Python-Common modules-logging modules

Python primarily uses the logging module for log processing

Many programs have logging requirements, and the log contains information that has a normal program Access log, there may be errors, warnings and other information output, Python's logging module provides a standard log interface,

You can store logs in various formats through it, logging logs can be divided into debug (), info (), warning (), error (), critical () 5 levels,

Log level:
DEBUG
INFO
WARNING
ERROR
CRITICAL
Rank in turn (less information is printed, debug most detailed)

1 Log Format:2%(name) s logger name (default root)3%(Levelno) The log level in the S-word form is:4Debug:10 info:20 warning:30 error:40 critical:505%(levelname) s log level in text form6%(pathname) s The full pathname of the module that invokes the log output function, possibly without7%(filename) s The file name of the module that invokes the log output function8%module Name of the log output function called by (module) s9%(message) s user-output messagesTen%(funcName) s function name of the call log output function One%(Lineno) d The line of code where the statement that invokes the log output function A%(created) F current time, represented by the UNIX standard floating-point number representing the time -%(relativecreated) d when the log information is output, the number of milliseconds since logger was created -% (asctime) s The current time in string form. The default format is "2003-07-08 16:49:45,896". The comma is followed by milliseconds the%(thread) d thread ID. Probably not . -%(threadname) s thread name. Probably not . -% (process) d process ID. Probably not.

The Log module uses:

1, the simplest use, print to the screen (without print, bring your own printing)

1 Import Logging 2 logging.warning ('user [root] attempted wrong password more than 3times') 
    3 logging.critical ('serveris down'

#想要debug (), info (), or error () Just like above, add it.

2. Set the time

1 Import Logging 2 logging.basicconfig (format='% (asctime) s% (message) s', datefmt=' %y-%m-%d%h:%m:%s ' )3 logging.warning ("is"when thisevent was logged. ')

3. Write the log to the file

1 ImportLogging2 3Logging.basicconfig (filename='./file/logging.log', level=logging. debug,format='% (asctime) s% (name) s-% (LevelName) s->% (Levelno) s:% (message) s', datefmt='%y-%m-%d%h:%m:%s')4Logging.debug ('This message should go to the log file')5Logging.info ('So should this')6Logging.warning ('and this, too')7Logging.error ('and this, too')8Logging.critical ('and this, too')

File contents:

2017-04-04 17:14:10 root-debug->10:this message should go to the log file
2017-04-04 17:14:10 Root-info->20:so should this
2017-04-04 17:14:10 root-warning->30:and This, too
2017-04-04 17:14:10 root-error->40:and This, too
2017-04-04 17:14:10 root-critical->50:and This, too

4. Write the log at the same time to the file and print to the screen

1 " "2 Python uses the logging module to log logs involving four main classes, which are best used in the official documentation:3 4 logger provides an interface that the application can use directly;5 Logger.setlevel (LEL): Specifies the lowest log level, and the level below LEL is ignored. Debug is the lowest built-in level, critical is the highest6 Logger.addfilter (filt), Logger.removefilter (filt): Add or remove the specified filter7 Logger.addhandler (HDLR), Logger.removehandler (HDLR): Add or remove the specified handler8 logger.debug (), Logger.info (), logger.warning (), Logger.error (), logger.critical (): Log levels you can set9 Ten handler sends the log record (created by logger) to the appropriate destination output; One Handler.setlevel (LEL): Specifies the level of information being processed, and information below the LEL level is ignored A handler.setformatter (): Choose a format for this Handler - Handler.addfilter (filt), Handler.removefilter (filt): Add or remove a filter object -  the Filter provides a fine-grained device to determine which log record to output; -  - Formatter determines the final output format of the log record.  - " " + ImportLogging -  + #Create Logger ALogger = Logging.getlogger ('Xt-log') at Logger.setlevel (logging. DEBUG) -      #set the global log level (global precedence is higher than local but local if local to global) -       - #Create a console handler, and set its log level to debug -CH =logging. Streamhandler () - Ch.setlevel (logging. DEBUG) in  - #Create a file handler, and set its log level to warning toFH = logging. Filehandler ('./file/logging.log') + Fh.setlevel (logging. WARNING) -  the #Create a formatter (format) *Formatter = logging. Formatter ('% (asctime) s-% (name) s-% (levelname) s-% (message) s', datefmt='%y-%m-%d%h:%m:%s') $ Panax Notoginseng #Add formatter to console handler and file handler - Ch.setformatter (Formatter) the Fh.setformatter (Formatter) +  A #Add Console handler and file handler to logger the logger.addhandler (CH) + Logger.addhandler (FH) -  $ #setting error Messages $Logger.debug ('Debug Message') -Logger.info ('Info Message') -Logger.warning ('warning Message') theLogger.error ('error Message') -Logger.critical ('Critical Message')

Above output to screen result:

2017-04-08 16:12:49-xt-log-debug-debug Message
2017-04-08 16:12:49-xt-log-info-info Message
2017-04-08 16:12:49-xt-log-warning-warning Message
2017-04-08 16:12:49-xt-log-error-error Message
2017-04-08 16:12:49-xt-log-critical-critical Message

Python-Common modules-logging modules