import logging
import logging.handlers

class myClass(object):
    def __init__(self):
        self.name = "Old Name"

    def __str__(self):
        return self.name

logger = logging.getLogger()
fh = logging.FileHandler('log.txt', mode='w')
fh.setLevel(0)  # log everything to file
mh = logging.handlers.MemoryHandler(1024, target=fh)
logger.addHandler(mh)
logger.setLevel(logging.DEBUG)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(filename)s:%(lineno)s - %(levelname)s - %(message)s')
fh.setFormatter(formatter)

myObj = myClass()
logging.debug("Old myObject: %s", myObj)
myObj.name = "New Name"
logging.debug("New myObject: %s", myObj)

print "Done"