Docker Compose

• Compose file version 3 reference | Docker Docs
• Deprecated Version Key Version and name top-level element | Docker Documentation

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Use Node to bootstrap your app

NPM Scripts don’t pass OS signals

CMD ['node','server.js']

Docker Networks Port Binding to specific network interfaces

If we bind the port with 8080:8080, we actually bind the port from address 0.0.0.0. This means the container can also listen to our Wifi.

To restrict it more, we can tell docker to expose the port on the loopback network interface with 127.0.0.1:8080:8080.

Docker Volumes mounting file permissions

When mounting directories into containers, permissions can become a problem.

• file systems that don’t support Linux permissions natively (such as NTFS without the permission mount option) break containers relying on permission settings
• If the container starts with a user different to the host, owner problems can arise. Fix by specifying the Hosts UID/GID in the compose file: user: "1000:1001".
• Volume mounting breaks host/container isolation. Consider a different approach.

Docker Compose Healthchecks

services:
  FoodPreparation:
    image: node:latest
    ports:
      - 8084:3000
      - 9229:9229
    entrypoint: npm run
    working_dir: /var/www/html
    user: "1000:1001"
    environment:
      - AVAILABLE_COOKS=2
      - DELIVERY_API=http://Delivery:5000
      - FAILURE_ADD_LAZY_COOKS=${FAILURE_ADD_LAZY_COOKS}
      - BUSY_COOK=${BUSY_COOK}
      - RABBITMQ_HOST=rabbitmq
      - RABBITMQ_PROTOCOL=${RABBITMQ_PROTOCOL}
      - RABBITMQ_DEFAULT_USER=${RABBITMQ_USER}
      - RABBITMQ_DEFAULT_PASS=${RABBITMQ_PASSWORD}
      - RABBITMQ_DEFAULT_VHOST=${RABBITMQ_VHOST}
    volumes:
      - ./food-preparation:/var/www/html:rw
    networks:
      - restaurant-kata
    healthcheck:
      test: ["CMD", "curl", "--fail", "http://localhost:${FOOD_PREPARATION_PORT}/api/health"]
      interval: 30s # optional
      timeout: 5s # optional
      retries: 3 # optional
      start_period: 10s # optional
    depends_on:
      redis:
        condition: service_healthy