Find out whether celery task exists

Question

Is it possible to find out whether a task with a certain task id exists? When I try to get the status, I will always get pending.

>>> AsyncResult(\'         


        

Answer 1

AsyncResult.state returns PENDING in case of unknown task ids.

PENDING

Task is waiting for execution or unknown. Any task id that is not known is implied to be in the pending state.

http://docs.celeryproject.org/en/latest/userguide/tasks.html#pending

You can provide custom task ids if you need to distinguish unknown ids from existing ones:

>>> from tasks import add
>>> from celery.utils import uuid
>>> r = add.apply_async(args=[1, 2], task_id="celery-task-id-"+uuid())
>>> id = r.task_id
>>> id
'celery-task-id-b774c3f9-5280-4ebe-a770-14a6977090cd'
>>> if not "blubb".startswith("celery-task-id-"): print "Unknown task id"
... 
Unknown task id
>>> if not id.startswith("celery-task-id-"): print "Unknown task id"
...