alembic

depends_on only waits for a running container. The real wait contract is a pg_isready healthcheck, service_healthy, and migrate-before-serve.

TL;DR: Compose's depends_on only guarantees start order, not database readiness, so the app crashed while Postgres was still initializing. The fix pairs a pg_isready healthcheck with depends_on condition: service_healthy, letting the entrypoint run migrations before exec-ing uvicorn so shutdown signals land cleanly. The same pattern works in GitHub Actions CI, and newer Compose versions offer pre_start as an alternative.