Better logging with logging

I've been using Python for more than 2 years now. It's sad that I never came across the amazing logging library. I was relying on the plain old print and used .format to its full potential.

Now that I know about logging, I can't think of using anything else.

There are various approaches to initialize the logging module. I prefer the one with the config file. That way it's easier to configure the format etc.

This is a sample python code using the logging library

import logging
import logging.config

logging.config.fileConfig('loggerconfig.ini')
logger = logging.getLogger('server')

def testmodule():
    logger.info("This is a test info message")
    logger.critical("This is a test critical message")

testmodule()

Output of this sample code:

[10-11-15 23:55:12]  INFO     test                      This is a test info message (testmodule:8)
[10-11-15 23:55:12]  CRITICAL test                      This is a test critical message (testmodule:9)

This is the sample loggerconfig.ini file used to achieve the above output

[loggers]
keys=root,server

[handlers]
keys=consoleHandler

[formatters]
keys=simpleFormatter

[logger_root]
level=DEBUG
handlers=consoleHandler

[logger_server]
level=DEBUG
handlers=consoleHandler
qualname=server
propagate=0

;Available debug levels
;CRITICAL 50 ERROR 40 WARNING 30 INFO 20 DEBUG 10 NOTSET 0
[handler_consoleHandler]
class=StreamHandler
level=DEBUG
formatter=simpleFormatter
args=(sys.stdout,)

[formatter_simpleFormatter]
format=[%(asctime)s]  %(levelname)-8s %(module)-25s %(message)s (%(funcName)s:%(lineno)d)
datefmt=%m-%d-%y %H:%M:%S

format and datefmt are the most important fields in the config file which you need to edit to get the desired output. List of all the attributes are documented here