Python: flush logging only at end of script run

Currently I use for logging a custom logging system that works as follow:
I have a Log class that ressemble the following:

class Log:
    def __init__(self):
        self.script = ""
        self.datetime = datetime.datetime.now().replace(second=0, microsecond=0)
        self.mssg = ""
        self.mssg_detail = ""
        self.err = ""
        self.err_detail = ""

I created a function decorator that perform a try/except on the function call, and add a message either to .mssg or .err on the Log object accordingly.

def logging(fun):
    @functools.wraps(fun)
    def inner(self, *args):
        try:
            f = fun(self, *args)
            self.logger.mssg += fun.__name__ +" :ok, "                
            return f               
        except Exception as e:
            self.logger.err += fun.__name__ +": error: "+str(e.args) 
    return inner 

So usually a script is a class that is composed of multiple methods that are run sequentially. I hence run those methods (decorated such as mentionned above) , and lastly I upload the Log object into a mysql db.

This works quite fine and alright. But now I want to modify those items so that they integrate with the "official" logging module of python.

What I dont like about that module is that it is not possible to "save" the messages onto 1 log object in order to upload/save to log only at the end of the run. Rather each logging call will write/send the message to a file etc. - which create lots of performances issues sometimes. I could usehandlers.MemoryHandler , but it still doesn't seems to perform as my original system: it is said to collect messages and flush them to another handler periodically - which is not what i want: I want to collect the messages in memory and to flush them on request with an explicit function.

Anyone has any suggestions?