class ConnectionLogger(object):
    """Connection-specific logger object.

    This provides a way to add some specific information to each log
    message without generated for a connection without creating a
    separately-managed logger object using the logging module.
    Managed logger objects are never discarded (since they're stored
    in a global table in the logging module), but these are discarded
    when the corresponding connection object is discarded.

    """
    __slots__ = "__logger", "__prefix"

    def __init__(self, logger, prefix):
        if "%" in prefix:
            raise ValueError("message prefix may not contain '%'")
        self.__logger = logger
        self.__prefix = prefix

    def debug(self, msg, *args, **kw):
        self.log(logging.DEBUG, msg, *args, **kw)

    def info(self, msg, *args, **kw):
        self.log(logging.INFO, msg, *args, **kw)

    def warning(self, msg, *args, **kw):
        self.log(logging.WARNING, msg, *args, **kw)

    warn = warning

    def error(self, msg, *args, **kw):
        self.log(logging.ERROR, msg, *args, **kw)

    def critical(self, msg, *args, **kw):
        self.log(logging.CRITICAL, msg, *args, **kw)

    fatal = critical

    def exception(self, msg, *args):
        self.__logger.exception(self.__prefix + msg, *args)

    def log(self, level, msg, *args, **kw):
        self.__logger.log(level, self.__prefix + msg, *args, **kw)