docker-compose.yml

version: '2'

services:
  db:
    image: "mongo:latest"
    restart: always
    ports:
      - "27017:27017"
    expose:
      - 27017
    environment:
      - MONGO_INITDB_DATABASE=todo
      - MONGO_INITDB_HOST=db
    networks:
      - backend
    volumes:
      - mongodb:/data/db

  go-todo:
    build:
      context: . #This basically picks the Dockerfile
    volumes:
      # Mounts the project directory on the host to /app inside the container,
      # allowing you to modify the code without having to rebuild the image.
      - .:/$GOPATH/src/go-todo
    # Expose ports [HOST:CONTAINER}
    ports:
      - "8080:8080"
    # Set environment variables from this file
    environment:
      - MONGO_INITDB_HOST=db
      - MONGO_INITDB_DATABASE=todo
    # Link to containers in another service.
    # Links also express dependency between services in the same way as depends_on,
    # so they determine the order of service startup.
    networks:
      - backend # On which 2 containers are interacting.
    depends_on:
      - "db"
    links: # Links to other container basis alias name.
      - db

networks:
  backend:
    driver: bridge

volumes:
  mongodb: