python日志模块logging

1.简单的将日志打印到屏幕

import logging
logging.debug('This is debug message')
logging.info('This is info message')
logging.warning('This is warning message')
屏幕上打印:
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。

2.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='myapp.log',
                filemode='w')
logging.debug('This is debug message')
logging.info('This is info message')
logging.warning('This is warning message')
./myapp.log文件中内容为:
Thur, 8 Jan 2015 21:48:54 demo2.py[line:11] DEBUG This is debug message
Thur, 8 Jan 2015 21:48:54 demo2.py[line:12] INFO This is info message
Thur, 8 Jan 2015 21:48:54 demo2.py[line:13] 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

3.将日志同时输出到文件和屏幕

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')
屏幕上打印:
root        : INFO     This is info message
root        : WARNING  This is warning message
./myapp.log文件中内容为:
Thur, 8 Jan 2015 21:48:54 demo2.py[line:11] DEBUG This is debug message
Thur, 8 Jan 2015 21:48:54 demo2.py[line:12] INFO This is info message
Thur, 8 Jan 2015 21:48:54 demo2.py[line:13] WARNING This is warning message

4.logging之日志回滚

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python手册!

5.通过logging.config模块配置日志

logger配置文件:

#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=

调用示例:

示例1:
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')
示例2:
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重定向strerr,strout

import logging
import sys
class StreamToLogger(object):
   """
   Fake file-like stream object that redirects writes to a logger instance.
   """
   def __init__(self, logger, log_level=logging.INFO):
      self.logger = logger
      self.log_level = log_level
      self.linebuf = ''
   def write(self, buf):
      for line in buf.rstrip().splitlines():
         self.logger.log(self.log_level, line.rstrip())
logging.basicConfig(
   level=logging.DEBUG,
   format='%(asctime)s:%(levelname)s:%(name)s:%(message)s',
   filename="out.log",
   filemode='a'
)
stdout_logger = logging.getLogger('STDOUT')
sl = StreamToLogger(stdout_logger, logging.INFO)
sys.stdout = sl
stderr_logger = logging.getLogger('STDERR')
sl = StreamToLogger(stderr_logger, logging.ERROR)
sys.stderr = sl
print "Test to standard out"
raise Exception('Test to standard error')

其输出格式类似如下:

2015-01-08 22:10:20,573:INFO:STDOUT:Test to standard out
2015-01-08 22:10:20,573:ERROR:STDERR:Traceback (most recent call last):
2015-01-08 22:10:20,574:ERROR:STDERR:  File "redirect.py", line 33, in
2015-01-08 22:10:20,574:ERROR:STDERR:raise Exception('Test to standard error')
2015-01-08 22:10:20,574:ERROR:STDERR:Exception
2015-01-08 22:10:20,574:ERROR:STDERR::
2015-01-08 22:10:20,574:ERROR:STDERR:Test to standard error
2015-01-08 22:10:20,573:INFO:STDOUT:Test to standard out
2015-01-08 22:10:20,573:ERROR:STDERR:Traceback (most recent call last):
2015-01-08 22:10:20,574:ERROR:STDERR:  File "redirect.py", line 33, in
2015-01-08 22:10:20,574:ERROR:STDERR:raise Exception('Test to standard error')
2015-01-08 22:10:20,574:ERROR:STDERR:Exception
2015-01-08 22:10:20,574:ERROR:STDERR::
2015-01-08 22:10:20,574:ERROR:STDERR:Test to standard error




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  1. 2016年6月4日22:14 | #1

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