Celery get() 在 python shell 中有效，但在 Django 视图中无效

Question

我想用code available here检查official demo Celery project for django中的基本Celery功能。

我的修改是demoapp/views.py（当然还有urls.py指向这个视图）：

from __future__ import absolute_import, unicode_literals
from django.http import HttpResponse
from demoapp.tasks import add, mul, xsum


def home(request):
    return HttpResponse("Your output is: %s" % mul.delay(22,4).get(timeout=1) )

虽然运行 Celery worker 的终端显示任务已收到并显示正确的返回值，但它总是给出超时错误。

但是，如果我启动 python shell python ./manage.py shell 然后运行

from demoapp.tasks import add, mul, xsum
mul.delay(22,4).get(timeout=1)

我立即得到预期的结果。可能是什么问题？

Rabbitmq 服务器正在运行，我使用 Celery 4.2.1，django 2.0.6。

demoapp/tasks.py：

from __future__ import absolute_import, unicode_literals
from celery import shared_task


@shared_task
def add(x, y):
    return x + y


@shared_task
def mul(x, y):
    return x * y


@shared_task
def xsum(numbers):
    return sum(numbers)

项目/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', 'proj.settings')

app = Celery('proj')

# Using a string here means the worker doesn't have to serialize
# the configuration object to child processes.
# - namespace='CELERY' means all celery-related configuration keys
#   should have a `CELERY_` prefix.
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))

项目/settings.py

...
CELERY_BROKER_URL = 'amqp://guest:guest@localhost//'
CELERY_ACCEPT_CONTENT = ['json']
CELERY_RESULT_BACKEND = 'db+sqlite:///results.sqlite'
CELERY_TASK_SERIALIZER = 'json'
...

Answer 1

如the bottom of this page 所述，通过安装结果后端解决了问题。