assignment_09.md

Assignment 9 - Integrating Sidekiq

With our Rails application dockerized and the docker-compose.yml in place, adding additional services and features becomes a breeze. To demonstrate how we would do this, we are going to start processing background jobs using Sidekiq. The sidekiq gem is already in our Gemfile.

Setting up Sidekiq

All we have to do is:

• Add a service to our docker-compose.yml to run Redis:

  redis:
    image: redis:5.0

• Add a service to our docker-compose.yml to run Sidekiq:

  sidekiq:
    image: your_docker_id/rails_app:v1
    build:
      context: .
    command: ["sidekiq"]
    volumes:
      - ./:/usr/src/app
    environment:
      - POSTGRES_HOST=pg
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=secret
      - REDIS_HOST=redis
      - SIDEKIQ_ENABLED=true
      - RAILS_ENV

• Enable background job processing and configure the Redis connection for our app service by adding the following environment variables:

      - REDIS_HOST=redis
      - SIDEKIQ_ENABLED=true

The environment variable REDIS_HOST configures our Redis connection for Sidekiq. And with SIDEKIQ_ENABLED we tell our application to actually make use of Sidekiq and enqueue jobs. This environment variable is used within the application code to enable/disable Sidekiq.

Check out the _examples/docker-compose.yml.with_sidekiq for a complete example.

Running Sidekiq

With the configuration in place, we can now spin up our services with docker-compose up -d. As always, make sure that all the services are up and running with docker-compose ps.

If everything looks good, let's keep an eye on the Sidekiq logs with:

docker-compose logs -f sidekiq

Browse http://localhost:3000 - you should see a new dashboard showing up. Whenever we add a record to the database a Sidekiq job is enqueued that updates the dashboard. Try logging some progress for a few books and keep an eye on the Sidekiq logs. You will see that jobs are being picked up and run.

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