Simply Python Logger

log.py

# Copyright (c) 2017 Brannon Dorsey
#               2017 Branger Briz, Inc
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import os

# reads value from LOG_LEVEL environment variable and conditionally
# logs messages accourdingly
def log(message, level, default='VERBOSE'):

	level = level.upper()
	log_level = str(os.getenv('LOG_LEVEL', default.upper())).upper()
	log_dict = {
		"VERBOSE": 1,
		"NOTICE": 2,
		"WARNING": 3,
		"ERROR": 4,
		"FATAL": 5,
		"SILENT": 0
	}

	if level not in log_dict:
		raise Exception('{} is not a supported log level'.format(level))
	if log_level not in log_dict:
		raise Exception('{} is not a supported log level'.format(log_level))

	if log_level == 'SILENT':
		return
	elif log_dict[level] >= log_dict[log_level]: 
		print('[{}] {}'.format(level.upper().center(7), message))

# tests the log function
def test_log():

	def log_test():
		print('')
		message = 'this is a test message.'
		log(message, 'verbose')
		log(message, 'notice')
		log(message, 'warning')
		log(message, 'error')
		log(message, 'fatal')
		print('')
	
	os.environ['LOG_LEVEL'] = 'VERBOSE'
	print('set log level VERBOSE')
	log_test()
	
	os.environ['LOG_LEVEL'] = 'NOTICE'
	print('set log level NOTICE')
	log_test()

	os.environ['LOG_LEVEL'] = 'WARNING'
	print('set log level WARNING')
	log_test()

	os.environ['LOG_LEVEL'] = 'ERROR'
	print('set log level ERROR')
	log_test()

	os.environ['LOG_LEVEL'] = 'FATAL'
	print('set log level FATAL')
	log_test()

if __name__ == '__main__':
	test_log()