duplicate output in simple python logging configuration

Question

I\'m setting up python logging as follows:

def setup_logging():
    loggers = (logging.getLogger(\"amcat\"), logging.getLogger(\"scrapers\"),logging.getLogge         


        

Answer 1

Basically, when one of your child logger displays a message, it goes backwards in the hierarchy, and the parents are also logging the same thing.

To cancel that behavior, you can add this:

logger.propagate = False

When it hits the child, it won't hit the parent afterwards.

Here is some documentation about this behavior.

Answer 2

I figured this out, thanks Paco for pointing me in the right direction

it turns out that when getLogger is called, handlers are added to it:

>>> print(effectivehandlers(logger))
[<logging.StreamHandler object at 0x305ad90>, <logging.FileHandler object at 0x305ae10>]
>>> logging.getLogger(name) #the same logger
<logging.Logger object at 0x7fa08fb9b2d0>
>>> print(effectivehandlers(logger))
[<logging.StreamHandler object at 0x305ad90>, <logging.FileHandler object at 0x305ae10>, <logging.StreamHandler object at 0x305ad90>, <logging.FileHandler object at 0x305ae10>]

Now, both the child and the parent have the same handlers. Hence duplicate outputs.

Answer 3

for python 2.7

logging.handlers.pop()

Reference by user "radtek": Python Logging - Messages appearing twice