问题描述

从Django应用程序调用导入任务的.delay()方法时，进程停滞，请求从未完成。

我们在控制台上也没有收到任何错误。 使用PDB设置set_trace()会产生相同的结果。

检查了以下无助于解决问题的问题：

Calling celery task hangs for delay and apply_async

celery .delay hangs (recent, not an auth problem)

例如：

Backend/settings.py

CELERY_BROKER_URL = os.environ.get("CELERY_BROKER", RABBIT_URL)
CELERY_RESULT_BACKEND = os.environ.get("CELERY_BROKER", RABBIT_URL)

后端/celery.py

from __future__ import absolute_import, unicode_literals

import os

from celery import Celery

# set the default Django settings module for the 'celery' program.
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'backend.settings')

app = Celery('backend')

app.config_from_object('django.conf:settings', namespace='CELERY')

# Load task modules from all registered Django app configs.
app.autodiscover_tasks()


@app.task(bind=True)
def debug_task(self):
    print('Request: {0!r}'.format(self.request))

app/tasks.py

import time
from celery import shared_task

@shared_task
def upload_file(request_id):
    time.sleep(request_id)
    return True

app/views.py

from rest_framework.views import APIView

from .tasks import upload_file

class UploadCreateAPIView(APIView):
    # other methods...

    def post(self, request, *args, **kwargs):
        id = request.data.get("id", None)
        # business logic ...
        print("Going to submit task.")
        import pdb; pdb.set_trace()
        upload_file.delay(id)                  # <- this hangs the runserver as well as the set_trace()
        print("Submitted task.")

---

解决方案

问题与使用Django设置芹菜应用程序有关。我们需要确保在以下文件中导入并初始化芹菜应用程序：

backend\__init__.py

from __future__ import absolute_import, unicode_literals

# This will make sure the app is always imported when
# Django starts so that shared_task will use this app.
from .celery import app as celery_app

__all__ = ('celery_app',)