normalizer.py 文件源码

def from_yaml(cls, loader, node):
        logging.debug('{}:process(loader={}, node={})'.format(cls.__name__,
                      loader, node))
        # e.g.:
        # SequenceNode(tag=u'!ArrayItem', value=[
        #   MappingNode(tag=u'tag:yaml.org,2002:map', value=[
        #     (ScalarNode(tag=u'tag:yaml.org,2002:str', value=u'SELECT'),
        #       MappingNode(tag=u'tag:yaml.org,2002:map', value=[
        #         (ScalarNode(tag=u'tag:yaml.org,2002:str', value=u'plugin'),
        #           , ...)
        #       ]), ...
        #     ), (key, value), ... ])
        #   , ... ])
        assert isinstance(node, yaml.SequenceNode), \
            "{} tag isn't YAML array".format(cls.__name__)
        select, index_keys, items, item_desc = list(), list(), list(), None
        for elem in node.value:
            for key, value in elem.value:
                if key.value == 'ITEM-DESC':
                    assert item_desc is None, "ITEM-DESC key already set"
                    item_desc = value
                if key.value == 'INDEX-KEY':
                    assert len(index_keys) == 0, "INDEX-KEY key already set"
                    index_keys = loader.construct_sequence(value)
                if key.value == 'SELECT':
                    select.append(loader.construct_mapping(value))
        # validate item description
        assert item_desc is not None, "Mandatory ITEM-DESC key isn't set"
        assert len(select) > 0 or len(index_keys) > 0, \
            "Mandatory key (INDEX-KEY or SELECT) isn't set"
        metrics = loader.collector.items(select)
        # select metrics based on INDEX-KEY provided
        if len(index_keys) > 0:
            metric_set = set()
            for metric in metrics:
                value = CollectdValue()
                for key in index_keys:
                    setattr(value, key, getattr(metric, key))
                metric_set.add(value)
            metrics = list(metric_set)
        # build items based on SELECT and/or INDEX-KEY criteria
        for metric in metrics:
            item = cls.format_node(item_desc,
                                   {'vl': metric, 'system': loader.system,
                                       'config': loader.config})
            items.append(loader.construct_mapping(item))
        return items