async implementation

libs/community/langchain_community/retrievers/elastic_search_bm25.py

@@ -183,3 +183,26 @@ def _get_relevant_documents(
                 )
             )
         return docs[: self.k]
+
+    async def _aget_relevant_documents(
+            self, query: str, *, run_manager: CallbackManagerForRetrieverRun
+        ) -> List[Document]:
+            """
+            Async implementation of the retriever 
+            
+            Async client (from elasticsearch import AsyncElasticsearch) need to be passed as an attribute to the class before invoking.
+            """
+            query_dict = self.build_query_body(query)
+            res = await self.client.search(
+                index=self.index_name, body=query_dict, source=["content", "metadata"]
+            )
+
+            docs = []
+            for r in res["hits"]["hits"]:
+                docs.append(
+                    Document(
+                        metadata=r["_source"]["metadata"],
+                        page_content=r["_source"]["content"],
+                    )
+                )
+            return docs[: self.k]