Why is logging not considering my configurations?

Question

I would like to use the logging Library to print logging messages on the console I am running my script, and in logging files.

However, I am facing two problems:

1) the setLevel function does not seem to work

2) When I print logging messages on the console, it appears that the buffer storing the logging messages of a run is not flushed between two run. How should I do to dispose of a clean StreamHandler?

To solve the first problem, I tried to change the logger level to the minimum (logging.DEBUG), but it doesn't work

To solve the second problem, I already tried the followings:

1) sys.stdout.flush() before declaring "Stream_log_handler = logging.StreamHandler(sys.stdout)"

2) logger.propagate = False

3) Stream_log_handler = logging.StreamHandler(sys.stdout)

handlers = logger.handlers for handler in handlers: logger.removeHandler(handler)

4) logging.shutdown()

None of these are successful.

Here is a portion of my code:

import logging
import sys

logger = logging.getLogger(__name__)
formatter = logging.Formatter('%(asctime)s:%(levelname)s:%(name)s:%(message)s')
level = 'DEBUG'

file_log_handler = logging.FileHandler('logging_test.log')
file_log_handler.setLevel(logging.DEBUG)
file_log_handler.setFormatter(formatter)
logger.addHandler(file_log_handler)

stream_log_handler = logging.StreamHandler(sys.stdout)
stream_log_handler.setLevel(logging.DEBUG)
stream_log_handler.setFormatter(formatter)
logger.addHandler(stream_log_handler)

def add(x,y):
    """Add function"""
    result = x+y
    logger.info('Add result : {}'.format(result))
    return result

def substract(x,y):
    """Substract function"""
    result = x-y
    logger.debug('Substract result : {}'.format(result))
    return result

def multiply(x,y):
    """Multiply function"""
    result = x*y
    logger.warning('Multiply result : {}'.format(result))
    return result

def divide(x,y):
    """Divide function"""
    try:
        result = x-y
        logger.debug('Divide result : {}'.format(result))
    except ZeroDivisionError:
        logger.error('Tried to divide by zero')
    else:
        return result


num_1 = 10
num_2 = 5

add_result = add(num_1, num_2)

sub_result = substract(num_1, num_2)

mul_result = multiply(num_1, num_2)

div_result = divide(num_1, num_2)

In the console, I get:

• At the first run:

In [3]: runfile('...')

2019-09-18 21:56:56,636:WARNING: main :Multiply result: 50

• At the second run:

In [4]: runfile('...')

2019-09-18 21:56:56,636:WARNING: main :Multiply result: 50

2019-09-18 21:56:56,636:WARNING: main :Multiply result: 50

• At the third run:

In [4]: runfile('...')

2019-09-18 21:56:56,636:WARNING: main :Multiply result: 50

2019-09-18 21:56:56,636:WARNING: main :Multiply result: 50

2019-09-18 21:56:56,636:WARNING: main :Multiply result: 50

• etc.

Why are the logging messages stacking from a run to another? Why are only the WARNING level messages that are printed?

Answer 1

You've only set the level on your two handlers, not on the logger itself.

logger = logging.getLogger(__name__)
formatter = logging.Formatter('%(asctime)s:%(levelname)s:%(name)s:%(message)s')

file_log_handler = logging.FileHandler('logging_test.log')
file_log_handler.setLevel(logging.DEBUG)
file_log_handler.setFormatter(formatter)
logger.addHandler(file_log_handler)

stream_log_handler = logging.StreamHandler(sys.stdout)
stream_log_handler.setLevel(logging.DEBUG)
stream_log_handler.setFormatter(formatter)
logger.addHandler(stream_log_handler)

logger.setLevel(logging.DEBUG)