日志机制的区别:API 和应用程序(python) [英] difference in logging mechanism: API and application(python)

问题描述

我目前正在编写一个 API 和一个使用该 API 的应用程序.我从人们那里得到了一些建议，他们说我应该在应用程序中使用处理程序执行日志记录，并使用记录器"对象从 API 进行日志记录.

I am currently writing an API and an application which uses the API. I have gotten suggestions from people stating that I should perform logging using handlers in the application and use a "logger" object for logging from the API.

根据我上面收到的建议，以下实现是否正确?

In light of the advice I received above, is the following implementation correct?

class test:
    def __init__(self, verbose):
        self.logger = logging.getLogger("test")
        self.logger.setLevel(verbose)

    def do_something(self):
        # do something
        self.logger.log("something")
        # by doing this i get the error message "No handlers could be found for logger "test"

我想到的实现如下:

 #!/usr/bin/python

 """ 
 ....
 ....
 create a logger with a handler 
 ....
 ....

 """

 myobject = test()
 try:
     myobject.do_something()
 except SomeError:
     logger.log("cant do something")

我想让我的基础知识扎实，我非常感谢您对代码的任何帮助和建议，我可能会推荐我查找.

Id like to get my basics strong, id be grateful for any help and suggestions for code you might recommend I look up.

谢谢！

推荐答案

你的问题是关于如何使用日志记录的细节还是关于日志记录异常，我不太清楚，但如果是后者，我会同意 Adam Crossland 的观点log-and-swallow 是一种需要避免的模式.

It's not very clear whether your question is about the specifics of how to use logging or about logging exceptions, but if the latter, I would agree with Adam Crossland that log-and-swallow is a pattern to be avoided.

就日志记录的机制而言，我会提出以下意见:

In terms of the mechanics of logging, I would make the following observations:

1. 您不需要将记录器作为实例成员.使用 logger = logging.getLogger(__name__) 在模块级别声明记录器更自然，这也将在子包中按预期工作.
2. 您的调用 logger.log("message") 无论如何都可能会失败，因为 log 方法将级别作为第一个参数，而不是消息.

1. You don't need to have a logger as an instance member. It's more natural to declare loggers at module level using logger = logging.getLogger(__name__), and this will also work as expected in sub-packages.
2. Your call logger.log("message") would likely fail anyway because the log method has a level as the first argument, rather than a message.

你应该声明处理程序，如果你的使用场景相当简单，你可以在你的 main 方法或 if __name__ == '__main__': 子句中添加例如

You should declare handlers, and if your usage scenario is fairly simple you can do this in your main method or if __name__ == '__main__': clause by adding for example

logging.basicConfig(filename='/tmp/myapp.log', level=logging.DEBUG, 
                    format='%(asctime)s %(levelname)s %(name)s %(message)s')

然后在您的代码中的其他地方，例如

and then elsewhere in your code, just do for example

import logging
logger = logging.getLogger(__name__)

在要使用日志记录的每个模块的顶部一次，然后

once at the top of each module where you want to use logging, and then

logger.debug('message with %s', 'arguments') # or .info, .warning, .error etc.

在您的代码中需要的地方.

in your code wherever needed.

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