Kitsune uses Celery to enable offline task processing for long-running jobs like sending email notifications and re-rendering the Knowledge Base.
Though Celery supports multiple message backends, we use Redis.
When is Celery Appropriate¶
You can use Celery to do any processing that doesn’t need to happen in the current request-response cycle. Examples are generating thumbnails, sending out notification emails, updating content that isn’t about to be displayed to the user, and others.
Ask yourself the question: “Is the user going to need this data on the page I’m about to send them?” If not, using a Celery task may be a good choice.
Configuring and Running¶
Celery will automatically start when you run:
We set some reasonable defaults for Celery in
These can be overriden in
If you don’t want to use Celery, you can set this in
CELERY_TASK_ALWAYS_EAGER = True
Setting this to
True causes all task processing to be done online.
This is useful when debugging tasks, for instance.
You can also configure the concurrency. Here is the default:
CELERY_WORKER_CONCURRENCY = 4
Then to restart the Celery workers, you just need to run:
docker-compose restart celery