuses every report with 500 and keeps nothing of it.
-The page sends the refused samples again in its next report, as long as it still
-holds them: at the 1-second interval one refused report already loses some of
-those in the history (see [Reporting](#reporting)). Reports already answered 200
-are lost only if the server stops before a write succeeds; the final flush at
-stop tries them too, and if it fails, the process exits non-zero.
-
 #### Report limits
 
 `POST /api/v1/reports` takes reports from anyone who can reach it, without
-credentials, so it is bounded instead. Each refusal below answers with the same
-`{"status":"error"}` body as any other error, except nginx's refusal of a body
-over the limit in the image.
+credentials, so it is bounded instead. Both refusals below answer with the same
+`{"status":"error"}` body as any other error.
 
-- **JSON only.** A report must be sent with `Content-Type: application/json`,
-  parameters such as `charset` allowed, as the page sends it; any other is
-  refused with 415, and nothing of it is stored. A page on another origin can
-  send a `text/plain` POST, or a form, without a CORS preflight; refusing them
-  keeps any site from making its visitors' browsers store reports (see
-  [CORS](#cors)).
-- **Body limit.** A report body may be at most 1 MiB, the backend's limit for
-  any request. Run on its own, the backend answers 413 before the route to a
-  request that declares a longer body. Without a declared length, the route
-  answers 413 only when the report it reads runs past 1 MiB; nothing after the
-  end of the report is read, so a longer body whose report ends sooner is
-  stored, and one that stops being valid JSON sooner is answered 400. In the
-  image, nginx refuses a body over 1 MiB first, with or without a declared
-  length, as its `client_max_body_size`, which `configs/nginx.conf` does not
-  set, is 1 MiB by default. nginx answers 413 with its own HTML error page, and
-  the backend never sees the request.
 - **Rate limit.** Each client address, resolved through `TRUSTED_PROXIES`, may
   send `REPORTS_PER_MINUTE` reports a minute; past that it gets 429 with
   `Retry-After: 60`. The minute slides: reports from the minute before still
@@ -314,22 +244,16 @@ over the limit in the image.
   `X-RateLimit-Reset` headers.
 - **Size cap.** The report files in `DATA_DIR` may total at most
   `DATA_DIR_MAX_BYTES`, counting the files already there at start. Reports
-  waiting in memory count at their uncompressed size until they are written,
-  those of a failed write included; the part of its file written is removed.
-  When a report would take the total past the cap, the oldest report files are
-  deleted to make room, and each deletion is logged with the file's name and
-  size; a file still being written is never deleted. A report is refused with
-  507, and nothing of it is stored, only when the reports waiting to be written
-  fill the cap on their own, and then no file is deleted. At start, report files
-  past the cap, as after lowering it, are deleted the same way. So the cap is
-  how much of the newest reports is kept: the default of 1 GiB is small enough
-  for any host; set it to the space you can give `DATA_DIR`.
-
-At the defaults, one address may send 60 reports of up to 1 MiB a minute, and a
-report made up to compress badly takes about as much room in the report files as
-its request body, so in about 17 minutes one address can fill the 1 GiB cap with
-its own reports, every report stored before them deleted to make room. Lowering
-`REPORTS_PER_MINUTE` or raising `DATA_DIR_MAX_BYTES` makes that take longer.
+  waiting in memory count at their uncompressed size until they are written;
+  those lost to a failed write stop counting, and the part of its file written
+  is removed. When a report would take the total past the cap, the oldest report
+  files are deleted to make room, and each deletion is logged with the file's
+  name and size; a file still being written is never deleted. A report is
+  refused with 507, and nothing of it is stored, only when the reports waiting
+  to be written fill the cap on their own, and then no file is deleted. At
+  start, report files past the cap, as after lowering it, are deleted the same
+  way. So the cap is how much of the newest reports is kept: the default of 1
+  GiB is small enough for any host; set it to the space you can give `DATA_DIR`.
 
 #### CORS
 
@@ -352,16 +276,12 @@ the metrics record its duration and response size, labelled with its path,
 method and status; they also count those requests in progress, and include Go's
 runtime and process metrics. No other request is recorded: not those to
 `/metrics` itself, and not those answered before they reach either route, such
-as a CORS preflight, or a request refused with 404 for a path no route has or
-405 for a method its route does not take. Run on its own, the backend also
-answers 413 before the route to a request declaring a body length over the 1 MiB
-limit, which is not recorded. A body over the limit sent without a declared
-length reaches the route and is recorded with the status the route answers,
-which is 413 only when the report it reads runs past the limit: nothing after
-the end of the report is read. In the image neither reaches the backend: nginx
-answers both with 413 itself (see [Report limits](#report-limits)), and nothing
-of them is recorded. Clients can make up any number of paths and methods, and
-each would add labels to the metrics for as long as the server runs.
+as a CORS preflight, or a request refused with 404 for a path no route has, 405
+for a method its route does not take, or 413 for declaring a body length over
+the 1 MiB limit. A report whose body goes over the limit without declaring its
+length reaches the route, is answered 413 there, and is recorded with that
+status. Clients can make up any number of paths and methods, and each would add
+labels to the metrics for as long as the server runs.
 
 `/metrics` is rate limited, so that its password cannot be guessed quickly: each
 client address, resolved through `TRUSTED_PROXIES`, may make 60 requests to it a
@@ -484,15 +404,11 @@ address nginx passes on and no other. The image:
 
 - Listens on port 8080 by default (override with `PORT` env var)
 - Takes the client address from `X-Forwarded-For` only on requests from the
-  reverse proxies named in `TRUSTED_PROXIES`, by default from any address in
-  `10.0.0.0/8`, `172.16.0.0/12` or `192.168.0.0/16`. `bin/entrypoint.sh` checks
-  each entry with `netwatch-server check-cidr`, which parses it as the backend
-  parses its own `TRUSTED_PROXIES`
+  reverse proxies named in `TRUSTED_PROXIES`, and by default from none.
+  `bin/entrypoint.sh` checks each entry with `netwatch-server check-cidr`, which
+  parses it as the backend parses its own `TRUSTED_PROXIES`
 - Sends access logs to stdout
-- Sends the page with `Cache-Control: no-cache`, so a browser that keeps a copy
-  checks with the server that it is current before using it again; only the
-  files under `/assets/`, whose names change whenever their contents do, are
-  cached as immutable
+- Caches static assets with immutable headers
 - Sends the security headers `REPO_POLICIES.md` requires on every response, as
   `configs/security-headers.conf` sets them, in place of the backend's own
 - Stores reports in `DATA_DIR`, `/data/reports` by default, on the `/data`
@@ -509,9 +425,9 @@ What the [upaas](https://git.eeqj.de/sneak/upaas) app for netwatch needs:
 
 - **Port:** container port `8080`.
 - **Volume:** container path `/data`; the reports are kept in `/data/reports`.
-- **Environment variables:** none is required. An empty one counts as unset,
-  except `TRUSTED_PROXIES`, and one set to a value netwatch cannot use stops the
-  container at start, with the reason in its log.
+- **Environment variables:** none is required. An empty one counts as unset, and
+  one set to a value netwatch cannot use stops the container at start, with the
+  reason in its log.
     - `PORT`, default `8080`: the container port, from 1 to 65535. `8081` cannot
       be used: the backend listens on it inside the container
     - `REPORTS_PER_MINUTE`, default `60`: reports each client address may send a
@@ -525,17 +441,16 @@ What the [upaas](https://git.eeqj.de/sneak/upaas) app for netwatch needs:
       in: `/data` or a path below it, with no `.` or `..` part and no extra `/`.
       The container also stops if the path goes through a symbolic link that
       leads out of `/data` or is written as a full path
-    - `TRUSTED_PROXIES`, default `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16`: the
-      addresses the reverse proxy in front of the container connects from, as IP
-      addresses or CIDRs separated by commas. nginx takes the client address
-      from `X-Forwarded-For` only on a request from one of them, and the rate
-      limit counts that address. A list replaces the default. Set and empty,
-      `X-Forwarded-For` is ignored and every client behind the proxy shares the
-      proxy's one allowance of `REPORTS_PER_MINUTE`. Any client that connects
-      from one of these addresses can write its own `X-Forwarded-For`, and
-      through a port Docker publishes, every client may connect from the Docker
-      network's gateway, such as `172.17.0.1`, which the default includes; where
-      that matters, name only the addresses nothing but the proxy connects from.
+    - `TRUSTED_PROXIES`, default empty: set it to the address the reverse proxy
+      in front of the container connects from, as an IP address or CIDR; several
+      are separated by commas. nginx takes the client address from
+      `X-Forwarded-For` only on a request from one of them, and the rate limit
+      counts that address. Unset, `X-Forwarded-For` is ignored and every client
+      behind the proxy shares the proxy's one allowance of `REPORTS_PER_MINUTE`.
+      Name only addresses nothing but the proxy connects from: any client that
+      connects from one can write its own `X-Forwarded-For`, and through a port
+      Docker publishes, every client may connect from the Docker network's
+      gateway, such as `172.17.0.1`.
     - `METRICS_USERNAME` and `METRICS_PASSWORD`, default empty: with both set,
       the backend records Prometheus metrics of its requests and serves them at
       `/metrics` on the container port, to requests with this user name and

REPO_POLICIES.md

@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-10-18
+last_modified: 2026-10-04
 ---
 
 This document covers repository structure, tooling, and workflow standards. Code
@@ -54,39 +54,34 @@ style conventions are in separate documents:
   `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 only when its major version is the pinned one; otherwise (node
-  missing, or another major, such as the node 24 the CI runner image ships) it
-  installs the PINNED node version via nvm and installs yarn and the packages
-  under it. nvm itself is installed first if missing, from a hash-verified
-  GitHub release archive (never `curl | sh`), with bash installed as an explicit
-  prerequisite since nvm requires bash. Only the major version is compared
-  because the `Dockerfile` stages start from a node image whose exact version is
-  not the pin, and nvm cannot install a prebuilt node on alpine. yarn is 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, runs `script/bootstrap`, runs `script/check`, and builds the
-  image with the version; the Gitea workflow calls it. **`script/cibuild` runs
+  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, runs `script/bootstrap`, runs `script/check`, and builds the image
+  with the version; the Gitea workflow calls it. **`script/cibuild` runs
   `script/bootstrap` first**, because the workflow checks out the repo and runs
   nothing else, while `script/fmt-check` runs the formatter on the host: on a
   pristine checkout with nothing installed the run dies there, after the
-  containerised gates have passed. **The bootstrap alone is not enough**: when
-  `script/bootstrap` installs node and yarn under nvm it leaves neither on the
-  `PATH` of the shell that called it, so a bare `yarn` either exits 127 or runs
-  under another node. The host entrypoints that need yarn — `script/fmt` and
-  `script/fmt-check` — therefore use the same test as `script/bootstrap`: when
-  the node on `PATH` has the pinned major version they run the `yarn` on `PATH`,
-  and otherwise they load nvm through `$HOME/.nvm/nvm.sh` and run yarn under the
-  pinned node. A runner carrying nothing but docker and git then gets through
-  `script/check`. 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
+  containerised gates have passed. **The bootstrap alone is not enough**:
+  `script/bootstrap` installs node and yarn under nvm and leaves neither on the
+  `PATH` of the shell that called it, so a bare `yarn` still exits 127. The host
+  entrypoints that need yarn — `script/fmt` and `script/fmt-check` — therefore
+  source nvm for the pinned node version before invoking it, exactly as
+  `script/bootstrap`'s own install step does. A runner carrying nothing but
+  docker and git then gets through `script/check`. 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).
@@ -123,10 +118,8 @@ style conventions are in separate documents:
   and nothing else:
 
     ```sh
-    docker build --build-arg CACHEBUST="$(date +%s)-$$" \
-        --target lint --output type=cacheonly .
-    docker build --build-arg CACHEBUST="$(date +%s)-$$" \
-        --target test --output type=cacheonly .
+    docker build --no-cache --target lint -t "$(script/projectname)-lint" .
+    docker build --no-cache --target test -t "$(script/projectname)-test" .
     ```
 
     **A stage that is not the last one in the file is built only when the final
@@ -136,15 +129,10 @@ style conventions are in separate documents:
     plain `docker build .` builds the last stage alone and exits 0 having linted
     and tested nothing.
 
-    **The gate builds write no image.** With `--output type=cacheonly` the phase
-    runs and a failing step fails the build, but the result is not exported.
-    Nothing uses those images, and writing one out is slow: a Go test phase's
-    image holds the toolchain. A build given neither `--output` nor `-t` writes
-    an untagged image and leaves it dangling, on every developer host and every
-    CI runner. `script/cibuild` and `script/docker` build the image that ships
-    and tag it, so each build replaces the previous image; each assigns the tag
-    on its own line before the build, so `set -e` stops it where
-    `script/projectname` fails.
+    **Every `docker build` in `script/` is tagged**, here and in
+    `script/cibuild` and `script/docker`. An untagged build leaves a dangling
+    image behind on every invocation, on every developer host and every CI
+    runner; a tagged one replaces the previous image.
 
     Inside a phase the tool is invoked directly — `golangci-lint`, `go test`,
     `eslint`, `prettier` — never through `make lint` or `script/test`, which are
@@ -159,42 +147,22 @@ style conventions are in separate documents:
     one's findings, and a host-global lock in `$TMPDIR` makes concurrent runs
     exit non-zero with `parallel golangci-lint is running` — a status a caller
     cannot tell from real findings. Both have produced wrong verdicts in this
-    org, in both directions. A container has its own `TMPDIR`, so the lock is
-    out of reach. The lint phase does keep golangci-lint's cache between check
-    builds (below), but it lints every checkout at `/src`, and a finding is
-    taken from that cache only for the same files, settings and golangci-lint
-    version.
+    org, in both directions. A container has its own cache, its own `TMPDIR` and
+    a digest-pinned binary, so neither is reachable.
 
-- **Any build that runs checks is given a new `CACHEBUST` value.** Docker
-  invalidates a `COPY` layer only when the copied content changes, so on an
-  unchanged tree the check `RUN` is served from cache, nothing executes, and the
-  build still exits 0. Every `docker build` in `script/` therefore passes
-  `--build-arg CACHEBUST="$(date +%s)-$$"`, the time and the script's process
-  id, so no two builds share a value, not even the three in one
-  `script/cibuild`. `script/lint`, `script/test`, `script/cibuild` and
-  `script/docker` are the four, and there is no fifth — `script/check` runs the
-  two gate phases and `script/fmt-check`, and builds no image of its own. In
-  every stage of the `Dockerfile`, `ARG CACHEBUST` comes right after the steps
-  that install system packages and download Go's modules, or right after `FROM`
-  in a stage with neither, and every step that lints, tests or compiles comes
-  after it. A step that installs anything else as well, such as a
-  `script/bootstrap` that also installs node packages, comes after it too. A new
-  value reruns every `RUN` step after that line; `COPY` steps are compared by
-  content and need nothing. Docker keeps the layers above the line until the
-  base image, their own lines or the files they copy change. A stage without the
-  `ARG` line is served from cache on an unchanged tree, so a repository
-  re-vendors the scripts and adds the `ARG` lines in one commit. The scripts do
-  not pass `--no-cache`: it reruns every step too, but it also builds the layers
-  above the line again and empties every cache mount, so Go's build cache and
-  golangci-lint's, which the canonical Go `Dockerfile` below mounts so that they
-  survive between check builds, would start empty every time. A bare
-  `docker build .` is not evidence that anything ran: a sub-second build
-  reporting success is a cache hit, not a result. Never invalidate by pruning —
-  `docker builder prune` and friends destroy a build cache shared with every
-  other build on the host. When a check is added or changed, prove it works by
-  planting a defect it must catch and watching the run fail on it, then revert
-  the defect. A green run alone shows neither that the check ran nor that it
-  covers what it should.
+- **Any build that runs checks is built with `--no-cache`.** Docker invalidates
+  a `COPY` layer only when the copied content changes, so on an unchanged tree
+  the check `RUN` is served from cache, nothing executes, and the build still
+  exits 0. Every `docker build` in `script/` therefore passes `--no-cache`:
+  `script/lint`, `script/test`, `script/cibuild` and `script/docker` are the
+  four, and there is no fifth — `script/check` runs the two gate phases and
+  `script/fmt-check`, and builds no image of its own. A bare `docker build .` is
+  not evidence that anything ran: a sub-second build reporting success is a
+  cache hit, not a result. Never invalidate by pruning — `docker builder prune`
+  and friends destroy a build cache shared with every other build on the host.
+  When a check is added or changed, prove it works by planting a defect it must
+  catch and watching the run fail on it, then revert the defect. A green run
+  alone shows neither that the check ran nor that it covers what it should.
 
 - **The gate phases are separate stages, and the build stage depends on both.**
   The lint phase is based on the `golangci/golangci-lint` image (pinned by
@@ -203,56 +171,40 @@ style conventions are in separate documents:
   `Dockerfile`:
 
     ```dockerfile
-    # In every stage ARG CACHEBUST comes right after the steps that install
-    # system packages and download Go's modules, or right after FROM in a
-    # stage with neither, and every step that lints, tests or compiles
-    # comes after it. script/ passes a new value on every build, which
-    # reruns every RUN step after it. Docker keeps the layers above it
-    # until the base image, their own lines or go.mod and go.sum change.
-    # The steps that compile mount Go's build cache, and golangci-lint run
-    # also mounts golangci-lint's; both survive from build to build.
-
     # Lint phase
     # 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
-    ARG CACHEBUST
     COPY . .
-    RUN --mount=type=cache,target=/root/.cache/go-build \
-        --mount=type=cache,target=/root/.cache/golangci-lint \
-        golangci-lint run --config .golangci.yml ./...
+    RUN golangci-lint run --config .golangci.yml ./...
 
     # Test phase. -race needs cgo and so a C compiler, which the Debian Go
-    # image ships and the alpine one does not. -count=1 because the mounted
-    # cache also holds test results, which go test would otherwise replay.
+    # image ships and the alpine one does not.
     # golang:1.x, YYYY-MM-DD
     FROM golang@sha256:... AS test
     WORKDIR /src
     COPY go.mod go.sum ./
     RUN go mod download
-    ARG CACHEBUST
     COPY . .
-    RUN --mount=type=cache,target=/root/.cache/go-build \
-        go test -count=1 -timeout 90s -race -cover ./... || \
+    RUN go test -timeout 90s -race -cover ./... || \
         { echo "--- Rerunning with -v for details ---"; \
-          go test -count=1 -timeout 90s -race -v ./...; exit 1; }
+          go test -timeout 90s -race -v ./...; exit 1; }
 
     # Build stage. Nothing is wanted from either phase above; the copies
-    # are what make BuildKit build them first, so nothing after them can
-    # run unless lint and test passed.
+    # are what make BuildKit build them first, so this stage cannot run
+    # unless lint and test passed.
     # golang:1.x-alpine, YYYY-MM-DD
     FROM golang@sha256:... AS builder
+    COPY --from=lint /src/go.sum /dev/null
+    COPY --from=test /src/go.sum /dev/null
     RUN apk add --no-cache git
+    # A tar-stream context keeps the sender's file owners, which git refuses.
+    RUN git config --system --add safe.directory /src
     WORKDIR /src
     COPY go.mod go.sum ./
     RUN go mod download
-    ARG CACHEBUST
-    COPY --from=lint /src/go.sum /dev/null
-    COPY --from=test /src/go.sum /dev/null
-    # A tar-stream context keeps the sender's file owners, which git refuses.
-    RUN git config --system --add safe.directory /src
     COPY . .
 
     # The VERSION build arg when one is given, otherwise
@@ -260,8 +212,7 @@ style conventions are in separate documents:
     # .git present, a version that is still empty, dev or unknown fails the
     # build: git is missing or could not read the checkout.
     ARG VERSION
-    RUN --mount=type=cache,target=/root/.cache/go-build \
-        VERSION="${VERSION:-$(git describe --tags --always)}"; \
+    RUN VERSION="${VERSION:-$(git describe --tags --always)}"; \
         if [ -e .git ]; then \
             case "$VERSION" in ""|dev|unknown) \
                 echo "version is '$VERSION' although .git is present" >&2; \
@@ -274,7 +225,6 @@ style conventions are in separate documents:
 
     # Runtime stage, and the last one
     FROM alpine@sha256:...
-    ARG CACHEBUST
     COPY --from=builder /app /usr/local/bin/app
     ENTRYPOINT ["app"]
     ```
@@ -289,26 +239,6 @@ style conventions are in separate documents:
     - Keep the runtime stage last, and if you add a stage after it, give it the
       same two copies. A plain `docker build .` builds the last stage's chain
       and nothing else.
-    - Check builds keep these, and none of them can hand back a stale result:
-        - The layers above `ARG CACHEBUST`: the system packages and Go's
-          modules. Docker installs the packages again when the base image or the
-          install line changes, and downloads the modules again when `go.mod` or
-          `go.sum` changes. Go checks every module against `go.sum` as it
-          downloads it, and no later build can change a kept layer. The modules
-          are kept in a layer rather than a cache mount because a cache mount is
-          shared by every build on the host, and Go builds from whatever files
-          it holds without checking them again (only `go mod verify` does), so a
-          file changed there would go unnoticed.
-        - Go's build cache (`/root/.cache/go-build`, where Go keeps it for
-          root), mounted on the steps that compile: `golangci-lint run`, both
-          `go test` runs and `go build`. Go reuses a compiled package only when
-          all its inputs are unchanged. The cache also holds test results, which
-          is why both `go test` runs carry `-count=1`.
-        - golangci-lint's cache (`/root/.cache/golangci-lint`, where the pinned
-          image keeps it), mounted on `golangci-lint run`. golangci-lint reuses
-          a package's findings only when the package's files and those of every
-          package it imports, `go.mod`, the linters and their settings in
-          `.golangci.yml`, and the golangci-lint version are all unchanged.
     - If the project uses `//go:embed` directives that reference build artifacts
       (e.g. a web frontend compiled in a separate stage), the lint phase must
       create placeholder files so the embed directives resolve. Example:
@@ -317,20 +247,12 @@ style conventions are in separate documents:
       in the lint phase. The `golangci/golangci-lint` image is Debian-based and
       has no `apk`, so install with `apt-get` under the Debian package name
       (`libvips-dev`, where alpine says `vips-dev`), and delete the package
-      lists in the same `RUN`, so the layer does not keep them. The test phase,
-      on the Debian Go image, installs the libraries its tests need the same
-      way. Either install goes right after `FROM`, above `ARG CACHEBUST`, so
-      Docker keeps it until the base image or the install line changes:
+      lists in the same `RUN`, so the layer does not keep them:
 
         ```dockerfile
-        FROM golangci/golangci-lint@sha256:... AS lint
         RUN apt-get update \
             && apt-get install -y --no-install-recommends libvips-dev \
             && rm -rf /var/lib/apt/lists/*
-        WORKDIR /src
-        COPY go.mod go.sum ./
-        RUN go mod download
-        ARG CACHEBUST
         ```
 
     - `.dockerignore` lets `.git` into the build context. It keeps out every git
@@ -356,39 +278,20 @@ style conventions are in separate documents:
       `.git` and the version still comes out empty, `dev` or `unknown`. A plain
       `docker build .` with no build arguments must succeed; a Dockerfile that
       refuses an empty build argument drops that refusal and keeps the argument.
-      A checkout whose `.git` is a file (a linked worktree, or a repository
-      checked out as a submodule) is the exception: that file points to a git
-      directory outside the build context, so the build cannot read the version
-      and a plain `docker build .` fails; pass the version with
-      `--build-arg VERSION=...`, as `script/docker` and `script/cibuild` already
-      do.
 
 - Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
-  runs `script/cibuild` on push, and checks out the repo as its only other step,
-  with `persist-credentials: false`: `script/cibuild` needs no token, and
-  without it the checkout leaves the job's token in `.git/config` for every
-  later step. The checkout step also sets `fetch-depth: 0`, which fetches the
-  tags `git describe` needs: by default it clones shallow with no tags, and a
-  tagged repository's CI build would stamp a bare short commit id. The
-  workflow's `concurrency` block groups runs by workflow and branch
-  (`${{ github.workflow }}-${{ github.ref }}`) with `cancel-in-progress: true`,
-  so a new push cancels the older run on the same branch, queued or running, and
-  no other: runs for replaced commits do not hold up the shared runner.
-  `script/cibuild` bootstraps, runs the gate phases, and then builds the image,
-  so a successful run means every check passed; a bare `docker build .` does not
+  runs `script/cibuild` on push, and checks out the repo as its only other step.
+  That script bootstraps, runs the gate phases, and then builds the image, so a
+  successful run means every check passed; a bare `docker build .` does not
   carry the same guarantee, because its gate phases may come from the cache. The
-  image build gets a `CACHEBUST` value of its own and so runs the gate phases a
-  second time. That is the price of the rule above, and it is worth paying: the
-  image that ships is built from a run of its own gates rather than from a cache
-  entry. The `check` job sets `timeout-minutes: 20`, so a hung build frees the
-  shared runner after 20 minutes. That allows for the three Docker builds
-  described above (the test phase, the lint phase, then the image), each held to
-  the 5-minute Docker build limit below, plus the bootstrap. A separate workflow
-  limited to `main` by a `branches` list under `on: push` cannot be checked by
-  review: to try a change to it, add the feature branch to that list and push,
-  then remove the branch from the list again before merging. Keep any job in it
-  that publishes behind `if: github.ref_name == 'main'`, so the run from the
-  feature branch publishes nothing.
+  image build is uncached and so runs the gate phases a second time. That is the
+  price of the rule above, and it is worth paying: the image that ships is built
+  from a run of its own gates rather than from a cache entry. A separate
+  workflow limited to `main` by a `branches` list under `on: push` cannot be
+  checked by review: to try a change to it, add the feature branch to that list
+  and push, then remove the branch from the list again before merging. Keep any
+  job in it that publishes behind `if: github.ref_name == 'main'`, so the run
+  from the feature branch publishes nothing.
 
 - Use platform-standard formatters: `black` for Python, `prettier` for
   JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
@@ -448,11 +351,12 @@ style conventions are in separate documents:
     That cache is Go's own, separate from Docker's layer cache. Go stores a
     passing result in its cache directory (`GOCACHE`), and when the same tests
     run again on unchanged code it prints that result, marked `(cached)`,
-    without running them. The directory lasts from one run to the next on a
-    developer's machine, where this target runs, and in the `test` phase of the
-    `Dockerfile`, which mounts it to keep compiled packages between check
-    builds, so the phase's `go test` runs carry `-count=1` too. A new
-    `CACHEBUST` value (above) is what makes that step run on an unchanged tree.
+    without running them. That matters on a developer's machine, where this
+    target runs and the directory lasts from one run to the next. The `test`
+    phase of the `Dockerfile` needs no `-count=1`: its base image holds no
+    result for this repo's tests and nothing before its `go test` step runs a
+    test, so there is nothing to replay. `--no-cache` (above) is what makes that
+    step run on an unchanged tree.
 
     Python example:
 
@@ -480,12 +384,9 @@ style conventions are in separate documents:
 
 - `.gitignore` should be comprehensive from the start: OS files (`.DS_Store`),
   editor files (`.swp`, `*~`), in-repo agent scratch directories (`.claude/`),
-  `node_modules/`, and the repo's own build outputs. Fetch the standard
-  `.gitignore` from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.gitignore` when setting up
-  a new repo. A repo's `.gitignore` is the standard file followed by the repo's
-  own entries, such as its binaries; a re-vendor replaces the standard part and
-  keeps those entries. These patterns are written to `.gitignore`'s own
+  language build artifacts, and `node_modules/`. Fetch the standard `.gitignore`
+  from `https://git.eeqj.de/sneak/prompts/raw/branch/main/.gitignore` when
+  setting up a new repo. These patterns are written to `.gitignore`'s own
   semantics, in which an unanchored pattern already matches at every depth; they
   are not a `.dockerignore` and must not be transplanted into one unmodified.
 
@@ -533,15 +434,13 @@ style conventions are in separate documents:
   byte-identically across repos:
 
     ```sh
-    # The version and the tag each get their own line: a failing command
-    # substitution inside an argument does not trip `set -e`, so the inline
-    # form degrades to an empty constant.
+    # Own line: a failing command substitution inside an argument does not
+    # trip `set -e`, so the inline form degrades to an empty constant.
     version="$(git describe --tags --always --dirty 2>/dev/null || true)"
     [ -n "$version" ] || version="unknown"
-    tag="$(script/projectname)"
-    docker build --build-arg CACHEBUST="$(date +%s)-$$" \
+    docker build --no-cache \
         --build-arg VERSION="$version" \
-        -t "$tag" .
+        -t "$(script/projectname)" .
     ```
 
     `--always` makes an untagged repo yield an abbreviated commit hash rather
@@ -553,8 +452,8 @@ style conventions are in separate documents:
     there because `ARG` is stage-scoped; passing `VERSION` to a repo whose
     Dockerfile declares no such `ARG` is ignored and costs nothing, which is why
     the scripts stay byte-identical. One consequence for CI: the standard
-    checkout action clones shallow and fetches no tags, so the canonical
-    `.gitea/workflows/check.yml` sets `fetch-depth: 0` on its checkout step.
+    checkout action clones shallow and fetches no tags, so a repo that embeds a
+    tag-derived version must set `fetch-depth: 0` on its checkout step.
 
 - **Verify `.dockerignore` by enumerating the image, not by reading the
   patterns.** Plant files at the root _and_ at least two directories deep, build
@@ -621,11 +520,6 @@ style conventions are in separate documents:
       function defined and never invoked has the same exit status and the same
       empty output as one that worked.
 
-    Node is the exception to the whole-token comparison: the canonical
-    `script/bootstrap` compares only its major version, because the node 22
-    alpine image the `Dockerfile` stages start from is not the exact pin, and
-    nvm cannot install a prebuilt node on alpine.
-
     Keep it POSIX sh: no arrays, no `[[`, no `grep -P`.
 
     A Go tool a repo needs on the host is installed with `go install` pinned to
@@ -742,11 +636,7 @@ style conventions are in separate documents:
       Never edit existing migrations after release.
 
 - All repos should have an `.editorconfig` enforcing the project's indentation
-  settings: the standard file from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.editorconfig`, which sets
-  tabs for `Makefile` and Go files, followed by the repo's own sections, such as
-  one for another language it uses. A re-vendor replaces the standard part and
-  keeps those sections.
+  settings.
 
 - Avoid putting files in the repo root unless necessary. Root should contain
   only project-level config files (`README.md`, `AGENTS.md`, `Makefile`,

TODO.md

@@ -21,137 +21,6 @@ Run `make frontend-viewport-test` in CI as its own step; it is not part of
 
 # Completed Steps
 
-- 2026-10-19: check builds keep Go's modules and compiled packages between runs
-  ([#118](https://git.eeqj.de/sneak/netwatch/issues/118)), on sneak's rulings in
-  [prompts#113](https://git.eeqj.de/sneak/prompts/issues/113) and
-  [prompts#130](https://git.eeqj.de/sneak/prompts/issues/130).
-  `REPO_POLICIES.md`, `script/test`, `script/lint`, `script/docker` and
-  `script/cibuild` are the sneak/prompts copies at `0653579`: the scripts pass a
-  new `CACHEBUST` value where they passed `--no-cache`, and the lint and test
-  builds write no image. In each stage of `Dockerfile`, `ARG CACHEBUST` comes
-  after the system packages and the Go module download, and before every step
-  that lints, tests or compiles and the node stages' `yarn install`. Go's build
-  cache and golangci-lint's are cache mounts, and both `go test` runs carry
-  `-count=1`. The test phase's Go caches used to be in memory, empty on every
-  build
-- 2026-10-19: the three unit tests of a check whose result is discarded (its
-  round given up, the user paused, or the first round) also check that the
-  host's history is still empty, its status still `pending`, and nothing was
-  written to the console
-  ([#151](https://git.eeqj.de/sneak/netwatch/issues/151)). They checked only the
-  row, so a change that recorded the result and skipped only the row would have
-  kept them passing
-- 2026-10-18: when the backend runs on its own, a `DATA_DIR` that cannot be
-  created or read, or where no file can be created, stops the start with an
-  error naming `DATA_DIR` and its value, as the other settings' errors do
-  ([#148](https://git.eeqj.de/sneak/netwatch/issues/148)); the first two named
-  only the path, and the third was found only at the first write of a report
-  file. At start the server creates a file in `DATA_DIR` and removes it. Unit
-  tests start the buffer with `DATA_DIR` below a regular file and with
-  `DATA_DIR` set to `/proc`, and check the error. The report file number is an
-  `atomic.Int64`, as the Go style guide asks for int types
-  ([#161](https://git.eeqj.de/sneak/netwatch/issues/161)); file names are
-  unchanged
-- 2026-10-18: the image's nginx sends the page with `Cache-Control: no-cache`
-  ([#141](https://git.eeqj.de/sneak/netwatch/issues/141)), so a browser that
-  keeps a copy checks with the server that it is current before using it again.
-  The page went out with no `Cache-Control`, so a browser could keep it after a
-  deploy and ask for files under `/assets/` that the new build no longer has,
-  and show an empty page. A path that `location /` answers with the page through
-  its `try_files` fallback gets the same header. `location /` now includes the
-  security headers again, as `/assets/` does, since its own `add_header` drops
-  the server's. `/assets/` keeps its immutable caching.
-  `make frontend-viewport-test` fails unless `/` and a path that falls back to
-  the page carry `Cache-Control: no-cache` and `Content-Security-Policy`, which
-  comes from the same file as the other security headers
-- 2026-10-18: `README.md` says what the page loses while reports are refused or
-  the page is paused ([#145](https://git.eeqj.de/sneak/netwatch/issues/145)),
-  how fast one address can replace the stored reports
-  ([#146](https://git.eeqj.de/sneak/netwatch/issues/146)), and that in the image
-  nginx answers a body over 1 MiB itself
-  ([#147](https://git.eeqj.de/sneak/netwatch/issues/147)). A sample in the
-  history that no report has delivered is sent only as long as the history holds
-  it: at the 1-second interval one refused or failed report loses the oldest 20
-  seconds of each host's samples, and a pause longer than the history loses
-  every sample between the last delivered report and the pause. Samples an
-  interval change cleared are kept apart, the last 100 per host, until they are
-  delivered. At the defaults, one address sending 1 MiB reports made up to
-  compress badly can fill the 1 GiB cap in about 17 minutes. nginx's
-  `client_max_body_size` is also 1 MiB by default, so in the image it answers a
-  larger body with 413 and its own HTML page, and the backend never sees or
-  records it; the backend's own 413 sentences now say they apply to it run on
-  its own. The reporter, the body limit and nginx are unchanged
-- 2026-10-18: a browser that cannot format the header's clocks still probes
-  ([#149](https://git.eeqj.de/sneak/netwatch/issues/149)). The clocks name the
-  local time zone through `Intl.DateTimeFormat`'s `shortGeneric` option, which
-  Chrome before 95, Firefox before 91 and Safari before 15.4 reject with an
-  error; it came before the first round started, so such a browser never checked
-  a target. The clocks now start last, after the rounds, and an error formatting
-  them leaves both blank. The footer's color legend reads `>=500ms` for red,
-  where it read `>500ms`, so 500 ms, which is red, is in one of its colors
-  ([#152](https://git.eeqj.de/sneak/netwatch/issues/152)). Unit tests check the
-  clocks with a working `Intl.DateTimeFormat` and with one that rejects
-  `shortGeneric`, and draw the page and check the legend against every entry of
-  `CONFIG.latencyColors`
-- 2026-10-18: `netwatch-server prepare-data-dir` no longer changes the owner of
-  a file outside `/data` through a hard link in the volume
-  ([#143](https://git.eeqj.de/sneak/netwatch/issues/143)). A file with a second
-  name (hard link) keeps its owner, and the start logs its path. Owners are now
-  set on the opened directory, file or link, never by name, so a hard link
-  swapped in after the check is caught too; a symbolic link is opened without
-  following it and given to the netwatch user itself, so the server can still
-  follow one in a sticky directory that anyone can write to. Devices, named
-  pipes and sockets keep their owner. Setting the owner on an open file that is
-  not a directory is built only for Linux: `prepare-data-dir` runs only in the
-  Linux image, and macOS, where the backend is also built for development, has
-  neither `O_PATH` nor `AT_EMPTY_PATH`. On any other system the package still
-  builds, and `prepare-data-dir` fails at the first file that is not a
-  directory. The test that runs as root hard-links a file, a symbolic link and a
-  named pipe from outside the volume into it and finds their owners unchanged
-- 2026-10-18: from a trusted proxy, the backend takes the client address from
-  the right-most `X-Forwarded-For` entry that is not in `TRUSTED_PROXIES`
-  ([#144](https://git.eeqj.de/sneak/netwatch/issues/144)). It took the left-most
-  entry, which the client writes itself behind a proxy that appends to the
-  header, so a client could choose the address the rate limit counts and the
-  request log records. An entry written as an address with a port is read as
-  that address. With only trusted addresses in the header, or an entry that is
-  not an address at all (such as `unknown`) met on the way, the direct peer is
-  used. `X-Real-IP` is read only without `X-Forwarded-For`, and every
-  `X-Forwarded-For` header line is read, not only the first. The image's nginx,
-  and the `TRUSTED_PROXIES=127.0.0.1/32` it starts the backend with, are
-  unchanged; the comment in `configs/nginx.conf` that said the backend takes the
-  first entry now says it takes the one address nginx passes on. Unit tests
-  resolve the address from chains ending in an untrusted address, in trusted
-  ones, of only trusted ones, with ports, with an entry that is not an address,
-  and split over two header lines
-- 2026-10-18: after an interval change, the summary's Reachable slot reads
-  `--/--` in white, as at page load, until the second round since the change
-  ends ([#140](https://git.eeqj.de/sneak/netwatch/issues/140)). It used to read
-  0/26 in red from the change on, as no WAN host had a check recorded, for up to
-  two intervals with the network fine. The summary update now writes `--/--`
-  while every WAN host still waits for its first check. A unit test resets the
-  hosts as the interval menu does and checks the slot; another checks that it
-  reads 0/26 in red once every WAN host's check has failed
-- 2026-10-14: stopping the server waits for a report file write already under
-  way, the periodic flush's or the one `Append` starts when 10 MiB are waiting,
-  before the final flush
-  ([#122](https://git.eeqj.de/sneak/netwatch/issues/122)). It used to return at
-  once, and the process exiting cut the write off, losing its reports. A write
-  under way that fails puts its reports back in memory, so the final flush
-  writes them; the stop fails, and the process exits non-zero, only if that
-  flush fails too. Two tests hold the periodic write and the one at 10 MiB open
-  and find the stop waiting until each is released; a third makes the held write
-  fail and finds its report written by the final flush. They run in a
-  `testing/synctest` bubble, so the periodic flush comes without waiting a
-  minute
-- 2026-10-14: `make test` no longer runs the frontend's production build, which
-  the tests do not need ([#118](https://git.eeqj.de/sneak/netwatch/issues/118)).
-  `yarn build` moved out of the stage that runs the frontend's unit tests, now
-  named `frontend-test`, into a new `frontend-build` stage, which starts from it
-  and, like the `builder` stage, waits on the lint and test phases, so the image
-  still cannot be built unless they pass. The runtime stage copies `dist/` from
-  it, and the `git` that `vite.config.js` reads the commit with is installed
-  there. No build cache was added
 - 2026-10-14: opening the debug log no longer raises the measured latencies
   ([#131](https://git.eeqj.de/sneak/netwatch/issues/131)). With the panel open,
   each line written drew the panel again with every line before it, up to 1000,
@@ -161,60 +30,6 @@ Run `make frontend-viewport-test` in CI as its own step; it is not part of
   frame rather than once a line; the whole panel is drawn only when it is
   opened. A unit test writes more lines than the panel keeps and checks that the
   lines already shown are left as they are
-- 2026-10-14: unset, the backend's own `TRUSTED_PROXIES` trusts `10.0.0.0/8`,
-  `172.16.0.0/12` and `192.168.0.0/16`, and no longer loopback; a list replaces
-  that; set and empty, it trusts no proxy, where it used to get the default, as
-  viper reads an empty environment variable as unset
-  ([#129](https://git.eeqj.de/sneak/netwatch/issues/129)). A value it cannot
-  parse still stops the start, and the image still starts the backend with
-  `TRUSTED_PROXIES=127.0.0.1/32`. Tests load the config with it unset, empty and
-  set to a list
-- 2026-10-14: while report files cannot be written, `POST /api/v1/reports`
-  answers 500, and storing recovers once writing works again, with no restart
-  ([#123](https://git.eeqj.de/sneak/netwatch/issues/123)). A failed write puts
-  its reports back in the report buffer, still counted against
-  `DATA_DIR_MAX_BYTES`, where they used to be lost; the next flush, within a
-  minute, tries them again. Until a write succeeds, every report is refused and
-  nothing of it is kept, so the buffer does not grow while writes fail. A test
-  posts reports through the report handler before, during and after a failure;
-  others check that a report appended while a write runs is kept, behind that
-  write's own, when the write fails, and that the cap still holds exactly once a
-  failed write's reports are written
-- 2026-10-14: a request whose handler panics is logged with status 500 and
-  counted with `code` 500 in the metrics
-  ([#125](https://git.eeqj.de/sneak/netwatch/issues/125)), not 200. `Recoverer`
-  is still the first middleware; `Write500OnPanic`, after the request log and
-  after the metrics, writes the 500 as the panic passes and lets it go on to
-  Sentry and `Recoverer`, which now writes a 500 only when no status was written
-- 2026-10-14: with `TRUSTED_PROXIES` unset, the container's nginx trusts the
-  three private ranges of RFC 1918, `10.0.0.0/8`, `172.16.0.0/12` and
-  `192.168.0.0/16` ([#119](https://git.eeqj.de/sneak/netwatch/issues/119)), as
-  sneak ruled on 2026-09-22 for every app; it trusted no proxy before. A list
-  replaces them, and set and empty it trusts none. The backend inside the
-  container still trusts only `127.0.0.1/32`
-- 2026-10-14: `POST /api/v1/reports` takes only a report sent with
-  `Content-Type: application/json`, parameters such as `charset` allowed, and
-  refuses any other with 415 and the usual error body, storing nothing
-  ([#126](https://git.eeqj.de/sneak/netwatch/issues/126)). A page on another
-  origin can send a `text/plain` POST without a CORS preflight, so any site
-  could make its visitors' browsers store reports; a JSON POST waits for the
-  preflight, which only an origin in `CORS_ALLOWED_ORIGINS` passes. The page
-  already sent `application/json`. A test posts a report as `text/plain`, as
-  `application/x-www-form-urlencoded`, as `multipart/form-data`, with no
-  `Content-Type`, and as `application/json` with and without a charset, and
-  checks which are stored
-- 2026-10-14: changing the interval no longer drops the samples not yet reported
-  to the backend ([#124](https://git.eeqj.de/sneak/netwatch/issues/124)). The
-  interval menu resets each host with the new `HostState.reset`, which moves the
-  history's entries to `clearedHistory`, keeping the last 100 of all it has
-  cleared, and `buildReport` reads both, so the next report has the samples
-  recorded before the change that no report has delivered. Until its next check,
-  such a host is sent with the status of its last check, not `pending`. The
-  page's history still starts over, and the per-host marks still leave out of a
-  report the samples a delivered one had. Unit tests reset a host as the
-  interval menu does and find its unreported samples in the next report, and
-  only the last 100 after more were cleared; `web/src/main.js` now exports
-  `Reporter` for them
 - 2026-10-14: the repo has the layout `REPO_POLICIES.md` gives
   ([#30](https://git.eeqj.de/sneak/netwatch/issues/30)). The Go module is at the
   root (`go.mod`, `go.sum`, `.golangci.yml`, `cmd/netwatch-server/`,

bin/entrypoint.sh

@@ -34,11 +34,9 @@ fi
 
 # TRUSTED_PROXIES names the reverse proxies in front of the container,
 # as IP addresses or CIDRs separated by commas. nginx takes the client
-# address from X-Forwarded-For only on a request from one of them.
-# Unset, they are the three private ranges of RFC 1918; set and empty,
-# nginx trusts no one, which is why the default below follows - and not
-# :-. configs/nginx.conf includes the file written here, one
-# set_real_ip_from line per entry.
+# address from X-Forwarded-For only on a request from one of them, so
+# unset or empty, it trusts no one. configs/nginx.conf includes the file
+# written here, one set_real_ip_from line per entry.
 #
 # nginx looks up an entry it cannot read as an address as a hostname,
 # and trusts what it finds (1.2.3 is found as 1.2.0.3). So each entry
@@ -47,7 +45,7 @@ fi
 # TRUSTED_PROXIES. Its error, naming the CIDR, is dropped for the one
 # below, naming the entry as written. set -f keeps a * in an entry from
 # becoming a list of file names.
-TRUSTED_PROXIES="${TRUSTED_PROXIES-10.0.0.0/8,172.16.0.0/12,192.168.0.0/16}"
+TRUSTED_PROXIES="${TRUSTED_PROXIES:-}"
 set -f
 for proxy in $(printf '%s' "$TRUSTED_PROXIES" | tr ',' ' '); do
     case "$proxy" in
@@ -66,13 +64,10 @@ done > /etc/nginx/trusted-proxies.conf
 # netwatch-server keeps its report files in DATA_DIR, on the /data
 # volume, which may be a host directory owned by root or by another
 # uid. Here, as root, netwatch-server prepare-data-dir creates DATA_DIR
-# and gives /data and the directories, regular files and symbolic links
-# in it to the netwatch user, so the host directory needs no preparing.
-# A file with a second name (hard link) keeps its owner, as that name
-# could be outside /data, and its path is logged. It stops the start,
-# naming DATA_DIR, unless DATA_DIR is /data or a path below it, and it
-# acts on nothing outside /data, whatever symbolic or hard links it
-# meets there.
+# and gives /data and everything in it to the netwatch user, so the
+# host directory needs no preparing. It stops the start, naming
+# DATA_DIR, unless DATA_DIR is /data or a path below it, and it acts on
+# nothing outside /data, whatever symbolic links it meets there.
 export DATA_DIR="${DATA_DIR:-/data/reports}"
 netwatch-server prepare-data-dir "$DATA_DIR" || exit 1
 

configs/nginx.conf

@@ -18,10 +18,9 @@ server {
 
     # The client address comes from X-Forwarded-For only on a request
     # from the reverse proxies in TRUSTED_PROXIES: bin/entrypoint.sh
-    # writes one set_real_ip_from line for each into this file. Unset,
-    # TRUSTED_PROXIES is the three private ranges of RFC 1918; set and
-    # empty, the file is empty and the client address is the one each
-    # request comes from.
+    # writes one set_real_ip_from line for each into this file, and
+    # leaves it empty when TRUSTED_PROXIES is unset, so that by default
+    # the client address is the one each request comes from.
     include /etc/nginx/trusted-proxies.conf;
     real_ip_header X-Forwarded-For;
     real_ip_recursive on;
@@ -30,13 +29,8 @@ server {
     access_log /dev/stdout combined;
     error_log  /dev/stderr warn;
 
-    # With no-cache, a browser never uses a copy of the page that names
-    # assets a newer build no longer has without first checking with the
-    # server that it is current.
     location / {
         try_files $uri $uri/ /index.html;
-        add_header Cache-Control no-cache;
-        include /etc/nginx/security-headers.conf;
     }
 
     # Cache static assets aggressively
@@ -51,9 +45,7 @@ server {
     # 127.0.0.1:8081. These headers go with every request passed to it.
     # X-Forwarded-For carries only the client address, as resolved by
     # the real IP settings above, and not the chain the request came
-    # with. bin/entrypoint.sh starts the backend with
-    # TRUSTED_PROXIES=127.0.0.1/32, the address nginx connects from, so
-    # the backend takes that one entry as the client address.
+    # with: the backend takes the first entry, which a client can write.
     proxy_set_header Host $host;
     proxy_set_header X-Real-IP $remote_addr;
     proxy_set_header X-Forwarded-For $remote_addr;

go.mod

@@ -17,7 +17,6 @@ require (
 	github.com/slok/go-http-metrics v0.13.0
 	github.com/spf13/viper v1.21.0
 	go.uber.org/fx v1.24.0
-	golang.org/x/sys v0.47.0
 )
 
 require (
@@ -42,6 +41,7 @@ require (
 	go.uber.org/multierr v1.10.0 // indirect
 	go.uber.org/zap v1.26.0 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
+	golang.org/x/sys v0.47.0 // indirect
 	golang.org/x/text v0.40.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
 )

internal/config/config.go

@@ -9,7 +9,6 @@ import (
 	"math"
 	"net/netip"
 	"net/url"
-	"os"
 	"strconv"
 	"strings"
 
@@ -22,11 +21,13 @@ import (
 )
 
 // defaultTrustedProxies lists the networks whose forwarded
-// headers are honoured when TRUSTED_PROXIES is unset: the
-// RFC 1918 ranges. The container image does not use it:
+// headers are honoured by default: IPv4 and IPv6 loopback,
+// for a reverse proxy on the same host, and the RFC1918
+// ranges. The container image does not use it:
 // bin/entrypoint.sh gives the server 127.0.0.1/32, since
 // nginx is its only client there.
-const defaultTrustedProxies = "10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"
+const defaultTrustedProxies = "127.0.0.1/32,::1/128," +
+	"10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"
 
 // Default limits on stored reports; README.md gives the reasons for
 // these values.
@@ -134,14 +135,6 @@ func New(
 			viper.GetString("DEBUG"), errNotBool)
 	}
 
-	// An empty TRUSTED_PROXIES trusts no proxy, but viper reads an
-	// empty environment variable as unset and would give the default,
-	// so the environment is read first.
-	trustedProxies, set := os.LookupEnv("TRUSTED_PROXIES")
-	if !set {
-		trustedProxies = viper.GetString("TRUSTED_PROXIES")
-	}
-
 	s := &Config{
 		BindAddress:        viper.GetString("BIND_ADDRESS"),
 		CORSAllowedOrigins: splitList(viper.GetString("CORS_ALLOWED_ORIGINS")),
@@ -153,7 +146,7 @@ func New(
 		Port:               port,
 		ReportsPerMinute:   viper.GetInt("REPORTS_PER_MINUTE"),
 		SentryDSN:          viper.GetString("SENTRY_DSN"),
-		TrustedProxies:     splitList(trustedProxies),
+		TrustedProxies:     splitList(viper.GetString("TRUSTED_PROXIES")),
 		log:                log,
 		params:             &params,
 	}

internal/config/config_test.go

@@ -1,8 +1,6 @@
 package config_test
 
 import (
-	"os"
-	"slices"
 	"strings"
 	"testing"
 
@@ -31,62 +29,6 @@ func requireConfigError(t *testing.T, setting string) {
 	}
 }
 
-// requireTrustedProxies builds the config as main does and fails the
-// test unless its TrustedProxies are want.
-func requireTrustedProxies(t *testing.T, want []string) {
-	t.Helper()
-
-	var cfg *config.Config
-
-	app := fx.New(
-		fx.NopLogger,
-		fx.Provide(globals.New, logger.New, config.New),
-		fx.Populate(&cfg),
-	)
-
-	err := app.Err()
-	if err != nil {
-		t.Fatalf("config error = %v", err)
-	}
-
-	if !slices.Equal(cfg.TrustedProxies, want) {
-		t.Fatalf("TrustedProxies = %q, want %q", cfg.TrustedProxies, want)
-	}
-}
-
-// TestTrustedProxiesUnsetTrustsRFC1918: unset, the server trusts the
-// RFC 1918 ranges and nothing else, loopback included.
-func TestTrustedProxiesUnsetTrustsRFC1918(t *testing.T) {
-	// t.Setenv first, so the variable is put back as it was after the
-	// test.
-	t.Setenv("TRUSTED_PROXIES", "")
-
-	err := os.Unsetenv("TRUSTED_PROXIES")
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	requireTrustedProxies(t,
-		[]string{"10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16"})
-}
-
-// TestTrustedProxiesEmptyTrustsNothing: set and empty, the server
-// trusts no proxy. viper alone would read the empty variable as unset
-// and give the default.
-func TestTrustedProxiesEmptyTrustsNothing(t *testing.T) {
-	t.Setenv("TRUSTED_PROXIES", "")
-
-	requireTrustedProxies(t, []string{})
-}
-
-// TestTrustedProxiesListReplacesDefault: a list is used as given, with
-// none of the default ranges added.
-func TestTrustedProxiesListReplacesDefault(t *testing.T) {
-	t.Setenv("TRUSTED_PROXIES", "172.17.0.1/32, 2001:db8::/32")
-
-	requireTrustedProxies(t, []string{"172.17.0.1/32", "2001:db8::/32"})
-}
-
 // TestSettingsLoadAsGiven: valid values pass the checks and are used
 // as given. bin/entrypoint.sh starts the server with these
 // BIND_ADDRESS and PORT values.

internal/handlers/handlers.go

@@ -5,9 +5,7 @@ package handlers
 import (
 	"context"
 	"encoding/json"
-	"errors"
 	"log/slog"
-	"mime"
 	"net/http"
 
 	"sneak.berlin/go/netwatch/internal/globals"
@@ -20,10 +18,6 @@ import (
 
 const jsonContentType = "application/json; charset=utf-8"
 
-// errNotJSON is what decodeJSON returns for a request whose
-// Content-Type is not application/json.
-var errNotJSON = errors.New("content type is not application/json")
-
 // reportAppender is the subset of the report buffer the handlers
 // depend on. Defining it here keeps the storage failure path
 // exercisable with a stub in tests.
@@ -86,25 +80,14 @@ func (s *Handlers) respondJSON(
 	}
 }
 
-// decodeJSON decodes the request body into v. It returns errNotJSON,
-// reading nothing, unless the request's Content-Type is
-// application/json, with or without parameters such as charset. The
-// body is expected to already be bounded by the body-size middleware,
-// so a caller can distinguish an over-limit body from malformed JSON
-// by testing the returned error for *http.MaxBytesError.
+// decodeJSON decodes the request body into v. The body is
+// expected to already be bounded by the body-size middleware, so
+// a caller can distinguish an over-limit body from malformed
+// JSON by testing the returned error for *http.MaxBytesError.
 func (s *Handlers) decodeJSON(
 	_ http.ResponseWriter,
 	r *http.Request,
 	v any,
 ) error {
-	// A page on another origin can POST text/plain or a form without
-	// a CORS preflight, so its visitors' browsers would send it
-	// whatever the CORS settings. A JSON POST waits for the
-	// preflight, so only JSON is taken.
-	mediaType, _, err := mime.ParseMediaType(r.Header.Get("Content-Type"))
-	if err != nil || mediaType != "application/json" {
-		return errNotJSON
-	}
-
 	return json.NewDecoder(r.Body).Decode(v)
 }

internal/handlers/report.go

@@ -30,7 +30,7 @@ type report struct {
 }
 
 // HandleReport returns a handler that accepts telemetry
-// reports from NetWatch clients, sent as application/json.
+// reports from NetWatch clients.
 func (s *Handlers) HandleReport() http.HandlerFunc {
 	type response struct {
 		Status string `json:"status"`
@@ -66,15 +66,9 @@ func (s *Handlers) HandleReport() http.HandlerFunc {
 }
 
 // decodeErrorStatus logs a report decode failure and returns the
-// status to send: 415 when the report was not sent as JSON, 413 when
-// the body exceeded the size limit, otherwise 400 for malformed JSON.
+// status to send: 413 when the body exceeded the size limit,
+// otherwise 400 for malformed JSON.
 func (s *Handlers) decodeErrorStatus(err error) int {
-	if errors.Is(err, errNotJSON) {
-		s.log.Warn("report refused: Content-Type is not application/json")
-
-		return http.StatusUnsupportedMediaType
-	}
-
 	var tooLarge *http.MaxBytesError
 	if errors.As(err, &tooLarge) {
 		s.log.Warn("report body too large", "limit_bytes", tooLarge.Limit)
@@ -93,7 +87,7 @@ func (s *Handlers) decodeErrorStatus(err error) int {
 
 // appendErrorStatus logs a failure to store a report and returns
 // the status to send: 507 when the reports waiting to be written fill
-// the size cap, otherwise 500, as when report files cannot be written.
+// the size cap, otherwise 500.
 func (s *Handlers) appendErrorStatus(err error) int {
 	if errors.Is(err, reportbuf.ErrFull) {
 		s.log.Warn("report refused: " +

internal/handlers/report_test.go

@@ -27,17 +27,6 @@ type stubAppender struct {
 
 func (s stubAppender) Append(any) error { return s.err }
 
-// recordingAppender keeps every report the handler stores.
-type recordingAppender struct {
-	reports []any
-}
-
-func (a *recordingAppender) Append(v any) error {
-	a.reports = append(a.reports, v)
-
-	return nil
-}
-
 func newTestHandlers(buf stubAppender, out io.Writer) *handlers.Handlers {
 	return handlers.NewForTest(buf, slog.New(slog.NewJSONHandler(out, nil)))
 }
@@ -94,7 +83,6 @@ func TestHandleReportAcceptsValidReports(t *testing.T) {
 				http.MethodPost, "/api/v1/reports",
 				strings.NewReader(tt.body),
 			)
-			req.Header.Set("Content-Type", "application/json")
 
 			h.HandleReport().ServeHTTP(rec, req)
 
@@ -115,89 +103,6 @@ func TestHandleReportAcceptsValidReports(t *testing.T) {
 	}
 }
 
-// TestHandleReportStoresOnlyJSON checks that a report is stored only
-// when sent as application/json, as the page sends it. One sent as
-// text/plain or as a form, which a page on another origin can send
-// without a CORS preflight, is refused with 415.
-func TestHandleReportStoresOnlyJSON(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name        string
-		contentType string
-		wantStatus  int
-		wantStored  int
-	}{
-		{
-			name:        "text/plain",
-			contentType: "text/plain;charset=UTF-8",
-			wantStatus:  http.StatusUnsupportedMediaType,
-			wantStored:  0,
-		},
-		{
-			name:        "a urlencoded form",
-			contentType: "application/x-www-form-urlencoded",
-			wantStatus:  http.StatusUnsupportedMediaType,
-			wantStored:  0,
-		},
-		{
-			name:        "a multipart form",
-			contentType: "multipart/form-data; boundary=x",
-			wantStatus:  http.StatusUnsupportedMediaType,
-			wantStored:  0,
-		},
-		{
-			name:        "no Content-Type",
-			contentType: "",
-			wantStatus:  http.StatusUnsupportedMediaType,
-			wantStored:  0,
-		},
-		{
-			name:        "application/json",
-			contentType: "application/json",
-			wantStatus:  http.StatusOK,
-			wantStored:  1,
-		},
-		{
-			name:        "application/json with a charset",
-			contentType: "application/json;charset=UTF-8",
-			wantStatus:  http.StatusOK,
-			wantStored:  1,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			var stored recordingAppender
-
-			h := handlers.NewForTest(&stored, slog.New(slog.DiscardHandler))
-
-			rec := httptest.NewRecorder()
-			req := httptest.NewRequestWithContext(t.Context(),
-				http.MethodPost, "/api/v1/reports",
-				strings.NewReader(`{"clientId":"c1","hosts":[]}`),
-			)
-
-			if tt.contentType != "" {
-				req.Header.Set("Content-Type", tt.contentType)
-			}
-
-			h.HandleReport().ServeHTTP(rec, req)
-
-			if rec.Code != tt.wantStatus {
-				t.Errorf("status = %d, want %d", rec.Code, tt.wantStatus)
-			}
-
-			if len(stored.reports) != tt.wantStored {
-				t.Errorf("reports stored = %d, want %d",
-					len(stored.reports), tt.wantStored)
-			}
-		})
-	}
-}
-
 func TestHandleReportStorageFailureIsNon2xx(t *testing.T) {
 	t.Parallel()
 
@@ -208,7 +113,6 @@ func TestHandleReportStorageFailureIsNon2xx(t *testing.T) {
 		http.MethodPost, "/api/v1/reports",
 		strings.NewReader(`{"clientId":"c1","hosts":[]}`),
 	)
-	req.Header.Set("Content-Type", "application/json")
 
 	h.HandleReport().ServeHTTP(rec, req)
 
@@ -234,7 +138,6 @@ func TestHandleReportFullIs507(t *testing.T) {
 		http.MethodPost, "/api/v1/reports",
 		strings.NewReader(`{"clientId":"c1","hosts":[]}`),
 	)
-	req.Header.Set("Content-Type", "application/json")
 
 	h.HandleReport().ServeHTTP(rec, req)
 
@@ -258,7 +161,6 @@ func TestHandleReportMalformedJSONIs400(t *testing.T) {
 		http.MethodPost, "/api/v1/reports",
 		strings.NewReader(`{not json`),
 	)
-	req.Header.Set("Content-Type", "application/json")
 
 	h.HandleReport().ServeHTTP(rec, req)
 
@@ -283,8 +185,6 @@ func TestHandleReportOversizeIs413(t *testing.T) {
 		http.MethodPost, "/api/v1/reports",
 		strings.NewReader(`{"clientId":"`+strings.Repeat("x", 200)+`"}`),
 	)
-	req.Header.Set("Content-Type", "application/json")
-
 	// No declared length, so only the middleware's read cap can
 	// stop this body.
 	req.ContentLength = -1
@@ -313,7 +213,6 @@ func TestHandleReportDoesNotLogRawGeo(t *testing.T) {
 			`{"clientId":"c1","geo":{"raw":"`+sentinel+`"},"hosts":[]}`,
 		),
 	)
-	req.Header.Set("Content-Type", "application/json")
 
 	h.HandleReport().ServeHTTP(rec, req)
 
@@ -346,7 +245,6 @@ func TestHandleReportLogsClientIDCutToBound(t *testing.T) {
 			`{"clientId":"`+long+`","timestamp":"`+long+`","hosts":[]}`,
 		),
 	)
-	req.Header.Set("Content-Type", "application/json")
 
 	h.HandleReport().ServeHTTP(rec, req)
 
@@ -386,7 +284,6 @@ func TestHandleReportDecodeErrorLogIsBounded(t *testing.T) {
 		http.MethodPost, "/api/v1/reports",
 		strings.NewReader(`{"hosts":[{"history":[{"t":`+huge+`}]}]}`),
 	)
-	req.Header.Set("Content-Type", "application/json")
 
 	h.HandleReport().ServeHTTP(rec, req)
 

internal/middleware/middleware.go

@@ -11,7 +11,6 @@ import (
 	"net/http"
 	"net/netip"
 	"runtime/debug"
-	"slices"
 	"strings"
 	"time"
 
@@ -134,17 +133,6 @@ func ipFromHostPort(hostPort string) string {
 // X-Real-IP are honoured only when the direct peer is a
 // trusted proxy; otherwise the direct peer is returned so a
 // spoofed header cannot forge the logged address.
-//
-// Each proxy appends to X-Forwarded-For the address it took the
-// request from, so the entries on the right are written by the
-// trusted proxies and those further left by the client. The
-// client's address is therefore the right-most entry that is not
-// a trusted proxy. An entry written as an address with a port is
-// read as that address, both for the trust check and as the
-// result. When every entry is a trusted proxy, or the walk from
-// the right meets an entry that is not an address at all (such as
-// "unknown"), the peer is used. X-Real-IP is read only when there
-// is no X-Forwarded-For entry at all.
 func clientIP(
 	remoteAddr string,
 	header http.Header,
@@ -156,49 +144,28 @@ func clientIP(
 		return peer
 	}
 
-	forwarded := forwardedFor(header)
-
-	if len(forwarded) == 0 {
-		if xr := strings.TrimSpace(header.Get("X-Real-IP")); validIP(xr) {
-			return xr
-		}
-
-		return peer
+	if xff := firstForwardedFor(header.Get("X-Forwarded-For")); xff != "" {
+		return xff
 	}
 
-	for _, entry := range slices.Backward(forwarded) {
-		if !validIP(entry) {
-			return peer
-		}
-
-		if !addrInAny(entry, trusted) {
-			return entry
-		}
+	if xr := strings.TrimSpace(header.Get("X-Real-IP")); validIP(xr) {
+		return xr
 	}
 
 	return peer
 }
 
-// forwardedFor returns the entries of X-Forwarded-For in order,
-// leaving out blank ones. A proxy may add its entry as a header
-// line of its own rather than append it to the line the client
-// sent, so every line is read, not only the first. Some proxies
-// write an entry as an address with a port, such as
-// 198.51.100.7:5000 or [2001:db8::1]:443; the port is removed so
-// that the entry is read as its address.
-func forwardedFor(header http.Header) []string {
-	value := strings.Join(header.Values("X-Forwarded-For"), ",")
-
-	var entries []string
-
+// firstForwardedFor returns the left-most valid address in an
+// X-Forwarded-For list (the original client), or "" if none.
+func firstForwardedFor(value string) string {
 	for part := range strings.SplitSeq(value, ",") {
-		entry := strings.TrimSpace(part)
-		if entry != "" {
-			entries = append(entries, ipFromHostPort(entry))
+		candidate := strings.TrimSpace(part)
+		if validIP(candidate) {
+			return candidate
 		}
 	}
 
-	return entries
+	return ""
 }
 
 func validIP(s string) bool {
@@ -330,16 +297,12 @@ func (s *Middleware) MaxBodyBytes(
 
 // Recoverer returns middleware that recovers from a panic in a
 // downstream handler, logs the panic and stack trace through
-// slog, and responds 500 with no body, unless a status was already
-// written, as Write500OnPanic writes one for a handler's panic.
-// http.ErrAbortHandler is re-panicked so the server can abort the
-// response as intended.
+// slog, and responds 500 with no body. http.ErrAbortHandler is
+// re-panicked so the server can abort the response as intended.
 func (s *Middleware) Recoverer() func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(
 			func(w http.ResponseWriter, r *http.Request) {
-				ww := middleware.NewWrapResponseWriter(w, r.ProtoMajor)
-
 				defer func() {
 					rec := recover()
 					if rec == nil {
@@ -357,43 +320,10 @@ func (s *Middleware) Recoverer() func(http.Handler) http.Handler {
 						"stack", string(debug.Stack()),
 					)
 
-					if ww.Status() == 0 {
-						ww.WriteHeader(http.StatusInternalServerError)
-					}
+					w.WriteHeader(http.StatusInternalServerError)
 				}()
 
-				next.ServeHTTP(ww, r)
-			},
-		)
-	}
-}
-
-// Write500OnPanic returns middleware that writes 500 when a downstream
-// handler panics before writing a status, and lets the panic go on to
-// Sentry and Recoverer. Recoverer, which comes first, would write its
-// 500 only after the request log and the metrics had recorded the
-// status they saw; placed after each of them, this makes them record
-// the 500.
-func (s *Middleware) Write500OnPanic() func(http.Handler) http.Handler {
-	return func(next http.Handler) http.Handler {
-		return http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				ww := middleware.NewWrapResponseWriter(w, r.ProtoMajor)
-
-				defer func() {
-					rec := recover()
-					if rec == nil {
-						return
-					}
-
-					if ww.Status() == 0 {
-						ww.WriteHeader(http.StatusInternalServerError)
-					}
-
-					panic(rec)
-				}()
-
-				next.ServeHTTP(ww, r)
+				next.ServeHTTP(w, r)
 			},
 		)
 	}

internal/middleware/middleware_test.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"errors"
-	"log"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
@@ -17,24 +16,16 @@ import (
 	"sneak.berlin/go/netwatch/internal/logger"
 	"sneak.berlin/go/netwatch/internal/middleware"
 
-	"github.com/go-chi/chi/v5"
 	chimiddleware "github.com/go-chi/chi/v5/middleware"
-	"github.com/prometheus/client_golang/prometheus"
 )
 
 const (
 	// loopbackPeer is a remote address inside the trusted-proxy allowlist.
 	loopbackPeer = "127.0.0.1:5000"
-	// loopbackIP is the address of loopbackPeer, which ClientIP returns
-	// when it uses the peer.
-	loopbackIP = "127.0.0.1"
 	// forwardedIP is the client address presented via X-Forwarded-For.
 	forwardedIP = "203.0.113.7"
 	// realIP is the client address presented via X-Real-IP.
 	realIP = "203.0.113.9"
-	// appendedIP is the X-Forwarded-For entry a trusted proxy appended
-	// after the entries the client wrote.
-	appendedIP = "198.51.100.7"
 )
 
 func mustPrefixes(t *testing.T, cidrs ...string) []netip.Prefix {
@@ -91,35 +82,10 @@ func clientIPCases() []clientIPCase {
 			want:       forwardedIP,
 		},
 		{
-			name:       "trusted proxy uses right-most of chain",
-			remoteAddr: loopbackPeer,
-			xff:        "203.0.113.9, " + appendedIP,
-			want:       appendedIP,
-		},
-		{
-			name:       "trusted proxy entries are skipped from the right",
-			remoteAddr: loopbackPeer,
-			xff:        "203.0.113.9, 10.0.0.5",
-			want:       "203.0.113.9",
-		},
-		{
-			name:       "chain of only trusted proxies uses peer",
-			remoteAddr: loopbackPeer,
-			xff:        "10.0.0.5, 10.1.2.3",
-			want:       loopbackIP,
-		},
-		{
-			name:       "entry that is not an address uses peer",
-			remoteAddr: loopbackPeer,
-			xff:        "203.0.113.9, unknown",
-			want:       loopbackIP,
-		},
-		{
-			name:       "x-real-ip ignored when forwarded-for has entries",
-			remoteAddr: loopbackPeer,
-			xff:        "10.0.0.5",
-			xRealIP:    realIP,
-			want:       loopbackIP,
+			name:       "trusted proxy uses left-most of chain",
+			remoteAddr: "10.1.2.3:5000",
+			xff:        forwardedIP + ", 10.1.2.3",
+			want:       forwardedIP,
 		},
 		{
 			name:       "trusted proxy falls back to x-real-ip",
@@ -148,7 +114,7 @@ func clientIPCases() []clientIPCase {
 			name:       "trusted proxy with garbage header uses peer",
 			remoteAddr: loopbackPeer,
 			xff:        "not-an-ip",
-			want:       loopbackIP,
+			want:       "127.0.0.1",
 		},
 	}
 }
@@ -179,47 +145,6 @@ func TestClientIP(t *testing.T) {
 	}
 }
 
-// TestClientIPReadsEveryForwardedForLine checks that an entry a proxy
-// adds as an X-Forwarded-For line of its own is read, and the line the
-// client sent before it is not taken.
-func TestClientIPReadsEveryForwardedForLine(t *testing.T) {
-	t.Parallel()
-
-	header := http.Header{}
-	header.Add("X-Forwarded-For", "203.0.113.9")
-	header.Add("X-Forwarded-For", appendedIP)
-
-	got := middleware.ClientIP(loopbackPeer, header,
-		mustPrefixes(t, "127.0.0.1/32"))
-	if got != appendedIP {
-		t.Errorf("ClientIP() = %q, want %q", got, appendedIP)
-	}
-}
-
-// TestClientIPReadsAddressWithPort checks that an X-Forwarded-For entry
-// written as an address with a port is read as that address, both for
-// the trust check and as the result.
-func TestClientIPReadsAddressWithPort(t *testing.T) {
-	t.Parallel()
-
-	trusted := mustPrefixes(t, "127.0.0.1/32", "10.0.0.0/8")
-
-	for xff, want := range map[string]string{
-		"203.0.113.9, " + appendedIP + ":5000": appendedIP,
-		"203.0.113.9, [2001:db8::1]:443":       "2001:db8::1",
-		"203.0.113.9, 10.0.0.5:5000":           "203.0.113.9",
-	} {
-		header := http.Header{}
-		header.Set("X-Forwarded-For", xff)
-
-		got := middleware.ClientIP(loopbackPeer, header, trusted)
-		if got != want {
-			t.Errorf("X-Forwarded-For %q: ClientIP() = %q, want %q",
-				xff, got, want)
-		}
-	}
-}
-
 func TestSecurityHeaders(t *testing.T) {
 	t.Parallel()
 
@@ -398,172 +323,6 @@ func TestRecovererRepanicsOnAbortHandler(t *testing.T) {
 	}
 }
 
-// TestHandlerPanicIsLoggedAndCountedAs500 sends a request to a handler
-// that panics through the middleware SetupRoutes puts around a route
-// with metrics, in its order, leaving out those that write no status
-// for a panic and Sentry, which TestSentry covers. The request log line
-// and the metrics must give the 500 the client gets, and the panic must
-// still reach Recoverer, which logs it.
-func TestHandlerPanicIsLoggedAndCountedAs500(t *testing.T) {
-	t.Parallel()
-
-	var logbuf bytes.Buffer
-
-	mw := middleware.NewWithLogger(
-		slog.New(slog.NewJSONHandler(&logbuf, nil)),
-	)
-	registry := prometheus.NewRegistry()
-
-	handler := chi.Chain(
-		mw.Recoverer(),
-		chimiddleware.RequestID,
-		mw.Logging(),
-		mw.Write500OnPanic(),
-		mw.Metrics(registry),
-		mw.Write500OnPanic(),
-	).HandlerFunc(func(http.ResponseWriter, *http.Request) {
-		panic("boom")
-	})
-
-	rec := httptest.NewRecorder()
-	req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", http.NoBody)
-	handler.ServeHTTP(rec, req)
-
-	if rec.Code != http.StatusInternalServerError {
-		t.Fatalf("status = %d, want %d",
-			rec.Code, http.StatusInternalServerError)
-	}
-
-	request := findLogLine(t, logbuf.Bytes(), "request")
-	if request.Status != http.StatusInternalServerError {
-		t.Errorf("request log status = %d, want %d",
-			request.Status, http.StatusInternalServerError)
-	}
-
-	recovered := findLogLine(t, logbuf.Bytes(), "panic recovered")
-	if recovered.Panic != "boom" {
-		t.Errorf("panic recovered line has panic %q, want %q",
-			recovered.Panic, "boom")
-	}
-
-	for _, name := range []string{
-		"http_request_duration_seconds", "http_response_size_bytes",
-	} {
-		codes := metricCodes(t, registry, name)
-		if len(codes) != 1 || codes[0] != "500" {
-			t.Errorf("%s code labels = %v, want [500]", name, codes)
-		}
-	}
-}
-
-// loggedLine holds the fields the tests read from a JSON log line.
-type loggedLine struct {
-	Msg    string `json:"msg"`
-	Status int    `json:"status"`
-	Panic  string `json:"panic"`
-}
-
-// findLogLine returns the first of the JSON log lines in logged whose
-// message is msg.
-func findLogLine(t *testing.T, logged []byte, msg string) loggedLine {
-	t.Helper()
-
-	dec := json.NewDecoder(bytes.NewReader(logged))
-
-	for {
-		var line loggedLine
-
-		err := dec.Decode(&line)
-		if err != nil {
-			t.Fatalf("no %q line in the log: %v (%q)", msg, err, logged)
-		}
-
-		if line.Msg == msg {
-			return line
-		}
-	}
-}
-
-// metricCodes returns the code label of each series of the metric
-// family name in registry.
-func metricCodes(
-	t *testing.T,
-	registry *prometheus.Registry,
-	name string,
-) []string {
-	t.Helper()
-
-	families, err := registry.Gather()
-	if err != nil {
-		t.Fatalf("gather metrics: %v", err)
-	}
-
-	var codes []string
-
-	for _, family := range families {
-		if family.GetName() != name {
-			continue
-		}
-
-		for _, metric := range family.GetMetric() {
-			for _, label := range metric.GetLabel() {
-				if label.GetName() == "code" {
-					codes = append(codes, label.GetValue())
-				}
-			}
-		}
-	}
-
-	return codes
-}
-
-// TestRecovererWritesNoSecondStatus checks, on a real server, that
-// Recoverer does not write its 500 again after Write500OnPanic has
-// written one, which the server would log as a superfluous
-// WriteHeader call.
-func TestRecovererWritesNoSecondStatus(t *testing.T) {
-	t.Parallel()
-
-	var serverLog bytes.Buffer
-
-	mw := middleware.NewWithLogger(slog.New(slog.DiscardHandler))
-
-	server := httptest.NewUnstartedServer(chi.Chain(
-		mw.Recoverer(),
-		mw.Write500OnPanic(),
-	).HandlerFunc(func(http.ResponseWriter, *http.Request) {
-		panic("boom")
-	}))
-	server.Config.ErrorLog = log.New(&serverLog, "", 0)
-	server.Start()
-
-	req, err := http.NewRequestWithContext(t.Context(),
-		http.MethodGet, server.URL, http.NoBody)
-	if err != nil {
-		t.Fatalf("new request: %v", err)
-	}
-
-	resp, err := server.Client().Do(req)
-	if err != nil {
-		t.Fatalf("request: %v", err)
-	}
-
-	_ = resp.Body.Close()
-
-	// Close waits for the handler to return, so whatever the server
-	// logs for this request is in serverLog after it.
-	server.Close()
-
-	if resp.StatusCode != http.StatusInternalServerError {
-		t.Errorf("status = %d, want %d",
-			resp.StatusCode, http.StatusInternalServerError)
-	}
-
-	if serverLog.Len() != 0 {
-		t.Errorf("server logged %q", serverLog.String())
-	}
-}
-
 // TestLoggingCutsRequestStringsToBound sends an over-long URL and
 // over-long header values, and checks the request log writes each
 // one cut to logger.MaxLoggedFieldBytes.

internal/reportbuf/datadir.go

@@ -18,15 +18,9 @@ var ErrDataDirOutsideVolume = errors.New(
 // PrepareDataDir gets dir, the server's DATA_DIR, ready for owner, the
 // user the server runs as, so that a host directory mounted at volume,
 // /data in the image, needs no preparing: it creates dir, gives volume
-// and the directories, regular files and symbolic links in it to
-// owner, and gives volume and dir the mode the server gives a directory
-// it creates. It leaves a file with a second name (hard link) as it
-// is, as that name could be outside volume, and logs its path; it
-// leaves a device, named pipe or socket as it is too (see chownFile).
-// dir must be volume or a path below it, with no '.', '..', empty part
-// or '/' at the end. On any system but Linux, the system of the image, it
-// fails at the first file in volume that is not a directory (see
-// chownFile).
+// and everything in it to owner, and gives volume and dir the mode the
+// server gives a directory it creates. dir must be volume or a path
+// below it, with no '.', '..', empty part or '/' at the end.
 //
 // bin/entrypoint.sh runs this as root, which would follow a symbolic
 // link anywhere, so every step goes through an os.Root opened on
@@ -38,9 +32,10 @@ var ErrDataDirOutsideVolume = errors.New(
 // open, never following a link at the name it creates, and follows a
 // link on the path only as the os.Root allows, so a relative link
 // inside volume can lead it to create directories elsewhere inside
-// volume. The owners and modes are set on files already opened (see
-// chownAll and chmodDir), so the most that process can do is make a
-// step fail or wait, or act on something else inside volume.
+// volume. Lchown never changes what a link points to, and the modes
+// are set on directories already opened (see chmodDir), so the most
+// that process can do is make a step fail or wait, or act on
+// something else inside volume.
 func PrepareDataDir(volume, dir string, owner *user.User) error {
 	// rel is dir as a path from volume; IsLocal is false for one that
 	// leads out of it.
@@ -71,7 +66,7 @@ func PrepareDataDir(volume, dir string, owner *user.User) error {
 		return err
 	}
 
-	err = chownAll(root, ".", uid, gid)
+	err = lchownAll(root, ".", uid, gid)
 	if err != nil {
 		return err
 	}
@@ -84,23 +79,28 @@ func PrepareDataDir(volume, dir string, owner *user.User) error {
 	return chmodDir(root, rel)
 }
 
-// chownAll gives name, a directory inside root, and the directories,
-// regular files and symbolic links in it to uid and gid, but not the
-// files chownFile leaves. It opens each through root and gives the
-// open file to them, as chmodDir sets a mode on the open directory.
-// Root.Lchown would not hold: it acts on whatever is at the name by
-// then, and a hard link swapped in there shares its owner with a file
-// that could be outside root. A symbolic link is given to them itself,
-// never what it points to, because in a directory that anyone can
-// write to and that has the sticky bit set, as /tmp has, the kernel
-// follows a link only for the link's owner or when the link and the
-// directory have the same owner. chownAll goes into an entry only when
-// the read found a directory there, so it follows no link it finds;
-// one swapped in afterwards for a directory is followed only as the
-// os.Root allows, and one swapped in for any other file is not
-// followed at all (see chownFile).
-func chownAll(root *os.Root, name string, uid, gid int) error {
-	entries, err := chownDir(root, name, uid, gid)
+// lchownAll gives name, a directory inside root, and everything in it
+// to uid and gid. It reads each directory opened through root, not
+// through root.FS(), which refuses a name that is not valid UTF-8, and
+// calls Lchown on every entry, which gives a symbolic link itself to
+// them, not what it points to. It goes into an entry only when the
+// read found a directory there, so it follows no link it finds; one
+// swapped in for that directory afterwards is followed only as the
+// os.Root allows.
+func lchownAll(root *os.Root, name string, uid, gid int) error {
+	err := root.Lchown(name, uid, gid)
+	if err != nil {
+		return err
+	}
+
+	dir, err := root.Open(name)
+	if err != nil {
+		return err
+	}
+
+	entries, err := dir.ReadDir(-1)
+	_ = dir.Close()
+
 	if err != nil {
 		return err
 	}
@@ -108,9 +108,9 @@ func chownAll(root *os.Root, name string, uid, gid int) error {
 	for _, entry := range entries {
 		entryName := filepath.Join(name, entry.Name())
 		if entry.IsDir() {
-			err = chownAll(root, entryName, uid, gid)
+			err = lchownAll(root, entryName, uid, gid)
 		} else {
-			err = chownFile(root, entryName, uid, gid)
+			err = root.Lchown(entryName, uid, gid)
 		}
 
 		if err != nil {
@@ -121,36 +121,6 @@ func chownAll(root *os.Root, name string, uid, gid int) error {
 	return nil
 }
 
-// chownDir gives name, a directory inside root, to uid and gid, and
-// returns what it holds. Like chmodDir, it opens name through root and
-// refuses anything but a directory, which has no second name (hard
-// link). It reads the open directory, not root.FS(), which refuses a
-// name that is not valid UTF-8.
-func chownDir(root *os.Root, name string, uid, gid int) ([]fs.DirEntry, error) {
-	dir, err := root.Open(name)
-	if err != nil {
-		return nil, err
-	}
-
-	defer func() { _ = dir.Close() }()
-
-	info, err := dir.Stat()
-	if err != nil {
-		return nil, err
-	}
-
-	if !info.IsDir() {
-		return nil, &fs.PathError{Op: "chown", Path: name, Err: syscall.ENOTDIR}
-	}
-
-	err = dir.Chown(uid, gid)
-	if err != nil {
-		return nil, err
-	}
-
-	return dir.ReadDir(-1)
-}
-
 // chmodDir gives name, a directory inside root, the mode the server
 // gives a directory it creates. Root.Chmod would not hold: on Linux it
 // checks that name is not a symbolic link, then sets the mode by name,

internal/reportbuf/datadir_linux.go

@@ -1,65 +0,0 @@
-//go:build linux
-
-package reportbuf
-
-import (
-	"io/fs"
-	"log/slog"
-	"os"
-	"syscall"
-
-	"golang.org/x/sys/unix"
-)
-
-// chownFile gives name, a file inside root that is not a directory, to
-// uid and gid if it is a regular file or symbolic link with one name.
-// It leaves, and logs, a file of any kind with a second name (hard
-// link): all the names of a file share its owner, and the other could
-// be outside root. It leaves any other file with one name, such as a
-// device, named pipe or socket: the server needs to own none of them.
-// It opens name through root with O_PATH, which reads nothing from the
-// file, so opening a device or named pipe neither waits nor acts on
-// it; os.Root adds O_NOFOLLOW, and the two together open a symbolic
-// link itself, never what it points to. It reads the kind of file and
-// its number of names from the open file and gives that file to them,
-// so a hard link swapped in at name is caught too.
-//
-// This file is built only on Linux: prepare-data-dir runs only in the
-// Linux image, and macOS, where the backend is also built for
-// development, has neither O_PATH nor AT_EMPTY_PATH. On any other
-// system chownFile returns an error (see datadir_other.go).
-func chownFile(root *os.Root, name string, uid, gid int) error {
-	file, err := root.OpenFile(name, unix.O_PATH, 0)
-	if err != nil {
-		return err
-	}
-
-	defer func() { _ = file.Close() }()
-
-	info, err := file.Stat()
-	if err != nil {
-		return err
-	}
-
-	stat, ok := info.Sys().(*syscall.Stat_t)
-	if !ok || stat.Nlink > 1 {
-		slog.Warn("owner not changed: file has a second name (hard link)",
-			"path", file.Name())
-
-		return nil
-	}
-
-	if !info.Mode().IsRegular() && info.Mode().Type() != fs.ModeSymlink {
-		return nil
-	}
-
-	// File.Chown would fail: fchown refuses a file opened with O_PATH.
-	// Fchownat with an empty name and AT_EMPTY_PATH acts on the open
-	// file instead.
-	err = unix.Fchownat(int(file.Fd()), "", uid, gid, unix.AT_EMPTY_PATH)
-	if err != nil {
-		return &fs.PathError{Op: "chown", Path: file.Name(), Err: err}
-	}
-
-	return nil
-}

internal/reportbuf/datadir_other.go

@@ -1,21 +0,0 @@
-//go:build !linux
-
-package reportbuf
-
-import (
-	"errors"
-	"io/fs"
-	"os"
-)
-
-// chownFile returns an error on every system but Linux. Opening a file
-// that is not a directory without reading it or following it, and
-// giving it to a user on the open file, never by name, is built only
-// for Linux (see datadir_linux.go): prepare-data-dir runs only in the
-// Linux image, and macOS, where the backend is also built for
-// development, has neither O_PATH nor AT_EMPTY_PATH. This file lets
-// the package build elsewhere, such as on macOS, where a developer
-// runs make build and make run.
-func chownFile(_ *os.Root, name string, _, _ int) error {
-	return &fs.PathError{Op: "chown", Path: name, Err: errors.ErrUnsupported}
-}

internal/reportbuf/datadir_test.go

@@ -254,13 +254,10 @@ func TestPrepareDataDirTakesDirectoryNamedInLatin1(t *testing.T) {
 	requireOwner(t, filepath.Join(latin1, "f"), uint32(uid), uint32(gid))
 }
 
-// TestPrepareDataDirGivesVolumeToOwner gives the directories, regular
-// files and symbolic links in the volume to a uid and gid that own
-// nothing, which only root can do. A symbolic link in the volume to a
-// directory outside it is given to them itself; what it points to is
-// left as it was. A hard link to a file outside the volume, one to a
-// symbolic link outside it and one to a named pipe outside it are left
-// as they were, and so is a named pipe in the volume.
+// TestPrepareDataDirGivesVolumeToOwner gives everything in the volume
+// to a uid and gid that own nothing, which only root can do. A
+// symbolic link in the volume to a directory outside it is given to
+// them itself; what it points to is left as it was.
 func TestPrepareDataDirGivesVolumeToOwner(t *testing.T) {
 	t.Parallel()
 
@@ -277,16 +274,6 @@ func TestPrepareDataDirGivesVolumeToOwner(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = os.Symlink("f", filepath.Join(outside, "link"))
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	err = syscall.Mkfifo(filepath.Join(outside, "fifo"), 0o600)
-	if err != nil {
-		t.Fatal(err)
-	}
-
 	err = os.Mkdir(old, 0o700)
 	if err != nil {
 		t.Fatal(err)
@@ -302,21 +289,6 @@ func TestPrepareDataDirGivesVolumeToOwner(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = syscall.Mkfifo(filepath.Join(old, "fifo"), 0o600)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	// os.Link does not follow a symbolic link: it gives the link itself
-	// a second name.
-	for _, name := range []string{"f", "link", "fifo"} {
-		err = os.Link(filepath.Join(outside, name),
-			filepath.Join(old, "hardlink-to-"+name))
-		if err != nil {
-			t.Fatal(err)
-		}
-	}
-
 	err = reportbuf.PrepareDataDir(volume, filepath.Join(volume, reports),
 		&user.User{Uid: "4242", Gid: "4343"})
 	if err != nil {
@@ -324,16 +296,12 @@ func TestPrepareDataDirGivesVolumeToOwner(t *testing.T) {
 	}
 
 	for _, path := range []string{
-		volume, filepath.Join(volume, reports), old, filepath.Join(old, "f"),
-		filepath.Join(old, "link"),
+		volume, filepath.Join(volume, reports), old,
+		filepath.Join(old, "f"), filepath.Join(old, "link"),
 	} {
 		requireOwner(t, path, 4242, 4343)
 	}
 
-	for _, path := range []string{
-		outside, filepath.Join(outside, "f"), filepath.Join(outside, "link"),
-		filepath.Join(outside, "fifo"), filepath.Join(old, "fifo"),
-	} {
-		requireOwner(t, path, 0, 0)
-	}
+	requireOwner(t, outside, 0, 0)
+	requireOwner(t, filepath.Join(outside, "f"), 0, 0)
 }

internal/reportbuf/reportbuf.go

@@ -1,9 +1,6 @@
 // Package reportbuf accumulates telemetry reports in memory
 // and periodically flushes them to zstd-compressed JSONL files,
-// deleting the oldest files to keep them under a size cap. Before the
-// server starts, PrepareDataDir gets the directory those files are
-// kept in, DATA_DIR, ready for the user the server runs as: it creates
-// it and gives it and the volume it is on to that user.
+// deleting the oldest files to keep them under a size cap.
 package reportbuf
 
 import (
@@ -88,21 +85,12 @@ type Buffer struct {
 	now func() time.Time
 	// seq numbers the report files, so that two named in the same
 	// millisecond still get different names.
-	seq      atomic.Int64
+	seq      atomic.Uint64
 	stopOnce sync.Once
 	// usedBytes is what Append checks against maxBytes: the size
 	// of the report files in dataDir, plus the reports waiting to
 	// be written to one at their uncompressed size.
 	usedBytes int64
-	// writeErr is the error of the last write of a report file to
-	// finish, nil if it succeeded or none has. While it is set, Append
-	// refuses reports, and the reports of that write wait in buf for
-	// the next flush.
-	writeErr error
-	// writers are the goroutines that write report files: flushLoop,
-	// and each one Append starts at flushSizeThreshold. OnStop waits
-	// for them before the final flush.
-	writers sync.WaitGroup
 }
 
 // New creates a Buffer and registers lifecycle hooks to
@@ -127,33 +115,16 @@ func New(
 
 	lc.Append(fx.Hook{
 		OnStart: func(_ context.Context) error {
-			// The errors name DATA_DIR, as config.New's do for the
-			// settings it checks.
 			err := os.MkdirAll(b.dataDir, dirPerms)
 			if err != nil {
-				return fmt.Errorf("DATA_DIR %q: %w", b.dataDir, err)
-			}
-
-			// Creating and removing a file stops the start when no
-			// file can be created in DATA_DIR, instead of the first
-			// write of a report file failing after reports were
-			// answered 200. A full disk is not caught: the empty
-			// file is still created.
-			f, err := os.CreateTemp(b.dataDir, "")
-			if err != nil {
-				return fmt.Errorf("DATA_DIR %q: %w", b.dataDir, err)
-			}
-
-			err = errors.Join(f.Close(), os.Remove(f.Name()))
-			if err != nil {
-				return fmt.Errorf("DATA_DIR %q: %w", b.dataDir, err)
+				return fmt.Errorf("create data dir: %w", err)
 			}
 
 			// Report files left by earlier runs count too, and are
 			// the first to be deleted to make room.
 			files, err := reportFiles(b.dataDir)
 			if err != nil {
-				return fmt.Errorf("DATA_DIR %q: %w", b.dataDir, err)
+				return err
 			}
 
 			b.mu.Lock()
@@ -171,7 +142,7 @@ func New(
 
 			b.mu.Unlock()
 
-			b.writers.Go(b.flushLoop)
+			go b.flushLoop()
 
 			return nil
 		},
@@ -182,14 +153,7 @@ func New(
 			var err error
 
 			b.stopOnce.Do(func() {
-				// Closing done ends flushLoop after any flush it is
-				// running. Wait for it and for the writes Append
-				// started, which the process exiting would cut off;
-				// one that fails puts its reports back in buf, for the
-				// final flush to write.
 				close(b.done)
-				b.writers.Wait()
-
 				err = b.flushLocked()
 			})
 
@@ -203,12 +167,11 @@ func New(
 }
 
 // Append marshals v as a single JSON line and appends it to
-// the buffer. It stores nothing and returns an error if the last
-// write of a report file failed, until a write succeeds again. If the
-// line would take usedBytes past maxBytes, the oldest report files are
-// deleted to make room; it stores nothing and returns ErrFull if that
-// cannot make room. If the buffer reaches the size threshold, it is
-// drained and written to disk asynchronously.
+// the buffer. If the line would take usedBytes past maxBytes, the
+// oldest report files are deleted to make room; it stores nothing
+// and returns ErrFull if that cannot make room. If the buffer
+// reaches the size threshold, it is drained and written to disk
+// asynchronously.
 func (b *Buffer) Append(v any) error {
 	line, err := json.Marshal(v)
 	if err != nil {
@@ -219,13 +182,6 @@ func (b *Buffer) Append(v any) error {
 
 	b.mu.Lock()
 
-	if b.writeErr != nil {
-		err = fmt.Errorf("report files cannot be written: %w", b.writeErr)
-		b.mu.Unlock()
-
-		return err
-	}
-
 	b.deleteOldestFiles(lineBytes)
 
 	if b.usedBytes+lineBytes > b.maxBytes {
@@ -242,12 +198,12 @@ func (b *Buffer) Append(v any) error {
 		data := b.drainBuf()
 		b.mu.Unlock()
 
-		b.writers.Go(func() {
+		go func() {
 			writeErr := b.writeFile(data)
 			if writeErr != nil {
 				b.log.Error("flush reports failed", "error", writeErr)
 			}
-		})
+		}()
 
 		return nil
 	}
@@ -335,8 +291,7 @@ func (b *Buffer) drainBuf() []byte {
 }
 
 // writeFile writes data, reports drained from the buffer, to a new
-// timestamped zstd-compressed JSONL file in the data directory. If the
-// write fails, it puts the reports back in the buffer.
+// timestamped zstd-compressed JSONL file in the data directory.
 func (b *Buffer) writeFile(data []byte) error {
 	// The timestamp comes first, so the names sort by time; the number
 	// after it tells apart files named in the same millisecond.
@@ -345,27 +300,19 @@ func (b *Buffer) writeFile(data []byte) error {
 
 	size, err := b.createFile(filepath.Join(b.dataDir, name), data)
 
+	// The reports no longer wait to be written, so they stop counting
+	// at their uncompressed size. If the write failed they are lost;
+	// otherwise they count as the file, which from here on may be
+	// deleted to make room.
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
-	b.writeErr = err
+	b.usedBytes -= int64(len(data))
 
 	if err != nil {
-		// The reports go back in front of any appended since, for the
-		// next flush to write, and still count at their uncompressed
-		// size.
-		appended := bytes.Clone(b.buf.Bytes())
-		b.buf.Reset()
-		b.buf.Write(data)
-		b.buf.Write(appended)
-
 		return err
 	}
 
-	// The reports no longer wait to be written, so they stop counting
-	// at their uncompressed size and count as the file, which from here
-	// on may be deleted to make room.
-	b.usedBytes -= int64(len(data))
 	b.usedBytes += size
 	b.filesBytes += size
 

internal/reportbuf/reportbuf_test.go

@@ -5,8 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
-	"net/http"
-	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"slices"
@@ -15,13 +13,10 @@ import (
 	"sync"
 	"sync/atomic"
 	"testing"
-	"testing/synctest"
 	"time"
 
 	"sneak.berlin/go/netwatch/internal/config"
 	"sneak.berlin/go/netwatch/internal/globals"
-	"sneak.berlin/go/netwatch/internal/handlers"
-	"sneak.berlin/go/netwatch/internal/healthcheck"
 	"sneak.berlin/go/netwatch/internal/logger"
 	"sneak.berlin/go/netwatch/internal/reportbuf"
 
@@ -108,236 +103,9 @@ func TestFailedFinalFlushFailsStop(t *testing.T) {
 	}
 }
 
-// TestUncreatableDataDirStopsStart sets DATA_DIR below a regular file,
-// where no directory can be created, even by root, as the tests run in
-// the backend image. The start must fail with an error naming DATA_DIR
-// and its value, as the errors for the other settings do.
-func TestUncreatableDataDirStopsStart(t *testing.T) {
-	file := filepath.Join(t.TempDir(), "file")
-	writeBytes(t, file, 1)
-
-	dir := filepath.Join(file, "reports")
-	t.Setenv("DATA_DIR", dir)
-
-	app := fxtest.New(t,
-		fx.Provide(
-			globals.New,
-			logger.New,
-			config.New,
-			reportbuf.New,
-		),
-		fx.Invoke(func(*reportbuf.Buffer) {}),
-	)
-
-	err := app.Start(t.Context())
-	if err == nil {
-		t.Fatal("start succeeded with DATA_DIR below a regular file")
-	}
-
-	want := fmt.Sprintf("DATA_DIR %q: ", dir)
-	if !strings.Contains(err.Error(), want) {
-		t.Fatalf("start error = %q, want it to contain %q", err, want)
-	}
-}
-
-// TestUnwritableDataDirStopsStart sets DATA_DIR to /proc, which exists
-// and can be read, but where no file can be created, even by root, as
-// the tests run in the backend image: root ignores a directory the test
-// makes read-only. The start must fail with an error naming DATA_DIR and
-// its value, rather than the first write of a report file.
-func TestUnwritableDataDirStopsStart(t *testing.T) {
-	dir := "/proc"
-	t.Setenv("DATA_DIR", dir)
-
-	app := fxtest.New(t,
-		fx.Provide(
-			globals.New,
-			logger.New,
-			config.New,
-			reportbuf.New,
-		),
-		fx.Invoke(func(*reportbuf.Buffer) {}),
-	)
-
-	err := app.Start(t.Context())
-	if err == nil {
-		t.Fatal("start succeeded with DATA_DIR /proc")
-	}
-
-	want := fmt.Sprintf("DATA_DIR %q: ", dir)
-	if !strings.Contains(err.Error(), want) {
-		t.Fatalf("start error = %q, want it to contain %q", err, want)
-	}
-}
-
-// TestStopWaitsForPeriodicWrite holds open the write the periodic flush
-// starts, then stops the app. The stop must wait until the write is
-// released, and the report must then be in its file. The test runs in
-// a synctest bubble, whose clock moves on at once when every goroutine
-// in it is waiting, so the periodic flush does not take a minute.
-func TestStopWaitsForPeriodicWrite(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("DATA_DIR", dir)
-
-	synctest.Test(t, func(t *testing.T) {
-		buf, app := startApp(t)
-
-		created := make(chan struct{})
-		release := make(chan struct{})
-
-		buf.OnFileCreated(func(*os.File) {
-			created <- struct{}{}
-
-			<-release
-		})
-
-		err := buf.Append(map[string]string{"id": "periodic"})
-		if err != nil {
-			t.Fatalf("append report: %v", err)
-		}
-
-		<-created
-
-		err = stopWhileHeld(t, app, release)
-		if err != nil {
-			t.Fatalf("stop: %v", err)
-		}
-
-		files, err := readReportFiles(dir)
-		if err != nil {
-			t.Fatalf("read report files: %v", err)
-		}
-
-		want := `{"id":"periodic"}` + "\n"
-		if len(files) != 1 || files[0] != want {
-			t.Fatalf("report files = %q, want one holding %q", files, want)
-		}
-	})
-}
-
-// TestStopWaitsForWriteAtSizeThreshold holds open the write Append
-// starts when the buffer reaches FlushSizeThreshold, then stops the
-// app. The stop must wait until the write is released, and the reports
-// must then be in its file.
-func TestStopWaitsForWriteAtSizeThreshold(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("DATA_DIR", dir)
-
-	synctest.Test(t, func(t *testing.T) {
-		buf, app := startApp(t)
-
-		created := make(chan struct{})
-		release := make(chan struct{})
-
-		buf.OnFileCreated(func(*os.File) {
-			created <- struct{}{}
-
-			<-release
-		})
-
-		appended := appendToThreshold(t, buf)
-
-		<-created
-
-		err := stopWhileHeld(t, app, release)
-		if err != nil {
-			t.Fatalf("stop: %v", err)
-		}
-
-		files, err := readReportFiles(dir)
-		if err != nil {
-			t.Fatalf("read report files: %v", err)
-		}
-
-		if len(files) != 1 || files[0] != appended {
-			t.Fatalf("%d report files, want one holding the %d bytes "+
-				"appended", len(files), len(appended))
-		}
-	})
-}
-
-// TestFinalFlushWritesReportsOfFailedWrite holds open the write the
-// periodic flush starts, makes it fail, then stops the app. The stop
-// waits for the write, which puts its report back in the buffer, and
-// the final flush writes it, so the stop succeeds with nothing lost.
-func TestFinalFlushWritesReportsOfFailedWrite(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("DATA_DIR", dir)
-
-	synctest.Test(t, func(t *testing.T) {
-		buf, app := startApp(t)
-
-		created := make(chan *os.File)
-		release := make(chan struct{})
-
-		buf.OnFileCreated(func(f *os.File) {
-			created <- f
-
-			<-release
-		})
-
-		err := buf.Append(map[string]string{"id": "failed"})
-		if err != nil {
-			t.Fatalf("append report: %v", err)
-		}
-
-		held := <-created
-
-		// Closing the file under the write makes the write fail.
-		_ = held.Close()
-
-		// The final flush's write goes through.
-		buf.OnFileCreated(func(*os.File) {})
-
-		err = stopWhileHeld(t, app, release)
-		if err != nil {
-			t.Fatalf("stop: %v", err)
-		}
-
-		files, err := readReportFiles(dir)
-		if err != nil {
-			t.Fatalf("read report files: %v", err)
-		}
-
-		want := `{"id":"failed"}` + "\n"
-		if len(files) != 1 || files[0] != want {
-			t.Fatalf("report files = %q, want one holding %q", files, want)
-		}
-	})
-}
-
-// stopWhileHeld stops app while a report file write is held open until
-// release is closed, and fails the test if the stop returns before
-// that. It then closes release and returns the stop's error. It must
-// be called in a synctest bubble.
-func stopWhileHeld(
-	t *testing.T,
-	app *fxtest.App,
-	release chan<- struct{},
-) error {
-	t.Helper()
-
-	stopped := make(chan error, 1)
-
-	go func() { stopped <- app.Stop(t.Context()) }()
-
-	// Wait returns once every other goroutine in the bubble is waiting:
-	// the stop has got as far as it can while the write is held.
-	synctest.Wait()
-
-	if len(stopped) != 0 {
-		t.Error("stop returned while a report file write was held open")
-	}
-
-	close(release)
-
-	return <-stopped
-}
-
-// startApp starts a Buffer through fx, as main does, with the DATA_DIR
-// and DATA_DIR_MAX_BYTES the calling test has set, and returns it with
-// the app, for tests that stop the app themselves.
-func startApp(t *testing.T) (*reportbuf.Buffer, *fxtest.App) {
+// startBuffer starts a Buffer through fx, as main does, with the
+// DATA_DIR and DATA_DIR_MAX_BYTES the calling test has set.
+func startBuffer(t *testing.T) *reportbuf.Buffer {
 	t.Helper()
 
 	var buf *reportbuf.Buffer
@@ -355,16 +123,6 @@ func startApp(t *testing.T) (*reportbuf.Buffer, *fxtest.App) {
 	app.RequireStart()
 	t.Cleanup(app.RequireStop)
 
-	return buf, app
-}
-
-// startBuffer starts a Buffer through fx, as main does, with the
-// DATA_DIR and DATA_DIR_MAX_BYTES the calling test has set.
-func startBuffer(t *testing.T) *reportbuf.Buffer {
-	t.Helper()
-
-	buf, _ := startApp(t)
-
 	return buf
 }
 
@@ -749,17 +507,13 @@ func TestFileBeingWrittenIsNeverDeleted(t *testing.T) {
 	}
 }
 
-// TestFailedWriteKeepsItsReports makes a write fail once its file is
-// created, under a cap with room for one report. The part of the file
-// written is removed, so it takes no room, and the report waits in
-// memory for the next flush, which writes it. Once written, it counts
-// as its file and no longer as a report waiting, so the cap still holds
-// exactly: one more report is taken and the one after it is refused.
-func TestFailedWriteKeepsItsReports(t *testing.T) {
-	report := map[string]string{"id": "kept"}
-	dir := t.TempDir()
+// TestFailedWriteStopsCounting makes a write fail once its file is
+// created. Its reports are lost, so they stop counting, and the part of
+// the file written is removed, so it takes no room.
+func TestFailedWriteStopsCounting(t *testing.T) {
+	report := map[string]string{"id": "failed"}
 
-	t.Setenv("DATA_DIR", dir)
+	t.Setenv("DATA_DIR", t.TempDir())
 	t.Setenv("DATA_DIR_MAX_BYTES", strconv.Itoa(lineBytes(t, report)))
 
 	buf := startBuffer(t)
@@ -790,213 +544,10 @@ func TestFailedWriteKeepsItsReports(t *testing.T) {
 	// Writes from here on, the final one at stop included, succeed.
 	buf.OnFileCreated(func(*os.File) {})
 
-	err = buf.Flush()
-	if err != nil {
-		t.Fatalf("flush after the failed write: %v", err)
-	}
-
-	files, err := readReportFiles(dir)
-	if err != nil {
-		t.Fatalf("read report files: %v", err)
-	}
-
-	want := `{"id":"kept"}` + "\n"
-	if len(files) != 1 || files[0] != want {
-		t.Fatalf("report files = %q, want one holding %q", files, want)
-	}
-
-	// The file is deleted to make room if need be.
 	err = buf.Append(report)
 	if err != nil {
-		t.Fatalf("report after the written one: %v", err)
+		t.Fatalf("report after the failed write: %v", err)
 	}
-
-	err = buf.Append(report)
-	if !errors.Is(err, reportbuf.ErrFull) {
-		t.Fatalf("report past the cap: error = %v, want ErrFull", err)
-	}
-}
-
-// TestFailedWriteKeepsReportsAppendedDuringIt holds a write open,
-// appends a report while it is held, then makes the held write fail.
-// Both reports are kept, and the next flush writes them in the order
-// they were appended, the held write's first.
-func TestFailedWriteKeepsReportsAppendedDuringIt(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("DATA_DIR", dir)
-
-	buf := startBuffer(t)
-
-	created := make(chan *os.File)
-	release := make(chan struct{})
-
-	buf.OnFileCreated(func(f *os.File) {
-		created <- f
-
-		<-release
-	})
-
-	err := buf.Append(map[string]string{"id": "held"})
-	if err != nil {
-		t.Fatalf("report of the held write: %v", err)
-	}
-
-	flushed := make(chan error)
-
-	go func() { flushed <- buf.Flush() }()
-
-	held := <-created
-
-	// Errorf, not Fatalf, until the held write is released, so that a
-	// failure here does not leave it held.
-	err = buf.Append(map[string]string{"id": "appended"})
-	if err != nil {
-		t.Errorf("report appended while the write was held: %v", err)
-	}
-
-	// Closing the file under the write makes the write fail.
-	_ = held.Close()
-
-	close(release)
-
-	err = <-flushed
-	if err == nil {
-		t.Fatal("held write succeeded, though its file was closed under it")
-	}
-
-	// Writes from here on, the final one at stop included, succeed.
-	buf.OnFileCreated(func(*os.File) {})
-
-	err = buf.Flush()
-	if err != nil {
-		t.Fatalf("flush after the failed write: %v", err)
-	}
-
-	files, err := readReportFiles(dir)
-	if err != nil {
-		t.Fatalf("read report files: %v", err)
-	}
-
-	want := `{"id":"held"}` + "\n" + `{"id":"appended"}` + "\n"
-	if len(files) != 1 || files[0] != want {
-		t.Fatalf("report files = %q, want one holding %q", files, want)
-	}
-}
-
-// TestReportsRefusedWhileWritesFail posts reports through the report
-// handler, as the page does. Once a write has failed, a report is
-// refused with 500 until a write succeeds again; the reports taken
-// before and after are stored, and the one refused is not.
-func TestReportsRefusedWhileWritesFail(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("DATA_DIR", dir)
-
-	buf, h := startBufferWithHandlers(t)
-
-	if code := postReport(t, h, "before"); code != http.StatusOK {
-		t.Fatalf("report before the failed write: status = %d, want %d",
-			code, http.StatusOK)
-	}
-
-	// With the data directory gone, the write has nowhere to go.
-	err := os.Remove(dir)
-	if err != nil {
-		t.Fatalf("remove data dir: %v", err)
-	}
-
-	err = buf.Flush()
-	if err == nil {
-		t.Fatal("flush succeeded with the data directory gone")
-	}
-
-	if code := postReport(t, h, "refused"); code != http.StatusInternalServerError {
-		t.Fatalf("report after the failed write: status = %d, want %d",
-			code, http.StatusInternalServerError)
-	}
-
-	err = os.Mkdir(dir, 0o750)
-	if err != nil {
-		t.Fatalf("make data dir: %v", err)
-	}
-
-	err = buf.Flush()
-	if err != nil {
-		t.Fatalf("flush with the data directory back: %v", err)
-	}
-
-	if code := postReport(t, h, "after"); code != http.StatusOK {
-		t.Fatalf("report after a write succeeded: status = %d, want %d",
-			code, http.StatusOK)
-	}
-
-	err = buf.Flush()
-	if err != nil {
-		t.Fatalf("flush of the report after: %v", err)
-	}
-
-	files, err := readReportFiles(dir)
-	if err != nil {
-		t.Fatalf("read report files: %v", err)
-	}
-
-	stored := strings.Join(files, "")
-
-	for _, clientID := range []string{"before", "after"} {
-		if !strings.Contains(stored, `"clientId":"`+clientID+`"`) {
-			t.Errorf("report %q not stored", clientID)
-		}
-	}
-
-	if strings.Contains(stored, `"clientId":"refused"`) {
-		t.Error("refused report stored")
-	}
-}
-
-// startBufferWithHandlers starts a Buffer and the Handlers that store
-// reports in it through fx, as main does, with the DATA_DIR the calling
-// test has set.
-func startBufferWithHandlers(
-	t *testing.T,
-) (*reportbuf.Buffer, *handlers.Handlers) {
-	t.Helper()
-
-	var (
-		buf *reportbuf.Buffer
-		h   *handlers.Handlers
-	)
-
-	app := fxtest.New(t,
-		fx.Provide(
-			config.New,
-			globals.New,
-			handlers.New,
-			healthcheck.New,
-			logger.New,
-			reportbuf.New,
-		),
-		fx.Populate(&buf, &h),
-	)
-
-	app.RequireStart()
-	t.Cleanup(app.RequireStop)
-
-	return buf, h
-}
-
-// postReport posts a report from clientID to the report handler, as the
-// page does, and returns the status of the answer.
-func postReport(t *testing.T, h *handlers.Handlers, clientID string) int {
-	t.Helper()
-
-	rec := httptest.NewRecorder()
-	req := httptest.NewRequestWithContext(t.Context(),
-		http.MethodPost, "/api/v1/reports",
-		strings.NewReader(`{"clientId":"`+clientID+`","hosts":[]}`),
-	)
-	req.Header.Set("Content-Type", "application/json")
-	h.HandleReport().ServeHTTP(rec, req)
-
-	return rec.Code
 }
 
 // TestConcurrentAppendsStopAtCap appends from many goroutines at once
@@ -1130,32 +681,6 @@ func TestFlushAtSizeThreshold(t *testing.T) {
 
 	buf := startBuffer(t)
 
-	appended := appendToThreshold(t, buf)
-
-	// Append writes the file in the background, so wait for it.
-	deadline := time.Now().Add(10 * time.Second)
-
-	for {
-		files, err := readReportFiles(dir)
-		if err == nil && len(files) == 1 && files[0] == appended {
-			return
-		}
-
-		if time.Now().After(deadline) {
-			t.Fatalf("%d report files (error: %v), want one holding the "+
-				"%d bytes appended", len(files), err, len(appended))
-		}
-
-		time.Sleep(10 * time.Millisecond)
-	}
-}
-
-// appendToThreshold appends reports to buf until it holds
-// FlushSizeThreshold bytes, so that the last append starts writing them
-// to a report file, and returns the lines appended.
-func appendToThreshold(t *testing.T, buf *reportbuf.Buffer) string {
-	t.Helper()
-
 	// Large reports, so the threshold takes a few hundred appends.
 	pad := strings.Repeat("a", 64<<10)
 
@@ -1178,7 +703,22 @@ func appendToThreshold(t *testing.T, buf *reportbuf.Buffer) string {
 		appended.WriteByte('\n')
 	}
 
-	return appended.String()
+	// Append writes the file in the background, so wait for it.
+	deadline := time.Now().Add(10 * time.Second)
+
+	for {
+		files, err := readReportFiles(dir)
+		if err == nil && len(files) == 1 && files[0] == appended.String() {
+			return
+		}
+
+		if time.Now().After(deadline) {
+			t.Fatalf("%d report files (error: %v), want one holding the "+
+				"%d bytes appended", len(files), err, appended.Len())
+		}
+
+		time.Sleep(10 * time.Millisecond)
+	}
 }
 
 // reportFilesBytes returns the total size of the report files in dir.

internal/server/routes.go

@@ -34,16 +34,13 @@ func (s *Server) SetupRoutes() {
 	s.router.Use(s.mw.Recoverer())
 	s.router.Use(middleware.RequestID)
 	s.router.Use(s.mw.Logging())
-	// s.mw.Recoverer would write a panic's 500 only after the panic has
-	// passed the request log, so it is written here, where the log sees it.
-	s.router.Use(s.mw.Write500OnPanic())
 	s.router.Use(s.mw.SecurityHeaders())
 	s.router.Use(s.mw.CORS(s.params.Config.CORSAllowedOrigins))
 	s.router.Use(s.mw.MaxBodyBytes(maxRequestBodyBytes))
 	s.router.Use(middleware.Timeout(requestTimeout))
 
-	// Sentry reports a panic, then panics again, so that it still
-	// reaches s.mw.Recoverer.
+	// Sentry reports a panic, then panics again, so that s.mw.Recoverer
+	// still answers 500.
 	if s.params.Config.SentryDSN != "" {
 		s.router.Use(sentryhttp.New(sentryhttp.Options{Repanic: true}).Handle)
 	}
@@ -67,8 +64,6 @@ func (s *Server) SetupRoutes() {
 		// other.
 		if s.params.Config.MetricsUsername != "" {
 			r.Use(s.mw.Metrics(registry))
-			// Likewise inside the metrics.
-			r.Use(s.mw.Write500OnPanic())
 		}
 
 		r.Get("/.well-known/healthcheck", s.h.HandleHealthCheck())

internal/server/routes_test.go

@@ -66,7 +66,6 @@ func TestReportsAreRateLimited(t *testing.T) {
 			http.MethodPost, "/api/v1/reports",
 			strings.NewReader(`{"clientId":"c1","hosts":[]}`),
 		)
-		req.Header.Set("Content-Type", "application/json")
 		srv.ServeHTTP(rec, req)
 
 		return rec.Code

script/cibuild

@@ -2,12 +2,9 @@
 # script/cibuild: run the CI build. It bootstraps first: a CI runner
 # checks out and runs this and nothing else, and script/fmt-check runs
 # the formatter on the host, which a pristine checkout cannot do.
-# A new CACHEBUST value reruns every RUN step after the ARG CACHEBUST
-# line, since a cached gate phase is a check that did not run; unlike
-# --no-cache, it keeps the layers above that line and the cache mounts.
-# This relies on every stage of the Dockerfile declaring ARG CACHEBUST
-# before every step that lints, tests or compiles; a stage without that
-# line is served from cache on an unchanged tree, with no warning.
+# --no-cache for the same reason as script/docker: the gate phases the
+# final stage depends on are RUN steps, and a cached one is a check that
+# did not run.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -17,17 +14,15 @@ main() {
     cd "$ROOT"
     "$SCRIPT_DIR/bootstrap"
     "$SCRIPT_DIR/check"
-    # The version and the tag each get their own line: a failing
-    # command substitution inside an argument does not trip `set -e`,
-    # so the inline form degrades silently to an empty constant. The
-    # VERSION build argument takes precedence over the version a build
-    # stage derives from the .git in the context.
+    # Own line: a failing command substitution inside an argument does
+    # not trip `set -e`, so the inline form degrades silently to an
+    # empty constant. The VERSION build argument takes precedence over
+    # the version a build stage derives from the .git in the context.
     version="$(git describe --tags --always --dirty 2>/dev/null || true)"
     [ -n "$version" ] || version="unknown"
-    tag="$("$SCRIPT_DIR/projectname")"
-    docker build --build-arg CACHEBUST="$(date +%s)-$$" \
+    docker build --no-cache \
         --build-arg VERSION="$version" \
-        -t "$tag" .
+        -t "$("$SCRIPT_DIR/projectname")" .
 }
 
 main "$@"

script/docker

@@ -1,12 +1,8 @@
 #!/bin/sh
 # script/docker: build the Docker image tagged with the project name.
 # Identical in all repos; the tag comes from script/projectname.
-# A new CACHEBUST value reruns every RUN step after the ARG CACHEBUST
-# line, since a cached gate phase is a check that did not run; unlike
-# --no-cache, it keeps the layers above that line and the cache mounts.
-# This relies on every stage of the Dockerfile declaring ARG CACHEBUST
-# before every step that lints, tests or compiles; a stage without that
-# line is served from cache on an unchanged tree, with no warning.
+# --no-cache because the gate phases the final stage depends on are RUN
+# steps, and a cached one is a check that did not run.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -14,17 +10,15 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    # The version and the tag each get their own line: a failing
-    # command substitution inside an argument does not trip `set -e`,
-    # so the inline form degrades silently to an empty constant. The
-    # VERSION build argument takes precedence over the version a build
-    # stage derives from the .git in the context.
+    # Own line: a failing command substitution inside an argument does
+    # not trip `set -e`, so the inline form degrades silently to an
+    # empty constant. The VERSION build argument takes precedence over
+    # the version a build stage derives from the .git in the context.
     version="$(git describe --tags --always --dirty 2>/dev/null || true)"
     [ -n "$version" ] || version="unknown"
-    tag="$("$SCRIPT_DIR/projectname")"
-    docker build --build-arg CACHEBUST="$(date +%s)-$$" \
+    docker build --no-cache \
         --build-arg VERSION="$version" \
-        -t "$tag" .
+        -t "$("$SCRIPT_DIR/projectname")" .
 }
 
 main "$@"

script/frontend-test

@@ -2,10 +2,9 @@
 # script/frontend-test: run the frontend test suite on the host: the
 # unit tests in test/unit/, through the test script in package.json,
 # then the production build, which fails on broken code. make test runs
-# the same tests in the frontend-test stage of Dockerfile, and the image
-# build runs the production build in its frontend-build stage. The tests
-# print a dot each; if any fails, they run again with every test listed,
-# and the script fails even if that run passes. NODE_OPTIONS chooses the
+# the same in the frontend stage of Dockerfile. The tests print a dot
+# each; if any fails, they run again with every test listed, and the
+# script fails even if that run passes. NODE_OPTIONS chooses the
 # reporter because yarn adds its arguments after the test files, where
 # node would take a reporter option for one more file.
 set -eu

script/frontend-viewport-test

@@ -7,8 +7,6 @@
 # headless Chrome at it over CDP, and asserts on computed layout at every
 # viewport width derived from the app's own CSS. See
 # test/viewport/README.md for what this covers and what it cannot.
-# Before the browser starts, it checks that the page is served with
-# Cache-Control: no-cache and Content-Security-Policy.
 #
 # Deliberately not part of script/check: it needs Docker and takes far
 # longer than the 20s budget make test has to stay inside.
@@ -66,8 +64,8 @@ main() {
     # configs/nginx.conf is a template: the image renders it over its own
     # default.conf, with the same port and limit bin/entrypoint.sh uses.
     # The empty file it includes trusts no proxy, as bin/entrypoint.sh
-    # writes it when TRUSTED_PROXIES is set and empty. It also includes
-    # the security headers, so the page runs under the shipped policy.
+    # writes it when TRUSTED_PROXIES is unset. It also includes the
+    # security headers, so the page runs under the shipped policy.
     docker run -d --rm --name "$SERVER" \
         --network "$NETWORK" --network-alias netwatch \
         -e PORT=8080 -e NGINX_ENVSUBST_FILTER='^PORT$' \
@@ -77,32 +75,6 @@ main() {
         -v "$ROOT/configs/security-headers.conf:/etc/nginx/security-headers.conf:ro" \
         "$SERVER_IMAGE" > /dev/null
 
-    # The page, and /no-such-page, which location / answers with the
-    # page through its try_files fallback, must go out with
-    # Cache-Control: no-cache. That add_header in its location drops the
-    # server's own unless the location includes the security headers
-    # again; only Content-Security-Policy is checked, as it comes from
-    # the same file as the rest. curl tries up to ten more times, a
-    # second apart, while nginx starts. It runs without -S, which would
-    # print an error for every failed attempt, even when a later one
-    # succeeds.
-    for path in / /no-such-page; do
-        if ! headers="$(docker exec "$SERVER" curl -s -o /dev/null -D - \
-            --retry 10 --retry-connrefused --retry-delay 1 \
-            "http://127.0.0.1:8080$path")"; then
-            echo "frontend-viewport-test: nginx did not answer $path" >&2
-            exit 1
-        fi
-        headers="$(printf '%s\n' "$headers" | tr -d '\r')"
-        if ! printf '%s\n' "$headers" | grep -qix 'Cache-Control: no-cache' ||
-            ! printf '%s\n' "$headers" | grep -qi '^Content-Security-Policy:'; then
-            echo "frontend-viewport-test: $path needs" \
-                "Cache-Control: no-cache and Content-Security-Policy; got:" >&2
-            printf '%s\n' "$headers" >&2
-            exit 1
-        fi
-    done
-
     # The image's own entrypoint already exposes CDP on 9222 and passes
     # --no-sandbox, so only extra flags belong here; re-specifying the
     # debugging port collides with it and leaves the endpoint bound to

script/lint

@@ -5,14 +5,9 @@
 # make its answer untrustworthy.
 #
 # The phase is not the last stage in the file, so it is built only when
-# --target names it. A new CACHEBUST value reruns every RUN step after
-# the ARG CACHEBUST line, since a cached lint layer is a lint that did
-# not run; unlike --no-cache, it keeps the layers above that line and
-# the cache mounts. This relies on every stage of the Dockerfile
-# declaring ARG CACHEBUST before every step that lints, tests or
-# compiles; a stage without that line is served from cache on an
-# unchanged tree, with no warning.
-# --output type=cacheonly writes no image, since nothing uses one.
+# --target names it. --no-cache because a cached lint layer is a lint
+# that did not run. The tag makes each build replace the previous image
+# instead of leaving a dangling one behind.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -20,9 +15,9 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    docker build --build-arg CACHEBUST="$(date +%s)-$$" \
+    docker build --no-cache \
         --target lint \
-        --output type=cacheonly .
+        -t "$("$SCRIPT_DIR/projectname")-lint" .
 }
 
 main "$@"

script/test

@@ -2,13 +2,8 @@
 # script/test: run the test suite. Testing is a phase of the Dockerfile
 # and this builds that phase alone, on the same terms as script/lint:
 # --target because a phase that is not the last stage is built only when
-# named, and a new CACHEBUST value because a cached test layer is a test
-# that did not run; unlike --no-cache, it keeps the layers above the ARG
-# CACHEBUST line and the cache mounts. This relies on every stage of the
-# Dockerfile declaring ARG CACHEBUST before every step that lints, tests
-# or compiles; a stage without that line is served from cache on an
-# unchanged tree, with no warning. --output type=cacheonly writes no
-# image, since nothing uses one.
+# named, --no-cache because a cached test layer is a test that did not
+# run, and a tag so each build replaces the previous image.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -16,9 +11,9 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    docker build --build-arg CACHEBUST="$(date +%s)-$$" \
+    docker build --no-cache \
         --target test \
-        --output type=cacheonly .
+        -t "$("$SCRIPT_DIR/projectname")-test" .
 }
 
 main "$@"

test/unit/main.test.js

@@ -6,7 +6,6 @@ import { beforeEach, test } from "node:test";
 import assert from "node:assert/strict";
 import {
     AppState,
-    buildUI,
     CONFIG,
     greyOutUI,
     hostRowHTML,
@@ -16,10 +15,7 @@ import {
     latencyHex,
     log,
     measureLatency,
-    Reporter,
     tick,
-    updateClocks,
-    updateSummary,
 } from "../../web/src/main.js";
 
 // There is no page here, so the tests stand in for it. The debug log looks
@@ -30,10 +26,8 @@ import {
 // selector until the next test starts. As on a page, writing its text
 // replaces its markup; the status dot greyOutUI looks for in it is not
 // there. Drawing a sparkline does nothing; it looks for the pixel ratio on
-// window and finds none. The commit the page's footer names, which
-// vite.config.js fills in when it builds the page, is blank. In each test,
-// console.error and console.info print nothing and keep what they are
-// given.
+// window and finds none. In each test, console.error and console.info
+// print nothing and keep what they are given.
 const doNothing = () => {};
 let elements;
 beforeEach((t) => {
@@ -55,8 +49,6 @@ const canvasContext = {
 globalThis.window = {};
 globalThis.requestAnimationFrame = doNothing;
 globalThis.cancelAnimationFrame = doNothing;
-globalThis.__COMMIT_HASH__ = "";
-globalThis.__COMMIT_FULL__ = "";
 globalThis.document = {
     getElementById: () => null,
     createElement: () => ({}),
@@ -83,11 +75,6 @@ function statusText(state, host) {
     return elements[`.status-text[data-host="${index}"]`]?.innerHTML;
 }
 
-// What this test wrote to the browser console with console[method].
-function consoleLines(method) {
-    return console[method].mock.calls.map((call) => call.arguments[0]);
-}
-
 // Mocks the clock for test t, so that a check lasting seconds takes no real
 // time, and replaces fetch with targets that each answer after
 // answerAfter(url) milliseconds of that clock, or never when that is
@@ -207,10 +194,9 @@ test("at a 30000ms interval, a target answering after 1000ms shows in its row wh
 });
 
 // In the next three tests, the answering target's check is still waiting
-// when something happens after which its result must not be recorded or
-// show in its row, and the check must write nothing to the console.
+// when something happens after which its result must not show.
 
-test("at a 30000ms interval, a check still waiting when its round is given up is not recorded and does not show in its row", async (t) => {
+test("at a 30000ms interval, a check still waiting when its round is given up does not show in its row", async (t) => {
     CONFIG.updateInterval = 30000;
     const state = new AppState([
         { name: "Answering", url: "https://answering.test" },
@@ -226,13 +212,9 @@ test("at a 30000ms interval, a check still waiting when its round is given up is
     roundChecks.abort();
     assert.notEqual(await settled(round), "still waiting");
     assert.equal(latencyFigure(state, answering), undefined);
-    assert.deepEqual(answering.history, []);
-    assert.equal(answering.status, "pending");
-    assert.deepEqual(consoleLines("error"), []);
-    assert.deepEqual(consoleLines("info"), []);
 });
 
-test("at a 30000ms interval, a check still waiting when the user pauses is not recorded and does not show in its row", async (t) => {
+test("at a 30000ms interval, a check still waiting when the user pauses does not show in its row", async (t) => {
     CONFIG.updateInterval = 30000;
     const state = new AppState([
         { name: "Answering", url: "https://answering.test" },
@@ -247,13 +229,9 @@ test("at a 30000ms interval, a check still waiting when the user pauses is not r
     t.mock.timers.tick(500);
     assert.equal(await settled(round), "still waiting");
     assert.equal(latencyFigure(state, answering), undefined);
-    assert.deepEqual(answering.history, []);
-    assert.equal(answering.status, "pending");
-    assert.deepEqual(consoleLines("error"), []);
-    assert.deepEqual(consoleLines("info"), []);
 });
 
-test("at a 30000ms interval, a check in the first round is not recorded and does not show in its row", async (t) => {
+test("at a 30000ms interval, a check in the first round does not show in its row", async (t) => {
     CONFIG.updateInterval = 30000;
     const state = new AppState([
         { name: "Answering", url: "https://answering.test" },
@@ -265,10 +243,6 @@ test("at a 30000ms interval, a check in the first round is not recorded and does
     t.mock.timers.tick(1000);
     assert.equal(await settled(round), "still waiting");
     assert.equal(latencyFigure(state, answering), undefined);
-    assert.deepEqual(answering.history, []);
-    assert.equal(answering.status, "pending");
-    assert.deepEqual(consoleLines("error"), []);
-    assert.deepEqual(consoleLines("info"), []);
 });
 
 test("at a 30000ms interval, after the user pauses and resumes during a round, no row reads paused once its last check ends", async (t) => {
@@ -318,6 +292,11 @@ function stateWithOneTarget() {
     return { state, target: state.local[0] };
 }
 
+// What this test wrote to the browser console with console[method].
+function consoleLines(method) {
+    return console[method].mock.calls.map((call) => call.arguments[0]);
+}
+
 test("a check that fails with a network error writes one console line with the target, the time, the error and how long the request took", async (t) => {
     const { state, target } = stateWithOneTarget();
     mockTargets(t, () => 23, target.url);
@@ -404,98 +383,6 @@ test("a check that fails in the first round, which is discarded, writes nothing
     assert.deepEqual(consoleLines("info"), []);
 });
 
-// The reports Reporter sent in this test, each as the hosts it sent.
-function reportedHosts() {
-    return fetch.mock.calls.map(
-        (call) => JSON.parse(call.arguments[1].body).hosts,
-    );
-}
-
-// In the next two tests every report is delivered, and only Target has
-// checks to report. target.reset() does to Target what the interval menu
-// does to each target.
-
-// The interval changes after the first report. The second report is sent
-// before Target's first check since then, and the third after it. A fourth
-// would hold no check the first three did not, so it is not sent.
-test("checks recorded before an interval change and not yet reported go in the next report, with the status of the last check, and no check is reported twice", async (t) => {
-    const state = new AppState([
-        { name: "Target", url: "https://target.test" },
-    ]);
-    const target = state.local[0];
-    const reporter = new Reporter(state, "client", CONFIG.reportInterval);
-    t.mock.method(globalThis, "fetch", async () => ({ ok: true }));
-
-    target.pushSample(1000, { latency: 10, error: null });
-    await reporter.flush();
-    target.pushSample(2000, { latency: 20, error: null });
-    target.pushSample(3000, { latency: null, error: "timeout" });
-    target.reset();
-    await reporter.flush();
-    target.pushSample(4000, { latency: 40, error: null });
-    await reporter.flush();
-    await reporter.flush();
-
-    const name = "Target";
-    const url = "https://target.test";
-    assert.deepEqual(reportedHosts(), [
-        [
-            {
-                name,
-                url,
-                status: "online",
-                history: [{ t: 1000, latency: 10, error: null }],
-            },
-        ],
-        [
-            {
-                name,
-                url,
-                status: "error",
-                history: [
-                    { t: 2000, latency: 20, error: null },
-                    { t: 3000, latency: null, error: "timeout" },
-                ],
-            },
-        ],
-        [
-            {
-                name,
-                url,
-                status: "online",
-                history: [{ t: 4000, latency: 40, error: null }],
-            },
-        ],
-    ]);
-    // The page's history starts over.
-    assert.deepEqual(target.history, [
-        { timestamp: 4000, latency: 40, error: null },
-    ]);
-});
-
-// The interval changes twice, after 60 checks each time, before the first
-// report. Of the 120 checks the interval menu cleared, the report has the
-// last 100 (CONFIG.maxHistoryPoints).
-test("of the checks interval changes cleared before they were reported, the next report has the last 100", async (t) => {
-    const state = new AppState([
-        { name: "Target", url: "https://target.test" },
-    ]);
-    const target = state.local[0];
-    const reporter = new Reporter(state, "client", CONFIG.reportInterval);
-    t.mock.method(globalThis, "fetch", async () => ({ ok: true }));
-
-    for (let n = 1; n <= 120; n++) {
-        target.pushSample(n * 1000, { latency: 10, error: null });
-        if (n % 60 === 0) target.reset();
-    }
-    await reporter.flush();
-
-    const sent = reportedHosts()[0][0].history;
-    assert.equal(sent.length, 100);
-    assert.equal(sent[0].t, 21000);
-    assert.equal(sent.at(-1).t, 120000);
-});
-
 // panel stands in for the open debug log panel, and for the element in it
 // that holds its lines, whichever the page looks up by id; the lines are
 // kept in order in lines. Drawing the whole panel, as opening it does,
@@ -598,32 +485,6 @@ test("a check that timed out or found its target unreachable has a grey figure a
     assert.equal(latencyHex(null), "#6b7280");
 });
 
-// buildUI draws the page into #app, here a plain object. Each entry in the
-// footer's color legend is a colored dot and the latencies it stands for,
-// with < and > written as &lt; and &gt;. A latency takes the color of the
-// first entry in CONFIG.latencyColors whose limit it is below, so the
-// legend has, for each of those entries in order, a dot of its color (a
-// bg- class where CONFIG.latencyColors has a text- one) and the latencies
-// below its limit, or, for the last, which has no limit, the latencies
-// from the limit before it up. A gray dot for offline comes after them.
-test("the footer's color legend has each entry in CONFIG.latencyColors, with its color and limit, then offline", (t) => {
-    const app = {};
-    t.mock.method(globalThis.document, "getElementById", () => app);
-    buildUI(new AppState([]));
-
-    const legend = [
-        ...app.innerHTML.matchAll(/(bg-\w+-500) [^"]*"><\/span>(\S+)/g),
-    ].map(([, dot, latencies]) => [dot, latencies]);
-    const colors = CONFIG.latencyColors;
-    const expected = colors.map((color, i) => [
-        color.className.replace("text-", "bg-"),
-        color.below === Infinity
-            ? `&gt;=${colors[i - 1].below}ms`
-            : `&lt;${color.below}ms`,
-    ]);
-    assert.deepEqual(legend, [...expected, ["bg-gray-500", "offline"]]);
-});
-
 // A target whose checks, in turn, answered after each of latencies ms, or,
 // for null, found it unreachable.
 function hostAfter(latencies) {
@@ -700,102 +561,6 @@ test("the summary's min, max, median and average latency over the WAN targets' l
     });
 });
 
-// In the next two tests each element of the summary that updateSummary
-// writes into is a plain object, made the first time it is looked up and
-// kept in elements under "#" and its id.
-
-// The interval menu resets each target and counts the rounds from 0 again,
-// then updates the summary, before any check since the change is recorded.
-test("after an interval change, the summary's Reachable slot reads --/-- in white, as at page load", (t) => {
-    t.mock.method(
-        globalThis.document,
-        "getElementById",
-        (id) => (elements[`#${id}`] ??= {}),
-    );
-    const state = new AppState([]);
-    for (const host of state.wan) {
-        host.pushSample(Date.now(), { latency: 30, error: null });
-    }
-    state.tickCount = 5;
-
-    for (const host of state.allHosts) host.reset();
-    state.tickCount = 0;
-    updateSummary(state);
-
-    assert.equal(elements["#summary-reachable"].textContent, "--/--");
-    assert.equal(elements["#summary-reachable"].className, "text-white");
-});
-
-test("once every WAN target's check has failed, the summary's Reachable slot reads 0 of them, in red", (t) => {
-    t.mock.method(
-        globalThis.document,
-        "getElementById",
-        (id) => (elements[`#${id}`] ??= {}),
-    );
-    const state = new AppState([]);
-    for (const host of state.wan) {
-        host.pushSample(Date.now(), { latency: null, error: "timeout" });
-    }
-
-    updateSummary(state);
-
-    assert.equal(
-        elements["#summary-reachable"].textContent,
-        `0/${state.wan.length}`,
-    );
-    assert.equal(elements["#summary-reachable"].className, "text-red-400");
-});
-
-// In the next two tests each of the header's clocks is a plain object, made
-// the first time updateClocks looks it up and kept in elements under "#" and
-// its id.
-
-// The mocked clock reads 1970-01-01T00:00:00.000Z.
-test("the header's clocks show the local time with its time zone's name, and the UTC time", (t) => {
-    t.mock.method(
-        globalThis.document,
-        "getElementById",
-        (id) => (elements[`#${id}`] ??= {}),
-    );
-    t.mock.timers.enable({ apis: ["Date"] });
-
-    updateClocks();
-
-    assert.match(
-        elements["#clock-local"].textContent,
-        /^Local: \d{4}-\d\d-\d\d \d\d:\d\d:\d\d \S/,
-    );
-    assert.equal(
-        elements["#clock-utc"].textContent,
-        "UTC: 1970-01-01 00:00:00 UTC",
-    );
-});
-
-// Here Intl.DateTimeFormat is as in Chrome before 95, Firefox before 91 or
-// Safari before 15.4: it throws a RangeError when asked for the time zone's
-// "shortGeneric" name.
-test("in a browser that cannot name the time zone, updating the clocks throws nothing and leaves them blank", (t) => {
-    t.mock.method(
-        globalThis.document,
-        "getElementById",
-        (id) => (elements[`#${id}`] ??= {}),
-    );
-    const DateTimeFormat = Intl.DateTimeFormat;
-    t.mock.method(Intl, "DateTimeFormat", function (locales, options) {
-        if (options?.timeZoneName === "shortGeneric") {
-            throw new RangeError(
-                "Value shortGeneric out of range for Intl.DateTimeFormat options property timeZoneName",
-            );
-        }
-        return new DateTimeFormat(locales, options);
-    });
-
-    updateClocks();
-
-    assert.equal(elements["#clock-local"].textContent, "");
-    assert.equal(elements["#clock-utc"].textContent, "");
-});
-
 // An app state in which, of the WAN targets, the first timedOut timed out,
 // the next unreachable were found unreachable, the next answered answered
 // after latency ms, and the rest have not been checked yet.

web/src/main.js

@@ -259,14 +259,6 @@ function latencyStats(latencies) {
     };
 }
 
-// The status a check's error gives its host: "error" for a timeout,
-// "offline" for any other error, and "online" for none.
-function statusFromError(error) {
-    if (error === "timeout") return "error";
-    if (error) return "offline";
-    return "online";
-}
-
 export class HostState {
     constructor(host, pinned = false) {
         this.name = host.name;
@@ -275,10 +267,6 @@ export class HostState {
         // error }, or a round skipped while paused, { timestamp,
         // latency: null, paused: true }.
         this.history = [];
-        // The last 100 (CONFIG.maxHistoryPoints) entries the interval menu
-        // has cleared from the history, which the reporter may not have
-        // sent yet.
-        this.clearedHistory = [];
         this.lastLatency = null;
         this.status = "pending"; // 'online' | 'offline' | 'error' | 'pending'
         this.pinned = pinned;
@@ -294,7 +282,9 @@ export class HostState {
         });
         this._trim();
         this.lastLatency = result.latency;
-        this.status = statusFromError(result.error);
+        if (result.error === "timeout") this.status = "error";
+        else if (result.error) this.status = "offline";
+        else this.status = "online";
         this.consecutiveFailures = result.error
             ? this.consecutiveFailures + 1
             : 0;
@@ -305,18 +295,6 @@ export class HostState {
         this._trim();
     }
 
-    // What the interval menu does to each host: the history starts over and
-    // the host waits for its next check. The history's entries move to
-    // clearedHistory, so the reporter still sends those it has not.
-    reset() {
-        this.clearedHistory = [...this.clearedHistory, ...this.history].slice(
-            -CONFIG.maxHistoryPoints,
-        );
-        this.history = [];
-        this.lastLatency = null;
-        this.status = "pending";
-    }
-
     // The min, max, median and average latency of the checks in the history
     // that got an answer.
     historyStats() {
@@ -453,12 +431,9 @@ function getClientId() {
 
 // Build the delta report body the backend decodes, plus the new per-host
 // high-water marks. Pure function of the passed state: `hosts` is an array
-// of { name, url, status, clearedHistory, history }, `since` maps a host url
-// to the Unix-ms timestamp of the last sample already reported for it, and
-// `now` is a Date. Only non-paused samples newer than the mark are included,
-// from clearedHistory as well as history. A host whose status is pending,
-// as the interval menu leaves it until its next check, is sent with the
-// status of its last check, which is the last sample sent. Returns null
+// of { name, url, status, history }, `since` maps a host url to the Unix-ms
+// timestamp of the last sample already reported for it, and `now` is a Date.
+// Only non-paused samples newer than the mark are included. Returns null
 // when no host has an unreported sample.
 export function buildReport(hosts, clientId, now, since) {
     const reportHosts = [];
@@ -467,7 +442,7 @@ export function buildReport(hosts, clientId, now, since) {
         const mark = since.get(host.url) ?? 0;
         const samples = [];
         let high = mark;
-        for (const p of [...host.clearedHistory, ...host.history]) {
+        for (const p of host.history) {
             if (p.paused) continue;
             if (p.timestamp <= mark) continue;
             samples.push({
@@ -481,10 +456,7 @@ export function buildReport(hosts, clientId, now, since) {
         reportHosts.push({
             name: host.name,
             url: host.url,
-            status:
-                host.status === "pending"
-                    ? statusFromError(samples.at(-1).error)
-                    : host.status,
+            status: host.status,
             history: samples,
         });
         marks.set(host.url, high);
@@ -511,7 +483,7 @@ export function buildReport(hosts, clientId, now, since) {
 // Only one report is ever in flight, and it is abandoned after half the
 // interval, so a slow POST can neither overlap the next report (which would
 // carry the same samples) nor stall reporting for good.
-export class Reporter {
+class Reporter {
     constructor(state, clientId, intervalMs) {
         this.state = state;
         this.clientId = clientId;
@@ -829,7 +801,7 @@ function wanRowsHTML(wanHosts) {
     return rows.join("");
 }
 
-export function buildUI(state) {
+function buildUI(state) {
     const app = document.getElementById("app");
     app.innerHTML = `
     <div class="mx-auto px-[5%] py-8">
@@ -911,7 +883,7 @@ export function buildUI(state) {
           <span class="inline-block w-3 h-3 rounded-full bg-lime-500 mr-1 ml-3 align-middle"></span>&lt;100ms
           <span class="inline-block w-3 h-3 rounded-full bg-yellow-500 mr-1 ml-3 align-middle"></span>&lt;200ms
           <span class="inline-block w-3 h-3 rounded-full bg-orange-500 mr-1 ml-3 align-middle"></span>&lt;500ms
-          <span class="inline-block w-3 h-3 rounded-full bg-red-500 mr-1 ml-3 align-middle"></span>&gt;=500ms
+          <span class="inline-block w-3 h-3 rounded-full bg-red-500 mr-1 ml-3 align-middle"></span>&gt;500ms
           <span class="inline-block w-3 h-3 rounded-full bg-gray-500 mr-1 ml-3 align-middle"></span>offline
         </p>
         <p class="mt-2"><a href="https://git.eeqj.de/sneak/netwatch/commit/${__COMMIT_FULL__}" target="_blank" rel="noopener" class="text-gray-600 hover:text-gray-400">${__COMMIT_HASH__}</a></p>
@@ -995,7 +967,7 @@ function updateHostRow(host, index) {
     SparklineRenderer.draw(canvas, host.history);
 }
 
-export function updateSummary(state) {
+function updateSummary(state) {
     const stats = state.wanStats();
     const hstats = state.wanHistoryStats();
 
@@ -1014,20 +986,13 @@ export function updateSummary(state) {
     const hmaxUnitEl = document.getElementById("summary-hmax-unit");
     if (!reachableEl) return;
 
-    // Before any WAN host's check is recorded, as after an interval change,
-    // no host has answered or failed, so the slot reads as at page load.
-    if (state.wan.every((h) => h.status === "pending")) {
-        reachableEl.textContent = "--/--";
-        reachableEl.className = "text-white";
-    } else {
-        reachableEl.textContent = `${stats.reachable}/${stats.total}`;
-        reachableEl.className =
-            stats.reachable === stats.total
-                ? "text-green-400"
-                : stats.reachable === 0
-                  ? "text-red-400"
-                  : "text-yellow-400";
-    }
+    reachableEl.textContent = `${stats.reachable}/${stats.total}`;
+    reachableEl.className =
+        stats.reachable === stats.total
+            ? "text-green-400"
+            : stats.reachable === 0
+              ? "text-red-400"
+              : "text-yellow-400";
 
     if (stats.min !== null) {
         minEl.textContent = `${stats.min}`;
@@ -1114,33 +1079,6 @@ function updateHealthBox(state) {
     else if (health === "healthy") log.notice(`Health: ${labels[health]}`);
 }
 
-// Writes the local time, with its time zone's name, and the UTC time into
-// the header's clocks. The clocks only decorate the page: in a browser
-// whose Intl.DateTimeFormat rejects the "shortGeneric" time zone name
-// (Chrome before 95, Firefox before 91, Safari before 15.4) they are left
-// blank.
-export function updateClocks() {
-    let local = "";
-    let utc = "";
-    try {
-        const now = new Date();
-        const zone = new Intl.DateTimeFormat("en-US", {
-            timeZoneName: "shortGeneric",
-        })
-            .formatToParts(now)
-            .find((p) => p.type === "timeZoneName").value;
-        const pad = (n) => String(n).padStart(2, "0");
-        local = `Local: ${now.toLocaleString("sv-SE", { hour12: false })} ${zone}`;
-        utc =
-            `UTC: ${now.getUTCFullYear()}-${pad(now.getUTCMonth() + 1)}-${pad(now.getUTCDate())} ` +
-            `${pad(now.getUTCHours())}:${pad(now.getUTCMinutes())}:${pad(now.getUTCSeconds())} UTC`;
-    } catch {
-        // Both clocks are left blank.
-    }
-    document.getElementById("clock-local").textContent = local;
-    document.getElementById("clock-utc").textContent = utc;
-}
-
 // --- Debug Log Renderer ------------------------------------------------------
 
 // One line of the debug log panel, its message set as text.
@@ -1536,6 +1474,24 @@ async function init() {
         sortAndRebuildWAN(state);
     });
 
+    function updateClocks() {
+        const now = new Date();
+        const pad = (n) => String(n).padStart(2, "0");
+        const utc =
+            `${now.getUTCFullYear()}-${pad(now.getUTCMonth() + 1)}-${pad(now.getUTCDate())} ` +
+            `${pad(now.getUTCHours())}:${pad(now.getUTCMinutes())}:${pad(now.getUTCSeconds())} UTC`;
+        const local =
+            now.toLocaleString("sv-SE", { hour12: false }) +
+            " " +
+            new Intl.DateTimeFormat("en-US", { timeZoneName: "shortGeneric" })
+                .formatToParts(now)
+                .find((p) => p.type === "timeZoneName").value;
+        document.getElementById("clock-local").textContent = "Local: " + local;
+        document.getElementById("clock-utc").textContent = "UTC: " + utc;
+    }
+    updateClocks();
+    setInterval(updateClocks, 1000);
+
     // Rounds never overlap: a round first gives up the last round's checks
     // if they are still waiting, and the last round then records nothing
     // more. At a steady interval they never are, as they time out at 80% of
@@ -1571,7 +1527,9 @@ async function init() {
 
             // Clear all host history and reset state
             for (const host of state.allHosts) {
-                host.reset();
+                host.history = [];
+                host.lastLatency = null;
+                host.status = "pending";
             }
             state.tickCount = 0;
 
@@ -1615,11 +1573,6 @@ async function init() {
 
     window.addEventListener("resize", () => handleResize(state));
     setTimeout(() => handleResize(state), CONFIG.resizeDelay);
-
-    // The clocks start last, after the rounds: they only decorate the page,
-    // so nothing in them may stop the monitor from probing.
-    updateClocks();
-    setInterval(updateClocks, 1000);
 }
 
 // Bootstrap only when loaded as the page: a real DOM containing the #app