log.py 文件源码

def _has_streamhandler(logger, level=None, fmt=LOG_FORMAT,
                       stream=DEFAULT_STREAM):
    """Check the named logger for an appropriate existing StreamHandler.

    This only returns True if a StreamHandler that exaclty matches
    our specification is found. If other StreamHandlers are seen,
    we assume they were added for a different purpose.
    """
    # Ensure we are talking the same type of logging levels
    # if they passed in a string we need to convert it to a number
    if isinstance(level, basestring):
        level = logging.getLevelName(level)

    for handler in logger.handlers:
        if not isinstance(handler, logging.StreamHandler):
            continue
        if handler.stream is not stream:
            continue
        if handler.level != level:
            continue
        if not handler.formatter or handler.formatter._fmt != fmt:
            continue
        return True
    return False