模块级函数
logging.getlogger([name]):返回一个logger对象，如果没有指定名字将返回root loggerlogging.debug()、logging.info()、logging.warning()、logging.error()、logging.critical()：设定root logger的日志级别logging.basicconfig():用默认formatter为日志系统建立一个streamhandler，设置基础配置并加到root logger中
示例：logging_level_example.py
代码如下:
import loggingimport syslevels = {‘debug’: logging.debug, ‘info’: logging.info, ‘warning’: logging.warning, ‘error’: logging.error, ‘critical’: logging.critical}if len(sys.argv) > 1: level_name = sys.argv[1] level = levels.get(level_name, logging.notset) logging.basicconfig(level=level)logging.debug(‘this is a debug message’)logging.info(‘this is an info message’)logging.warning(‘this is a warning message’)logging.error(‘this is an error message’)logging.critical(‘this is a critical error message’)
输出：
代码如下:
$ python logging_level_example.py debugdebug:root:this is a debug messageinfo:root:this is an info messagewarning:root:this is a warning messageerror:root:this is an error messagecritical:root:this is a critical error message
$ python logging_level_example.py infoinfo:root:this is an info messagewarning:root:this is a warning messageerror:root:this is an error messagecritical:root:this is a critical error message
loggers
logger.setlevel(lel):指定最低的日志级别，低于lel的级别将被忽略。debug是最低的内置级别，critical为最高logger.addfilter(filt)、logger.removefilter(filt):添加或删除指定的filterlogger.addhandler(hdlr)、logger.removehandler(hdlr)：增加或删除指定的handlerlogger.debug()、logger.info()、logger.warning()、logger.error()、logger.critical()：可以设置的日志级别
示例：simple_logging_module.py
代码如下:
import logging# create loggerlogger = logging.getlogger(“simple_example”)logger.setlevel(logging.debug)# create console handler and set level to debugch = logging.streamhandler()ch.setlevel(logging.debug)# create formatterformatter = logging.formatter(“%(asctime)s – %(name)s – %(levelname)s – %(message)s”)# add formatter to chch.setformatter(formatter)# add ch to loggerlogger.addhandler(ch)# “application” codelogger.debug(“debug message”)logger.info(“info message”)logger.warn(“warn message”)logger.error(“error message”)logger.critical(“critical message”)
输出：
代码如下:
$ python simple_logging_module.py2005-03-19 15:10:26,618 – simple_example – debug – debug message2005-03-19 15:10:26,620 – simple_example – info – info message2005-03-19 15:10:26,695 – simple_example – warning – warn message2005-03-19 15:10:26,697 – simple_example – error – error message2005-03-19 15:10:26,773 – simple_example – critical – critical message
handlers
handler对象负责发送相关的信息到指定目的地。可以通过addhandler()方法添加多个多handlerhandler.setlevel(lel):指定被处理的信息级别，低于lel级别的信息将被忽略handler.setformatter()：给这个handler选择一个格式handler.addfilter(filt)、handler.removefilter(filt)：新增或删除一个filter对象
formatters
formatter对象设置日志信息最后的规则、结构和内容，默认的时间格式为%y-%m-%d %h:%m:%s，下面是formatter常用的一些信息
%(name)s
logger的名字
%(levelno)s
数字形式的日志级别
%(levelname)s
文本形式的日志级别
%(pathname)s
调用日志输出函数的模块的完整路径名，可能没有
%(filename)s
调用日志输出函数的模块的文件名
%(module)s
调用日志输出函数的模块名
%(funcname)s
调用日志输出函数的函数名
%(lineno)d
调用日志输出函数的语句所在的代码行
%(created)f
当前时间，用unix标准的表示时间的浮 点数表示
%(relativecreated)d
输出日志信息时的，自logger创建以 来的毫秒数
%(asctime)s
字符串形式的当前时间。默认格式是 “2003-07-08 16:49:45,896”。逗号后面的是毫秒
%(thread)d
线程id。可能没有
%(threadname)s
线程名。可能没有
%(process)d
进程id。可能没有
%(message)s
用户输出的消息
最后来个完整例子：
代码如下:
import logging# set up logging to file – see previous section for more detailslogging.basicconfig(level=logging.debug, format=’%(asctime)s %(name)-12s %(levelname)-8s %(message)s’, datefmt=’%m-%d %h:%m’, filename=’/temp/myapp.log’, filemode=’w’)# define a handler which writes info messages or higher to the sys.stderrconsole = logging.streamhandler()console.setlevel(logging.info)# set a format which is simpler for console useformatter = logging.formatter(‘%(name)-12s: %(levelname)-8s %(message)s’)# tell the handler to use this formatconsole.setformatter(formatter)# add the handler to the root loggerlogging.getlogger(”).addhandler(console)# now, we can log to the root logger, or any other logger. first the root…logging.info(‘jackdaws love my big sphinx of quartz.’)# now, define a couple of other loggers which might represent areas in your# application:logger1 = logging.getlogger(‘myapp.area1’)logger2 = logging.getlogger(‘myapp.area2’)logger1.debug(‘quick zephyrs blow, vexing daft jim.’)logger1.info(‘how quickly daft jumping zebras vex.’)logger2.warning(‘jail zesty vixen who grabbed pay from quack.’)logger2.error(‘the five boxing wizards jump quickly.’)
运行后，在终端看到的结果
代码如下:
root : info jackdaws love my big sphinx of quartz.myapp.area1 : info how quickly daft jumping zebras vex.myapp.area2 : warning jail zesty vixen who grabbed pay from quack.myapp.area2 : error the five boxing wizards jump quickly.
在日志文件中的结果
代码如下:
10-22 22:19 root info jackdaws love my big sphinx of quartz.10-22 22:19 myapp.area1 debug quick zephyrs blow, vexing daft jim.10-22 22:19 myapp.area1 info how quickly daft jumping zebras vex.10-22 22:19 myapp.area2 warning jail zesty vixen who grabbed pay from quack.10-22 22:19 myapp.area2 error the five boxing wizards jump quickly.
发现debug信息只有在文件中出现，这是因为streamhandler中setlevel是info，可以看出logger.setlevel()和handler.setlevel()的区别
详细信息请参阅 http://docs.python.org/library/logging.html