Python记录器:是否会覆盖原始日志?

问题描述

因此，当我将以下x次复制粘贴到python提示符时，它将日志x次添加到指定文件的末尾.

So, when I copy paste the following x times to the python prompt, it add the log x times to the end of the designated file.

如何更改代码，以便每次复制时都将其粘贴到提示中，我只是覆盖了现有文件(代码似乎不接受 mode ='w'选项，或者我似乎不明白其含义)

How can I change the code so that each time I copy paste this to the prompt,I simply overwrite the existing file (the code seems to not accept themode = 'w' option or I do not seem to understand its meaning)

def MinimalLogginf():
    import logging
    import os
    paths = {'work': ''}
    logger = logging.getLogger('oneDayFileLoader')
    LogHandler = logging.FileHandler(os.path.join(paths["work"] , "oneDayFileLoader.log"), mode='w')
    formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
    LogHandler.setFormatter(formatter)
    logger.addHandler(LogHandler)
    logger.setLevel(logging.DEBUG)
    #Let's say this is an error:
    if(1 == 1):
        logger.error('overwrite')

所以我运行了一次:MinmalLoggingf()

So I run it once: MinmalLoggingf()

现在，我希望新的日志文件覆盖上一次运行时创建的日志文件:

Now, I want the new log file to overwrite the log file created on the previous run:

MinmalLoggingf()

推荐答案

如果我正确理解，您一次要运行几天的某个Python进程，并且希望每天轮换一次日志.我建议您使用自动旋转日志文件的处理程序(例如， http://www.blog.pythonlibrary.org/2014/02/11/python-how-to-create-rotating-logs/

If I understand correctly, you're running a certain Python process for days at a time, and want to rotate the log every day. I'd recommend you go a different route, using a handler that automatically rotates the log file, e.g. http://www.blog.pythonlibrary.org/2014/02/11/python-how-to-create-rotating-logs/

但是，如果您想以自己喜欢的相同方法使用过程来控制日志(Python控制台，粘贴代码.任务)，嗯...

But, if you want to control the log using the process in the same method you're comfortable with (Python console, pasting in code.. extremely unpretty and error prone, but sometimes quick-n-dirty is sufficient for the task at hand), well...

您的问题是，每次粘贴代码时，您都会创建一个新的FileHandler，并将其添加到Logger对象.您最终得到了一个附加了X FileHandler的记录器，所有记录器都写入同一文件.试试这个:

Your issue is that you create a new FileHandler each time you paste in the code, and you add it to the Logger object. You end up with a logger that has X FileHandlers attached to it, all of them writing to the same file. Try this:

import logging
paths = {'work': ''}
logger = logging.getLogger('oneDayFileLoader')
if logger.handlers:
   logger.handlers[0].close()
   logger.handlers = []
logHandler = logging.FileHandler(os.path.join(paths["work"] , "oneDayFileLoader.log"), mode='w')
formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
logHandler.setFormatter(formatter)
logger.addHandler(logHandler)
logger.setLevel(logging.DEBUG)
logger.error('overwrite')

根据您的请求，我还添加了一个使用TimedRotatingFileHandler的示例.请注意，我尚未在本地对其进行测试，因此，如果您遇到问题，请回信.

Based on your request, I've also added an example using TimedRotatingFileHandler. Note I haven't tested it locally, so if you have issues ping back.

import logging
from logging.handlers import TimedRotatingFileHandler

logPath = os.path.join('', "fileLoaderLog")
logger = logging.getLogger('oneDayFileLoader')
logHandler = TimedRotatingFileHandler(logPath,
                                   when="midnight",
                                   interval=1)
formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
logHandler.setFormatter(formatter)
logger.addHandler(logHandler)
logger.setLevel(logging.DEBUG)
logger.error('overwrite')

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