def create_logger(app):
    """Creates a logger for the given application.  This logger works
    similar to a regular Python logger but changes the effective logging
    level based on the application's debug flag.  Furthermore this
    function also removes all attached handlers in case there was a
    logger with the log name before.
    """
    Logger = getLoggerClass()

    class DebugLogger(Logger):
        def getEffectiveLevel(self):
            if self.level == 0 and app.debug:
                return DEBUG
            return Logger.getEffectiveLevel(self)

    class DebugHandler(StreamHandler):
        def emit(self, record):
            if app.debug and _should_log_for(app, 'debug'):
                StreamHandler.emit(self, record)

    class ProductionHandler(StreamHandler):
        def emit(self, record):
            if not app.debug and _should_log_for(app, 'production'):
                StreamHandler.emit(self, record)

    debug_handler = DebugHandler()
    debug_handler.setLevel(DEBUG)
    debug_handler.setFormatter(Formatter(DEBUG_LOG_FORMAT))

    prod_handler = ProductionHandler(_proxy_stream)
    prod_handler.setLevel(ERROR)
    prod_handler.setFormatter(Formatter(PROD_LOG_FORMAT))

    logger = getLogger(app.logger_name)
    # just in case that was not a new logger, get rid of all the handlers
    # already attached to it.
    del logger.handlers[:]
    logger.__class__ = DebugLogger
    logger.addHandler(debug_handler)
    logger.addHandler(prod_handler)
    return logger
dataset/ETHPy150Open pallets/flask/flask/logging.py/create_logger/original