Python's log module logging and syslog

The Syslog module is a module that works in a UNIX environment and is not available for Windows, and can be used with the logging module in a Windows environment.

　First, syslog

The Syslog module can be used to record information about the operation of the system, which is provided by a syslog (Priority,message), which feeds a message into the system log, and the default option for priority is Log_info,openlog ([ Ident[,logoption[,facility]]), which is used to open the log, ident will be added to each log, Logoption is the log option, facility is an optional tool parameter. Closelog () is used to close the log.

The order of priority priorities from high to low is: Log_emerg, Log_alert, Log_crit, Log_err, log_warning, Log_notice,log_info, Log_debug,

By default, it is Log_info.

Syslog logging options are log_cons,log_ndelay,log_nowait,log_pid,log_perror.

The options for facility are LOG_AUTH,LOG_CRON,LOG_DAEMON,LOG_KERN,LOG_LOCALX,LOG_MAIL,LOG_NEWS,LOG_USER,LOG_UUCP.

#!/usr/bin/env pythonImportSyslog,sys,ossys.openlog (): Syslog.openlog ("%s[%d]") %(Os.path.basename (Sys.argv[0],os.getpid ()), 0,syslog. Log_daemon) Syslog.syslog ("stared")Try:    Raiseruntimeerror,e:except: Type,exception,trace=sys.exc_info () Excclass=str (Exception.__class__) Message=Str (Exception) Syslog.syslog (syslog. ERROR,"%s:%s"% (Excclass,message))

Openlog,syslog These two functions and combined with the syslog.conf configuration, you can customize a very good logging function. Through the Openlog function, we can classify the information into what file and take the Syslog function parameters to what kind of service level can be recorded to what kind of file, the premise needs to syslog.conf the match. Below I will use popular language and examples to illustrate the following functions: Syslog.openlog (ident[, logopt[, facility]) This is the function that initializes the Syslog interface, where there is a required parameter and two optional parameters. The first parameter, ident, is an identity string, which is the name of the program in each line of the log, such as: Syslog.openlog ("test.py") Syslog.syslog ("The process is test.py") Tail-n 1/ VAR/LOG/MESSAGESAPR 16:26:52 databak test.py:The process is test.py right? You got it, don't you? Second parameter, logopt option name: Log_cons,log_ndelay,log_nowait,log_pid,log_perror You can select one or more (to use or operator "|"), such as: Syslog.openlog ("test.py", syslog.) Log_pid|syslog. Log_perror) Syslog.syslog ("The messages print PID and messages print to stderr") >>> Syslog.syslog ("the messages P Rint PID and messages print to stderr ") test.py[16826]: The messages print PID and messages print to stderr This function, you understand? Next, we look at the Syslog function in the above example, the Syslog function has been accompanied by us, I believe that we have seen a bit of the doorway, and now I still put the function of publicity to everyone. Syslog.syslog ([ Priority], messageThere are two parameters, an optional one must write. The message is needless to say, I have all the examples, just to illustrate the optional parameters. Priority, Name: Log_emerg,log_alert,log_crit,log_err,log_warning,log_info,log_debug (default = Log_info) We want to write the authentication error information to the Python.err file, then modify the Syslog.confauth.err/var/log/python.err See program: Syslog . Openlog ("test.py", syslog. Log_pid,syslog. Log_auth) Syslog.syslog (Syslog. Log_err, "Add error information to python.err file") Second, logging1. Simply print the log to the screen

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

By default, logging prints the log to the screen with a log level of warning;
Log level size relationships are: CRITICAL > ERROR > WARNING > INFO > DEBUG > NOTSET, and of course you can define the log level yourself.

2. Configure the output format and mode of the log by Logging.basicconfig function

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

Parameters of the Logging.basicconfig function:
FileName: Specify the log file name
FileMode: Same as file function, specify open mode of log file, ' W ' or ' a '
Format: Specifies the formats and contents of the output, format can output a lot of useful information, as in the example above:
% (Levelno) S: Print the value of the log level
% (levelname) S: Print log level name
% (pathname) s: Prints the path of the currently executing program, which is actually sys.argv[0]
% (filename) s: Prints the current name of the executing program
% (funcName) s: Print the current function of the log
% (Lineno) d: Print the current line number of the log
% (asctime) s: Time to print logs
% (thread) d: Print thread ID
% (threadname) s: Print thread name
% (process) d: Print process ID
% (message) s: Print log information
DATEFMT: Specify time format, same as Time.strftime ()
Level: Sets the log levels by default to logging. WARNING
Stream: Specifies the output stream that will log, can specify output to Sys.stderr,sys.stdout or file, default output to Sys.stderr, stream is ignored when stream and filename are specified simultaneously

3. Output logs to both file and screen at the same time

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, print Info-level or higher log information to a standard error and add it to the current log-processing object # 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 Log Rollback

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) ################################################################################################

As can be seen from the above example and in this example, logging has a main object of log processing, and other processing methods are added through AddHandler.
Several handle methods of logging are as follows:

Logging. Streamhandler: Log output to stream, can be sys.stderr, sys.stdout, or file Logging. Filehandler: Log output to File Log rollback method, using Rotatingfilehandler and Timedrotatingfilehandler when actually used Logging.handlers.BaseRotatingHandler Logging.handlers.RotatingFileHandler Logging.handlers.TimedRotatingFileHandler Logging.handlers.SocketHandler: Remote output log to TCP/IP sockets Logging.handlers.DatagramHandler: Remote output log to UDP sockets Logging.handlers.SMTPHandler: Remote output log to e-mail address Logging.handlers.SysLogHandler: Log Output to Syslog Logging.handlers.NTEventLogHandler: Remote output log to Windows NT/2000/XP event log Logging.handlers.MemoryHandler: Log output to in-memory development buffer Logging.handlers.HTTPHandler: Remote output to HTTP server via "GET" or "POST"

Because Streamhandler and filehandler are common log processing methods, they are included directly in the logging module, while others are included in the Logging.handlers module.
Please refer to the python2.5 manual for the use of the other processing methods described above.

5. Configuring logs via the Logging.config module

#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=

In Example 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‘)

In Example 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 is thread-safe

Python's log module logging and syslog