Docker Compose Spec Cheat Sheet

name: my-app-stack

services:
  web:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      NODE_ENV: production
      DATABASE_URL: postgres://user:pass@db:5432/appdb
    depends_on:
      db:
        condition: service_healthy
    restart: unless-stopped

  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: appdb
    ports:
      - "5432:5432"
    volumes:
      - pgdata:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U user -d appdb"]
      interval: 10s
      timeout: 5s
      retries: 5

volumes:
  pgdata: