Configuring Celery on Windows

Question

I have installed Celery 3.1.5, RabbitMQ server 3.2.1 and Python 2.7.5 on Windows 7 64 bit machine. Here is my code which copied from first-steps-with-celery.

from celery import Celery

app = Celery('tasks', backend='amqp', broker='amqp://guest@localhost//')

@app.task
def add(x, y):
    return x + y

When I execute task from python shell I got "The operation timed out" exception message. And state and ready() always returns PENDING & False.

>>> from tasks import *
>>> result = add.delay(4, 4)
>>> result.ready()
False
>>> result.state
'PENDING'
>>> result.get(timeout=20)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python27\lib\site-packages\celery\result.py", line 136, in get
    interval=interval)
  File "C:\Python27\lib\site-packages\celery\backends\amqp.py", line 154, in wait_for
    raise TimeoutError('The operation timed out.')
celery.exceptions.TimeoutError: The operation timed out.
>>>

I verified RabbitMQ server is running however I have no clue why celery throwing exception.

score 4 · Answer 1 · answered Sep 24 '15 at 06:28

4

You can try to start the worker with command

celery -A proj worker -l info --pool==solo

answered Sep 24 '15 at 06:28

Deja_vu

101
6

Please elaborate your answer for those who are trying to use this command for production.. It works in production environment however, solo execution mode is single threaded which isn't good for production as it ignores concurrency option.. – hackwithharsha Jun 24 '21 at 14:25

score 4 · Answer 2 · edited May 23 '17 at 12:08

Though there are lots of things that can cause the result.get() call to fail -- because there are a lot of steps in the chain between sending the message via the .delay() command, to Celery, to the broker (RabbitMQ), and back to a Celery worker, which does the work, and posts the results back, etc. -- I had this problem and the solution was the one that @Deja_vu suggested of "--pool=solo" (note one equals sign, not two).

The default "pool" option is "prefork" (see http://docs.celeryproject.org/en/latest/reference/celery.bin.worker.html#module-celery.bin.worker ). So this may be a Celery bug in its "prefork" system under Windows: see https://github.com/celery/celery/issues/2146

Configuring Celery on Windows

2 Answers2