How to log messages _only once_ from all modules ?

[Soltys]

Ron Barak pisze:
> On Nov 24, 3:45 pm, Soltys <sol... at noabuse.com> wrote:
>> 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 readinghttp://docs.python.org/library/logging.htmldidn'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 athttp://docs.python.org/library/logging.html#logger-objects
>> First thing mentioned is Logger.propagate which is, what I believe, you're
>> looking for ;)
>>
>> --
>> Soltys
>>
>> "Free software is a matter of liberty not price"- Hide quoted text -
>>
>> - Show quoted text -
> 
> Hi Soltys,
> I actually tried that, without any noticeable effects, viz.:
> 
> $ cat server.py
> import logging
> import logging.handlers
> 
> class Server():
>     def __init__(self):
>         self.client_logger = logging.getLogger("client")
>         self.client_logger.setLevel(logging.DEBUG)
>         h = logging.FileHandler("client.log")
>         h.setLevel(logging.DEBUG)
>         formatter = logging.Formatter("%(asctime)s %(name)-12s %
> (levelname)-8s %(message)s")
>         h.setFormatter(formatter)
>         self.client_logger.addHandler(h)
>         self.client_logger.propagate = 0
> 
>     def util(self):
>         self.client_logger.warning('This message comes from Server
> module')
> 
> $ cat client.py
> import logging
> import logging.handlers
> from server import Server
> 
> class Client():
>     def __init__(self):
>         self.client_logger = logging.getLogger("client")
>         self.client_logger.setLevel(logging.DEBUG)
>         h = logging.FileHandler("client.log")
>         h.setLevel(logging.DEBUG)
>         formatter = logging.Formatter("%(asctime)s %(name)-12s %
> (levelname)-8s %(message)s")
>         h.setFormatter(formatter)
>         self.client_logger.addHandler(h)
>         self.client_logger.propagate = 0
> 
>     def client_test(self):
>         self.client_logger.warning("This message comes from Client
> module")
> 
> if __name__ == "__main__":
>     ser = Server()
>     cli = Client()
>     ser.util()
>     cli.client_test()
> 
> $ rm client.log ; python client.py ; cat client.log
> 2009-11-24 16:06:35,710 client       WARNING  This message comes from
> Server module
> 2009-11-24 16:06:35,710 client       WARNING  This message comes from
> Server module
> 2009-11-24 16:06:35,710 client       WARNING  This message comes from
> Client module
> 2009-11-24 16:06:35,710 client       WARNING  This message comes from
> Client module
> 
> $
> 

Rename logger in server.py to server:
self.client_logger = logging.getLogger("server")

Rerun, you should get sth. like this:
$ cat client.log
2009-11-24 16:06:54,990 server       WARNING  This message comes from Server module
2009-11-24 16:06:54,990 client       WARNING  This message comes from Client module



-- 
Soltys

"Free software is a matter of liberty not price"