logger.py

# -*- coding: utf-8 -*-
# open source project
import logging
import os


DEFAULT_CONSOLE_LEVEL = logging.INFO


def _initialize_logger(output_dir, logger_name="custom"):
    _logger = logging.getLogger(logger_name)
    _logger.setLevel(logging.DEBUG)

    # create console handler and set level to info
    handler = logging.StreamHandler()
    handler.setLevel(DEFAULT_CONSOLE_LEVEL)
    formatter = logging.Formatter(u"%(asctime)s - %(levelname)s - %(module)s %(funcName)s %(lineno)d - %(message)s")
    handler.setFormatter(formatter)
    _logger.addHandler(handler)

    # create error file handler and set level to error
    handler = logging.FileHandler(os.path.join(output_dir, "error.log"), "w", encoding=None, delay=True)
    handler.setLevel(logging.ERROR)
    formatter = logging.Formatter(u"%(asctime)s - %(levelname)s - %(message)s")
    handler.setFormatter(formatter)
    _logger.addHandler(handler)

    # create debug file handler and set level to debug
    handler = logging.FileHandler(os.path.join(output_dir, "debug.log"), "w")
    handler.setLevel(logging.DEBUG)
    formatter = logging.Formatter(u"%(asctime)s - %(levelname)s - %(module)s %(funcName)s %(lineno)d - %(message)s")
    handler.setFormatter(formatter)
    _logger.addHandler(handler)
    return _logger


_log_path = os.path.join(os.getcwd(), 'logs/')
os.makedirs(_log_path, exist_ok=True)

logger = _initialize_logger(_log_path)
logger.debug("Logger loaded successfully. Logging directory: {}".format(_log_path))


def change_logger_level(level=logging.INFO, logger=logger, handler_index=0):
    conv_lvl = {"debug": logging.DEBUG, "info": logging.INFO,
                "warning": logging.WARNING, "warn": logging.WARN,
                "error": logging.ERROR, "critical": logging.CRITICAL}
    if isinstance(level, str):
        level = level.lower()
        level = conv_lvl.get(level, logging.INFO)
    logger.handlers[handler_index].setLevel(level)
    logger.debug("Logger level has been changed to '{}' (handler n°{}).".format(level, handler_index))
    return logger


# For testing purposes.
if __name__ == '__main__':
    logger.debug("Debug message.")
    logger.info("Info message.")
    logger.warning("Warning message.")
    logger.error("Error message.")
    logger.exception(TypeError("Test exception."))