调整代码结构，同时修改重定义提示词的方式。

backend/app/engine/engine.py

@@ -0,0 +1,83 @@
+import os
+
+from llama_index.core import SummaryIndex, SQLDatabase, VectorStoreIndex
+from llama_index.core.indices.struct_store import SQLTableRetrieverQueryEngine
+from llama_index.core.objects import SQLTableNodeMapping, ObjectIndex
+from llama_index.core.query_engine import RetrieverQueryEngine
+from llama_index.core.response_synthesizers import ResponseMode
+from sqlalchemy import create_engine
+
+from app.engine import makeDescriptionByEngine
+from app.engine.prompt import text_qa_template, refine_template, summary_template, simple_template
+from app.engine.retriever.HybridRetriever import HybridRetriever
+from app.settings import get_node_postprocessors
+
+
+
+def get_Retriever(index,**kwargs):
+    bEnableHybrid = True if os.getenv("HYBRID_ENABLED",False).title() == 'True' else False
+    if bEnableHybrid:
+        alpha = float(os.getenv("HYBRID_ALPHA", "0.5"))
+        retriever = HybridRetriever(index,alpha = alpha,**kwargs)
+    else:
+        retriever = index.as_retriever(**kwargs)
+    return retriever
+
+
+sql_database = None
+sql_obj_index = None
+
+# Create a summary query engine
+def create_summary_query_engine(top_k=3, use_reranker=False, filters=None):
+    global sql_obj_index
+    global sql_database
+    if sql_obj_index is None or sql_database is None:
+        sqlengine = create_engine(os.getenv("SQL_DATABASE_URL", ""))
+        sql_database = SQLDatabase(sqlengine)
+        table_schema_objs = makeDescriptionByEngine(sql_database)
+        table_node_mapping = SQLTableNodeMapping(sql_database)
+
+        sql_obj_index = ObjectIndex.from_objects(
+            table_schema_objs,
+            table_node_mapping,
+            index_cls=VectorStoreIndex,
+        )
+
+    # 创建SQL查询工具
+    sql_query_engine = SQLTableRetrieverQueryEngine(sql_database,
+                                                    sql_obj_index.as_retriever(similarity_top_k=top_k),
+                                                    verbose=True,
+                                                    )
+    return sql_query_engine
+
+# Create a summary query engine
+def create_summary_query_engine(index, top_k=3, use_reranker=False, filters=None):
+    summary_index = SummaryIndex(index.vector_store.get_nodes(node_ids=None))
+    summary_query_engine = summary_index.as_query_engine(
+    response_mode=ResponseMode.TREE_SUMMARIZE,
+    use_async=True,
+    streaming=True,
+    )
+    return summary_query_engine
+
+# Create a query engine
+def create_query_engine(index, top_k=3, use_reranker=False, filters=None):
+    # 创建向量检索查询工具
+    postprocess = None
+    if use_reranker:
+        postprocess = get_node_postprocessors()
+
+    query_engine = RetrieverQueryEngine.from_args(
+        get_Retriever(index,
+                      similarity_top_k=top_k,
+                      filters=filters),
+        text_qa_template=text_qa_template,
+        refine_template=refine_template,
+        summary_template = summary_template,
+        simple_template = simple_template,
+        node_postprocessors=postprocess,
+        use_async=True,
+        streaming=True,
+    )
+
+    return query_engine