def _add_node(self, node, depth=0):
if depth > self._depth_threshold:
raise DagException("Node dependency too deep")
if node.id in self._nodes:
return self._nodes[id]
else:
self._nodes[id] = node
if self._is_node_terminal(node):
node.satisfied = True
return node
# find node ancestors and generators
for generator_class in self._generators:
required_events = generator_class.required_events(node.params)
if required_events is None:
continue
for events_join in required_events:
edge = Edge(generator_class)
for event in events_join:
parent_node = self._add_node(Node(event), depth + 1)
edge.nodes[parent_node.id] = parent_node
if edge.id in self._edges:
edge = self._edges[edge.id]
else:
self._edges[edge.id] = edge
node.edges[edge.id] = edge
return node
