python - Django - 无法选择自定义日志记录处理程序类

Question

我正在开发一个 Django 应用程序(Django 2.0.7、Python 3.7、Windows 10、PyCharm)，我需要编写一个自定义日志处理程序以便将日志消息存储到数据库中。

当我尝试运行该应用程序时收到此错误:

pydev debugger: process 27148 is connecting

Connected to pydev debugger (build 192.6817.19)
pydev debugger: process 28448 is connecting

Unhandled exception in thread started by <_pydev_bundle.pydev_monkey._NewThreadStartupWithTrace object at 0x000001F1C52AD648>
Traceback (most recent call last):
  File "C:\Program Files\Python\lib\logging\config.py", line 387, in resolve
    found = getattr(found, frag)
AttributeError: module 'Inmobiliaria.inmobiliaria.utils.logs' has no attribute 'handlers'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files\Python\lib\logging\config.py", line 562, in configure
    handler = self.configure_handler(handlers[name])
  File "C:\Program Files\Python\lib\logging\config.py", line 712, in configure_handler
    klass = self.resolve(cname)
  File "C:\Program Files\Python\lib\logging\config.py", line 389, in resolve
    self.importer(used)
  File "C:\Users\facun\Desktop\DEV\forreal\backend\Inmobiliaria\inmobiliaria\utils\logs\handlers.py", line 2, in <module>
    from Inmobiliaria.inmobiliaria.services.application_log_services import create_application_log
  File "C:\Users\facun\Desktop\DEV\forreal\backend\Inmobiliaria\inmobiliaria\services\application_log_services.py", line 1, in <module>
    from Inmobiliaria.inmobiliaria.models import Applicationlog
  File "C:\Users\facun\Desktop\DEV\forreal\backend\Inmobiliaria\inmobiliaria\models.py", line 9, in <module>
    UserModel = get_user_model()
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\contrib\auth\__init__.py", line 194, in get_user_model
    return django_apps.get_model(settings.AUTH_USER_MODEL, require_ready=False)
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\apps\registry.py", line 192, in get_model
    self.check_apps_ready()
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\apps\registry.py", line 127, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Program Files\JetBrains\PyCharm 2019.2.2\helpers\pydev\_pydev_bundle\pydev_monkey.py", line 747, in __call__
    ret = self.original_func(*self.args, **self.kwargs)
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\utils\autoreload.py", line 225, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\core\management\commands\runserver.py", line 112, in inner_run
    autoreload.raise_last_exception()
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\utils\autoreload.py", line 248, in raise_last_exception
    raise _exception[1]
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\core\management\__init__.py", line 327, in execute
    autoreload.check_errors(django.setup)()
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\utils\autoreload.py", line 225, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\__init__.py", line 19, in setup
    configure_logging(settings.LOGGING_CONFIG, settings.LOGGING)
  File "C:\Users\facun\Envs\for-real\lib\site-packages\django\utils\log.py", line 73, in configure_logging
    logging_config_func(logging_settings)
  File "C:\Program Files\Python\lib\logging\config.py", line 799, in dictConfig
    dictConfigClass(config).configure()
  File "C:\Program Files\Python\lib\logging\config.py", line 570, in configure
    '%r' % name) from e
ValueError: Unable to configure handler 'db_handler'

这是我到目前为止的代码:

----settings.py(LOGGING 字典的处理程序部分)----

'handlers': {
        'debug_file': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': 'Logs/DebugTest.log',
        },
        'info_file': {
            'level': 'INFO',
            'class': 'logging.handlers.RotatingFileHandler',
            'maxBytes': 1024*1024*10,  # 10MB
            'backupCount': 10,
            'filename': 'Logs/InfoTest.log',
            'formatter': 'verbose',
        },
        'db_handler': {
            'level': 'INFO',
            'class': 'Inmobiliaria.inmobiliaria.utils.logs.handlers.DatabaseHandler',
            'formatter': 'verbose',
        },
    },

----handlers.py----

import logging
from Inmobiliaria.inmobiliaria.services.application_log_services import create_application_log


class DatabaseHandler(logging.Handler):
    """
    Logging handler that inserts log messages into the database
    """
    def __init__(self):
        logging.Handler.__init__(self)

    def emit(self, record):
        msg: logging.LogRecord = self.format(record)
        ret_val = create_application_log(msg.msg, msg.levelname, msg.thread, msg.process, msg.filename, msg.lineno, msg.created)
        print(ret_val)

此handlers.py文件位于

Inmobiliaria
    inmobiliaria
        utils
            logs
                handlers.py <-----

希望你能帮助我。

非常感谢!

Answer 1

此错误是由先有鸡还是先有蛋的问题引起的。如果我理解正确的话，处理程序正在使用 django 模型记录到数据库。所有 django 模型都需要加载设置并初始化 django 应用程序才能使用。但必须先初始化日志记录，然后才能加载应用程序。为了解决这个问题，您必须删除处理程序对模型的依赖，例如，在 django 模型外部创建连接并将其插入。或者，您可以尝试通过将其设为本地导入来延迟导入模型的使用。