lliendo/Radar

# -*- coding: utf-8 -*-

"""
This file is part of Radar.

Radar is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Radar is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Lesser GNU General Public License for more details.

You should have received a copy of the Lesser GNU General Public License
along with Radar. If not, see <http://www.gnu.org/licenses/>.

Copyright 2015 Lucas Liendo.
"""


from logging import getLogger, Formatter, shutdown, INFO
from logging.handlers import RotatingFileHandler
from os.path import dirname
from os import mkdir
from errno import EEXIST
from sys import stderr


class LoggerError(Exception):
    pass


class RadarLogger(object):

    _shared_state = {'logger': None}

    def __init__(self, path, logger_name='radar', max_size=100, rotations=5):
        self.__dict__ = self._shared_state
        self._create_dir(path)
        self._shared_state['logger'] = self._configure_logger(path, logger_name, max_size * (1024 ** 2), rotations)

    def _create_dir(self, path):
        try:
            mkdir(dirname(path))
        except OSError as e:
            if e.errno != EEXIST:
                raise LoggerError('Error - Couldn\'t create directory : \'{:}\'. Details : {:}.'.format(path, e.strerror))

    def _configure_logger(self, path, logger_name, max_size, rotations):
        try:
            logger = getLogger(logger_name)
            logger.setLevel(INFO)
            file_handler = RotatingFileHandler(path, maxBytes=max_size, backupCount=rotations)
            file_handler.setFormatter(Formatter(fmt='%(asctime)s - %(message)s', datefmt='%b %d %H:%M:%S'))
            logger.addHandler(file_handler)
        except Exception as e:
            raise LoggerError('Error - Couldn\'t configure Radar logger. Details : {:}.'.format(e))

        return logger

    @staticmethod
    def log(message):
        try:
            RadarLogger._shared_state['logger'].info(message)
        except Exception as e:
            stderr.write('Error - Couldn\'t log to Radar logger. Details : {:}.'.format(e))

    @staticmethod
    def shutdown():
        shutdown()