python打印日志

https://blog.csdn.net/lxc521wjh/article/details/53212729

通过logging.basicConfig函数对日志的输出格式及方式做相关配置。logging.basicConfig(**kwargs) 该函数必须在main函数线程除外的子线程启动之前调用，否则可能会造成日志重复记录

import logging   fmt = '%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s: %(message)s' logging.basicConfig(level=logging.DEBUG,                     format=fmt,                     filename='D:\Python\logs.txt',                     filemode='w',                     datefmt='%a, %d %b %Y %H:%M:%S'                     ) logging.debug('this is a debug level message') logging.info("this is a info level message") logging.warning("this is a warning level message") logging.error("this is a error level message") logging.critical("this is a critical level message")

 

运行：

'D:\Python\logs.txt',

 

将日志同时输出到文件和屏幕

import logging   fmt = '%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s: %(message)s' logging.basicConfig(level=logging.DEBUG,                     format=fmt,                     filename='D:\Python\logs.txt',                     filemode='w+',                     datefmt='%a, %d %b %Y %H:%M:%S'                     )     console = logging.StreamHandler() console.setLevel(logging.DEBUG) #设置控制台日志输出的级别。如果设置为logging.INFO，就不会输出DEBUG日志信息   formatter = logging.Formatter(fmt) console.setFormatter(formatter) logging.getLogger().addHandler(console)   logging.debug('this is a debug level message') logging.info("this is a info level message") logging.warning("this is a warning level message") logging.error("this is a error level message") logging.critical("this is a critical level message")

运行：

D:\Python\logs.txt:

 

RotatingFileHander模块，用于自动切换日志写入文件，保证单个日志文件不会太大

import logging from logging.handlers import RotatingFileHandler   fmt = '%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s: %(message)s' logging.basicConfig(level=logging.DEBUG,                     format=fmt,                     filename='D:\Python\logs.txt',                     filemode='w+',                     datefmt='%a, %d %b %Y %H:%M:%S'                     )     console = logging.StreamHandler() console.setLevel(logging.DEBUG)   formatter = logging.Formatter(fmt) console.setFormatter(formatter) logging.getLogger().addHandler(console)       rt_file_handler = RotatingFileHandler('d:\Python\logs1.txt',maxBytes = 100,backupCount=5) rt_file_handler.setLevel(logging.INFO) formatter = logging.Formatter('%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s') rt_file_handler.setFormatter(formatter)   logger = logging.getLogger() logger.addHandler(rt_file_handler)   logging.debug('this is a debug level message') logging.info("this is a info level message") logging.warning("this is a warning level message") logging.error("this is a error level message") logging.critical("this is a critical level message")

运行:

  

通过logging.config模块配置日志

注意：配置文件必须包含[loggers], [handlers],[formatters], 且每个节点下的logger, handler, formatter都必须有对应的节点，且格式正确：[loggers_logger], [handlers_handler], [handlers_formatter]

 

D:/log.conf文件如下： [loggers] keys=root,eg01,eg02    #注：[logger_root]为root logger专用 [logger_root] level=NOTSET handlers=handler01, handler02   [logger_eg01] handlers=handler01 qualname=eg01 propagate=0 #propagete=0,表示输出日志，但消息不传递；propagate=1是输出日志，同时消息往更高级别的地方传递。若这里的参数progagate=1，那么将会看到重复的消息记录   [logger_eg02] handlers=handler02 qualname=eg02 #qualname指定logger的名称 propagate=0   [handlers] keys=handler01,handler02   [handler_handler01] class=StreamHandler #指定handler的类型 level=WARNING formatter=form01 args=(sys.stdout,) #根据class的不同而不同，即handler类型的初始化参数。详情可参考官方logging.conf模块。   [handler_handler02] class=FileHandler level=ERROR formatter=form02 args=('d:/logs.txt', 'a')   [formatters] keys=form01,form02   [formatter_form01] format=%(name)s: %(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s datefmt=%a, %d %b %Y %H:%M:%S   [formatter_form02] format=%(name)-12s: %(levelname)-8s %(message)s datefmt=

说明：当[logger_logname]和[handler_handlername]中同时指定了level值时，使用[handler_handlername]中设置的level。