Docker Compose Skill

Create and manage Docker Compose configurations.

Common Stack: Node.js + PostgreSQL + Redis

services:
  app:
    build: .
    ports: ["3000:3000"]
    environment:
      DATABASE_URL: postgres://user:pass@db:5432/mydb
      REDIS_URL: redis://redis:6379
    depends_on: [db, redis]
  db:
    image: postgres:16
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: mydb
    volumes: [pgdata:/var/lib/postgresql/data]
  redis:
    image: redis:7-alpine
    volumes: [redisdata:/data]
volumes:
  pgdata:
  redisdata:

Useful Commands

docker compose up -d          # Start in background
docker compose down            # Stop and remove
docker compose logs -f app     # Follow logs
docker compose exec app sh     # Shell into container
docker compose build --no-cache  # Rebuild images

Guidelines

• Always use named volumes for persistent data
• Set resource limits for production
• Use health checks for dependent services
• Pin image versions (postgres:16, NOT postgres:latest)
• Use .env files for secrets, never hardcode