Python logging

2019-11-11 01:57:57

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python的logging主要有四个组件： * logger: 日志类，应用程序往往通过调用它提供的api来记录日志； * handler: 对日志信息处理，可以将日志发送(保存)到不同的目标域中； * filter: 对日志信息进行过滤； * formatter:日志的格式化；

logging是线程安全的。

控制台输出

默认情况下，logging将日志打印到屏幕，日志级别为WARNING。日志级别大小关系为：CRITICAL > ERROR > WARNING > INFO > DEBUG > NOTSET。

# -*- coding: utf-8 -*-import logginglogging.debug('This is debug message')logging.info('This is info message')logging.warning('This is warning message')

输出

WARNING:root:This is warning message

通过logging.basicConfig函数对日志的输出格式及方式做相关配置

# -*- coding: utf-8 -*-import logginglogging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s', datefmt='%a, %d %b %Y %H:%M:%S', filename='test.log', filemode='w')logging.debug('This is debug message')logging.info('This is info message')logging.warning('This is warning message')

当前目录下test.log内容：

Tue, 07 Feb 2017 19:51:36 python-logging.py[line:10] DEBUG This is debug messageTue, 07 Feb 2017 19:51:36 python-logging.py[line:11] INFO This is info messageTue, 07 Feb 2017 19:51:36 python-logging.py[line:12] WARNING This is warning message

logging.basicConfig函数各参数: - filename: 指定日志文件名 - filemode: 和file函数意义相同，指定日志文件的打开模式，’w’或’a’ - format: 指定输出的格式和内容，format可以输出很多有用信息，如上例所示: - %(levelno)s: 打印日志级别的数值 - %(levelname)s: 打印日志级别名称 - %(pathname)s: 打印当前执行程序的路径，其实就是sys.argv[0] - %(filename)s: 打印当前执行程序名 - %(funcName)s: 打印日志的当前函数 - %(lineno)d: 打印日志的当前行号 - %(asctime)s: 打印日志的时间 - %(thread)d: 打印线程ID - %(threadName)s: 打印线程名称 - %(PRocess)d: 打印进程ID - %(message)s: 打印日志信息 - datefmt: 指定时间格式，同time.strftime() - level: 设置日志级别，默认为logging.WARNING - stream: 指定将日志的输出流，可以指定输出到sys.stderr,sys.stdout或者文件，默认输出到sys.stderr，当stream和filename同时指定时，stream被忽略

将日志同时输出到文件和屏幕

# -*- coding: utf-8 -*-import logginglogging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s', datefmt='%a, %d %b %Y %H:%M:%S', filename='test.log', filemode='w')################################################################################################## 定义一个StreamHandler，将INFO级别或更高的日志信息打印到标准错误，并将其添加到当前的日志处理对象console = logging.StreamHandler()console.setLevel(logging.INFO)formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')console.setFormatter(formatter)logging.getLogger('').addHandler(console)#################################################################################################logging.debug('This is debug message')logging.info('This is info message')logging.warning('This is warning message')

当前目录下test.log内容：

Tue, 07 Feb 2017 19:56:23 python-logging.py[line:19] DEBUG This is debug messageTue, 07 Feb 2017 19:56:23 python-logging.py[line:20] INFO This is info messageTue, 07 Feb 2017 19:56:23 python-logging.py[line:21] WARNING This is warning message

控制台输出：

root : INFO This is info messageroot : WARNING This is warning message

日志回滚

# -*- coding: utf-8 -*-import loggingfrom logging.handlers import RotatingFileHandler################################################################################################## 定义一个RotatingFileHandler，最多备份5个日志文件，每个日志文件最大10Mr_handler = RotatingFileHandler('test.log', maxBytes=10*1024*1024, backupCount=5)r_handler.setLevel(logging.INFO)formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')r_handler.setFormatter(formatter)logging.getLogger('').addHandler(r_handler)

通过logging.config模块配置日志

#logger.conf###############################################[loggers]keys=root,example01,example02[logger_root]level=DEBUGhandlers=hand01,hand02[logger_example01]handlers=hand01,hand02qualname=example01propagate=0[logger_example02]handlers=hand01,hand03qualname=example02propagate=0###############################################[handlers]keys=hand01,hand02,hand03[handler_hand01]class=StreamHandlerlevel=INFOformatter=form02args=(sys.stderr,)[handler_hand02]class=FileHandlerlevel=DEBUGformatter=form01args=('test.log', 'a')[handler_hand03]class=handlers.RotatingFileHandlerlevel=INFOformatter=form02args=('test.log', 'a', 10*1024*1024, 5)###############################################[formatters]keys=form01,form02[formatter_form01]format=%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)sdatefmt=%a, %d %b %Y %H:%M:%S[formatter_form02]format=%(name)-12s: %(levelname)-8s %(message)sdatefmt=%a, %d %b %Y %H:%M:%S

将日志同时输出到文件和屏幕的例子：

# -*- coding: utf-8 -*-import logging.configlogging.config.fileConfig("logger.conf")logger = logging.getLogger("example01")logger.debug('This is debug message')logger.info('This is info message')logger.warning('This is warning message')

日志回滚的例子：

# -*- coding: utf-8 -*-import logging.configlogging.config.fileConfig("logger.conf")logger = logging.getLogger("example02")logger.debug('This is debug message')logger.info('This is info message')logger.warning('This is warning message')

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