来自多个模块的Python日志记录问题 [英] Python logging issues from multiple modules

问题描述

我有3个python模块.

I have 3 python modules.

LogManager.py
Runner.py
Other.py

Runner.py是事件链中的第一个主要模块，并且从该模块中调用Other.py内部的功能.

Runner.py is the first main module in the chain of events, and from that module functions inside Other.py are called.

因此，在Runner.py内部，我有一个对LogManager.py

So, inside Runner.py I have a function call to the LogManager.py

logger = LogManager.get_log()

从那里，我可以制作简单的日志，例如logger.critical("OHNOES")

and from there, I can make simple logs, e.g. logger.critical("OHNOES")

我想要get_log函数要做的事情类似于单例模式，如果未设置记录器，它将设置记录器并返回它.否则，它将返回记录器.

What I WANT the get_log function to do, is something similar to a singleton pattern, where if the logger has not been set up, it will set up the logger and return it. Else, it will just return the logger.

LogManager.py的内容:

Contents of LogManager.py:

import logging

def get_log():
    logger = logging.getLogger('PyPro')
    logger.setLevel(logging.DEBUG)

    # create file handler which logs even debug messages
    fh = logging.FileHandler('pypro.log')
    fh.setLevel(logging.DEBUG)

    # create console handler with a higher log level
    ch = logging.StreamHandler()
    ch.setLevel(logging.WARNING)

    # create formatter and add it to the handlers
    fhFormatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
    chFormatter = logging.Formatter('%(levelname)s - %(filename)s - Line: %(lineno)d - %(message)s')
    fh.setFormatter(fhFormatter)
    ch.setFormatter(chFormatter)

    # add the handlers to logger
    logger.addHandler(ch)
    logger.addHandler(fh)

    logger.info("-----------------------------------")
    logger.info("Log system successfully initialised")
    logger.info("-----------------------------------")

    return logger

如您所见，LogManager.get_log()将在每次调用日志时尝试设置日志.真的，我对正在发生的事情有些困惑...

As you can see, LogManager.get_log() will attempt to set up a log each time it is called. Really, I am a bit confused as to exactly what is happening...

Runner.py在其main方法中调用get_log函数. Other.py在全局范围内调用get_log(在导入后立即调用，而不是在任何函数中)

Runner.py calls the get_log function in it's main method. Other.py calls the get_log in the global scope (right after imports, not in any function)

结果是，我所做的所有日志都记录了两次，因为为记录器创建了两次处理程序.

The result is that all of the logs I make are logged twice, as handlers are made twice for the logger.

使get_log函数以其他方式返回同一日志的实例的最简单方法是什么?

What is the simplest way that I am missing to make the get_log function to return an instance of the same log elsewise?

推荐答案

logging模块已经为您实现了单例模式-当您调用logger.getLogger(name)时，它将创建记录器(如果尚未创建)并退回.尽管并不是您要的完全是 ，但我建议您将get_log()重命名为setup_log()，因为这样做是正确的.然后，您只需在代码开头调用一次setup_log().然后，当您实际需要记录器时，只需使用logging.getLogger()，它将返回已配置的记录器.

The logging module already implements a singleton pattern for you - when you call logger.getLogger(name), it will create the logger if it hasn't done so already and return it. Although it's not exactly what you're asking for, I would suggest just renaming get_log() to setup_log(), since that's what it does. Then you can just call setup_log() once, at the beginning of your code. Afterwards, when you actually need the logger, just use logging.getLogger() and it will return the already-configured logger.

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