如何在python日志记录中插入换行符? [英] How to insert newline in python logging?

问题描述

import logging
logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)s %(message)s', datefmt='%H:%M:%S')
logging.info('hello')
logging.warning('\n new hello')

11:15:01信息你好
11:16:49警告
 新问好

11:15:01 INFO hello
11:16:49 WARNING
 new hello

由于日志很拥挤，我想在之前 asctime和levelname显式插入换行符.无需修改format，这是否可能?

Because the log is crowded, I want to explicitly insert a newline before asctime and levelname. Is this possible without modifying format?

我调查了logging模块并用谷歌搜索了一下，找不到可行的方法.

I looked into logging module and googled a bit and could not find a viable way.

推荐答案

我有两个解决方案，第一个很简单，但是输出不是很干净.第二种方法将产生所需的确切输出，但涉及更多.

I have two solutions, the first is very easy, but the output is not very clean. The second method will produce the exact output you want, but it is a little more involved.

要产生空白行，只需用新行记录一个空字符串:

To produce a blank line, just log an empty string with a new line:

import logging
logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)s %(message)s', datefmt='%H:%M:%S')
logging.info('hello')
logging.info('\n')
logging.warning('new hello')

输出将有一个空的信息行，这不是很干净:

The output will have an empty info line, which is not very clean:

16:07:26信息你好
16:07:26信息

16:07:26 INFO hello
16:07:26 INFO

16:07:26警告您好

16:07:26 WARNING new hello

方法2

在此方法中，我创建了两个不同的处理程序.我大部分时间使用的console_handler.当我需要换行时，我切换到第二个处理程序blank_handler.

Method 2

In this method, I created two different handlers. The console_handler which I use most of the time. When I need a new line, I switch to a second handler, blank_handler.

import logging
import types

def log_newline(self, how_many_lines=1):
    # Switch handler, output a blank line
    self.removeHandler(self.console_handler)
    self.addHandler(self.blank_handler)
    for i in range(how_many_lines):
        self.info('')

    # Switch back
    self.removeHandler(self.blank_handler)
    self.addHandler(self.console_handler)

def create_logger():
    # Create a handler
    console_handler = logging.StreamHandler()
    console_handler.setLevel(logging.DEBUG)
    console_handler.setFormatter(logging.Formatter(fmt="%(name)s %(levelname)-8s: %(message)s"))

    # Create a "blank line" handler
    blank_handler = logging.StreamHandler()
    blank_handler.setLevel(logging.DEBUG)
    blank_handler.setFormatter(logging.Formatter(fmt=''))

    # Create a logger, with the previously-defined handler
    logger = logging.getLogger('logging_test')
    logger.setLevel(logging.DEBUG)
    logger.addHandler(console_handler)

    # Save some data and add a method to logger object
    logger.console_handler = console_handler
    logger.blank_handler = blank_handler
    logger.newline = types.MethodType(log_newline, logger)

    return logger

if __name__ == '__main__':
    logger = create_logger()
    logger.info('Start reading database')
    logger.info('Updating records ...')
    logger.newline()
    logger.info('Finish updating records')

输出就是您想要看到的:

The output is what you want to see:

logging_test INFO    : Start reading database
logging_test INFO    : Updating records ...

logging_test INFO    : Finish updating records

讨论

• 如果您可以接受效果不理想的输出，则方法1是可行的.它的优点是简单，省力.
• 第二种方法可以正确地完成工作，但是涉及到一点点.它会创建两个不同的处理程序并进行切换，以实现您的目标.
• 使用方法2的另一个缺点是，您必须通过搜索logging并将其替换为logger来更改代码.您必须注意只更换相关的部件，并保留诸如logging.DEBUG之类的文本.

Discussion

• If you can put up with the less-than-perfect output, method 1 is the way to go. It has the advantage of being simple, least amount of effort.
• The second method does the job correctly, but it is a little involved. It creates two different handlers and switch them in order to achieve your goal.
• Another disadvantage of using method 2 is you have to change your code by searching for logging and replacing them with logger. You must take care replacing only relevant parts and leave such text as logging.DEBUG in tact.

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