My goto Python logging template - lints 10/10 in pylint

logger.py

#!/usr/bin/env python

"""
Global Python log configuration settings
@author mblum
"""

from __future__ import division
from __future__ import absolute_import
from __future__ import print_function

import logging
import os

LEVELS = {'debug': logging.DEBUG,
          'info': logging.INFO,
          'warning': logging.WARNING,
          'error': logging.ERROR,
          'critical': logging.CRITICAL}

LOG_FORMAT = '%(asctime)s %(name)s:%(levelname)-8s %(message)s'
LOG_DATE_FORMAT = '%a, %d %b %Y %H:%M:%S'


def instantiate_logger(name):
    """
    Instantiate a global named logger
    Configure OS variables for logfile and level
    LOG_FILE - defaults to temp.log in the working directory
    LOG_LEVEL - defaults to DEBUG

    Find configuration details here:
    https://docs.python.org/2/howto/logging-cookbook.html
    """
    log_file = None
    log_level = None

    try:
        log_file = os.environ['LOG_FILE']
    except KeyError as exp:
        print('LOG_FILE OS variable not configured {}'.format(str(exp)))
        if log_file is None:
            log_file = 'temp.log'
    try:
        log_level = os.environ['LOG_LEVEL']
    except KeyError as exp:
        print('LOG_LEVEL OS variable not configured {}'.format(str(exp)))
        if log_level is None:
            log_level = 'debug'
    if log_level not in LEVELS:
        print('log level not specified - falling back to debug')
        log_level = 'debug'
    logging.basicConfig(filename=log_file,
                        level=LEVELS[log_level],
                        format=LOG_FORMAT,
                        datefmt=LOG_DATE_FORMAT)
    print('configuring logging: {level} to {log}'.format(level=log_level,
                                                         log=log_file))
    logger = logging.getLogger(name)
    logger.info('Logger ready...')
    return logger

if __name__ == '__main__':
    instantiate_logger('main')