Logging from multiple modules in package not working from __main__ - python-3.x

Question

I am trying to implement logging in my project and want all modules to log to the same file. I managed to get this to work if I set up the logger in init, but not if I set it up in main. When I set it up in main it only logs the statements from main and not other modules.
I want to set it up in main so that I can place the configuration of the logger in dictConfig in a config.py file. When I do this from init something goes wrong with the import statements.
Here is what I have in ___main____.py:
import logging
from logging.config import dictConfig
import config as cfg
if __name__ == '__main__':
dictConfig(cfg.logging)
logger = logging.getLogger()
logger.info('Completed configuring logger()!')
main()
In config.py:
logging = dict(
version = 1,
formatters = {
'f': {'format':
'%(asctime)s %(name)-12s %(levelname)-8s %(message)s'}
},
handlers = {
'h': {'class': 'logging.StreamHandler',
'formatter': 'f',
'level': logging.INFO},
'r': {'class': 'logging.handlers.RotatingFileHandler',
'filename': 'data/logger.log',
'formatter':'f',
'maxBytes': 10000,
'backupCount':5},
},
root = {
'handlers': ['h', 'r'],
'level': logging.INFO,
},
)
In backend.py:
import logging
logger = logging.getLogger(__name__)
class Backend(object):
def __init__(self, dbi):
self._dbi = dbi
def getDimensionTableColumns(self, table_name):
logger.warning('still not working')
The output in my logger.log file and terminal is:
2018-03-07 09:48:00,858 root INFO Completed configuring logger()!
And I know that the getDimensionTableColumns is running because if I put a print statement it outputs to the terminal.
Could someone please explain what is going wrong and why?

Answer 1

you are using two different loggers: the root logger (which is configured) in your __main__ module (the one you get with logger = logging.getLogger()) and a logger called __name__ = 'backend'(which is not).
you can either use the default logger in backend.py using
logger = logging.getLogger() # no __name__ !
or you could configure a named logger and use that in both modules.