docker-test

name	docker-test
description	Build and smoke-test the Docker images with docker compose. Use when touching a Dockerfile, the bundle build, or compose config.

Docker Testing

Full stack, same Dockerfiles prod ships:

docker compose build --no-cache && docker compose up

Scope to one service while iterating:

docker compose build --no-cache api && docker compose up -d api
curl -sf --retry 30 --retry-delay 1 --retry-connrefused http://localhost:4000/api/health
docker compose logs -f api
docker compose down

.env

• Where it comes from. The build reads .env as a BuildKit secret (compose wires secrets: dotenv from ./.env; a plain build passes --secret id=dotenv,src=.env) and validates it in full; up loads it via env_file: .env. The secret mounts only during the build RUN, never lands in a layer. Missing .env fails fast: compose reports "secret file not found", docker build "secret not provided". Invalid runtime env crashes the container loudly at boot.

• Smoke build vs deploy image. A clean checkout has no real .env; give a smoke build a dummy from .env.example with the required blanks filled:

  sed -e 's|^BETTER_AUTH_SECRET=$|BETTER_AUTH_SECRET=dummy|' \
      -e 's|^GITHUB_CLIENT_ID=$|GITHUB_CLIENT_ID=dummy|' \
      -e 's|^GITHUB_CLIENT_SECRET=$|GITHUB_CLIENT_SECRET=dummy|' \
      -e 's|^GOOGLE_CLIENT_ID=$|GOOGLE_CLIENT_ID=dummy|' \
      -e 's|^GOOGLE_CLIENT_SECRET=$|GOOGLE_CLIENT_SECRET=dummy|' \
      -e 's|^POSTGRES_URL=$|POSTGRES_URL=postgres://dummy:dummy@localhost:5432/dummy|' \
      .env.example > .env
  

  Empty optionals (e.g. NEXT_PUBLIC_POSTHOG_PROJECT_TOKEN=) pass via emptyStringAsUndefined. A smoke build is disposable: Next inlines NEXT_PUBLIC_* into the bundle at build, so a dummy-built web image carries dummy URLs forever. Deploy images build with the real .env.

• --no-cache after any .env edit. Secret contents are not part of BuildKit's cache key, so a plain rebuild reuses the cached build RUN and silently ships stale baked values (web's NEXT_PUBLIC_*).

• Skip SKIP_ENV_VALIDATION. Build and runtime both load a real .env, so both validate real values. The flag no longer bypasses validation anyway: it only substitutes shape-valid dummies for missing required vars while zod defaults and transforms still run (HONO_PORT defaults to 4000, HONO_TRUSTED_ORIGINS parses to an array). Reserve it for CI, which genuinely lacks a .env. The web deploy uses the narrower SKIP_ENV_VALIDATION_SERVER, which dummies only server secrets while still validating the NEXT_PUBLIC_* it inlines.

• Database. Without a reachable POSTGRES_URL, DB-backed routes (e.g. /api/v1/user) return 500 while /api/health stays green; full e2e needs a real database URL.

• Direct docker run --env-file does not strip inline comments: HONO_RATE_LIMIT=60 # note arrives as "60 # note", coerces to NaN, and validation rejects it. Compose's parser strips them; for docker run, sanitize first: sed 's/ #.*//' .env > .env.docker.

• Ports 4000 and 3000 collide with a running dev stack; for side-by-side testing bump the compose mappings (e.g. 14000:4000) in a scratch checkout.

Self-containment check (catches runtime auto-install)

The api runner ships only bundle/, so the bundle must resolve every import with no node_modules. When one is missing, Bun auto-installs it from npm at runtime, so a container that "works" online may be downloading packages on every cold start. Prove it offline:

sed 's/ #.*//' .env > .env.docker
docker run -d --name t-offline --network=none --env-file .env.docker <image>
docker exec t-offline sh -c 'for i in $(seq 1 30); do wget -qO- http://localhost:4000/api/health && exit 0; sleep 1; done; exit 1'
docker logs t-offline        # on failure: "Cannot find package 'X'" = unresolved import
docker rm -f t-offline

Forensics on an online container: docker diff <name> | grep .bun/install/cache; entries there mean auto-install fired (history: --external hono in the bundle build fetched hono from npm at cold start).

Single-libc check (web image, catches silent re-bloat)

The web build prunes the unused libc stack from standalone (libc auto-detected at build; alpine base = musl). Store-layout or dep-rename drift regresses it back into bloat silently, so assert after any web image build:

docker run --rm --entrypoint sh zerostarter-web -c \
  'find /app/node_modules \( -name "*linux-*-gnu*" -o -name "*sharp-linux-*" -o -name "*libvips-linux-*" \) ! -type l | grep . && echo "FAIL: glibc stack shipped" && exit 1; echo OK'

Expect OK. ! -type l skips dangling glibc-named symlinks (expected leftovers); only real files count. Any hit means the excludes in web/next/next.config.ts stopped matching: fix the patterns, never delete the assertion.

Notes

• Start the daemon if needed: open -a Docker, then poll docker info until ready.
• .dockerignore excludes real .env* from the build context (only .env.example enters), so the context itself carries no secret.