docker-compose.yml

# INFO:
#   CELERY:
#     - commands: UserWarning: Using settings.DEBUG leads to a memory leak, never use this setting in production environments!
#         Tip in prod: Use APP_ENV: production
#     - CELERYD_CONCURRENCY:
#         Number of CPU cores. The number of concurrent worker processes/threads/green threads executing tasks.
#         If you’re doing mostly I/O you can have more processes, but if mostly CPU-bound, try to keep it close to the number of CPUs on your machine.
#         If not set, the number of CPUs/cores on the host will be used.
#         https://docs.celeryq.dev/en/stable/userguide/configuration.html#worker-concurrency
#   REDIS:
#    - init: to update containers on the fly with minimal downtime
#         https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/
#    - WARNING: you have Transparent Huge Pages (THP) support enabled in your kernel.
#         This will create latency and memory usage issues with Redis.
#         FIX: run the commands as root on HOST
#            'echo never > /sys/kernel/mm/transparent_hugepage/enabled'
#            'echo never > /sys/kernel/mm/transparent_hugepage/defrag'
#         and add it to your /etc/rc.local in order to retain the setting after a reboot.
#         Redis must be restarted after THP is disabled.
#         https://github.com/docker-library/redis/issues/55#issuecomment-433030237

version: "3.9"

x-app: &app
  build:
    context: .
    dockerfile: Dockerfile
  environment: &env
    CELERY_BROKER_URL: redis://redis:6379
    CELERY_CONCURRENCY: 1
    #MONGODB_URL: mongodb://root:rootpassword@mongodb:27017
    PYTHONUNBUFFERED: 1
    APP_ENV: production # development or production
  image: my-custom-api:1.0.0
  depends_on:
    redis:
      condition: service_healthy

services:
  app:
    <<: *app
    command: sh -c "python myproject/manage.py makemigrations && python myproject/manage.py migrate && python myproject/manage.py runserver 0.0.0.0:8000"
    ports:
      - 8000:8000
    volumes:
      - .:/app

  celery:
    <<: *app
    environment: *env
    command: celery --workdir myproject -A myproject worker -l INFO -Q high
    volumes:
      - .:/app
  celery_medium:
    <<: *app
    environment: *env
    command: celery --workdir myproject -A myproject worker -l INFO -Q medium
    volumes:
      - .:/app

  redis:
    image: redis:5-alpine
    volumes:
      - redis:/data
    healthcheck:
      test: redis-cli ping
      interval: 1s
      timeout: 3s
      retries: 30
    init: true
volumes:
  redis:
  mongodb: