导入错误：无法导入名称“Celery”

Question

我正在尝试学习 Celery，我正在使用 Django 2.0 和 celery 5.0.2，我的操作系统是 Ubuntu。

这是我的结构我的项目结构是：

celery/
  manage.py
  celery/
    __init__.py
    cerely_app.py
    settings.py
    urls.py
    wsgi.py
  apps/
      main/ 
        __init__.py
        admin.py
        apps.py
        models.py
        task.py
        views.py
        test.py          

我的 cerely_app 配置基于文档：

import os
from celery import Celery

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'celery.settings')

app = Celery('celery')

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

app.autodiscover_tasks()


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

还有我的init.py：

from .celery_app import app as celery_app
__all__ = ('celery_app',)

但是当我使用命令 python3 manage.py runserver 时 django 给出导入错误：

$python3 manage.py runserver
Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "/home/brayan/Envs/celery/lib/python3.8/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line
    utility.execute()
  File "/home/brayan/Envs/celery/lib/python3.8/site-packages/django/core/management/__init__.py", line 317, in execute
    settings.INSTALLED_APPS
  File "/home/brayan/Envs/celery/lib/python3.8/site-packages/django/conf/__init__.py", line 56, in __getattr__
    self._setup(name)
  File "/home/brayan/Envs/celery/lib/python3.8/site-packages/django/conf/__init__.py", line 43, in _setup
    self._wrapped = Settings(settings_module)
  File "/home/brayan/Envs/celery/lib/python3.8/site-packages/django/conf/__init__.py", line 106, in __init__
    mod = importlib.import_module(self.SETTINGS_MODULE)
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/brayan/dev/python/celery/celery/celery/__init__.py", line 3, in <module>
    from .celery_app import app as celery_app
  File "/home/brayan/dev/python/celery/celery/celery/celery_app.py", line 2, in <module>
    from celery import Celery
ImportError: cannot import name 'Celery' from partially initialized module 'celery' (most likely due to a circular import) (/home/brayan/dev/python/celery/celery/celery/__init__.py)

Answer 1

我最近从 Python 3.6 升级到Python 3.7，并且使用Celery 4.4.6和Django 2.2.x，它也给了我一个类似的错误：

ImportError: cannot import name 'Celery' from 'celery'

然而，正如我按照文档中所述进行项目设置时，它指的是正确的包。只是在损失了一些时间之后，我才在这里偶然发现了这个问题。然后我修复了

importlib-metadata==4.8.3

问题就解决了。根据 GitHub 的说法，所有 < 5 版本都可以解决该问题。显然，Celery 在特定的 Python 版本上使用此包中的接口，但在版本 5 中已弃用。