一、将日志打印到屏幕

import logging

logging.debug('This is debug message')
logging.info('This is info message')
logging.warning('This is warning message')


屏幕输出为:

WARNING:root:This is warning message


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,当然也可以自己定义日志级别。


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

import logging
logging.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')


./Test.log文件中内容为:


Wed, 20 Sep 2017 09:59:34 Test.py[line:14] DEBUG This is debug message
Wed, 20 Sep 2017 09:59:34 Test.py[line:15] INFO This is info message
Wed, 20 Sep 2017 09:59:34 Test.py[line:16] 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


三、将日志同时输出到文件和屏幕


#-*- coding:utf-8 -*-
import logging
logging.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')


屏幕输出为:


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



./Test.log文件输出为:


Wed, 20 Sep 2017 10:17:29 Test.py[line:21] DEBUG This is debug message
Wed, 20 Sep 2017 10:17:29 Test.py[line:22] INFO This is info message
Wed, 20 Sep 2017 10:17:29 Test.py[line:23] WARNING This is warning message


四、日志回滚


import logging
from 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10M
Rthandler = RotatingFileHandler('myapp.log', maxBytes=10*1024*1024,backupCount=5)
Rthandler.setLevel(logging.INFO)
formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')
Rthandler.setFormatter(formatter)
logging.getLogger('').addHandler(Rthandler)
################################################################################################


从上例和本例可以看出,logging有一个日志处理的主对象,其它处理方式都是通过addHandler添加进去的。

logging的几种handle方式如下:


logging.StreamHandler: 日志输出到流,可以是sys.stderr、sys.stdout或者文件
logging.FileHandler: 日志输出到文件

日志回滚方式,实际使用时用RotatingFileHandler和TimedRotatingFileHandler
logging.handlers.BaseRotatingHandler
logging.handlers.RotatingFileHandler
logging.handlers.TimedRotatingFileHandler

logging.handlers.SocketHandler: 远程输出日志到TCP/IP sockets
logging.handlers.DatagramHandler:  远程输出日志到UDP sockets
logging.handlers.SMTPHandler:  远程输出日志到邮件地址
logging.handlers.SysLogHandler: 日志输出到syslog
logging.handlers.NTEventLogHandler: 远程输出日志到Windows NT/2000/XP的事件日志
logging.handlers.MemoryHandler: 日志输出到内存中的制定buffer
logging.handlers.HTTPHandler: 通过"GET"或"POST"远程输出到HTTP服务器


由于StreamHandler和FileHandler是常用的日志处理方式,所以直接包含在logging模块中,而其他方式则包含在logging.handlers模块中,

上述其它处理方式的使用请参见python2.5手册!


五、通过logging.config模块配置日志

#logger.conf

###############################################

[loggers]
keys=root,example01,example02

[logger_root]
level=DEBUG
handlers=hand01,hand02

[logger_example01]
handlers=hand01,hand02
qualname=example01
propagate=0

[logger_example02]
handlers=hand01,hand03
qualname=example02
propagate=0

###############################################

[handlers]
keys=hand01,hand02,hand03

[handler_hand01]
class=StreamHandler
level=INFO
formatter=form02
args=(sys.stderr,)

[handler_hand02]
class=FileHandler
level=DEBUG
formatter=form01
args=('myapp.log', 'a')

[handler_hand03]
class=handlers.RotatingFileHandler
level=INFO
formatter=form02
args=('myapp.log', 'a', 10*1024*1024, 5)

###############################################

[formatters]
keys=form01,form02

[formatter_form01]
format=%(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=


上例3:


import logging
import logging.config

logging.config.fileConfig("logger.conf")
logger = logging.getLogger("example01")

logger.debug('This is debug message')
('This is info message')
logger.warning('This is warning message')


上例4:


import logging
import logging.config

logging.config.fileConfig("logger.conf")
logger = logging.getLogger("example02")

logger.debug('This is debug message')
('This is info message')
logger.warning('This is warning message')