Celery task chain cancelling?

Question

I found that celery supports task chains: http://celery.readthedocs.org/en/latest/userguide/canvas.html#chains.

Question is: how can I stop chain's execution in a task?

For example, we got a chain of N items (N > 2). And in the second task we realize that we do not need all the rest tasks to be executed. What to do?

What about raising an exception in the task when you want it to stop? — RickyA, Oct 10 '12 at 13:12
Raising an exception didn't work for me. I have posted a detailed explanation here: http://stackoverflow.com/questions/17461374/celery-stop-execution-of-a-chain — Salami, Jul 04 '13 at 03:32

score 5 · Accepted Answer · answered Dec 12 '13 at 22:14

In newer versions of celery (3.1.6) you can revoke an entire chain by simply walking the chain and revoking each item in turn.

# Build a chain for results
from tasks import addd
from celery import chain

def revoke_chain(result):
    while result:
        result.revoke()
        result = result.parent

# independent tasks (with immutable signatures)
c = chain(*tuple(add.si(i,i) for i in xrange(50)))
h = c()

# some time later ...
revoke_chain(h)

# dependant task
c = add.s(1,1) | add.s(2) | add.s(3)
h = c()

# some time later ...
revoke_chain(h)

Celery task chain cancelling?

1 Answers1

Linked

Related