Cancel an already executed Task

Question

Hi My question is How do you cancel an already executed task. Lets say I have 10 tasks and I have put these tasks in a timer based  async  method. Since it is a timer based application these tasks will be executed again and again. But I don't want this to happen. If Task 1 is already finished then it should not be executed again. Can anyone help me out in this regard with an example.

Mukil Vendhan · Answer

If a task is revoked the workers ignore the task and do not execute it. If you don't use persistent revokes your task can be executed after worker's restart. http://docs.celeryproject.org/en/latest/userguide/workers.html#worker-persistent-revokes revoke has an terminate option which is False by default. If you need to kill the executing task you need to set terminate to True. >>> from celery.task.control import revoke >>> revoke(task_id terminate=True) http://docs.celeryproject.org/en/latest/userguide/workers.html#revoke-revoking-tasks In Celery 3.1 the API of revoking tasks is changed. According to the Celery FAQ you should use result.revoke: >>> result = add.apply_async(args=[2 2] countdown=120) >>> result.revoke() or if you only have the task id: >>> from proj.celery import app >>> app.control.revoke(task_id)

Akhil Garg · Answer

You can check TaskStatus.