[7601] Install and configure Celery

[hklarner]

No description provided.

[github-actions]

Coverage report

Total coverage

Status	Category	Percentage	Covered / Total
🔴	Statements	11.88%	84/707
🔴	Branches	13.41%	48/358
🔴	Functions	9.73%	25/257
🔴	Lines	23.18%	529/2282

Status of coverage: 🟢 - ok, 🟡 - slightly more than threshold, 🔴 - under the threshold

Report generated by 🧪jest coverage report action from 30a6e10

[m4ra]

Looks very good!
just few tiny corrections

[m4ra]

background task need the migration to zero as we discussed, then we can remove them from settings + requirements

[hklarner]

I have added a new celery configuration parameter:

CELERY_RESULT_EXTENDED = True

that instructs celery to save more information in the results backend. So what used to be:

$ redis-cli GET celery-task-meta-8b3be356-9e50-4c41-8b62-ec766504bf04 | jq
{
  "status": "SUCCESS",
  "result": null,
  "traceback": null,
  "children": [],
  "date_done": "2023-09-19T12:33:11.118701",
  "task_id": "8b3be356-9e50-4c41-8b62-ec766504bf04"
}

is now

$ redis-cli GET celery-task-meta-467e1aff-a7c6-4fb8-aa47-093aa86150d8 | jq
{
  "status": "SUCCESS",
  "result": null,
  "traceback": null,
  "children": [],
  "date_done": "2023-09-20T07:53:10.285548",
  "name": "adhocracy4.emails.tasks.send_async",
  "args": [],
  "kwargs": {
    "email_module_name": "apps.notifications.emails",
    "email_class_name": "NotifyCreatorOnModeratorFeedback",
    "app_label": "a4_candy_ideas",
    "model_name": "idea",
    "object_pk": 62,
    "args": [],
    "kwargs": {}
  },
  "worker": "celery@tuxedo86",
  "retries": 0,
  "queue": "celery",
  "task_id": "467e1aff-a7c6-4fb8-aa47-093aa86150d8"
}

[hklarner]

As discussed with goapunk, I have added redis == 5.0.0 back to requirements/dev.txt to avoid this attribute error when developing locally:

AttributeError: 'NoneType' object has no attribute 'Redis'

[m4ra]

Looks ready to merge once we merge a4 PR and update the requirements here

[hklarner]

Looks ready to merge once we merge a4 PR and update the requirements here

I have replaced the last version bump commit with one that imports the latest a4, namely db03f3.

[goapunk]

LGTM, nice work! Will leave for @m4ra to give final review and merge