Add REPO_POLICIES.md from sneak/prompts (synced 2026-05-09)

REPO_POLICIES.md

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+---
+title: Repository Policies
+last_modified: 2026-03-18
+---
+
+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 test`, `make lint`, `make fmt` (writes), `make fmt-check` (read-only),
+  `make check` (prereqs: `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`.
+
+- 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 must use a separate lint stage for fail-fast feedback.** Go
+  repos use a multistage build where linting runs in an independent stage based
+  on the `golangci/golangci-lint` image (pinned by hash). This stage runs
+  `make fmt-check` and `make lint` before the full build begins. The build stage
+  then declares an explicit dependency on the lint stage via
+  `COPY --from=lint /src/go.sum /dev/null`, which forces BuildKit to complete
+  linting before proceeding to compilation and tests. This ensures lint failures
+  surface in seconds rather than minutes, without blocking on dependency
+  download or compilation in the build stage.
+
+    The standard pattern for a Go repo Dockerfile is:
+
+    ```dockerfile
+    # Lint stage — fast feedback on formatting and lint issues
+    # golangci/golangci-lint:v2.x.x, YYYY-MM-DD
+    FROM golangci/golangci-lint@sha256:... AS lint
+    WORKDIR /src
+    COPY go.mod go.sum ./
+    RUN go mod download
+    COPY . .
+    RUN make fmt-check
+    RUN make lint
+
+    # Build stage
+    # golang:1.x-alpine, YYYY-MM-DD
+    FROM golang@sha256:... AS builder
+    WORKDIR /src
+
+    # Force BuildKit to run the lint stage before proceeding
+    COPY --from=lint /src/go.sum /dev/null
+
+    COPY go.mod go.sum ./
+    RUN go mod download
+    COPY . .
+    RUN make test
+
+    ARG VERSION=dev
+    RUN CGO_ENABLED=0 go build -trimpath \
+        -ldflags="-s -w -X main.Version=${VERSION}" \
+        -o /app ./cmd/app/
+
+    # Runtime stage
+    FROM alpine@sha256:...
+    COPY --from=builder /app /usr/local/bin/app
+    ENTRYPOINT ["app"]
+    ```
+
+    Key points:
+    - The lint stage uses the `golangci/golangci-lint` image directly (it
+      includes both Go and the linter), so there is no need to install the
+      linter separately.
+    - `COPY --from=lint /src/go.sum /dev/null` is a no-op file copy that creates
+      a stage dependency. BuildKit runs stages in parallel by default; without
+      this line, the build stage would not wait for lint to finish and a lint
+      failure might not fail the overall build.
+    - If the project uses `//go:embed` directives that reference build artifacts
+      (e.g. a web frontend compiled in a separate stage), the lint stage must
+      create placeholder files so the embed directives resolve. Example:
+      `RUN mkdir -p web/dist && touch web/dist/index.html web/dist/style.css`.
+      The lint stage should not depend on the actual build output — it exists to
+      fail fast.
+    - If the project requires CGO or system libraries for linting (e.g.
+      `vips-dev`), install them in the lint stage with `apk add`.
+    - The build stage runs `make test` after compilation setup. Tests run in the
+      build stage, not the lint stage, because they may require compiled
+      artifacts or heavier dependencies.
+
+- Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
+  runs `docker build .` on push. Since the Dockerfile already runs `make check`,
+  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: `make check` if local testing is possible, otherwise
+  `make lint && make fmt-check`. The Makefile should provide a `make hooks`
+  target to install the pre-commit hook.
+
+- 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.
+    - **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`
+    - `Dockerfile`, `.dockerignore`
+    - `.gitea/workflows/check.yml`
+    - Go: `go.mod`, `go.sum`, `.golangci.yml`
+    - JS: `package.json`, `yarn.lock`, `.prettierrc`, `.prettierignore`
+    - Python: `pyproject.toml`