Python Module Learning Logging

1. 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 ')



On-screen printing:
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 information message ')
Logging.warning (' This is warning message ')



./myapp.log file:
Sun, May 2 009 21:48:54 Demo2.py[line:11] Debug This is DEBUG message
Sun, $21:48:54 demo2.py[line:12] INFO this is INF O message
Sun, 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 ')



On-screen printing:
Root:info This is INFO message
Root:warning This is WARNING message

The contents of the./myapp.log file are:
Sun, 21:48:54 demo2.py[line:11] Debug this is debug message
Sun, 21:48:54 Demo2.py[line:12] Info this is info message
Sun, 21:48:54 demo2.py[line:13] WARNING This is WARNING message

4.logging Log Rollback

Import loggingfrom logging.handlers Import rotatingfilehandler#################################################### ############################################# #定义一个RotatingFileHandler, backup up to 5 log files, maximum 10MRthandler per log file 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 in practice 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=
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 ')
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 is thread-safe

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