Documentation for periodic tasks is incorrect

[alexdewar]

I needed to add a periodic task to the deployment of Invenio I'm working on, but found that the documentation is not quite correct (it may possibly just be outdated).

The documentation suggests creating a dict called CELERYBEAT_SCHEDULE in config.py like so:

# config.py
CELERYBEAT_SCHEDULE = {
    'indexer': {
        'task': 'invenio_indexer.tasks.process_bulk_queue',
        'schedule': timedelta(minutes=5),
    },
}

For one thing, it appears the correct name of the variable is CELERY_BEAT_SCHEDULE (note the extra underscore!), but it may also be worth mentioning that you need to import this variable from invenio_app_rdm.config -- it won't work if you create a new variable by that name in your config.py.

You also probably want to add a new entry to the dict rather than replacing it. Here's what I did:

# Periodic tasks
# --------------
CELERY_BEAT_SCHEDULE["update_imperial_users"] = {
    "task": "ic_data_repo.tasks.update_imperial_users",
    "schedule": timedelta(weeks=1),
}

I also missed the step where you have to define the invenio_celery.tasks entrypoint to your package. I've noticed it is mentioned in passing, but maybe this information should be a bit more prominent?