How to write to a file, using the logging Python module?

How to write to a file, using the logging Python module?

An example of using logging.basicConfig rather than logging.fileHandler()

logging.basicConfig(filename=logname,
                            filemode=a,
                            format=%(asctime)s,%(msecs)d %(name)s %(levelname)s %(message)s,
                            datefmt=%H:%M:%S,
                            level=logging.DEBUG)

logging.info(Running Urban Planning)

self.logger = logging.getLogger(urbanGUI)

In order, the five parts do the following:

1. set the output file (filename=logname)
2. set it to append rather than overwrite (filemode=a)
3. determine the format of the output message (format=...)
4. determine the format of the output time (datefmt=%H:%M:%S)
5. and determine the minimum message level it will accept (level=logging.DEBUG).

Taken from the logging cookbook:

# create logger with spam_application
logger = logging.getLogger(spam_application)
logger.setLevel(logging.DEBUG)
# create file handler which logs even debug messages
fh = logging.FileHandler(spam.log)
fh.setLevel(logging.DEBUG)
logger.addHandler(fh)

And youre good to go.

P.S. Make sure to read the logging HOWTO as well.

How to write to a file, using the logging Python module?

I prefer to use a configuration file. It allows me to switch logging levels, locations, etc without changing code when I go from development to release. I simply package a different config file with the same name, and with the same defined loggers.

import logging.config
if __name__ == __main__:
    # Configure the logger
    # loggerConfigFileName: The name and path of your configuration file
    logging.config.fileConfig(path.normpath(loggerConfigFileName))

    # Create the logger
    # Admin_Client: The name of a logger defined in the config file
    mylogger = logging.getLogger(Admin_Client)

    msg=Bite Me
    myLogger.debug(msg)
    myLogger.info(msg)
    myLogger.warn(msg)
    myLogger.error(msg)
    myLogger.critical(msg)

    # Shut down the logger
    logging.shutdown()

Here is my code for the log config file

#These are the loggers that are available from the code
#Each logger requires a handler, but can have more than one
[loggers]
keys=root,Admin_Client


#Each handler requires a single formatter
[handlers]
keys=fileHandler, consoleHandler


[formatters]
keys=logFormatter, consoleFormatter


[logger_root]
level=DEBUG
handlers=fileHandler


[logger_Admin_Client]
level=DEBUG
handlers=fileHandler, consoleHandler
qualname=Admin_Client
#propagate=0 Does not pass messages to ancestor loggers(root)
propagate=0


# Do not use a console logger when running scripts from a bat file without a console
# because it hangs!
[handler_consoleHandler]
class=StreamHandler
level=DEBUG
formatter=consoleFormatter
args=(sys.stdout,)# The comma is correct, because the parser is looking for args


[handler_fileHandler]
class=FileHandler
level=DEBUG
formatter=logFormatter
# This causes a new file to be created for each script
# Change time.strftime(%Y%m%d%H%M%S) to time.strftime(%Y%m%d)
# And only one log per day will be created. All messages will be amended to it.
args=(D:\Logs\PyLogs\ + time.strftime(%Y%m%d%H%M%S)+.log, a)


[formatter_logFormatter]
#name is the name of the logger root or Admin_Client
#levelname is the log message level debug, warn, ect 
#lineno is the line number from where the call to log is made
#04d is simple formatting to ensure there are four numeric places with leading zeros
#4s would work as well, but would simply pad the string with leading spaces, right justify
#-4s would work as well, but would simply pad the string with trailing spaces, left justify
#filename is the file name from where the call to log is made
#funcName is the method name from where the call to log is made
#format=%(asctime)s | %(lineno)d | %(message)s
#format=%(asctime)s | %(name)s | %(levelname)s | %(message)s
#format=%(asctime)s | %(name)s | %(module)s-%(lineno) | %(levelname)s | %(message)s
#format=%(asctime)s | %(name)s | %(module)s-%(lineno)04d | %(levelname)s | %(message)s
#format=%(asctime)s | %(name)s | %(module)s-%(lineno)4s | %(levelname)-8s | %(message)s

format=%(asctime)s | %(levelname)-8s | %(lineno)04d | %(message)s


#Use a separate formatter for the console if you want
[formatter_consoleFormatter]
format=%(asctime)s | %(levelname)-8s | %(filename)s-%(funcName)s-%(lineno)04d | %(message)s