Python+Celery: Chaining jobs?

Question

The Celery documentation suggests that it\'s a bad idea to have tasks wait on the results of other tasks… But the suggested solution (see “good” heading) leaves a something

Answer 1

You can do it with a celery chain. See https://celery.readthedocs.org/en/latest/userguide/canvas.html#chains

@task()
def add(a, b):
    time.sleep(5) # simulate long time processing
    return a + b

Chaining job:

# import chain from celery import chain
# the result of the first add job will be 
# the first argument of the second add job
ret = chain(add.s(1, 2), add.s(3)).apply_async()

# another way to express a chain using pipes
ret2 = (add.s(1, 2) | add.s(3)).apply_async()

...

# check ret status to get result
if ret.status == u'SUCCESS':
    print "result:", ret.get()