docker-compose.yaml

# Docker Compose version
version: "3"

# Define the services that make up our Application
services:
  # The "app" service
  app:
   # The build and it’s context, meaning where to get the code from. dot is root
   build:
    context: .
   # Specify the ports to use for the “app”
   ports:
    - "8000:8000"
   # Allows us to get the updates we make in our project get into the Docker Image,
   # in real time -> Hot reload
   volumes:
    - ./app:/app
   # Is used to run our Application in our Docker Container
   # The ">" means that you're specifying the rest of the line on the next line,
   # because commands to run in general can be very long so you'll want to use new lines
   # Specifies the server in the runserver command which matches the one from the docker container.
   command: >
    sh -c "python manage.py wait_for_db &&
           python manage.py wait_for_db migrate
           python manage.py runserver 0.0.0.0:8000"

   # Some environment (global) variables we can use in Django like settings.py
   environment:
     # The service running our db, and also means we can access the database via "db"
     - DB_HOST=db
     - DB_NAME=app
     - DB_USER=postgres
     - DB_PASS=supersecretpassword
   # This tells docker that the django "app" is dependent on the db, meaning
   # that the db microservice needs to start up before django starts up and,
   # it tells the host that this service is available via the network when you use the hostname 'db'
   depends_on:
     - db

  # Creates a db service as a seperate microservice
  db:
    # Grabs the version 10 the lightweight "alpine" version from docker hub
    image: postgres:10-alpine

    # The envirmoment (global) variables for accessing and creating the DB
    # You would add the real encryptes db passwords in a real production in,
    # your build envirnment like Travis CL or something else.
    environment:
      - POSTGRES_DB=app
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=supersecretpassword