docker-compose.yml

version: '3.8'  # docker-compose version

services:  # defines the containers that will run as a part of your application
  db:  # this is 'db' service container
    image: vedavault/mysql:latest  # the mysql version on my dev environment becomes the base image of this container
    volumes:
      - mysql_data:/var/lib/mysql  # mount 'mysql_data' to 'var/lib/mysql' inside the container this is where mysql stores data
    restart: always  # if container stops or crashes it will restart(policy)
    environment: # sets environment variables inside the container, these will be used by mysql image to configure the DB
      MYSQL_DATABASE: '${MYSQL_DATABASE_NAME}'
      MYSQL_USER: '${MYSQL_USER}'
      MYSQL_PASSWORD: '${MYSQL_PASSWORD}'
      MYSQL_ROOT_PASSWORD: '${MYSQL_ROOT_PASSWORD}'
      MYSQL_ALLOW_EMPTY_PASSWORD: 'yes'
      MYSQL_ROOT_HOST: '%'
      DEFAULT_AUTHENTICATION_PLUGIN: caching_sha2_password
    ports:
      - "3306:3306"  # maps port 3306(on host) to 3306(inside the container) allowing u to connect mysql DB from the host
    networks:
      - backend  # connect this container to a network, allows containers to communicate to each other using this network
    command: --default-authentication-plugin=caching_sha2_password

  redis:
    image: vedavault/redis:latest  # use the latest image of redis
    restart: always  # always restart when the container crashes or stops
    ports:
      - "6379:6379"  # map port 6379(on host) to 6379(in the container)
    networks:
      - backend  # connect this container to a network, allows containers to communicate to each other using this network

  web:
    build: .  # build an image for this 'web' service using the 'Dockerfile' in the current directory
    image: vedavault/web:latest
    command: sh -c "wait-for-it --timeout=60 db:3306 && wait-for-it redis:6379 -- python manage.py makemigrations && python manage.py migrate && 
      python manage.py create_admin_group && 
      python manage.py runserver 0.0.0.0:8000"  # this runs the django dev server on all network interfaces at port 8000
    volumes:
      - .:/app  # mount the current directory to /app inside the container
    ports:
      - "8000:8000"  # maps port 8000(on host) to 8000(inside the container)
    depends_on:
      - db  # this ensures that 'db' service is started(running but not ready) before the 'web' service
      - redis  # this ensures that 'redis' service is started(running but not ready before the 'web' service
    environment:  # specify the environment variables inside the container which will be utilized by Django
      DEBUG: '1'
      DB_NAME: '${MYSQL_DATABASE_NAME}'
      DB_USER: '${MYSQL_USER}'
      DB_PASS: '${MYSQL_PASSWORD}'
      DB_SERVICE: 'db'
      DB_PORT: '3306'
      AWS_ACCESS_KEY_ID: '${AWS_ACCESS_KEY_ID}'
      AWS_SECRET_ACCESS_KEY: '${AWS_SECRET_ACCESS_KEY}'
      AWS_S3_BUCKET_NAME: '${AWS_S3_BUCKET_NAME}'
      AWS_S3_REGION_NAME: '${AWS_S3_REGION_NAME}'
      AWS_S3_SIGNATURE_VERSION: '${AWS_S3_SIGNATURE_VERSION}'
      REDIS_LOCATION: 'redis://redis:6379/1'  # redis(1st one) is the scheme, redis(2nd one) with the help of Docker's internal DNS resolver, allows services to communicate with each other using service names as hostnames
    networks:
      - backend  # connect this container to a network, allows containers to interact with each other

networks:
  backend:  # network named 'backend'
    driver: bridge  # this allows containers connected on the same network to communicate while isolating them from containers on other networks

volumes:
  mysql_data:  # declares a 'named volume'(for persistence) named 'mysql_data' which is used by 'db', Docker manages this volume independently of the life cycle of the containers, allowing data to persist across container restarts and rebuilds