[Answered ]-Global variable with Django and Celery

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3👍

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If you’re doing anything with global variables in a Django project, you’re doing it wrong. In this case, Celery and Django are running in completely separate processes, so cannot share data. You need to get Celery to store that data somewhere – in the db, or a file – so that Django can pick it up and serve it.

👤Daniel Roseman

-1👍

The code below works with the global variable num for me in Django 3.1.7 and Celery 5.1.2. *However sometimes global variables don’t work properly between celery tasks which have different code from below so you should avoid to use global variables with celery tasks:

# "store/tasks.py"

from celery import shared_task

num = 0

@shared_task
def test1():
    global num
    num += 1
    return num

@shared_task
def test2():
    global num
    num += 1
    return num

@shared_task
def test3():
    global num
    num += 1
    return num

# "store/views.py"

from django.http import HttpResponse
from .tasks import test1, test2, test3

def test(request):
    test1.delay()
    test2.delay()
    test3.delay()
    return HttpResponse("Test")

Output:

Task store.tasks.test1[c222183b-73be-4fba-9813-be8141c6669c] received
Task store.tasks.test1[c222183b-73be-4fba-9813-be8141c6669c] succeeded in 0.0s: 1
Task store.tasks.test2[aa4bc9e5-95c6-4f8b-8122-3df273822ab5] received
Task store.tasks.test2[aa4bc9e5-95c6-4f8b-8122-3df273822ab5] succeeded in 0.0s: 2
Task store.tasks.test3[472727f3-368f-48ad-9d49-72f14962e8c5] received
Task store.tasks.test3[472727f3-368f-48ad-9d49-72f14962e8c5] succeeded in 0.0s: 3
👤Super Kai – Kazuya Ito

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