feat: 修改bisheng_retriever对象类型 (#704)

src/bisheng-langchain/bisheng_langchain/rag/bisheng_rag_tool.py

@@ -3,6 +3,8 @@
 import yaml
 import httpx
 from typing import Any, Dict, Tuple, Type, Union, Optional
+
+from langchain_core.vectorstores import VectorStoreRetriever
 from loguru import logger
 from langchain_core.tools import BaseTool, Tool
 from langchain_core.pydantic_v1 import BaseModel, Extra, Field, root_validator
@@ -73,7 +75,11 @@ def __init__(
 
         # init milvus
         if vector_store:
-            self.vector_store = vector_store
+            # if vector_store is retriever, get vector_store instance
+            if isinstance(vector_store, VectorStoreRetriever):
+                self.vector_store = vector_store.vectorstore
+            else:
+                self.vector_store = vector_store
         else:
             # init embeddings
             embedding_params = self.params['embedding']