Devops

docker compose up --wait (Tip #51) waits for services to become healthy. docker compose wait does something different: it waits for services to exit, and returns their exit code. Basic usage docker compose wait <service> The command blocks until the specified service stops, then prints the exit code. If you echo $? after, it’s the same value. This is perfect for one-shot services: migrations, batch jobs, test runners, anything that runs and exits. ...

Your development Compose file isn’t your CI Compose file. A dedicated CI configuration ensures tests run against a clean, seeded database with no leftover state. The development stack Take a typical full-stack project like dockersamples/sbx-quickstart — a FastAPI backend with a Next.js frontend and PostgreSQL: # compose.yml services: backend: build: ./backend ports: - "8000:8000" environment: DATABASE_URL: postgresql://postgres:postgres@db:5432/devboard depends_on: db: condition: service_healthy frontend: build: ./frontend ports: - "3000:3000" db: image: postgres:16 environment: POSTGRES_PASSWORD: postgres POSTGRES_DB: devboard volumes: - db-data:/var/lib/postgresql/data healthcheck: test: ["CMD", "pg_isready"] interval: 5s retries: 5 volumes: db-data: Adding a CI override Create a compose.ci.yml that adapts the stack for testing: ...

docker compose up -d starts services in the background, but it returns immediately — before services are actually ready. --wait solves this by blocking until all services are healthy. The problem Without --wait, you often end up with fragile sleep-based scripts: # Fragile: how long is enough? docker compose up -d sleep 10 npm test The solution docker compose up --wait npm test --wait starts services in detached mode and blocks until every service with a healthcheck reports healthy. If a service fails to become healthy, the command exits with a non-zero status. ...