dag.py 文件源码

def match_node(self, key):
        found_node = None
        for regex_key, node in six.viewitems(self._key_node_dict):
            match_object = re.match("(?:%s)\Z" % regex_key, key)
            if match_object is not None:
                if found_node is None:
                    found_node = node
                    found_regex_key = regex_key
                    found_match_object = match_object
                else:
                    raise ValueError("The data key '{}' matches multiple keys: "
                                     "'{}' for {} and '{}' for {}.".format(
                                         key, found_regex_key, found_node,
                                         regex_key, node))
        if found_node is None:
            raise KeyError(key)
        return found_regex_key, found_node, found_match_object