Merge pull request #928 from danielaskdd/impl-get-kg-grap

Implement Knowledge Graph API for NetworkX Storage

Author: LarFii

lightrag/api/routers/graph_routes.py

@@ -22,6 +22,6 @@ async def get_graph_labels():
     @router.get("/graphs", dependencies=[Depends(optional_api_key)])
     async def get_knowledge_graph(label: str):
         """Get knowledge graph for a specific label"""
-        return await rag.get_knowledge_graph(nodel_label=label, max_depth=100)
+        return await rag.get_knowledge_graph(node_label=label, max_depth=3)
 
     return router

lightrag/kg/networkx_impl.py

@@ -5,7 +5,7 @@
 import numpy as np
 
 
-from lightrag.types import KnowledgeGraph
+from lightrag.types import KnowledgeGraph, KnowledgeGraphNode, KnowledgeGraphEdge
 from lightrag.utils import (
     logger,
 )
@@ -169,9 +169,118 @@ def remove_edges(self, edges: list[tuple[str, str]]):
                 self._graph.remove_edge(source, target)
 
     async def get_all_labels(self) -> list[str]:
-        raise NotImplementedError
+        """
+        Get all node labels in the graph
+        Returns:
+            [label1, label2, ...]  # Alphabetically sorted label list
+        """
+        labels = set()
+        for node in self._graph.nodes():
+            labels.add(str(node))  # Add node id as a label
+
+        # Return sorted list
+        return sorted(list(labels))
 
     async def get_knowledge_graph(
         self, node_label: str, max_depth: int = 5
     ) -> KnowledgeGraph:
-        raise NotImplementedError
+        """
+        Get complete connected subgraph for specified node (including the starting node itself)
+
+        Args:
+            node_label: Label of the starting node
+            max_depth: Maximum depth of the subgraph
+
+        Returns:
+            KnowledgeGraph object containing nodes and edges
+        """
+        result = KnowledgeGraph()
+        seen_nodes = set()
+        seen_edges = set()
+
+        # Handle special case for "*" label
+        if node_label == "*":
+            # For "*", return the entire graph including all nodes and edges
+            subgraph = (
+                self._graph.copy()
+            )  # Create a copy to avoid modifying the original graph
+        else:
+            # Find nodes with matching node id (partial match)
+            nodes_to_explore = []
+            for n, attr in self._graph.nodes(data=True):
+                if node_label in str(n):  # Use partial matching
+                    nodes_to_explore.append(n)
+
+            if not nodes_to_explore:
+                logger.warning(f"No nodes found with label {node_label}")
+                return result
+
+            # Get subgraph using ego_graph
+            subgraph = nx.ego_graph(self._graph, nodes_to_explore[0], radius=max_depth)
+
+        # Check if number of nodes exceeds max_graph_nodes
+        max_graph_nodes = 500
+        if len(subgraph.nodes()) > max_graph_nodes:
+            origin_nodes = len(subgraph.nodes())
+            node_degrees = dict(subgraph.degree())
+            top_nodes = sorted(node_degrees.items(), key=lambda x: x[1], reverse=True)[
+                :max_graph_nodes
+            ]
+            top_node_ids = [node[0] for node in top_nodes]
+            # Create new subgraph with only top nodes
+            subgraph = subgraph.subgraph(top_node_ids)
+            logger.info(
+                f"Reduced graph from {origin_nodes} nodes to {max_graph_nodes} nodes (depth={max_depth})"
+            )
+
+        # Add nodes to result
+        for node in subgraph.nodes():
+            if str(node) in seen_nodes:
+                continue
+
+            node_data = dict(subgraph.nodes[node])
+            # Get entity_type as labels
+            labels = []
+            if "entity_type" in node_data:
+                if isinstance(node_data["entity_type"], list):
+                    labels.extend(node_data["entity_type"])
+                else:
+                    labels.append(node_data["entity_type"])
+
+            # Create node with properties
+            node_properties = {k: v for k, v in node_data.items()}
+
+            result.nodes.append(
+                KnowledgeGraphNode(
+                    id=str(node), labels=[str(node)], properties=node_properties
+                )
+            )
+            seen_nodes.add(str(node))
+
+        # Add edges to result
+        for edge in subgraph.edges():
+            source, target = edge
+            edge_id = f"{source}-{target}"
+            if edge_id in seen_edges:
+                continue
+
+            edge_data = dict(subgraph.edges[edge])
+
+            # Create edge with complete information
+            result.edges.append(
+                KnowledgeGraphEdge(
+                    id=edge_id,
+                    type="DIRECTED",
+                    source=str(source),
+                    target=str(target),
+                    properties=edge_data,
+                )
+            )
+            seen_edges.add(edge_id)
+
+        # logger.info(result.edges)
+
+        logger.info(
+            f"Subgraph query successful | Node count: {len(result.nodes)} | Edge count: {len(result.edges)}"
+        )
+        return result

lightrag/lightrag.py

@@ -466,10 +466,10 @@ async def get_graph_labels(self):
         return text
 
     async def get_knowledge_graph(
-        self, nodel_label: str, max_depth: int
+        self, node_label: str, max_depth: int
     ) -> KnowledgeGraph:
         return await self.chunk_entity_relation_graph.get_knowledge_graph(
-            node_label=nodel_label, max_depth=max_depth
+            node_label=node_label, max_depth=max_depth
         )
 
     def _get_storage_class(self, storage_name: str) -> Callable[..., Any]: