Example of how to log one file per day to /var/log with Python 3

rotating_logger.py

#!/usr/bin/env python3

from logging import getLogger, Formatter
from logging.handlers import TimedRotatingFileHandler
from os.path import basename

def daylogger( name ):
  logger = getLogger( name )
  logger.setLevel( 'INFO' )

  handler = TimedRotatingFileHandler(
    '/var/log/%s/%s.log' % ( basename( name ), basename( name ) ),
    when='midnight',
    interval=1,
    backupCount=7
  )

  fmt = Formatter(
    '%(asctime)s %(levelname)s %(message)s',
    '%Y-%m-%d %H:%M:%S'
  )
  handler.setFormatter( fmt )

  logger.addHandler( handler )
  return logger

if __name__ == '__main__':
  log = daylogger( 'test' )
  log.info( 'Something informative has happened' )
  log.warning( 'Potentially dangerous event' )