1.簡單的將日志打印到屏幕

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

屏幕上打印:

WARNING:root:This is warning message

默認(rèn)情況下，logging將日志打印到屏幕，日志級別為WARNING；日志級別大小關(guān)系為：CRITICAL > ERROR > WARNING > INFO > DEBUG > NOTSET，當(dāng)然也可以自己定義日志級別。

2.通過logging.basicConfig函數(shù)對日志的輸出格式及方式做相關(guān)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='myapp.log',
    filemode='w')   
logging.debug('This is debug message')
logging.info('This is info message')
logging.warning('This is warning message')

./myapp.log文件中內(nèi)容為:

Sun, 24 May 2009 21:48:54 demo2.py[line:11] DEBUG This is debug message
Sun, 24 May 2009 21:48:54 demo2.py[line:12] INFO This is info message
Sun, 24 May 2009 21:48:54 demo2.py[line:13] WARNING This is warning message

logging.basicConfig函數(shù)各參數(shù):

日志格式format:

3.將日志同時(shí)輸出到文件和屏幕

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='myapp.log',
                filemode='w')

#############################################################################
#定義一個(gè)StreamHandler，將INFO級別或更高的日志信息打印到標(biāo)準(zhǔn)錯(cuò)誤,并將其添加到當(dāng)前的日志處理對象
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')

屏幕上打印:

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

./myapp.log文件中內(nèi)容為:

Sun, 24 May 2009 21:48:54 demo2.py[line:11] DEBUG This is debug message
Sun, 24 May 2009 21:48:54 demo2.py[line:12] INFO This is info message
Sun, 24 May 2009 21:48:54 demo2.py[line:13] WARNING This is warning message

4.logging之日志回滾

import logging
from logging.handlers import RotatingFileHandler
#############################################################################
#定義一個(gè)RotatingFileHandler，最多備份5個(gè)日志文件，每個(gè)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)
#############################################################################

從上例和本例可以看出，logging有一個(gè)日志處理的主對象，其它處理方式都是通過addHandler添加進(jìn)去的。logging的幾種handle方式如下：

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

日志回滾方式，實(shí)際使用時(shí)用RotatingFileHandler和TimedRotatingFileHandler
logging.handlers.BaseRotatingHandler
logging.handlers.RotatingFileHandler
logging.handlers.TimedRotatingFileHandler

logging.handlers.SocketHandler: 遠(yuǎn)程輸出日志到TCP/IP socketslogging.handlers.DatagramHandler:  遠(yuǎn)程輸出日志到UDP socketslogging.handlers.SMTPHandler:  遠(yuǎn)程輸出日志到郵件地址
logging.handlers.SysLogHandler: 日志輸出到syslog
logging.handlers.NTEventLogHandler: 遠(yuǎn)程輸出日志到Windows NT/2000/XP的事件日志
logging.handlers.MemoryHandler: 日志輸出到內(nèi)存中的制定buffer
logging.handlers.HTTPHandler: 通過"GET"或"POST"遠(yuǎn)程輸出到HTTP服務(wù)器

由于StreamHandler和FileHandler是常用的日志處理方式，所以直接包含在logging模塊中，而其他方式則包含在logging.handlers模塊中，上述其它處理方式的使用請參見python2.5手冊！

5.通過logging.config模塊配置日志

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

6.logging是線程安全的