Chord with tasks from two different apps throws "unregistered task of type"

[ghost]

I have the following codes to test chord tasks with two apps (could be deployed on different worker nodes), why does it throw "unregistered task of type" issue? How can I fix it? Any suggestion would be appreciated.

celery: 4.0.2 python: 3.5

app1.py

from celery import Celery
from celery import chord
from celery.utils.log import get_task_logger

logger = get_task_logger(__name__)

app = Celery("app1", broker="redis://localhost:6379/10", backend="redis://localhost:6379/11")

if __name__ == "__main__":
    app.start()

@app.task
def app1_task(s):

    from app2 import app2_task
    tasks = [app2_task.s("app2_task_1"), app2_task.s("app2_task_2"), app2_task.s("app2_task_3")]
    workflow = chord(tasks, body=app1_task_callback.s())
    workflow.apply_async()
    return "app1_task is {0}".format(s)

@app.task
def app1_task_callback(res):
    return "app1_task1_callback is {0}".format(res)

app2.py

import time

from celery import Celery
from celery.utils.log import get_task_logger

logger = get_task_logger(__name__)

app = Celery("app1", broker="redis://localhost:6379/12", backend="redis://localhost:6379/13")

if __name__ == "__main__":
    app.start()

@app.task
def app2_task(s):
    time.sleep(5)
    return "app2_task2 is {0}".format(s)

Start two apps using the following command:

_celery multi start test_app1 -A app1 --pidfile=logs/app1.pid -l info -f logs/app1.log celery multi start testapp2 -A app2 --pidfile=logs/app2.pid -l info -f logs/app2.log

To test tasks:

app = Celery(broker="redis://localhost:6379/10")
app.send_task("app1.app1_task", args=["test1"])

app1.log

[2017-01-03 23:34:08,173: INFO/MainProcess] Connected to redis://localhost:6379/10 [2017-01-03 23:34:08,180: INFO/MainProcess] mingle: searching for neighbors [2017-01-03 23:34:09,196: INFO/MainProcess] mingle: all alone [2017-01-03 23:34:09,204: INFO/MainProcess] test_app1@rw-MacBook-Pro.local ready. [2017-01-03 23:34:11,235: INFO/MainProcess] Received task: app1.app1_task[6788aade-1f1b-4046-9f9a-d7aaa7dab860]
[2017-01-03 23:34:11,268: INFO/PoolWorker-3] Task app1.app1_task[6788aade-1f1b-4046-9f9a-d7aaa7dab860] succeeded in 0.032366810000894475s: 'app1_task is test1'

app2.log

[2017-01-03 23:34:08,798: INFO/MainProcess] Connected to redis://localhost:6379/12 [2017-01-03 23:34:08,806: INFO/MainProcess] mingle: searching for neighbors [2017-01-03 23:34:09,825: INFO/MainProcess] mingle: all alone [2017-01-03 23:34:09,837: INFO/MainProcess] test_app2@rw-MacBook-Pro.local ready. [2017-01-03 23:34:11,266: INFO/MainProcess] Received task: app2.app2_task[ebdc3d10-1e60-4b68-a740-525aaf8430dd]
[2017-01-03 23:34:11,268: INFO/MainProcess] Received task: app2.app2_task[d9b7a304-3dfe-4be3-a554-a0c45f7824ff]
[2017-01-03 23:34:11,270: INFO/MainProcess] Received task: app2.app2_task[299136c8-0b51-419a-8507-868baad4d85c]
[2017-01-03 23:34:16,280: INFO/PoolWorker-2] Task app2.app2_task[ebdc3d10-1e60-4b68-a740-525aaf8430dd] succeeded in 5.009632268000132s: 'app1_task1 input is app2_task_1' [2017-01-03 23:34:16,280: INFO/PoolWorker-3] Task app2.app2_task[d9b7a304-3dfe-4be3-a554-a0c45f7824ff] succeeded in 5.009859617999609s: 'app1_task1 input is app2_task_2' [2017-01-03 23:34:16,303: INFO/PoolWorker-7] Task app2.app2_task[299136c8-0b51-419a-8507-868baad4d85c] succeeded in 5.031090483000298s: 'app1_task1 input is app2_task_3' [2017-01-03 23:34:16,303: ERROR/MainProcess] Received unregistered task of type 'app1.app1_task_callback'. The message has been ignored and discarded.

Did you remember to import the module containing this task? Or maybe you're using relative imports?

Please see http://docs.celeryq.org/en/latest/internals/protocol.html for more information.

The full contents of the message body was: b'[[["app1_task1 input is app2_task_1", "app1_task1 input is app2_task_2", "app1_task1 input is app2_task_3"]], {}, {"errbacks": null, "chain": null, "callbacks": null, "chord": null}]' (182b) Traceback (most recent call last): File "/Users/rudongw/work/projects/isplunk/venv/lib/python3.5/site-packages/celery/worker/consumer/consumer.py", line 559, in on_taskreceived strategy = strategies[type] KeyError: 'app1.app1_task_callback'

[auvipy]

is this still the case in master?

[auvipy]

plz try the new release and post your support questions to mailing list. report here again if the issue still exists after following proper guideline.