How do I change the format of a Python log message on a per-logger basis?

Question

After reading the documentation on logging, I know I can use code like this to perform simple logging:

import logging  def main():     logging.basicConfig(filename="messages.log",                         level=logging.WARNING,                         format='%(filename)s: '                                     '%(levelname)s: '                                 '%(funcName)s(): '                                 '%(lineno)d:\t'                                 '%(message)s')      logging.debug("Only for debug purposes\n")     logging.shutdown()  main() 

However, I realised I don't know how to change the format of log messages on a per-logger basis, since basicConfig is a module-level function. This code works for creating different loggers with different levels, names, etc. but is there a way to change the format of those log messages on a per-logger basis as well, in a way similar to basicConfig?

import inspect import logging  def function_logger(level=logging.DEBUG):     function_name = inspect.stack()[1][3]     logger = logging.getLogger(function_name)     logger.setLevel(level)     logger.addHandler(logging.FileHandler("{0}.log".format(function_name)))     return logger  def f1():     f1_logger = function_logger()     f1_logger.debug("f1 Debug message")     f1_logger.warning("f1 Warning message")     f1_logger.critical("f1 Critical message")  def f2():     f2_logger = function_logger(logging.WARNING)     f2_logger.debug("f2 Debug message")     f2_logger.warning("f2 Warning message")     f2_logger.critical("f2 Critical message")  def main():     f1()     f2()     logging.shutdown()  main() 

Answer 1

Try this

import logging  logger = logging.getLogger('simple_example') logger.setLevel(logging.DEBUG) # create file handler that logs debug and higher level messages fh = logging.FileHandler('spam.log') fh.setLevel(logging.DEBUG) # create console handler with a higher log level ch = logging.StreamHandler() ch.setLevel(logging.ERROR) # create formatter and add it to the handlers formatter = logging.Formatter(     '%(asctime)s - %(name)s - %(levelname)s - %(message)s') ch.setFormatter(formatter) fh.setFormatter(formatter) # add the handlers to logger logger.addHandler(ch) logger.addHandler(fh)  # 'application' code logger.debug('debug message') logger.info('info message') logger.warn('warn message') logger.error('error message') logger.critical('critical message') 

See http://docs.python.org/howto/logging-cookbook.html#multiple-handlers-and-formatters for more information