python之强大的日志模块--logging

╰+攻爆jí腚メ 2022-05-31 13:37 216阅读 0赞

### 1.简单的将[日志][Link 1]打印到屏幕 ###

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 <td><code style="font-size:14px;line-height:22px;">import&nbsp;logg<a href="http://www.haogongju.net/tag/in" title="in" style="margin:0px;padding:0px;" rel="nofollow">in</a>g logging.de<a href="http://www.haogongju.net/tag/BUG" title="bug" style="margin:0px;padding:0px;" rel="nofollow">bug</a>('This is debug message') logging.<a href="http://www.haogongju.net/tag/info" title="info" style="margin:0px;padding:0px;" rel="nofollow">info</a>('This is info message') logging.warning('This is warning message')</code>&nbsp;<code style="font-size:14px;line-height:22px;">屏幕上打印: WARNING:root:This is warning message</code></td> 
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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][Link 2]为：CR[IT][]ICAL > ERROR > WARNING > INFO > DEBUG > NOTSET，当然也[可以][Link 3]自己[定义][Link 4]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 ###

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 <td><code style="font-size:14px;line-height:22px;">import&nbsp;logging logging.basicConfig(level=logging.DEBUG, &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="http://www.haogongju.net/tag/for" title="for" style="margin:0px;padding:0px;" rel="nofollow">for</a>mat='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s', &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;datefmt='%a, %d %b %Y %H:%M:%S', &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;filename='myapp.log', &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;filemode='w') &nbsp;&nbsp;&nbsp;&nbsp; logging.debug('This is debug message') logging.info('This is info message') logging.warning('This is warning message')</code>&nbsp;<code style="font-size:14px;line-height:22px;">./myapp.log<a href="http://www.haogongju.net/tag/%E6%96%87%E4%BB%B6" title="文件" style="margin:0px;padding:0px;font-weight:400;" rel="nofollow">文件</a>中<a href="http://www.haogongju.net/tag/%E5%86%85%E5%AE%B9" title="内容" style="margin:0px;padding:0px;font-weight:400;" rel="nofollow">内容</a>为: 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</code></td> 
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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][Link 5]，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][Link 6]程序的[路径][Link 7]，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][Link 8]  
 %(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 ###

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 <td><code style="font-size:14px;line-height:22px;">import&nbsp;logging logging.basicConfig(level=logging.DEBUG, &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;format='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s', &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;datefmt='%a, %d %b %Y %H:%M:%S', &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;filename='myapp.log', &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;filemode='w') ################################################################################################# #定义一个StreamHandler，将INFO级别或更高的日志信息打印到<a href="http://www.haogongju.net/tag/%E6%A0%87%E5%87%86" title="标准" style="margin:0px;padding:0px;" rel="nofollow">标准</a>错误，并将其添加到当前的日志处理对象# console&nbsp;=&nbsp;logging.StreamHandler() console.setLevel(logging.INFO) formatter&nbsp;=&nbsp;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')</code>&nbsp;<code style="font-size:14px;line-height:22px;">屏幕上打印: root&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;: INFO&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This is info message root&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;: WARNING&nbsp;&nbsp;This is warning message</code><code style="font-size:14px;line-height:22px;">./myapp.log文件中内容为: 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</code></td> 
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### 4.logging之日志回滚 ###

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：

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 <td>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.TimedRotatingFileHandlerlogging.handlers.SocketHandler: 远程输出日志到TCP/<a href="http://www.haogongju.net/tag/IP" title="IP" style="margin:0px;padding:0px;" rel="nofollow">IP</a>&nbsp;sockets logging.handlers.DatagramHandler:&nbsp;&nbsp;远程输出日志到UDP sockets logging.handlers.SMTPHandler:&nbsp;&nbsp;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<a href="http://www.haogongju.net/tag/Windows" title="Windows" style="margin:0px;padding:0px;" rel="nofollow">Windows</a>&nbsp;NT/2000/<a href="http://www.haogongju.net/tag/XP" title="XP" style="margin:0px;padding:0px;" rel="nofollow">XP</a>的事件日志 logging.handlers.MemoryHandler: 日志输出到<a href="http://www.haogongju.net/tag/%E5%86%85%E5%AD%98" title="内存" style="margin:0px;padding:0px;" rel="nofollow">内存</a>中的制定buffer logging.handlers.HTTPHandler: 通过"GET"或"P<a href="http://www.haogongju.net/tag/OS" title="OS" style="margin:0px;padding:0px;" rel="nofollow">OS</a>T"远程输出到HTTP<a href="http://www.haogongju.net/tag/%E6%9C%8D%E5%8A%A1%E5%99%A8" title="服务器" style="margin:0px;padding:0px;" rel="nofollow">服务器</a></td> 
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由于StreamHandler和FileHandler是[常用][Link 9]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！

### 5.通过logging.config模块配置日志 ###

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 <td><code style="font-size:14px;line-height:22px;">#logger.conf </code><code style="font-size:14px;line-height:22px;">###############################################</code><code style="font-size:14px;line-height:22px;">[loggers] keys=root,example01,example02</code><code style="font-size:14px;line-height:22px;">[logger_root] level=DEBUG handlers=hand01,hand02</code><code style="font-size:14px;line-height:22px;">[logger_example01] handlers=hand01,hand02 qualname=example01 propagate=0</code><code style="font-size:14px;line-height:22px;">[logger_example02] handlers=hand01,hand03 qualname=example02 propagate=0</code><code style="font-size:14px;line-height:22px;">###############################################</code><code style="font-size:14px;line-height:22px;">[handlers] keys=hand01,hand02,hand03</code><code style="font-size:14px;line-height:22px;">[handler_hand01] class=StreamHandler level=INFO formatter=form02 args=(sys.stderr,)</code><code style="font-size:14px;line-height:22px;">[handler_hand02] class=FileHandler level=DEBUG formatter=form01 args=('myapp.log', 'a')</code><code style="font-size:14px;line-height:22px;">[handler_hand03] class=handlers.RotatingFileHandler level=INFO formatter=form02 args=('myapp.log', 'a', 10*1024*1024, 5)</code><code style="font-size:14px;line-height:22px;">###############################################</code><code style="font-size:14px;line-height:22px;">[formatters] keys=form01,form02</code><code style="font-size:14px;line-height:22px;">[formatter_form01] format=%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s datefmt=%a, %d %b %Y %H:%M:%S</code><code style="font-size:14px;line-height:22px;">[formatter_form02] format=%(name)-12s: %(levelname)-8s %(message)s datefmt=</code></td> 
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上例3：

上例4：

### 6.logging是线程[安全][Link 10]的 ###

### 7.logging[重定向][Link 11]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')

We define a custom file-like object called StreamToLogger object which sends anything written to it to a logger instead. We then create two instances of that object and replace sys.stdout and sys.stderr with our fake file-like instances.

The output logfile looks like this:

2011-08-14 14:46:20,573:INFO:STDOUT:Test to standard out  
    2011-08-14 14:46:20,573:ERROR:STDERR:Traceback (most recent call last):  
    2011-08-14 14:46:20,574:ERROR:STDERR:  File "redirect.py", line 33, in   
    2011-08-14 14:46:20,574:ERROR:STDERR:raise Exception('Test to standard error')  
    2011-08-14 14:46:20,574:ERROR:STDERR:Exception  
    2011-08-14 14:46:20,574:ERROR:STDERR::  
    2011-08-14 14:46:20,574:ERROR:STDERR:Test to standard error  
    2011-08-14 14:46:20,573:INFO:STDOUT:Test to standard out
    2011-08-14 14:46:20,573:ERROR:STDERR:Traceback (most recent call last):
    2011-08-14 14:46:20,574:ERROR:STDERR:  File "redirect.py", line 33, in 
    2011-08-14 14:46:20,574:ERROR:STDERR:raise Exception('Test to standard error')
    2011-08-14 14:46:20,574:ERROR:STDERR:Exception
    2011-08-14 14:46:20,574:ERROR:STDERR::
    2011-08-14 14:46:20,574:ERROR:STDERR:Test to standard error

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