How to log messages _only once_ from all modules ?

[Soltys]

Barak, Ron pisze:
> Hi,
> 
> I'm trying to add the logging module to my application, but I seem to be missing something.
> My application (a wxPython one) has a main script that calls various helper classes.
> I want the log messages from all modules to go to one central log file.
> 
> When I implement logging, I think that due to preparation, I get the same message more than once.
> 
> Here's an example:
> 
> $ cat -n server.py
>      1  import logging
>      2  import logging.handlers
>      3
>      4  class Server():
>      5      def __init__(self):
>      6          self.client_logger = logging.getLogger("client")
>      7          self.client_logger.setLevel(logging.DEBUG)
>      8          h = logging.FileHandler("client.log")
>      9          h.setLevel(logging.DEBUG)
>     10          formatter = logging.Formatter("%(asctime)s %(name)-12s %(levelname)-8s %(message)s")
>     11          h.setFormatter(formatter)
>     12          self.client_logger.addHandler(h)
>     13
>     14      def util(self):
>     15          self.client_logger.warning('This message comes from Server module')
> 
> $ cat -n client.py
>      1  import logging
>      2  import logging.handlers
>      3  from server import Server
>      4
>      5  class Client():
>      6      def __init__(self):
>      7          self.client_logger = logging.getLogger("client")
>      8          self.client_logger.setLevel(logging.DEBUG)
>      9          h = logging.FileHandler("client.log")
>     10          h.setLevel(logging.DEBUG)
>     11          formatter = logging.Formatter("%(asctime)s %(name)-12s %(levelname)-8s %(message)s")
>     12          h.setFormatter(formatter)
>     13          self.client_logger.addHandler(h)
>     14
>     15      def client_test(self):
>     16          self.client_logger.warning("This message comes from Client module")
>     17
>     18  if __name__ == "__main__":
>     19      ser = Server()
>     20      cli = Client()
>     21      ser.util()
>     22      cli.client_test()
> $ rm client.log ; python client.py ; cat client.log
> 2009-11-24 14:40:39,762 client       WARNING  This message comes from Server module
> 2009-11-24 14:40:39,762 client       WARNING  This message comes from Server module
> 2009-11-24 14:40:39,762 client       WARNING  This message comes from Client module
> 2009-11-24 14:40:39,762 client       WARNING  This message comes from Client module
> Googling and reading http://docs.python.org/library/logging.html didn't enlighten me.
> 
> Could you suggest what should I change in the above scripts so that the log messages would appear only once ?
> 
> Thanks,
> Ron.
> 
> 

Have a look at http://docs.python.org/library/logging.html#logger-objects
First thing mentioned is Logger.propagate which is, what I believe, you're
looking for ;)

-- 
Soltys

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