django celery chord task error

Question

I have error when i am trying to use chord to send a task after all the tasks have been sent.

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/wenzhixue/projects/workspace/fallfor_core/twitter/tasks.py", line 13, in bulk_change_bio
    chord([change_bio_task.delay(account,'http://fallfor.com') for account in account_list ])(shutdown.s(c))
  File "/Library/Python/2.7/site-packages/celery/canvas.py", line 470, in __call__
    _chord = self.type
  File "/Library/Python/2.7/site-packages/celery/canvas.py", line 467, in type
    return self._type or self.tasks[0].type.app.tasks['celery.chord']
AttributeError: 'AsyncResult' object has no attribute 'type'

-

@task()
def shutdown(ec2):
    print "shutting down!!!!"
    time.sleep(300)
    return True

c = Ec2()
account_list = Account.objects.all()
chord([change_bio_task.delay() for account in account_list ])(shutdown.s(c))

daniula daniula · Accepted Answer · 2014-04-14T18:47:57

Chord accepts two parameters: first one list of subtasks which is called as a group and second optional is subtask used as a callback after whole tasks from list are finished.

Example from API referance:

res = chord([add.s(2, 2), add.s(4, 4)])(sum_task.s())

In your code you are passing as a first parameter list of AsyncResults not subtasks. This should be correct:

chord([change_bio_task.s() for account in account_list ])(shutdown.si(c))

Take a look that I changed shutdown.s(c) to shutdown.si(c) which is immutable and ignores results returned finished change_bio_task.

django celery chord task error

1 Answers