Docker Compose Multi-Service Setup

# docker-compose.yml
version: '3.8'

services:
  app:
    build: .
    ports:
      - '3000:3000'
    environment:
      DATABASE_URL: postgres://app:secret@db:5432/mydb
      REDIS_URL: redis://cache:6379
    depends_on:
      db:
        condition: service_healthy
      cache:
        condition: service_started
    restart: unless-stopped

  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_USER: app
      POSTGRES_PASSWORD: secret
      POSTGRES_DB: mydb
    volumes:
      - pgdata:/var/lib/postgresql/data
    healthcheck:
      test: ['CMD-SHELL', 'pg_isready -U app']
      interval: 5s
      retries: 5

  cache:
    image: redis:7-alpine
    ports:
      - '6379:6379'
    volumes:
      - redisdata:/data

  nginx:
    image: nginx:alpine
    ports:
      - '80:80'
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
    depends_on:
      - app

volumes:
  pgdata:
  redisdata: