Give the webhook handler a timeout (closes #38)

The webhook handler's client had no timeout, and slog calls the handler
inside the log call, so a server that accepted the connection and never
answered stopped that log call for good, and every later one. A request
still running after 5 seconds, reading the answer included, now fails
with a timeout error. The handler also reads the answer to the end
before closing it, so the connection is reused for the next record.

Two new tests point the handler at a server that never answers and at
one that sends its status and then stalls the answer, and check that
Handle returns a timeout error within the timeout. The README states
the timeout.

Model: opus-5-5

.gitea/workflows/check.yml

@@ -9,4 +9,4 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-      - run: docker build .
+      - run: script/cibuild

Dockerfile

@@ -6,15 +6,23 @@ COPY go.mod go.sum ./
 RUN go mod download
 COPY . .
 RUN make fmt-check
-RUN make lint
+# Called directly: make lint is itself a docker build of this stage.
+RUN golangci-lint run --config .golangci.yml ./...
 
-# Test stage: run full test suite
-# golang 1.22.12 (2025-02-04)
+# Test stage: run full test suite under the race detector
+# golang 1.22.12 (Debian-based; -race needs its C toolchain), 2025-02-04
 FROM golang@sha256:1cf6c45ba39db9fd6db16922041d074a63c935556a05c5ccb62d181034df7f02 AS test
-# Depend on lint stage so both stages always run
-COPY --from=lint /src/go.sum /dev/null
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
 COPY . .
-RUN make test
+# Called directly: make test is itself a docker build of this stage.
+RUN go test -timeout 90s -race -cover ./... || \
+    { echo "--- Rerunning with -v for details ---"; \
+      go test -timeout 90s -race -v ./...; exit 1; }
+
+# Final stage: the copies make a plain docker build run both stages above.
+# golang 1.22.12 (2025-02-04)
+FROM golang@sha256:1cf6c45ba39db9fd6db16922041d074a63c935556a05c5ccb62d181034df7f02
+COPY --from=lint /src/go.sum /dev/null
+COPY --from=test /src/go.sum /dev/null

Makefile

@@ -1,28 +1,30 @@
-.PHONY: test fmt fmt-check lint check docker hooks
+.PHONY: bootstrap setup test fmt fmt-check lint check docker hooks
 
 default: check
 
+bootstrap:
+	@script/bootstrap
+
+setup:
+	@script/setup
+
 test:
-	@go test -v ./...
+	@script/test
 
 fmt:
-	goimports -l -w .
-	golangci-lint run --fix
+	@script/fmt
 
 fmt-check:
-	@test -z "$$(gofmt -l .)" || { echo "gofmt would reformat:"; gofmt -l .; exit 1; }
+	@script/fmt-check
 
 lint:
-	golangci-lint run
+	@script/lint
 
-check: fmt-check lint test
+check:
+	@script/check
 
 docker:
-	docker build --progress plain .
+	@script/docker
 
 hooks:
-	@echo "Installing git hooks..."
-	@mkdir -p .git/hooks
-	@printf '#!/bin/sh\nmake check\n' > .git/hooks/pre-commit
-	@chmod +x .git/hooks/pre-commit
-	@echo "Pre-commit hook installed."
+	@script/install-precommit

README.md

@@ -25,6 +25,9 @@ Released v1.0.0 2024-06-14.  Works as intended.  No known bugs.
     in console output they are appended as `key=value` pairs, with grouped
     keys written as `group.key=value`. See
     [Attribute output](#attribute-output) for the details worth knowing
+-   reports a record that could not be delivered as an error from the
+    handler's `Handle` method. See
+    [When delivery fails](#when-delivery-fails) for how to receive it
 
 ## Planned Features
 
@@ -104,6 +107,72 @@ ignored, an empty group is elided along with its key, a group with an
 empty key is inlined into its parent, and `WithGroup("")` returns the
 handler unchanged.
 
+## When delivery fails
+
+Every handler returns an error from `Handle` when it could not deliver
+the record:
+
+-   `ConsoleHandler` and `JSONHandler` return the error from their write to
+    stdout, wrapped, so `errors.Is` still matches the original
+-   `WebhookHandler` returns an error when the request fails, and also when
+    the server answers with a status outside 2xx, a redirect included,
+    since it does not follow redirects. A request that has not finished
+    after 5 seconds fails with a timeout error, so a webhook server that
+    never answers holds up a log call for 5 seconds at most
+-   `MultiplexHandler`, which simplelog installs as the default, passes the
+    record to every handler it holds even after one of them fails, then
+    returns all their errors joined with `errors.Join` (nil if none failed)
+
+`slog.Info`, `slog.Error` and the other `slog.Logger` methods throw that
+error away. That is how `log/slog` works, and simplelog cannot change it.
+To find out whether a record was delivered, build a `slog.Record` and pass
+it to the handler yourself, for example
+`slog.Default().Handler().Handle(ctx, record)`, then check the error it
+returns. Console output takes the file and line from the record's `PC`,
+which you set with `runtime.Callers` as the `log/slog` documentation
+shows. A record whose `PC` is zero prints `???:0` instead.
+
+## Entrypoints
+
+This repository adheres to the
+[Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
+standard: normalized scripts in `script/` are the entrypoints for the
+development workflow, and the Makefile targets are thin shims that call them.
+The scripts are POSIX sh (not bash) so they run in minimal containers such as
+alpine. We provide:
+
+- `script/bootstrap` — install all dependencies (go if missing, then
+  `go mod download`); golangci-lint is not installed, since it runs only in
+  Docker
+- `script/setup` — set up the repo for development after a fresh clone: runs
+  `script/bootstrap`, then `script/install-precommit`
+- `script/projectname` — output the project name (our own extension); used by
+  `script/docker` for the image tag
+- `script/test` — run the test suite under the race detector in Docker by
+  building only the `test` stage of the `Dockerfile`, without the build cache,
+  so every run tests; the image is tagged `simplelog-test`
+- `script/lint` — run golangci-lint in Docker by building only the `lint`
+  stage of the `Dockerfile` (which also runs the format check), without the
+  build cache, so every run lints; the image is tagged `simplelog-lint`
+- `script/fmt` — format all files with goimports (writes)
+- `script/fmt-check` — check formatting (read-only); fails if `gofmt -l`
+  reports files
+- `script/check` — run all checks: `test`, `lint`, `fmt-check` (our own
+  extension)
+- `script/docker` — build the Docker image without the build cache, tagged
+  via `script/projectname` (byte-identical across repos); it also passes the
+  output of `git describe` as the `VERSION` build argument, which is ignored
+  because this `Dockerfile` does not declare it
+- `script/cibuild` — cd to the repo root and build the Docker image without the
+  build cache, tagged via `script/projectname` (what CI runs; the image build
+  runs the checks)
+- `script/precommit` — run by the git pre-commit hook (our own extension);
+  runs a `go mod tidy` guard, then `script/check`
+- `script/install-precommit` — installs the git pre-commit hook (our own
+  extension); `make hooks` shims to it
+
+`make hooks` installs the pre-commit hook that runs `script/precommit`.
+
 ## License
 
 [WTFPL](./LICENSE)

REPO_POLICIES.md

@@ -0,0 +1,408 @@
+---
+title: Repository Policies
+last_modified: 2026-07-06
+---
+
+This document covers repository structure, tooling, and workflow standards. Code
+style conventions are in separate documents:
+
+- [Code Styleguide](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE.md)
+  (general, bash, Docker)
+- [Go](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_GO.md)
+- [JavaScript](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_JS.md)
+- [Python](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_PYTHON.md)
+- [Go HTTP Server Conventions](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/GO_HTTP_SERVER_CONVENTIONS.md)
+
+---
+
+- Cross-project documentation (such as this file) must include
+  `last_modified: YYYY-MM-DD` in the YAML front matter so it can be kept in sync
+  with the authoritative source as policies evolve.
+
+- **ALL external references must be pinned by cryptographic hash.** This
+  includes Docker base images, Go modules, npm packages, GitHub Actions, and
+  anything else fetched from a remote source. Version tags (`@v4`, `@latest`,
+  `:3.21`, etc.) are server-mutable and therefore remote code execution
+  vulnerabilities. The ONLY acceptable way to reference an external dependency
+  is by its content hash (Docker `@sha256:...`, Go module hash in `go.sum`, npm
+  integrity hash in lockfile, GitHub Actions `@<commit-sha>`). No exceptions.
+  This also means never `curl | bash` to install tools like pyenv, nvm, rustup,
+  etc. Instead, download a specific release archive from GitHub, verify its hash
+  (hardcoded in the Dockerfile or script), and only then install. Unverified
+  install scripts are arbitrary remote code execution. This is the single most
+  important rule in this document. Double-check every external reference in
+  every file before committing. There are zero exceptions to this rule.
+
+- Every repo with software must have a root `Makefile` with these targets:
+  `make bootstrap`, `make setup`, `make test`, `make lint`, `make fmt` (writes),
+  `make fmt-check` (read-only), `make check` (runs `test`, `lint`, `fmt-check`),
+  `make docker`, and `make hooks` (installs pre-commit hook). A model Makefile
+  is at `https://git.eeqj.de/sneak/prompts/raw/branch/main/Makefile`.
+
+- Repos follow the
+  [Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
+  pattern: the implementation of each Makefile target lives in an executable
+  script in `script/` (`script/bootstrap`, `script/setup`, `script/test`,
+  `script/lint`, `script/fmt`, `script/fmt-check`, `script/check`,
+  `script/docker`), and the Makefile targets are thin shims that call them. The
+  scripts must be POSIX sh (`#!/bin/sh`, `set -eu`, no bashisms) so they run in
+  minimal containers (e.g. alpine images have no bash); locate the repo root
+  with `$(cd "$(dirname "$0")/.." && pwd -P)` and `cd` there before acting. From
+  the standard's canonical set we use `bootstrap`, `setup` (make the repo ready
+  for development after a fresh clone: runs `bootstrap`, then
+  `install-precommit`, plus any repo-specific initialization), `test`, and
+  `cibuild`. `script/bootstrap` installs all dependencies idempotently and
+  assumes nothing is present: base tools come from nix, apt, brew, or apk
+  (detected in that order; apt runs noninteractive). For node it uses the
+  installed node if present; otherwise it installs a PINNED node version via
+  nvm, first installing nvm itself if missing — from a hash-verified GitHub
+  release archive (never `curl | sh`), with bash installed as an explicit
+  prerequisite since nvm requires bash. yarn is then pinned via
+  `corepack prepare yarn@<version> --activate`. Never install "latest" or "lts";
+  always exact versions. `script/cibuild` runs the CI build: it changes to the
+  repo root and runs `docker build .`; the Gitea workflow calls it. Four further
+  scripts are our own extensions to the standard: `script/check` runs
+  `script/test`, `script/lint`, and `script/fmt-check`; `script/precommit` is
+  what the git pre-commit hook runs, and it calls `script/check`;
+  `script/install-precommit` installs the git pre-commit hook (the `make hooks`
+  target shims to it); and `script/projectname` (literally that filename) simply
+  outputs the project's name. Scripts that need the name call
+  `script/projectname` — e.g. `script/docker` assembles its image tag from it —
+  so those scripts stay byte-identical across all repos. Repo-type-specific
+  pre-commit extras (e.g. `go mod tidy` verification in Go repos) belong in
+  `script/precommit`, not in the hook itself. Model scripts are at
+  `https://git.eeqj.de/sneak/prompts/raw/branch/main/script/<name>`. The README
+  must document the provided scripts in an **Entrypoints** section (see the
+  README requirements below).
+
+- Always use Makefile targets (`make fmt`, `make test`, `make lint`, etc.)
+  instead of invoking the underlying tools directly. The Makefile is the single
+  source of truth for how these operations are run.
+
+- The Makefile is authoritative documentation for how the repo is used. Beyond
+  the required targets above, it should have targets for every common operation:
+  running a local development server (`make run`, `make dev`), re-initializing
+  or migrating the database (`make db-reset`, `make migrate`), building
+  artifacts (`make build`), generating code, seeding data, or anything else a
+  developer would do regularly. If someone checks out the repo and types
+  `make<tab>`, they should see every meaningful operation available. A new
+  contributor should be able to understand the entire development workflow by
+  reading the Makefile.
+
+- Every repo should have a `Dockerfile`. All Dockerfiles must run `make check`
+  as a build step so the build fails if the branch is not green. For non-server
+  repos, the Dockerfile should bring up a development environment and run
+  `make check`. For server repos, `make check` should run as an early build
+  stage before the final image is assembled. Dockerfiles install development
+  prerequisites by running `script/bootstrap` rather than duplicating installs
+  inline; COPY `script/` and the dependency manifests (`package.json` +
+  `yarn.lock`, `go.mod` + `go.sum`, etc.) before running it so the bootstrap
+  layer stays cached until dependencies change.
+
+- **Dockerfiles must use a separate lint stage for fail-fast feedback.** Go
+  repos use a multistage build where linting runs in an independent stage based
+  on the `golangci/golangci-lint` image (pinned by hash). This stage runs
+  `make fmt-check` and `make lint` before the full build begins. The build stage
+  then declares an explicit dependency on the lint stage via
+  `COPY --from=lint /src/go.sum /dev/null`, which forces BuildKit to complete
+  linting before proceeding to compilation and tests. This ensures lint failures
+  surface in seconds rather than minutes, without blocking on dependency
+  download or compilation in the build stage.
+
+    The standard pattern for a Go repo Dockerfile is:
+
+    ```dockerfile
+    # Lint stage — fast feedback on formatting and lint issues
+    # golangci/golangci-lint:v2.x.x, YYYY-MM-DD
+    FROM golangci/golangci-lint@sha256:... AS lint
+    WORKDIR /src
+    COPY go.mod go.sum ./
+    RUN go mod download
+    COPY . .
+    RUN make fmt-check
+    RUN make lint
+
+    # Build stage
+    # golang:1.x-alpine, YYYY-MM-DD
+    FROM golang@sha256:... AS builder
+    WORKDIR /src
+
+    # Force BuildKit to run the lint stage before proceeding
+    COPY --from=lint /src/go.sum /dev/null
+
+    COPY go.mod go.sum ./
+    RUN go mod download
+    COPY . .
+    RUN make test
+
+    ARG VERSION=dev
+    RUN CGO_ENABLED=0 go build -trimpath \
+        -ldflags="-s -w -X main.Version=${VERSION}" \
+        -o /app ./cmd/app/
+
+    # Runtime stage
+    FROM alpine@sha256:...
+    COPY --from=builder /app /usr/local/bin/app
+    ENTRYPOINT ["app"]
+    ```
+
+    Key points:
+    - The lint stage uses the `golangci/golangci-lint` image directly (it
+      includes both Go and the linter), so there is no need to install the
+      linter separately.
+    - `COPY --from=lint /src/go.sum /dev/null` is a no-op file copy that creates
+      a stage dependency. BuildKit runs stages in parallel by default; without
+      this line, the build stage would not wait for lint to finish and a lint
+      failure might not fail the overall build.
+    - If the project uses `//go:embed` directives that reference build artifacts
+      (e.g. a web frontend compiled in a separate stage), the lint stage must
+      create placeholder files so the embed directives resolve. Example:
+      `RUN mkdir -p web/dist && touch web/dist/index.html web/dist/style.css`.
+      The lint stage should not depend on the actual build output — it exists to
+      fail fast.
+    - If the project requires CGO or system libraries for linting (e.g.
+      `vips-dev`), install them in the lint stage with `apk add`.
+    - The build stage runs `make test` after compilation setup. Tests run in the
+      build stage, not the lint stage, because they may require compiled
+      artifacts or heavier dependencies.
+
+- Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
+  runs `script/cibuild` (which runs `docker build .`) on push. Since the
+  Dockerfile already runs `make check`, a successful build implies all checks
+  pass.
+
+- Use platform-standard formatters: `black` for Python, `prettier` for
+  JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
+  two exceptions: four-space indents (except Go), and `proseWrap: always` for
+  Markdown (hard-wrap at 80 columns). Documentation and writing repos (Markdown,
+  HTML, CSS) should also have `.prettierrc` and `.prettierignore`.
+
+- Pre-commit hook: runs `script/precommit`, which calls `script/check`. If local
+  testing is not possible in the repo, `script/precommit` may skip `script/test`
+  and run only `script/lint` and `script/fmt-check`. The hook is installed by
+  `script/install-precommit`; the Makefile must provide a `make hooks` target
+  that shims to it.
+
+- All repos with software must have tests that run via the platform-standard
+  test framework (`go test`, `pytest`, `jest`/`vitest`, etc.). If no meaningful
+  tests exist yet, add the most minimal test possible — e.g. importing the
+  module under test to verify it compiles/parses. There is no excuse for
+  `make test` to be a no-op.
+
+- `make test` must complete in under 20 seconds. Add a 30-second timeout in the
+  Makefile.
+
+- **`make test` should use the conditional verbose rerun pattern.** Run tests
+  without `-v` (verbose) first. If tests fail, automatically rerun with `-v` to
+  show full output. This keeps CI logs and `docker build` output clean on
+  success (just package/suite summaries) while providing full diagnostic detail
+  on failure (every test case, every assertion). The general shell pattern:
+
+    ```makefile
+    test:
+    	@<test-command> || \
+    		{ echo "--- Rerunning with -v for details ---"; \
+    		  <test-command-with-v>; exit 1; }
+    ```
+
+    Go example:
+
+    ```makefile
+    test:
+    	@go test -timeout 30s -race -cover ./... || \
+    		{ echo "--- Rerunning with -v for details ---"; \
+    		  go test -timeout 30s -race -v ./...; exit 1; }
+    ```
+
+    Python example:
+
+    ```makefile
+    test:
+    	@python -m pytest || \
+    		{ echo "--- Rerunning with -v for details ---"; \
+    		  python -m pytest -v; exit 1; }
+    ```
+
+    The `exit 1` ensures the target always fails after a rerun — the first run
+    already proved the tests are broken, so the build must not pass even if a
+    flaky test happens to succeed on the second attempt. The rerun exists solely
+    for diagnostic output.
+
+- Docker builds must complete in under 5 minutes.
+
+- `make check` must not modify any files in the repo. Tests may use temporary
+  directories.
+
+- `main` must always pass `make check`, no exceptions.
+
+- Never commit secrets. `.env` files, credentials, API keys, and private keys
+  must be in `.gitignore`. No exceptions.
+
+- `.gitignore` should be comprehensive from the start: OS files (`.DS_Store`),
+  editor files (`.swp`, `*~`), 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.
+
+- **No build artifacts in version control.** Code-derived data (compiled
+  bundles, minified output, generated assets) must never be committed to the
+  repository if it can be avoided. The build process (e.g. Dockerfile, Makefile)
+  should generate these at build time. Notable exception: Go protobuf generated
+  files (`.pb.go`) ARE committed because repos need to work with `go get`, which
+  downloads code but does not execute code generation.
+
+- Never use `git add -A` or `git add .`. Always stage files explicitly by name.
+
+- Never force-push to `main`.
+
+- Make all changes on a feature branch. You can do whatever you want on a
+  feature branch.
+
+- `.golangci.yml` is standardized and must _NEVER_ be modified by an agent, only
+  manually by the user. Fetch from
+  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml`.
+
+- When pinning images or packages by hash, add a comment above the reference
+  with the version and date (YYYY-MM-DD).
+
+- Use `yarn`, not `npm`.
+
+- Write all dates as YYYY-MM-DD (ISO 8601).
+
+- Simple projects should be configured with environment variables.
+
+- Dockerized web services listen on port 8080 by default, overridable with
+  `PORT`.
+
+- **HTTP/web services must be hardened for production internet exposure before
+  tagging 1.0.** This means full compliance with security best practices
+  including, without limitation, all of the following:
+    - **Security headers** on every response:
+        - `Strict-Transport-Security` (HSTS) with `max-age` of at least one year
+          and `includeSubDomains`.
+        - `Content-Security-Policy` (CSP) with a restrictive default policy
+          (`default-src 'self'` as a baseline, tightened per-resource as
+          needed). Never use `unsafe-inline` or `unsafe-eval` unless
+          unavoidable, and document the reason.
+        - `X-Frame-Options: DENY` (or `SAMEORIGIN` if framing is required).
+          Prefer the `frame-ancestors` CSP directive as the primary control.
+        - `X-Content-Type-Options: nosniff`.
+        - `Referrer-Policy: strict-origin-when-cross-origin` (or stricter).
+        - `Permissions-Policy` restricting access to browser features the
+          application does not use (camera, microphone, geolocation, etc.).
+    - **Request and response limits:**
+        - Maximum request body size enforced on all endpoints (e.g. Go
+          `http.MaxBytesReader`). Choose a sane default per-route; never accept
+          unbounded input.
+        - Maximum response body size where applicable (e.g. paginated APIs).
+        - `ReadTimeout` and `ReadHeaderTimeout` on the `http.Server` to defend
+          against slowloris attacks.
+        - `WriteTimeout` on the `http.Server`.
+        - `IdleTimeout` on the `http.Server`.
+        - Per-handler execution time limits via `context.WithTimeout` or
+          chi/stdlib `middleware.Timeout`.
+    - **Authentication and session security:**
+        - Rate limiting on password-based authentication endpoints. API keys are
+          high-entropy and not susceptible to brute force, so they are exempt.
+        - CSRF tokens on all state-mutating HTML forms. API endpoints
+          authenticated via `Authorization` header (Bearer token, API key) are
+          exempt because the browser does not attach these automatically.
+        - Passwords stored using bcrypt, scrypt, or argon2 — never plain-text,
+          MD5, or SHA.
+        - Session cookies set with `HttpOnly`, `Secure`, and `SameSite=Lax` (or
+          `Strict`) attributes.
+    - **Reverse proxy awareness:**
+        - True client IP detection when behind a reverse proxy
+          (`X-Forwarded-For`, `X-Real-IP`). The application must accept
+          forwarded headers only from a configured set of trusted proxy
+          addresses — never trust `X-Forwarded-For` unconditionally.
+    - **CORS:**
+        - Authenticated endpoints must restrict `Access-Control-Allow-Origin` to
+          an explicit allowlist of known origins. Wildcard (`*`) is acceptable
+          only for public, unauthenticated read-only APIs.
+    - **Error handling:**
+        - Internal errors must never leak stack traces, SQL queries, file paths,
+          or other implementation details to the client. Return generic error
+          messages in production; detailed errors only when `DEBUG` is enabled.
+    - **TLS:**
+        - Services never terminate TLS directly. They are always deployed behind
+          a TLS-terminating reverse proxy. The service itself listens on plain
+          HTTP. However, HSTS headers and `Secure` cookie flags must still be
+          set by the application so that the browser enforces HTTPS end-to-end.
+
+    This list is non-exhaustive. Apply defense-in-depth: if a standard security
+    hardening measure exists for HTTP services and is not listed here, it is
+    still expected. When in doubt, harden.
+
+- `README.md` is the primary documentation. Required sections:
+    - **Description**: First line must include the project name, purpose,
+      category (web server, SPA, CLI tool, etc.), license, and author. Example:
+      "µPaaS is an MIT-licensed Go web application by @sneak that receives
+      git-frontend webhooks and deploys applications via Docker in realtime."
+    - **Getting Started**: Copy-pasteable install/usage code block.
+    - **Entrypoints**: Opens by stating that the repo adheres to the
+      [Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
+      standard (with that link), then documents each provided `script/`
+      entrypoint and its purpose.
+    - **Rationale**: Why does this exist?
+    - **Design**: How is the program structured?
+    - **TODO**: Update meticulously, even between commits. When planning, put
+      the todo list in the README so a new agent can pick up where the last one
+      left off.
+    - **License**: MIT, GPL, or WTFPL. Ask the user for new projects. Include a
+      `LICENSE` file in the repo root and a License section in the README.
+    - **Author**: [@sneak](https://sneak.berlin).
+
+- First commit of a new repo should contain only `README.md`.
+
+- Go module root: `sneak.berlin/go/<name>`. Always run `go mod tidy` before
+  committing.
+
+- Use SemVer.
+
+- Database migrations live in `internal/db/migrations/` and must be embedded in
+  the binary.
+    - `000_migration.sql` — contains ONLY the creation of the migrations
+      tracking table itself. Nothing else.
+    - `001_schema.sql` — the full application schema.
+    - **Pre-1.0.0:** never add additional migration files (002, 003, etc.).
+      There is no installed base to migrate. Edit `001_schema.sql` directly.
+    - **Post-1.0.0:** add new numbered migration files for each schema change.
+      Never edit existing migrations after release.
+
+- All repos should have an `.editorconfig` enforcing the project's indentation
+  settings.
+
+- Avoid putting files in the repo root unless necessary. Root should contain
+  only project-level config files (`README.md`, `Makefile`, `Dockerfile`,
+  `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`, and
+  language-specific config). Everything else goes in a subdirectory. Canonical
+  subdirectory names:
+    - `bin/` — executable scripts and tools
+    - `cmd/` — Go command entrypoints
+    - `configs/` — configuration templates and examples
+    - `deploy/` — deployment manifests (k8s, compose, terraform)
+    - `docs/` — documentation and markdown (README.md stays in root)
+    - `internal/` — Go internal packages
+    - `internal/db/migrations/` — database migrations
+    - `pkg/` — Go library packages
+    - `share/` — systemd units, data files
+    - `static/` — static assets (images, fonts, etc.)
+    - `web/` — web frontend source
+
+- When setting up a new repo, files from the `prompts` repo may be used as
+  templates. Fetch them from
+  `https://git.eeqj.de/sneak/prompts/raw/branch/main/<path>`.
+
+- New repos must contain at minimum:
+    - `README.md`, `.git`, `.gitignore`, `.editorconfig`
+    - `LICENSE`, `REPO_POLICIES.md` (copy from the `prompts` repo)
+    - `Makefile`
+    - `script/` entrypoints (`bootstrap`, `setup`, `projectname`, `test`,
+      `lint`, `fmt`, `fmt-check`, `check`, `docker`, `cibuild`, `precommit`,
+      `install-precommit`)
+    - `Dockerfile`, `.dockerignore`
+    - `.gitea/workflows/check.yml`
+    - Go: `go.mod`, `go.sum`, `.golangci.yml`
+    - JS: `package.json`, `yarn.lock`, `.prettierrc`, `.prettierignore`
+    - Python: `pyproject.toml`

TODO.md

@@ -24,6 +24,25 @@ files it depends on: .golangci.yml, REPO_POLICIES.md, .editorconfig,
 
 # Completed Steps
 
+* 2026-10-06: a webhook request now times out after 5 seconds, so a
+    server that never answers no longer stops every log call; the webhook
+    handler also reads each answer to the end so its connection is reused
+* 2026-10-06: the console handler takes the file and line it prints from
+    the record's `PC` instead of counting stack frames, so they name the
+    call site whether the record came through a `slog.Logger` or straight
+    to `Handle`
+* 2026-10-06: the tests run under the race detector, in Docker:
+    `script/test` builds the `test` stage of the `Dockerfile`, which runs
+    `go test -race`, and a new final stage makes a plain `docker build`
+    run both the `lint` and `test` stages
+* 2026-10-06: the linter runs only in Docker: `script/lint` builds the
+    `lint` stage of the `Dockerfile`, every `docker build` in `script/`
+    runs without the build cache, and `script/bootstrap` no longer
+    installs golangci-lint
+* 2026-10-06: every handler now returns a failed delivery from `Handle`
+    instead of discarding it: console and JSON return the stdout write
+    error, the webhook also fails on a non-2xx answer, and the multiplex
+    delivers to every handler and returns their errors joined
 * 2026-08-10: fixed every handler discarding slog attributes: console,
     JSON and webhook handlers now emit record attributes, accumulate
     WithAttrs without mutating the receiver, and honour WithGroup;
@@ -33,6 +52,8 @@ files it depends on: .golangci.yml, REPO_POLICIES.md, .editorconfig,
     `Dockerfile` lint stage to golangci-lint v2.12.2 (tag+digest), and
     fixed all findings the v1→v2 jump surfaced without changing any
     exported signatures or behavior
+- 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints,
+    Makefile shims, README Entrypoints section
 * 2026-02-08: fixed JSONHandler deadlock from recursive log.Println,
     with regression test; tagged 1.0.1
 * 2024-06-14: 1.0 prep: lint and fmt enforced in Docker build, call
@@ -45,9 +66,6 @@ files it depends on: .golangci.yml, REPO_POLICIES.md, .editorconfig,
 
 # Future Steps
 
-* Rewrite the Dockerfile to run make check with sha256-pinned base
-    images (currently golangci/golangci-lint:latest and golang:1.22,
-    unpinned, duplicating Makefile logic instead of calling it)
 * Restructure README.md into the standard sections: Description,
     Getting Started, Rationale, Design, TODO, License, Author
 * Delete the old plain TODO file once this TODO.md lands

console_handler.go

@@ -3,6 +3,7 @@ package simplelog
 import (
 	"context"
 	"fmt"
+	"io"
 	"log/slog"
 	"os"
 	"runtime"
@@ -11,12 +12,11 @@ import (
 	"github.com/fatih/color"
 )
 
-// callerSkipFrames is the number of stack frames between runtime.Caller
-// and the slog call site that produced the record.
-const callerSkipFrames = 4
-
 // ConsoleHandler writes human-readable, colored log lines to stdout.
 type ConsoleHandler struct {
+	// out is where records are written. Nil means os.Stdout, looked up on
+	// every write so that a reassigned os.Stdout is followed.
+	out   io.Writer
 	attrs handlerAttrs
 }
 
@@ -27,7 +27,7 @@ func NewConsoleHandler() *ConsoleHandler {
 
 // Handle writes the record to stdout as a colored, timestamped line
 // including the caller file and line, followed by the attributes as
-// key=value pairs.
+// key=value pairs. A failed write is returned as an error.
 func (c *ConsoleHandler) Handle(
 	_ context.Context,
 	record slog.Record,
@@ -49,15 +49,22 @@ func (c *ConsoleHandler) Handle(
 		colorFunc = color.New(color.FgWhite).SprintfFunc()
 	}
 
-	// Get the caller information
-	_, file, line, ok := runtime.Caller(callerSkipFrames)
-	if !ok {
-		file = "???"
-		line = 0
+	// The file and line come from the record's PC, the call site; a record
+	// without one prints a placeholder.
+	file, line := "???", 0
+
+	if record.PC != 0 {
+		frame, _ := runtime.CallersFrames([]uintptr{record.PC}).Next()
+		file, line = frame.File, frame.Line
 	}
 
-	_, _ = fmt.Fprintln(
-		os.Stdout,
+	out := c.out
+	if out == nil {
+		out = os.Stdout
+	}
+
+	_, err := fmt.Fprintln(
+		out,
 		colorFunc(
 			"%s [%s] %s:%d: %s%s",
 			timestamp,
@@ -68,6 +75,9 @@ func (c *ConsoleHandler) Handle(
 			attrsToText(c.attrs.forRecord(record)),
 		),
 	)
+	if err != nil {
+		return fmt.Errorf("error writing log record: %w", err)
+	}
 
 	return nil
 }
@@ -88,7 +98,7 @@ func (c *ConsoleHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
 		return c
 	}
 
-	return &ConsoleHandler{attrs: c.attrs.withAttrs(attrs)}
+	return &ConsoleHandler{out: c.out, attrs: c.attrs.withAttrs(attrs)}
 }
 
 // WithGroup returns a new handler that qualifies later attributes with
@@ -98,5 +108,5 @@ func (c *ConsoleHandler) WithGroup(name string) slog.Handler {
 		return c
 	}
 
-	return &ConsoleHandler{attrs: c.attrs.withGroup(name)}
+	return &ConsoleHandler{out: c.out, attrs: c.attrs.withGroup(name)}
 }

console_handler_internal_test.go

@@ -0,0 +1,102 @@
+package simplelog
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log/slog"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+)
+
+// These tests sit inside the package so they can read the console line
+// from a buffer instead of from stdout.
+
+// lineOf calls logCall and returns "file:line" for the line lineOf was
+// called from. Each test writes its log call inside logCall on that same
+// line, so the result is the location the console line must name.
+func lineOf(logCall func()) string {
+	_, file, line, _ := runtime.Caller(1)
+
+	logCall()
+
+	return fmt.Sprintf("%s:%d", file, line)
+}
+
+// wantLocation fails the test unless the console line names location as
+// where the record "casting" was logged.
+func wantLocation(t *testing.T, output, location string) {
+	t.Helper()
+
+	if !strings.Contains(output, location+": casting") {
+		t.Fatalf("console line %q does not name %s", output, location)
+	}
+}
+
+// The default handler as simplelog installs it when stdout is a terminal:
+// a MultiplexHandler holding a ConsoleHandler.
+func TestConsoleHandlerNamesCallSiteThroughDefaultHandler(t *testing.T) {
+	t.Parallel()
+
+	var output bytes.Buffer
+
+	logger := slog.New(&MultiplexHandler{handlers: []ExtendedHandler{
+		&ConsoleHandler{out: &output},
+	}})
+
+	want := lineOf(func() { logger.Info("casting") })
+
+	wantLocation(t, output.String(), want)
+}
+
+func TestConsoleHandlerNamesCallSiteUsedWithSlogNew(t *testing.T) {
+	t.Parallel()
+
+	var output bytes.Buffer
+
+	logger := slog.New(&ConsoleHandler{out: &output})
+
+	want := lineOf(func() { logger.Info("casting") })
+
+	wantLocation(t, output.String(), want)
+}
+
+// The record is built as the log/slog package documentation shows for a
+// function that logs on its caller's behalf: runtime.Callers supplies the
+// PC.
+func TestConsoleHandlerNamesCallSiteOfRecordPassedToHandle(t *testing.T) {
+	t.Parallel()
+
+	var (
+		output bytes.Buffer
+		pcs    [1]uintptr
+	)
+
+	want := lineOf(func() { runtime.Callers(1, pcs[:]) })
+
+	record := slog.NewRecord(time.Now(), slog.LevelInfo, "casting", pcs[0])
+
+	err := (&ConsoleHandler{out: &output}).Handle(context.Background(), record)
+	if err != nil {
+		t.Fatalf("Handle: %v", err)
+	}
+
+	wantLocation(t, output.String(), want)
+}
+
+func TestConsoleHandlerPrintsPlaceholderWithoutPC(t *testing.T) {
+	t.Parallel()
+
+	var output bytes.Buffer
+
+	record := slog.NewRecord(time.Now(), slog.LevelInfo, "casting", 0)
+
+	err := (&ConsoleHandler{out: &output}).Handle(context.Background(), record)
+	if err != nil {
+		t.Fatalf("Handle: %v", err)
+	}
+
+	wantLocation(t, output.String(), "???:0")
+}

handler_errors_internal_test.go

@@ -0,0 +1,263 @@
+package simplelog
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"log/slog"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+// These tests sit inside the package so they can point a handler at a sink
+// that fails, which callers outside the package cannot do.
+
+// errSinkFailed is what failingWriter returns from every write.
+var errSinkFailed = errors.New("sink failed")
+
+// failingWriter is a sink whose every write fails.
+type failingWriter struct{}
+
+func (failingWriter) Write(_ []byte) (int, error) {
+	return 0, errSinkFailed
+}
+
+func errorTestRecord() slog.Record {
+	return slog.NewRecord(time.Now(), slog.LevelInfo, "casting", 0)
+}
+
+// The handler is derived with WithAttrs and WithGroup, so the test also
+// fails if either of them drops the sink.
+func TestJSONHandlerReturnsWriteError(t *testing.T) {
+	t.Parallel()
+
+	handler := (&JSONHandler{out: failingWriter{}}).
+		WithAttrs([]slog.Attr{slog.String("service", "cattbox")}).
+		WithGroup("cast")
+
+	err := handler.Handle(context.Background(), errorTestRecord())
+	if !errors.Is(err, errSinkFailed) {
+		t.Fatalf("Handle returned %v, want the sink's error", err)
+	}
+}
+
+func TestConsoleHandlerReturnsWriteError(t *testing.T) {
+	t.Parallel()
+
+	handler := (&ConsoleHandler{out: failingWriter{}}).
+		WithAttrs([]slog.Attr{slog.String("service", "cattbox")}).
+		WithGroup("cast")
+
+	err := handler.Handle(context.Background(), errorTestRecord())
+	if !errors.Is(err, errSinkFailed) {
+		t.Fatalf("Handle returned %v, want the sink's error", err)
+	}
+}
+
+// A failing handler must not stop the record reaching the handlers after
+// it, and its error must still reach the caller.
+func TestMultiplexHandlerDeliversPastFailingHandler(t *testing.T) {
+	t.Parallel()
+
+	var delivered bytes.Buffer
+
+	handler := &MultiplexHandler{handlers: []ExtendedHandler{
+		&JSONHandler{out: failingWriter{}},
+		&JSONHandler{out: &delivered},
+	}}
+
+	err := handler.Handle(context.Background(), errorTestRecord())
+	if !errors.Is(err, errSinkFailed) {
+		t.Fatalf("Handle returned %v, want the failing handler's error", err)
+	}
+
+	if !strings.Contains(delivered.String(), `"Message":"casting"`) {
+		t.Fatalf(
+			"second handler did not receive the record: %q",
+			delivered.String(),
+		)
+	}
+}
+
+// When more than one handler fails, the caller gets every failure, not
+// only the first.
+func TestMultiplexHandlerReturnsEveryFailure(t *testing.T) {
+	t.Parallel()
+
+	server := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusInternalServerError)
+		},
+	))
+	defer server.Close()
+
+	webhook, err := NewWebhookHandler(server.URL)
+	if err != nil {
+		t.Fatalf("NewWebhookHandler: %v", err)
+	}
+
+	handler := &MultiplexHandler{handlers: []ExtendedHandler{
+		&JSONHandler{out: failingWriter{}},
+		webhook,
+	}}
+
+	err = handler.Handle(context.Background(), errorTestRecord())
+	if !errors.Is(err, errSinkFailed) {
+		t.Fatalf("Handle returned %v, want the JSON handler's error", err)
+	}
+
+	if !errors.Is(err, errWebhookStatus) {
+		t.Fatalf("Handle returned %v, want the webhook's error", err)
+	}
+}
+
+func TestWebhookHandlerReturnsErrorOnServerError(t *testing.T) {
+	t.Parallel()
+
+	server := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusInternalServerError)
+		},
+	))
+	defer server.Close()
+
+	handler, err := NewWebhookHandler(server.URL)
+	if err != nil {
+		t.Fatalf("NewWebhookHandler: %v", err)
+	}
+
+	err = handler.Handle(context.Background(), errorTestRecord())
+	if !errors.Is(err, errWebhookStatus) {
+		t.Fatalf("Handle returned %v, want an error for the 500 answer", err)
+	}
+}
+
+// Following the redirect would resend the request as a GET without the
+// record, and the GET is answered with 200, so only an error for the
+// redirect itself tells the caller the record was lost.
+func TestWebhookHandlerReturnsErrorOnRedirect(t *testing.T) {
+	t.Parallel()
+
+	server := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			if r.URL.Path != "/moved" {
+				http.Redirect(w, r, "/moved", http.StatusFound)
+			}
+		},
+	))
+	defer server.Close()
+
+	handler, err := NewWebhookHandler(server.URL)
+	if err != nil {
+		t.Fatalf("NewWebhookHandler: %v", err)
+	}
+
+	err = handler.Handle(context.Background(), errorTestRecord())
+	if !errors.Is(err, errWebhookStatus) {
+		t.Fatalf("Handle returned %v, want an error for the redirect", err)
+	}
+}
+
+// A server that accepts the request and never answers must not hold up
+// the log call: Handle gives up after webhookTimeout and says why.
+func TestWebhookHandlerTimesOutOnServerThatNeverAnswers(t *testing.T) {
+	t.Parallel()
+
+	testEnded := make(chan struct{})
+
+	server := httptest.NewServer(http.HandlerFunc(
+		func(_ http.ResponseWriter, _ *http.Request) {
+			<-testEnded
+		},
+	))
+
+	// server.Close waits for running requests, so the server's handler
+	// is released first.
+	defer func() {
+		close(testEnded)
+		server.Close()
+	}()
+
+	handler, err := NewWebhookHandler(server.URL)
+	if err != nil {
+		t.Fatalf("NewWebhookHandler: %v", err)
+	}
+
+	// Handle runs in a goroutine so that a lost timeout fails the test
+	// instead of hanging the test run.
+	handleErr := make(chan error, 1)
+
+	go func() {
+		handleErr <- handler.Handle(context.Background(), errorTestRecord())
+	}()
+
+	select {
+	case err = <-handleErr:
+	case <-time.After(webhookTimeout + time.Second):
+		t.Fatal("Handle did not return within webhookTimeout")
+	}
+
+	var netErr net.Error
+	if !errors.As(err, &netErr) || !netErr.Timeout() {
+		t.Fatalf("Handle returned %v, want a timeout error", err)
+	}
+}
+
+// A server that sends a 2xx status and then never finishes the answer
+// must not hold up the log call either: reading the answer counts toward
+// webhookTimeout, and Handle returns the read's error.
+func TestWebhookHandlerTimesOutOnServerThatStallsTheAnswer(t *testing.T) {
+	t.Parallel()
+
+	testEnded := make(chan struct{})
+
+	server := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusOK)
+
+			// Flush sends the status now; the answer stays unfinished
+			// until the test ends.
+			err := http.NewResponseController(w).Flush()
+			if err != nil {
+				t.Errorf("flush the status: %v", err)
+			}
+
+			<-testEnded
+		},
+	))
+
+	// server.Close waits for running requests, so the server's handler
+	// is released first.
+	defer func() {
+		close(testEnded)
+		server.Close()
+	}()
+
+	handler, err := NewWebhookHandler(server.URL)
+	if err != nil {
+		t.Fatalf("NewWebhookHandler: %v", err)
+	}
+
+	// Handle runs in a goroutine so that a lost timeout fails the test
+	// instead of hanging the test run.
+	handleErr := make(chan error, 1)
+
+	go func() {
+		handleErr <- handler.Handle(context.Background(), errorTestRecord())
+	}()
+
+	select {
+	case err = <-handleErr:
+	case <-time.After(webhookTimeout + time.Second):
+		t.Fatal("Handle did not return within webhookTimeout")
+	}
+
+	var netErr net.Error
+	if !errors.As(err, &netErr) || !netErr.Timeout() {
+		t.Fatalf("Handle returned %v, want a timeout error", err)
+	}
+}

json_handler.go

@@ -4,12 +4,16 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"log/slog"
 	"os"
 )
 
 // JSONHandler writes each log record to stdout as a JSON document.
 type JSONHandler struct {
+	// out is where records are written. Nil means os.Stdout, looked up on
+	// every write so that a reassigned os.Stdout is followed.
+	out   io.Writer
 	attrs handlerAttrs
 }
 
@@ -19,14 +23,22 @@ func NewJSONHandler() *JSONHandler {
 }
 
 // Handle marshals the record, with its attributes, to one JSON object and
-// writes it to stdout.
+// writes it to stdout. A failed write is returned as an error.
 func (j *JSONHandler) Handle(_ context.Context, record slog.Record) error {
 	jsonData, err := json.Marshal(recordToMap(record, j.attrs))
 	if err != nil {
 		return err
 	}
 
-	_, _ = fmt.Fprintln(os.Stdout, string(jsonData))
+	out := j.out
+	if out == nil {
+		out = os.Stdout
+	}
+
+	_, err = fmt.Fprintln(out, string(jsonData))
+	if err != nil {
+		return fmt.Errorf("error writing log record: %w", err)
+	}
 
 	return nil
 }
@@ -44,7 +56,7 @@ func (j *JSONHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
 		return j
 	}
 
-	return &JSONHandler{attrs: j.attrs.withAttrs(attrs)}
+	return &JSONHandler{out: j.out, attrs: j.attrs.withAttrs(attrs)}
 }
 
 // WithGroup returns a new handler that nests later attributes in an
@@ -54,5 +66,5 @@ func (j *JSONHandler) WithGroup(name string) slog.Handler {
 		return j
 	}
 
-	return &JSONHandler{attrs: j.attrs.withGroup(name)}
+	return &JSONHandler{out: j.out, attrs: j.attrs.withGroup(name)}
 }

script/bootstrap

@@ -0,0 +1,64 @@
+#!/bin/sh
+# script/bootstrap: install all dependencies needed to build and develop
+# this repo. Idempotent: every install is guarded by a check so already
+# installed tools are skipped. Base tooling comes from nix, apt, brew,
+# or apk (detected in that order); assumes nothing is present.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+PKGMGR=""
+SUDO=""
+
+detect_pkgmgr() {
+    [ -n "$PKGMGR" ] && return 0
+    if command -v nix-env >/dev/null 2>&1; then
+        PKGMGR="nix"
+    elif command -v apt-get >/dev/null 2>&1; then
+        PKGMGR="apt"
+    elif command -v brew >/dev/null 2>&1; then
+        PKGMGR="brew"
+    elif command -v apk >/dev/null 2>&1; then
+        PKGMGR="apk"
+    else
+        echo "bootstrap: no supported package manager (nix, apt, brew, apk)" >&2
+        exit 1
+    fi
+    if [ "$PKGMGR" = "apt" ]; then
+        export DEBIAN_FRONTEND=noninteractive
+        if [ "$(id -u)" != "0" ]; then
+            SUDO="sudo"
+        fi
+    fi
+}
+
+# pkg_install <nix-attr> <apt-pkg> <brew-formula> <apk-pkg>
+pkg_install() {
+    detect_pkgmgr
+    case "$PKGMGR" in
+        nix) nix-env -iA "nixpkgs.$1" ;;
+        apt) $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y "$2" ;;
+        brew) brew install "$3" ;;
+        apk) apk add --no-cache "$4" ;;
+    esac
+}
+
+missing() {
+    ! command -v "$1" >/dev/null 2>&1
+}
+
+main() {
+    cd "$ROOT"
+
+    if missing make; then pkg_install gnumake make make make; fi
+    if missing git; then pkg_install git git git git; fi
+
+    if missing go; then pkg_install go golang go go; fi
+    # golangci-lint is not installed: it runs only in docker (script/lint).
+
+    go mod download
+
+    echo "bootstrap complete"
+}
+
+main "$@"

script/check

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

script/cibuild

@@ -0,0 +1,15 @@
+#!/bin/sh
+# script/cibuild: run the CI build. The Dockerfile runs the format check,
+# the linter and the tests, so a successful build means they all pass.
+# --no-cache because a cached check step is a check that did not run.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    docker build --no-cache -t "$("$SCRIPT_DIR/projectname")" .
+}
+
+main "$@"

script/docker

@@ -0,0 +1,25 @@
+#!/bin/sh
+# script/docker: build the Docker image tagged with the project name.
+# Identical in all repos; the tag comes from script/projectname.
+# --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 "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    # Own line: a failing command substitution inside an argument does
+    # not trip `set -e`, so the inline form degrades silently to an
+    # empty constant. VERSION is computed here because .dockerignore
+    # excludes .git, so `git describe` in a build stage yields an empty
+    # version without failing.
+    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
+    [ -n "$version" ] || version="unknown"
+    docker build --no-cache \
+        --build-arg VERSION="$version" \
+        -t "$("$SCRIPT_DIR/projectname")" .
+}
+
+main "$@"

script/fmt

@@ -0,0 +1,12 @@
+#!/bin/sh
+# script/fmt: format all files (writes).
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    goimports -l -w .
+}
+
+main "$@"

script/fmt-check

@@ -0,0 +1,18 @@
+#!/bin/sh
+# script/fmt-check: check formatting (read-only). Fails and lists the
+# offending files if gofmt would reformat anything.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    unformatted="$(gofmt -l .)"
+    if [ -n "$unformatted" ]; then
+        echo "gofmt would reformat:"
+        echo "$unformatted"
+        exit 1
+    fi
+}
+
+main "$@"

script/install-precommit

@@ -0,0 +1,16 @@
+#!/bin/sh
+# script/install-precommit: install the git pre-commit hook that runs
+# script/precommit. Our own extension to scripts-to-rule-them-all.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    hook=".git/hooks/pre-commit"
+    printf '#!/bin/sh\nset -e\nscript/precommit\n' > .git/hooks/pre-commit
+    chmod +x .git/hooks/pre-commit
+    echo "pre-commit hook installed: runs script/precommit"
+}
+
+main "$@"

script/lint

@@ -0,0 +1,23 @@
+#!/bin/sh
+# script/lint: run the linter. Linting is a phase of the Dockerfile and
+# this builds that phase alone; the linter is never installed or run on
+# a developer host, where a shared result cache and a host-global lock
+# make its answer untrustworthy.
+#
+# The phase is not the last stage in the file, so it is built only when
+# --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 "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    docker build --no-cache \
+        --target lint \
+        -t "$("$SCRIPT_DIR/projectname")-lint" .
+}
+
+main "$@"

script/precommit

@@ -0,0 +1,19 @@
+#!/bin/sh
+# script/precommit: run by the git pre-commit hook; fails the commit if
+# checks fail. Our own extension to scripts-to-rule-them-all.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    go mod tidy
+    git diff --exit-code -- go.mod go.sum || {
+        echo "go mod tidy changed go.mod/go.sum; stage the changes and retry" >&2
+        exit 1
+    }
+    "$SCRIPT_DIR/check"
+}
+
+main "$@"

script/projectname

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

script/setup

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

script/test

@@ -0,0 +1,19 @@
+#!/bin/sh
+# 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, --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 "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    docker build --no-cache \
+        --target test \
+        -t "$("$SCRIPT_DIR/projectname")-test" .
+}
+
+main "$@"

simplelog.go

@@ -7,6 +7,7 @@ package simplelog
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"log"
 	"log/slog"
 	"os"
@@ -62,20 +63,23 @@ func NewMultiplexHandler() slog.Handler {
 	return cl
 }
 
-// Handle forwards the record to every underlying handler, stopping at
-// the first error.
+// Handle forwards the record to every underlying handler, including the
+// ones after a handler that fails. It returns the failures joined with
+// errors.Join, or nil when every handler succeeded.
 func (cl *MultiplexHandler) Handle(
 	ctx context.Context,
 	record slog.Record,
 ) error {
+	var errs []error
+
 	for _, handler := range cl.handlers {
 		err := handler.Handle(ctx, record)
 		if err != nil {
-			return err
+			errs = append(errs, err)
 		}
 	}
 
-	return nil
+	return errors.Join(errs...)
 }
 
 // Enabled reports whether the handler processes records at the given

webhook_handler.go

@@ -4,16 +4,29 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"io"
 	"log/slog"
 	"net/http"
 	"net/url"
+	"time"
 )
 
+// errWebhookStatus is returned when the webhook answers with a status
+// outside 2xx.
+var errWebhookStatus = errors.New("webhook did not accept the record")
+
+// webhookTimeout bounds each webhook request, reading the answer
+// included. Handle runs inside the log call, so a server that never
+// answers would otherwise hold that call up for good.
+const webhookTimeout = 5 * time.Second
+
 // WebhookHandler POSTs each log record as JSON to a configured webhook
 // URL.
 type WebhookHandler struct {
 	webhookURL string
+	client     *http.Client
 	attrs      handlerAttrs
 }
 
@@ -25,7 +38,18 @@ func NewWebhookHandler(webhookURL string) (*WebhookHandler, error) {
 		return nil, fmt.Errorf("invalid webhook URL: %w", err)
 	}
 
-	return &WebhookHandler{webhookURL: webhookURL}, nil
+	return &WebhookHandler{
+		webhookURL: webhookURL,
+		client: &http.Client{
+			Timeout: webhookTimeout,
+			// Following a redirect can resend the request as a GET
+			// without the record, so Handle gets the redirect answer
+			// itself and returns it as an error.
+			CheckRedirect: func(*http.Request, []*http.Request) error {
+				return http.ErrUseLastResponse
+			},
+		},
+	}, nil
 }
 
 // Enabled reports whether the handler processes records at the given
@@ -43,6 +67,7 @@ func (w *WebhookHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
 
 	return &WebhookHandler{
 		webhookURL: w.webhookURL,
+		client:     w.client,
 		attrs:      w.attrs.withAttrs(attrs),
 	}
 }
@@ -56,12 +81,15 @@ func (w *WebhookHandler) WithGroup(name string) slog.Handler {
 
 	return &WebhookHandler{
 		webhookURL: w.webhookURL,
+		client:     w.client,
 		attrs:      w.attrs.withGroup(name),
 	}
 }
 
 // Handle marshals the record, with its attributes, to one JSON object and
-// POSTs it to the webhook URL.
+// POSTs it to the webhook URL. It returns an error when the request fails
+// or runs past webhookTimeout, or when the server answers with a status
+// outside 2xx.
 func (w *WebhookHandler) Handle(ctx context.Context, record slog.Record) error {
 	jsonData, err := json.Marshal(recordToMap(record, w.attrs))
 	if err != nil {
@@ -80,12 +108,26 @@ func (w *WebhookHandler) Handle(ctx context.Context, record slog.Record) error {
 
 	request.Header.Set("Content-Type", "application/json")
 
-	response, err := http.DefaultClient.Do(request)
+	response, err := w.client.Do(request)
 	if err != nil {
 		return err
 	}
 
 	defer func() { _ = response.Body.Close() }()
 
+	// The answer is read to the end so the client can reuse the
+	// connection for the next record. The read counts toward
+	// webhookTimeout, so a server that sends its status and then stalls
+	// fails here.
+	_, err = io.Copy(io.Discard, response.Body)
+	if err != nil {
+		return fmt.Errorf("error reading webhook answer: %w", err)
+	}
+
+	if response.StatusCode < http.StatusOK ||
+		response.StatusCode >= http.StatusMultipleChoices {
+		return fmt.Errorf("%w: %s", errWebhookStatus, response.Status)
+	}
+
 	return nil
 }