@classmethod
def get_index_name(cls, now=None, mode=None):
    """Override to generate index suffix."""
    from datetime import datetime
    if not now:
        now = datetime.now()
    if mode == 'all_index':
        suffix = '*'
    else:
        suffix = now.strftime(cls.INDEX_SUFFIX_FORMAT)
    prefix = cls.ELASTIC_INDEX_PREFIX
    if cls.ENV == 'test':
        prefix += 'test_'
    return prefix + cls.INDEX_PREFIX + suffix
