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python之django post_migrate 信号问题

2024年10月24日28insus

我遇到以下错误，因为我的 myproject/apps.py 文件中有以下导入行。当我删除这个导入文件时，出现错误，如找不到权限或组

from django.contrib.auth.models import Group, Permission

错误信息；

C:\django\myproject>python manage.py migrate myproject 
Traceback (most recent call last): 
  File "manage.py", line 10, in <module> 
    execute_from_command_line(sys.argv) 
  File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 
353, in execute_from_command_line 
    utility.execute() 
  File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 
327, in execute 
    django.setup() 
  File "C:\Python27\lib\site-packages\django\__init__.py", line 18, in setup 
    apps.populate(settings.INSTALLED_APPS) 
  File "C:\Python27\lib\site-packages\django\apps\registry.py", line 85, in popu 
late 
    app_config = AppConfig.create(entry) 
  File "C:\Python27\lib\site-packages\django\apps\config.py", line 90, in create 
 
    module = import_module(entry) 
  File "C:\Python27\lib\importlib\__init__.py", line 37, in import_module 
    __import__(name) 
  File "C:\django\myproject\myproject\apps.py", line 3, in <module> 
    from django.contrib.auth.models import Group, Permission 
  File "C:\Python27\lib\site-packages\django\contrib\auth\models.py", line 4, in 
 <module> 
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager 
  File "C:\Python27\lib\site-packages\django\contrib\auth\base_user.py", line 49 
, in <module> 
    class AbstractBaseUser(models.Model): 
  File "C:\Python27\lib\site-packages\django\db\models\base.py", line 94, in __n 
ew__ 
    app_config = apps.get_containing_app_config(module) 
  File "C:\Python27\lib\site-packages\django\apps\registry.py", line 239, in get 
_containing_app_config 
    self.check_apps_ready() 
  File "C:\Python27\lib\site-packages\django\apps\registry.py", line 124, in che 
ck_apps_ready 
    raise AppRegistryNotReady("Apps aren't loaded yet.") 
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

我的项目/apps.py

from django.db.models.signals import post_migrate 
from django.apps import AppConfig 
from django.contrib.auth.models import Group, Permission 
 
 
def create_group(name, permissions): 
    group = Group.objects.create(name=name) 
    [group.permissions.add(permission) for permission in permissions] 
 
 
def define_company_groups(sender, **kwargs): 
    permissions = [ 
        Permission.objects.get(codename='add_group1_profile'), 
        Permission.objects.get(codename='change_group1_profile'), 
    ] 
    create_group('group1', permissions) 
 
 
class MyAppConfig(AppConfig): 
    name = 'myproject' 
 
 
    def ready(self): 
        post_migrate.connect(define_company_groups, sender=self)

我在 models.py 中也有一些东西来确保 post_migrate 被触发 模型.py;

from django.db import models 
 
class testmodel(models.Model): 
 
    field1 = models.CharField( max_length=10) 
    field2 = models.CharField( max_length=10) 
    field3 = models.CharField( max_length=10)

我试图将下面的行添加到 init.py 但它没有帮助 初始化.py;

default_app_config = 'myproject.apps.MyAppConfig'

设置.py

# Build paths inside the project like this: os.path.join(BASE_DIR, ...) 
import os 
from django.contrib.messages import constants as messages 
 
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__))) 
PROJECT_ROOT = os.path.abspath(os.path.dirname(__file__)) 
 
# SECURITY WARNING: keep the secret key used in production secret! 
SECRET_KEY = 'fhhc#5%c1gn*fdgf4o#a0d*@k)d56^sl*l)aydl5!_sk9_7' 
 
# SECURITY WARNING: don't run with debug turned on in production! 
DEBUG = True 
TEMPLATE_DEBUG = DEBUG 
 
ADMINS = ( 
    # ('Your Name', 'your_email@example.com'), 
) 
 
ALLOWED_HOSTS = [] 
 
DATABASES = { 
    'default': { 
        'ENGINE': 'django.db.backends.sqlite3', 
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'), 
    } 
} 
 
# MANAGERS = ADMINS 
INTERNAL_IPS = ('127.0.0.1',) 
 
# AUTH_USER_MODEL = '' 
# AUTHENTICATION_BACKENDS = ('',) 
LOGIN_URL = '/login' 
 
SESSION_EXPIRATION_SECONDS = 3600 
SESSION_EXPIRE_AT_BROWSER_CLOSE = True 
 
ALLOWED_HOSTS = [] 
TIME_ZONE = 'GMT' 
 
LANGUAGE_CODE = 'en-us' 
 
LANGUAGES = ( 
    ('tr', 'Turkish'), 
    ('en', 'English'), 
    ('de', 'German'), 
) 
 
SITE_ID = 1 
USE_I18N = True 
USE_L10N = True 
USE_TZ = True 
 
# Where to look for translations *first* 
LOCALE_PATHS = (os.path.join(BASE_DIR, 'locale'), 
) 
 
# MEDIA_ROOT = '/var/lib/myproject/media/' 
MEDIA_URL = '/media/' 
 
# STATIC_ROOT = '/usr/lib/myproject/static/' 
# STATIC_ROOT = os.path.join(BASE_DIR, 'static/') 
STATIC_URL = '/static/' 
PROJECT_ROOT = os.path.abspath(os.path.dirname(__file__)) 
 
# Additional locations of static files 
STATICFILES_DIRS = ( 
    # Put strings here, like "/home/html/static" or "C:/www/django/static". 
    # Always use forward slashes, even on Windows. 
    # Don't forget to use absolute paths, not relative paths. 
    os.path.join(BASE_DIR, 'static'), 
) 
 
# List of finder classes that know how to find static files in various 
# locations. 
STATICFILES_FINDERS = ( 
    'django.contrib.staticfiles.finders.FileSystemFinder', 
    'django.contrib.staticfiles.finders.AppDirectoriesFinder', 
) 
 
TEMPLATE_LOADERS = ( 
    'django.template.loaders.filesystem.Loader', 
    'django.template.loaders.app_directories.Loader', 
) 
 
# FILE_UPLOAD_HANDLERS = ('',) 
 
MIDDLEWARE_CLASSES = ( 
    'django.contrib.sessions.middleware.SessionMiddleware', 
    'django.middleware.locale.LocaleMiddleware', 
    'django.middleware.common.CommonMiddleware', 
    'django.middleware.csrf.CsrfViewMiddleware', 
    'django.contrib.auth.middleware.AuthenticationMiddleware', 
    'django.contrib.messages.middleware.MessageMiddleware', 
    'django.contrib.auth.middleware.SessionAuthenticationMiddleware', 
    'django.contrib.messages.middleware.MessageMiddleware', 
    'django.middleware.security.SecurityMiddleware', 
) 
 
ROOT_URLCONF = 'myproject.urls' 
 
WSGI_APPLICATION = 'myproject.wsgi.application' 
 
TEMPLATE_DIRS = ( 
    # Put strings here, like "/home/html/django_templates" or 
    # "C:/www/django/templates". 
    # Always use forward slashes, even on Windows. 
    # Don't forget to use absolute paths, not relative paths. 
    os.path.join(BASE_DIR, 'myproject/templates'), 
    os.path.join(BASE_DIR, 'myapp1/templates'), 
    os.path.join(BASE_DIR, 'myapp2/templates'), 
    os.path.join(BASE_DIR, 'help/templates'), 
) 
 
# Application definition 
INSTALLED_APPS = ( 
    'django.contrib.auth', 
    'django.contrib.contenttypes', 
    'django.contrib.sessions', 
    'django.contrib.messages', 
    'django.contrib.staticfiles', 
    'django.contrib.admin', 
    'registration', 
    'myapp1', 
    'myapp2', 
    'help', 
    'myproject.apps.MyAppConfig', 
) 
 
SESSION_SERIALIZER = 'django.contrib.sessions.serializers.JSONSerializer' 
 
LOGGING = { 
    'version': 1, 
    'disable_existing_loggers': False, 
    'formatters': { 
        'myproject_format': { 
            'format': 
                '%(asctime)s %(levelname)s [%(threadName)s]: %(message)s\n' 
        }, 
    }, 
    'handlers': { 
        'django_file': { 
            'level': 'ERROR', 
            'class': 'logging.FileHandler', 
            'filename': os.path.join(BASE_DIR, 'django.log'), 
            'formatter': 'myproject_format', 
            'encoding': 'utf8', 
        }, 
        'personal_file': { 
            'level': 'DEBUG', 
            'class': 'logging.FileHandler', 
            'filename': os.path.join(BASE_DIR, 'myapp1.log'), 
            'formatter': 'myproject_format', 
            'encoding': 'utf8', 
        }, 
        'commercial_file': { 
            'level': 'DEBUG', 
            'class': 'logging.FileHandler', 
            'filename': os.path.join(BASE_DIR, 'myapp2.log'), 
            'formatter': 'myproject_format', 
            'encoding': 'utf8', 
        }, 
        'help_file': { 
            'level': 'DEBUG', 
            'class': 'logging.FileHandler', 
            'filename': os.path.join(BASE_DIR, 'help.log'), 
            'formatter': 'myproject_format', 
            'encoding': 'utf8', 
        }, 
    }, 
    'loggers': { 
        'django': { 
            'handlers': ['django_file'], 
            'propagate': True, 
            'level': 'ERROR', 
        }, 
        'personal': { 
            'handlers': ['myapp1_file'], 
            'propagate': True, 
            'level': 'DEBUG', 
        }, 
        'commercial': { 
            'handlers': ['myapp2_file'], 
            'propagate': True, 
            'level': 'DEBUG', 
        }, 
        'help': { 
            'handlers': ['help_file'], 
            'propagate': True, 
            'level': 'DEBUG', 
        }, 
    } 
} 
 
 
MESSAGE_TAGS = { 
    messages.SUCCESS: 'fa fa-check', 
    messages.INFO: 'fa fa-info', 
    messages.ERROR: 'fa fa-times', 
    messages.WARNING: 'fa fa-exclamation', 
} 
 
# ********************************************************************************************************************** 
 
if DEBUG: 
    INTERNAL_IPS = ('127.0.0.1',) 
    MIDDLEWARE_CLASSES += ( 
        'debug_toolbar.middleware.DebugToolbarMiddleware', 
    ) 
 
    INSTALLED_APPS += ( 
        'debug_toolbar', 
        'django_extensions', 
    ) 
 
    DEBUG_TOOLBAR_PANELS = [ 
        'debug_toolbar.panels.versions.VersionsPanel', 
        'debug_toolbar.panels.timer.TimerPanel', 
        'debug_toolbar.panels.settings.SettingsPanel', 
        'debug_toolbar.panels.headers.HeadersPanel', 
        'debug_toolbar.panels.request.RequestPanel', 
        'debug_toolbar.panels.sql.SQLPanel', 
        'debug_toolbar.panels.staticfiles.StaticFilesPanel', 
        'debug_toolbar.panels.templates.TemplatesPanel', 
        'debug_toolbar.panels.cache.CachePanel', 
        'debug_toolbar.panels.signals.SignalsPanel', 
        'debug_toolbar.panels.logging.LoggingPanel', 
        'debug_toolbar.panels.redirects.RedirectsPanel', 
    ] 
 
    DEBUG_TOOLBAR_CONFIG = { 
        'INTERCEPT_REDIRECTS': False, 
    }

请您参考如下方法:

app.py 在 django 模型启动之前加载。因此，在执行 django\db\models\base.py 中的代码时，在那里导入模型会导致错误。

解决方案是将导入语句移动到方法中:

def create_group(name, permissions): 
    from django.contrib.auth.models import Group 
 
    group = Group.objects.create(name=name) 
    [group.permissions.add(permission) for permission in permissions] 
 
 
def define_company_groups(sender, **kwargs): 
    from django.contrib.auth.models import Permission 
    permissions = [ 
        Permission.objects.get(codename='add_group1_profile'), 
        Permission.objects.get(codename='change_group1_profile'), 
    ] 
    create_group('group1', permissions)


  文章来源：
  https://blog.windname.com/post/ighjb2b9.html
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