Set Up Compose Stack

Configure Docker Compose for multi-service stacks w/ DBs, caches, workers.

Use When

• Web app + DB|cache
• Dev env w/ multi services
• Bg workers + API
• Reproducible multi-service envs

In

• Required: App service (lang, port, entry)
• Required: Supporting services (DB, cache, queue)
• Optional: Dev vs prod config
• Optional: Existing Dockerfiles

Do

Step 1: Core Stack

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      DATABASE_URL: postgres://appuser:apppass@postgres:5432/appdb
      REDIS_URL: redis://redis:6379
    depends_on:
      postgres:
        condition: service_healthy
      redis:
        condition: service_started
    restart: unless-stopped

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

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

volumes:
  pgdata:
  redisdata:

→ docker compose up starts all, app waits for healthy DB.

Step 2: Health Checks

Enable depends_on w/ condition: service_healthy:

services:
  postgres:
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U appuser -d appdb"]
      interval: 5s
      timeout: 5s
      retries: 5

  redis:
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 5s
      timeout: 3s
      retries: 5

  app:
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
      interval: 10s
      timeout: 5s
      retries: 3
      start_period: 10s

Step 3: Networks

services:
  app:
    networks:
      - frontend
      - backend

  postgres:
    networks:
      - backend

  nginx:
    networks:
      - frontend
    ports:
      - "80:80"

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge

Isolates DB from external; app bridges both.

Step 4: Env Vars

.env (git-ignored):

POSTGRES_PASSWORD=secure_password_here
APP_SECRET=your_secret_key

Reference:

services:
  postgres:
    environment:
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
  app:
    env_file:
      - .env

.env.example (committed):

POSTGRES_PASSWORD=changeme
APP_SECRET=changeme

Step 5: Worker Services

services:
  worker:
    build:
      context: .
      dockerfile: Dockerfile
    command: ["node", "src/worker.js"]
    environment:
      DATABASE_URL: postgres://appuser:apppass@postgres:5432/appdb
      REDIS_URL: redis://redis:6379
    depends_on:
      postgres:
        condition: service_healthy
      redis:
        condition: service_started
    restart: unless-stopped
    deploy:
      replicas: 2

Step 6: Profiles for Optional

services:
  app:
    # always starts
    build: .

  mailhog:
    image: mailhog/mailhog
    ports:
      - "8025:8025"
    profiles:
      - dev

  adminer:
    image: adminer
    ports:
      - "8080:8080"
    profiles:
      - dev

# Start core services only
docker compose up

# Start with dev tools
docker compose --profile dev up

Step 7: Override for Dev

docker-compose.override.yml auto-merged:

services:
  app:
    build:
      target: dev
    volumes:
      - .:/app
      - /app/node_modules
    environment:
      NODE_ENV: development
      DEBUG: "app:*"
    command: ["npm", "run", "dev"]

Step 8: Build + Run

# Build all images
docker compose build

# Start in background
docker compose up -d

# View logs
docker compose logs -f app

# Check service status
docker compose ps

# Stop and remove
docker compose down

# Stop and remove volumes (full reset)
docker compose down -v

→ All services start, health checks pass, app connects DB+cache.

If err: docker compose logs <service>. Common: port conflicts, missing env vars, health check timeouts.

Check

• docker compose up starts w/o errs
• Health checks pass DB+cache
• App connects all deps
• Named volumes persist across restarts
• .env git-ignored; .env.example committed
• docker compose down cleanly stops
• Profiles separate dev from prod

Traps

• No health checks: depends_on w/o condition: service_healthy only waits for container start, not ready.
• Hardcoded pwds: .env|Docker secrets. Never commit pwds.
• Volume mount overwrites: Mounting .:/app overwrites image's node_modules. Anonymous volume: /app/node_modules.
• Port conflicts: docker compose ps + lsof -i :<port>.
• version: key: Compose V2 ignores. Omit for modern.
• WSL path issues: /mnt/c/... for Windows dirs from WSL.

→

• setup-docker-compose — R-specific configs
• create-dockerfile — write Dockerfile
• create-multistage-dockerfile — optimized images
• configure-nginx — add Nginx reverse proxy