python之强大的日志模块

py3study

发布于 2020-01-10 11:13:57

3490

发布于 2020-01-10 11:13:57

作者：txw1958 | 出处：博客园 | 2011/10/21 19:41:55 | 阅读43次

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:
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: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之日志回滚

import loggingfrom 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TimedRotatingFileHandlerlogging.handlers.BaseRotatingHandlerlogging.handlers.RotatingFileHandlerlogging.handlers.TimedRotatingFileHandler
logging.handlers.SocketHandler: 远程输出日志到TCP/IP socketslogging.handlers.DatagramHandler:  远程输出日志到UDP socketslogging.handlers.SMTPHandler:  远程输出日志到邮件地址logging.handlers.SysLogHandler: 日志输出到sysloglogging.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bufferlogging.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！

5.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 loggingimport 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 loggingimport 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是线程安全的

7.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')

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

本文参与腾讯云自媒体分享计划，分享自作者个人站点/博客。

原始发表：2019-07-26 ，如有侵权请联系 cloudcommunity@tencent.com 删除

日志服务

python

本文分享自作者个人站点/博客前往查看

如有侵权，请联系 cloudcommunity@tencent.com 删除。

本文参与腾讯云自媒体分享计划，欢迎热爱写作的你一起参与！

日志服务

python

登录后参与评论

0 条评论

热度