为啥当我尝试在 celery 任务中使用模型时，django 会引发“应用程序尚未加载”错误？

Posted 2023-02-24

【中文标题】为啥当我尝试在 celery 任务中使用模型时，django 会引发“应用程序尚未加载”错误？

【英文标题】：Why when I try to use models in celery tasks django raises "Apps aren't loaded yet" error?为什么当我尝试在 celery 任务中使用模型时，django 会引发“应用程序尚未加载”错误？

【发布时间】：2017-07-04 02:19:17

【问题描述】：

我使用 django 1.10.5 和 celery 4.0.2。我有这样的结构。

-proj
  -application
    __init__.py
    celery.py
    celery_conf.py
    settings.py
    tasks.py
    urls.py
    wsgi.py
  -extuser (application with extended UserModel)
  -pages
    -migrations
    -templates
    __init__.py
    admin.py
    apps.py
    forms.py
    models.py
    tasks.py
    tests.py
    views.py

我的任务是使用包含我的扩展用户模型的文件中的模型。如果我尝试使用此命令运行 celery：

celery -A application worker -l INFO -B

然后我看到这个错误：

Traceback (most recent call last):
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/bin/celery", line 11, in <module>
    sys.exit(main())
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/__main__.py", line 14, in main
    _main()
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/celery.py", line 326, in main
    cmd.execute_from_commandline(argv)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/celery.py", line 488, in execute_from_commandline
    super(CeleryCommand, self).execute_from_commandline(argv)))
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/base.py", line 281, in execute_from_commandline
    return self.handle_argv(self.prog_name, argv[1:])
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/celery.py", line 480, in handle_argv
    return self.execute(command, argv)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/celery.py", line 412, in execute
    ).run_from_argv(self.prog_name, argv[1:], command=argv[0])
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/worker.py", line 221, in run_from_argv
    return self(*args, **options)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/base.py", line 244, in __call__
    ret = self.run(*args, **kwargs)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/bin/worker.py", line 255, in run
    **kwargs)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/worker/worker.py", line 94, in __init__
    self.app.loader.init_worker()
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/loaders/base.py", line 116, in init_worker
    self.import_default_modules()
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/loaders/base.py", line 111, in import_default_modules
    return [self.import_task_module(m) for m in self.default_modules]
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/loaders/base.py", line 97, in import_task_module
    return self.import_from_cwd(module)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/loaders/base.py", line 106, in import_from_cwd
    package=package,
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/utils/imports.py", line 101, in import_from_cwd
    return imp(module, package=package)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/celery/loaders/base.py", line 100, in import_module
    return importlib.import_module(module, package=package)
  File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/src/pages/tasks.py", line 4, in <module>
    from extuser.models import UserLinksArchive
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/src/extuser/models.py", line 5, in <module>
    from django.contrib.auth.models import AbstractBaseUser
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/django/contrib/auth/models.py", line 4, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/django/contrib/auth/base_user.py", line 52, in <module>
    class AbstractBaseUser(models.Model):
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/django/db/models/base.py", line 105, in __new__
    app_config = apps.get_containing_app_config(module)
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/django/apps/registry.py", line 237, in get_containing_app_config
    self.check_apps_ready()
  File "/home/dmitriy/MyEnv/DjangoProjects/sPrint/env/local/lib/python2.7/site-packages/django/apps/registry.py", line 124, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

文件 pages/tasks.py 如下所示：

from __future__ import absolute_import, unicode_literals
from application.celery import app
from extuser.models import UserLinksArchive


@app.task
def link_destroy_task(link_id):
    link = UserLinksArchive.objects.get(id=link_id)
    link.delete() 

另外，如果我在本地导入 UserLinksArchive，那么 celery 就会启动，但是当运行 async_task 时，我会遇到同样的错误。 如您所见，问题可能与 AbstractBaseUser 导入有关。但我不知道如何解决这个问题。 可能，extuser/models.py 代码会有所帮助。

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.conf import settings
from django.contrib.auth.models import AbstractBaseUser
from django.contrib.auth.models import PermissionsMixin
from django.contrib.auth.models import BaseUserManager
from django.core.validators import MinValueValidator, MinLengthValidator
from django.db import models


class MyUserManager(BaseUserManager):
    def create_user(self, username, password=None, **extra_fields):
        if not username:
            raise ValueError(u'No user')

        user = self.model(username=username)
        if password:
            user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, username, password):
        user = self.create_user(username, password)
        user.is_admin = True
        user.is_superuser = True
        user.save(using=self._db)
        return user


class ExtUser(AbstractBaseUser, PermissionsMixin):
    username = models.CharField(
        max_length=255,
        null=False,
        unique=True,
        validators=[MinLengthValidator(6)]
    )
    balance = models.FloatField(
        default=0.0,
        validators=[MinValueValidator(0.0)]
    )
    is_active = models.BooleanField(
        default=True
    )
    is_admin = models.BooleanField(
        default=False
    )

    def get_full_name(self):
        return self.username

    @property
    def is_staff(self):
        return self.is_admin

    def get_short_name(self):
        return self.username

    def __str__(self):
        return self.username

    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = []

    objects = MyUserManager()

    class Meta:
    db_table = 'auth_user'


LINKTYPE = (
    ('p', 'Password restore'),
    ('o', 'Other'),
)


class UserLinksArchive(models.Model):
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        default=1
    )
    hash = models.CharField(
        max_length=32,
        default=None,
        unique=True
    )
    created_at = models.DateTimeField(
        auto_now_add=True
    )
    type = models.CharField(
        max_length=1,
        default='o',
        choices=LINKTYPE
    )

还有我的 celery.py：

#application/celery.py
# coding=utf-8
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', 'application.settings')

app = Celery('application')

# Using a string here means the worker don'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('application.celery_conf', namespace='CELERY')

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

和 celery_conf.py：

#application/celery_conf.py
# CELERY SETTINGS ALARMA
from django.conf import settings
CELERY_IMPORTS = ("application.tasks", "pages.tasks")

CELERY_BROKER_BACKEND = 'redis'
CELERY_BROKER_URL = settings.REDIS_URL
CELERY_RESULT_BACKEND = settings.REDIS_URL

CELERY_TASK_RESULT_EXPIRES = 60 * 60 * 24

CELERY_TIMEZONE = 'Europe/Moscow'

【参考方案1】：

如果您在 tasks.py 的方法中导入 UserLinksArchive，则可以解决此问题

类似这样的：

@app.task
def link_destroy_task(link_id):
    from extuser.models import UserLinksArchive
    link = UserLinksArchive.objects.get(id=link_id)
    link.delete() 

【讨论】：

我试过“另外，如果我在本地导入 UserLinksArchive，那么 celery 就会启动，但是当运行 async_task 时，我会遇到同样的错误”。

这对我没有帮助！ :(

【参考方案2】：

我已将 import 放入任务中，但我写的问题仍然存在。

所以，经过几个小时的研究，我找到了原因。就我而言，问题出在我的要求中的一个包中。我什至不知道它是如何出现在那里的，真的，不知道（也许会知道是否会掉下来）。这是我的要求.txt

amqp==2.1.4
anyjson==0.3.3
billiard==3.5.0.2
celery==4.0.2
Django==1.10.5
django-categories==1.4.2
django-celery==3.1.17
django-celery-beat==1.0.1
django-mptt==0.8.7
django-multiupload==0.5.1
django-shell-plus==1.1.7
django-widget-tweaks==1.4.1
gunicorn==19.6.0
kombu==4.0.2
lorem-ipsum-generator==0.3
lxml==3.7.2
mysqlclient==1.3.9
oauthlib==2.0.0
printer==2.0.0 <==(this package)
PyJWT==1.4.2
python-openid==2.2.5
python-social-auth==0.2.21
pytz==2016.10
redis==2.10.5
requests==2.11.1
requests-oauthlib==0.7.0
six==1.10.0
transliterate==1.8.1
tzlocal==1.3
unicode-slugify==0.1.1
vine==1.1.3

我发现我什至无法从其他应用程序导入包。 Runserver 出现如下错误：

/env/local/lib/python2.7/site-packages/printer.py", line 8
    print("\t",end='')
                  ^
SyntaxError: invalid syntax

我的 python 版本是 2.7，这不起作用。 这是我第一次感受到difference between 2.7 and 3.x print

最后，我刚刚删除了这个包。

目前飞行正常。