Migrate Celery settings to new format with CELERY_ namespace

[Copilot]

Celery 6.x will drop support for deprecated settings and require explicit CELERY namespace prefix. This migrates all settings to the new lowercase format.

Changes

• worker.py: Add namespace="CELERY" to config_from_object():

  application.config_from_object("django.conf:settings", namespace="CELERY")

• Settings renamed (base.py, test.py, docker_compose.py):

  • CELERY_ALWAYS_EAGER → CELERY_TASK_ALWAYS_EAGER
  • CELERYD_TASK_TIME_LIMIT → CELERY_TASK_TIME_LIMIT
  • CELERYD_HIJACK_ROOT_LOGGER → CELERY_WORKER_HIJACK_ROOT_LOGGER
  • CELERYD_PREFETCH_MULTIPLIER → CELERY_WORKER_PREFETCH_MULTIPLIER
  • CELERY_ACKS_LATE → CELERY_TASK_ACKS_LATE
  • CELERY_IGNORE_RESULT → CELERY_TASK_IGNORE_RESULT
  • CELERY_CREATE_MISSING_QUEUES → CELERY_TASK_CREATE_MISSING_QUEUES
  • CELERY_DEFAULT_QUEUE → CELERY_TASK_DEFAULT_QUEUE
  • CELERYBEAT_SCHEDULER → CELERY_BEAT_SCHEDULER
  • CELERYBEAT_SCHEDULE → CELERY_BEAT_SCHEDULE
  • BROKER_URL → CELERY_BROKER_URL
  • BROKER_TRANSPORT_OPTIONS → CELERY_BROKER_TRANSPORT_OPTIONS

• Code references updated:

  • core/utils/tasks/public.py: settings.CELERY_TASK_ALWAYS_EAGER
  • core/tasks.py: settings.CELERY_BROKER_URL

Refs: https://docs.celeryq.dev/en/stable/userguide/configuration.html#new-lowercase-settings

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Migrate celery settings to new ones</issue_title>
<issue_description>Celery 6.x will drop support for some deprecated settings, and it will require to explicitly set CELERY as the prefix.

https://docs.celeryq.dev/en/stable/userguide/configuration.html#new-lowercase-settings

They do provide a tool for renaming the settings, but we should also check for settings set from the ops repos.

https://docs.celeryq.dev/en/stable/history/whatsnew-4.0.html#latentcall-django-admonition
</issue_description>

Comments on the Issue (you are @copilot in this section)

@humitos We are already using `CELERY_` prefix in all our settings, so it seems we only need to update how we load them at https://github.com/readthedocs/readthedocs.org/blob/main/readthedocs/worker.py#L18

diff --git a/readthedocs/worker.py b/readthedocs/worker.py
index 527ee509b..8a2de7dac 100644
--- a/readthedocs/worker.py
+++ b/readthedocs/worker.py
@@ -15,7 +15,7 @@ def create_application():
     )
 
     application = Celery(settings.CELERY_APP_NAME)
-    application.config_from_object("django.conf:settings")
+    application.config_from_object("django.conf:settings", namespace='CELERY')
     application.autodiscover_tasks(None)
 
     # A step to initialize django-structlog

We need to do the same on commercial.

I put this in Q4, but I'm not sure when Celery 6.x is going to be released. Maybe we can already make this change, tho.</comment_new>
<comment_new>@stsewd
We are using the CELERYD prefix for some settings</comment_new>

• Fixes Migrate celery settings to new ones #12490

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[humitos]

Looks good after answering my question.

Also, we need to check the settings in https://github.com/readthedocs/readthedocs-ops and https://github.com/readthedocs/readthedocs-corporate-ops and migrate them as well. @copilot can you do that?

[Copilot]

Looks good after answering my question.

Also, we need to check the settings in https://github.com/readthedocs/readthedocs-ops and https://github.com/readthedocs/readthedocs-corporate-ops and migrate ...

I can only work on the current repository (readthedocs.org). I don't have access to the readthedocs-ops and readthedocs-corporate-ops repositories. Someone with access to those repos will need to migrate the settings there using the same naming conventions from this PR.

[humitos]

Also, we need to check the settings in readthedocs/readthedocs-ops and readthedocs/readthedocs-corporate-ops and migrate them as well. @copilot can you do that?

I checked in -ops repositories and opened:

• https://github.com/readthedocs/readthedocs-ops/pull/1704
• https://github.com/readthedocs/readthedocs-corporate/pull/2069
• no changes required in corporate-ops

[humitos]

We can merge this after today's deploy, so we have a full week to test it locally just in case.

[humitos]

Well, we didn't merge this for this deploy, but that's fine. We don't want to deal with Celery issues during Xmas 😄 . I add this PR to one of the first sprints of 2026.