api.py 文件源码

def MetricSchema(v):
    """metric keyword schema

    It could be:

    ["metric", "metric-ref", "aggregation"]

    or

    ["metric, ["metric-ref", "aggregation"], ["metric-ref", "aggregation"]]
    """
    if not isinstance(v, (list, tuple)):
        raise voluptuous.Invalid("Expected a tuple/list, got a %s" % type(v))
    elif not v:
        raise voluptuous.Invalid("Operation must not be empty")
    elif len(v) < 2:
        raise voluptuous.Invalid("Operation need at least one argument")
    elif v[0] != u"metric":
        # NOTE(sileht): this error message doesn't looks related to "metric",
        # but because that the last schema validated by voluptuous, we have
        # good chance (voluptuous.Any is not predictable) to print this
        # message even if it's an other operation that invalid.
        raise voluptuous.Invalid("'%s' operation invalid" % v[0])

    return [u"metric"] + voluptuous.Schema(voluptuous.Any(
        voluptuous.ExactSequence([six.text_type, six.text_type]),
        voluptuous.All(
            voluptuous.Length(min=1),
            [voluptuous.ExactSequence([six.text_type, six.text_type])],
        )), required=True)(v[1:])