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This article mainly introduces "what is the knowledge of logging module in Python". In daily operation, I believe that many people have doubts about the knowledge of logging module in Python. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the question of "what is the knowledge of logging module in Python?" Next, please follow the editor to study!

Preface

Logging module is a built-in standard module of Python, which is mainly used to output script running log, and can set the level of output log, log saving path and so on.

By setting different log levels, you can output only important information in the release version without displaying a large amount of debugging information.

Logging can determine the location and content of the output information.

Logging threads are safer

I. Log level

Ranking: CRITICAL > ERROR > WARNING > INFO > DEBUG

Debug: print all logs and details, usually only when diagnosing problems

Info: print info,warning,error,critical-level logs and output normally

Warning: print warning,error,critical-level logs with some exceptions that do not affect the program

Error: print error,critical-level logs, affecting some functions of the program

Critical: print the critical level, affecting the running of the program

Import logging # introduces logging module # to print information to the console logging.debug ("debug") logging.info ("info") logging.warning ("warning") logging.error ("error") logging.critical ("critical") [root@zijie ~] # python log.pyWARNING:root:warningERROR:root:errorCRITICAL:root:critical

The level of the generated root logger by default is logging.WARNING, and it is not output below this level. If you want to display content below the WARNING level, you can import logging.basicConfig to specify the log level logging.basicConfig (level=logging.DEBUG).

BasicConfig format description filename specifies that the FileHandler is created using the specified file name instead of StreamHandler. Filemode if filename is specified, the file ('r','w','a') is opened in this mode. The default is "a". Format uses the specified format string for the handler. Datefmt uses the specified date / time format accepted by time.strftime (). Style uses this style for format strings if the format is specified.' % 'for printf style,' {'for str.format (), and' $'for string. The default is "%". Level sets the root logger level to the specified level. By default, the level of the generated root logger is logging.WARNING, and those below this level will not be output. Level order: CRITICAL > ERROR > WARNING > INFO > DEBUG. (if you need to display all levels of content, you can level=logging.NOTSET) stream initializes the StreamHandler with the specified stream. Note that this parameter is not compatible with filename-- if both exist, a ValueError is thrown. Handlers if specified, this should be an iteration of the handler that has been created to add to the root logger. Any handler that does not have a formatting assembly will be assigned to the default formatter created in this function. Note that this parameter is not compatible with filename or stream-- if both exist, a ValueError is thrown. Import logginglogging.basicConfig (level=logging.INFO, format='% (asctime) s% (filename) s% (levelname) s% (message) s% (message) slots, datefmt='%a% d% Y% Hpurs% MRO% slots, filename='xuehui.log' Filemode='w') logging.info ('This is an info.') logging.debug (' This is a debug message.') logging.warning ('This is a warning.') 3. Log write file import loggingimport os.pathimport time# create loggerlogger = logging.getLogger () logger.setLevel (logging.DEBUG) # create handler Used to write to the log file logdate = time.strftime ('% Y% m% d% H% M% slots, time.localtime (time.time ()) log_path = 'logs/'log_name = log_path + logdate +'. Log'logfile = log_namefh = logging.FileHandler (logfile) Mode='w') fh.setLevel (logging.DEBUG) # defines the output format formatter = logging.Formatter ("% (asctime) s -% (filename) s [line:% (lineno) d] -% (levelname) s:% (message) s") fh.setFormatter (formatter) # add logger to handlerlogger.addHandler (fh) # log logger.debug ('this is a logger debug message') logger.info (' this is a logger info message') logger.warning (' This is a logger warning message') logger.error ('this is a logger error message') logger.critical (' this is a logger critical message') IV. Traceback record import loggingimport os.pathimport time# create loggerlogger = logging.getLogger () logger.setLevel (logging.DEBUG) # create handler Used to write to the log file logdate = time.strftime ('% Y% m% d% H% M% slots, time.localtime (time.time ()) log_path = 'logs/'log_name = log_path + logdate +'. Log'logfile = log_namefh = logging.FileHandler (logfile) Mode='w') fh.setLevel (logging.DEBUG) # defines the output format formatter = logging.Formatter ("% (asctime) s -% (filename) s [line:% (lineno) d] -% (levelname) s:% (message) s") fh.setFormatter (formatter) # add logger to handlerlogger.addHandler (fh) # log try: open ('/ data/exist', 'rb') except BaseException ase: logger.error (' Failed to open file', exc_info=True) here The study on "what is the knowledge of logging module in Python" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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