Python logging multiple files using the same logger

Question

This is my scenario: I want to log my_module's activity. This needs to be done, depending on the method executed (let's say, INPUT and OUTPUT), to two different files.

So I have two Handlers, each one point to a different file (my_in_.log & my_out_.log), with the same log level. I would like to know if I can use the same logger to achieve this or I have to define two loggers. My config is:

[loggers]
keys=root, my_log

[handlers]
keys=my_in_hand, my_out_hand

[formatters]
keys=generic_form


...


[logger_my_log]
level=NOTSET
handlers=my_in_hand, my_out_hand
qualname=ws_log

[handler_my_in_hand]
class=handlers.TimeRotatingFileHandler
level=NOTSET
formatter=generic_form
args=('my_in_.log', 'h', 1, 0, None, False, True)

[handler_my_out_hand]
class=handlers.TimeRotatingFileHandler
level=NOTSET
formatter=generic_form
args=('my_out_.log', 'h', 1, 0, None, False, True)

Do I have to define a logger per handler/destination (because I want to log different information in different files)? Is there a way to indicate to the logger which handler will do this? I mean, I have two handlers for one logger, then choose only one handler to log one method.

Answer 1

You should instantiate an Handler for each destination you want to send your log to, then add the 2 handlers to your logger. The following should work (didn't test it though):

logger = logging.getLogger()
handler1 = logging.TimedRotatingFileHandler()
handler2 = logging.TimedRotatingFileHandler()
logger.addHandler(handler1)
logger.addHandler(handler2)

Of course add all your configuration and formatting options you may need. Basically it is just to show you that when you instantiate the logging handler you can add it to the logger. From that moment on, your log records will be emitted to every handler added to the logger.