Add custom vector fields and text fields for OpenSearch (#2652)

**Description**
Add custom vector field name and text field name while indexing and
querying for OpenSearch

**Issues**
https://github.com/hwchase17/langchain/issues/2500

Signed-off-by: Naveen Tatikonda <navtat@amazon.com>

docs/modules/indexes/vectorstores/examples/opensearch.ipynb

@@ -55,7 +55,7 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\")\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\")\n",
     "\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
     "docs = docsearch.similarity_search(query)"
@@ -94,7 +94,7 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\", engine=\"faiss\", space_type=\"innerproduct\", ef_construction=256, m=48)\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\", engine=\"faiss\", space_type=\"innerproduct\", ef_construction=256, m=48)\n",
     "\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
     "docs = docsearch.similarity_search(query)"
@@ -133,7 +133,7 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
     "\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
     "docs = docsearch.similarity_search(\"What did the president say about Ketanji Brown Jackson\", k=1, search_type=\"script_scoring\")"
@@ -172,10 +172,10 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
     "filter = {\"bool\": {\"filter\": {\"term\": {\"text\": \"smuggling\"}}}}\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
-    "docs = docsearch.similarity_search(\"What did the president say about Ketanji Brown Jackson\", search_type=\"painless_scripting\", space_type=\"cosinesimil\", pre_filter=filter)"
+    "docs = docsearch.similarity_search(\"What did the president say about Ketanji Brown Jackson\", search_type=\"painless_scripting\", space_type=\"cosineSimilarity\", pre_filter=filter)"
    ]
   },
   {

langchain/vectorstores/opensearch_vector_search.py

@@ -65,6 +65,8 @@ def _bulk_ingest_embeddings(
     embeddings: List[List[float]],
     texts: Iterable[str],
     metadatas: Optional[List[dict]] = None,
+    vector_field: str = "vector_field",
+    text_field: str = "text",
 ) -> List[str]:
     """Bulk Ingest Embeddings into given index."""
     bulk = _import_bulk()
@@ -76,8 +78,8 @@ def _bulk_ingest_embeddings(
         request = {
             "_op_type": "index",
             "_index": index_name,
-            "vector_field": embeddings[i],
+            vector_field: embeddings[i],
-            "text": text,
+            text_field: text,
             "metadata": metadata,
             "_id": _id,
         }
@@ -88,12 +90,15 @@ def _bulk_ingest_embeddings(
     return ids
 
 
-def _default_scripting_text_mapping(dim: int) -> Dict:
+def _default_scripting_text_mapping(
+    dim: int,
+    vector_field: str = "vector_field",
+) -> Dict:
     """For Painless Scripting or Script Scoring,the default mapping to create index."""
     return {
         "mappings": {
             "properties": {
-                "vector_field": {"type": "knn_vector", "dimension": dim},
+                vector_field: {"type": "knn_vector", "dimension": dim},
             }
         }
     }
@@ -106,13 +111,14 @@ def _default_text_mapping(
     ef_search: int = 512,
     ef_construction: int = 512,
     m: int = 16,
+    vector_field: str = "vector_field",
 ) -> Dict:
     """For Approximate k-NN Search, this is the default mapping to create index."""
     return {
         "settings": {"index": {"knn": True, "knn.algo_param.ef_search": ef_search}},
         "mappings": {
             "properties": {
-                "vector_field": {
+                vector_field: {
                     "type": "knn_vector",
                     "dimension": dim,
                     "method": {
@@ -165,10 +171,18 @@ def _default_script_query(
     }
 
 
-def __get_painless_scripting_source(space_type: str, query_vector: List[float]) -> str:
+def __get_painless_scripting_source(
+    space_type: str, query_vector: List[float], vector_field: str = "vector_field"
+) -> str:
     """For Painless Scripting, it returns the script source based on space type."""
     source_value = (
-        "(1.0 + " + space_type + "(" + str(query_vector) + ", doc['vector_field']))"
+        "(1.0 + "
+        + space_type
+        + "("
+        + str(query_vector)
+        + ", doc['"
+        + vector_field
+        + "']))"
     )
     if space_type == "cosineSimilarity":
         return source_value
@@ -250,13 +264,26 @@ class OpenSearchVectorSearch(VectorStore):
 
         Returns:
             List of ids from adding the texts into the vectorstore.
+
+        Optional Args:
+            vector_field: Document field embeddings are stored in. Defaults to
+            "vector_field".
+
+            text_field: Document field the text of the document is stored in. Defaults
+            to "text".
         """
-        embeddings = [
+        embeddings = self.embedding_function.embed_documents(list(texts))
-            self.embedding_function.embed_documents([text])[0] for text in texts
-        ]
         _validate_embeddings_and_bulk_size(len(embeddings), bulk_size)
+        vector_field = _get_kwargs_value(kwargs, "vector_field", "vector_field")
+        text_field = _get_kwargs_value(kwargs, "text_field", "text")
         return _bulk_ingest_embeddings(
-            self.client, self.index_name, embeddings, texts, metadatas
+            self.client,
+            self.index_name,
+            embeddings,
+            texts,
+            metadatas,
+            vector_field,
+            text_field,
         )
 
     def similarity_search(
@@ -277,14 +304,17 @@ class OpenSearchVectorSearch(VectorStore):
         Optional Args:
             vector_field: Document field embeddings are stored in. Defaults to
             "vector_field".
+
             text_field: Document field the text of the document is stored in. Defaults
             to "text".
+
             metadata_field: Document field that metadata is stored in. Defaults to
             "metadata".
             Can be set to a special value "*" to include the entire document.
 
         Optional Args for Approximate Search:
             search_type: "approximate_search"; default: "approximate_search"
+
             size: number of results the query actually returns; default: 4
 
         Optional Args for Script Scoring Search:
@@ -298,6 +328,7 @@ class OpenSearchVectorSearch(VectorStore):
 
         Optional Args for Painless Scripting Search:
             search_type: "painless_scripting"; default: "approximate_search"
+
             space_type: "l2Squared", "l1Norm", "cosineSimilarity"; default: "l2Squared"
 
             pre_filter: script_score query to pre-filter documents before identifying
@@ -307,23 +338,21 @@ class OpenSearchVectorSearch(VectorStore):
         search_type = _get_kwargs_value(kwargs, "search_type", "approximate_search")
         text_field = _get_kwargs_value(kwargs, "text_field", "text")
         metadata_field = _get_kwargs_value(kwargs, "metadata_field", "metadata")
+        vector_field = _get_kwargs_value(kwargs, "vector_field", "vector_field")
         if search_type == "approximate_search":
             size = _get_kwargs_value(kwargs, "size", 4)
-            vector_field = _get_kwargs_value(kwargs, "vector_field", "vector_field")
             search_query = _default_approximate_search_query(
                 embedding, size, k, vector_field
             )
         elif search_type == SCRIPT_SCORING_SEARCH:
             space_type = _get_kwargs_value(kwargs, "space_type", "l2")
             pre_filter = _get_kwargs_value(kwargs, "pre_filter", MATCH_ALL_QUERY)
-            vector_field = _get_kwargs_value(kwargs, "vector_field", "vector_field")
             search_query = _default_script_query(
                 embedding, space_type, pre_filter, vector_field
             )
         elif search_type == PAINLESS_SCRIPTING_SEARCH:
             space_type = _get_kwargs_value(kwargs, "space_type", "l2Squared")
             pre_filter = _get_kwargs_value(kwargs, "pre_filter", MATCH_ALL_QUERY)
-            vector_field = _get_kwargs_value(kwargs, "vector_field", "vector_field")
             search_query = _default_painless_scripting_query(
                 embedding, space_type, pre_filter, vector_field
             )
@@ -370,6 +399,13 @@ class OpenSearchVectorSearch(VectorStore):
         and lucene engines recommended for large datasets. Also supports brute force
         search through Script Scoring and Painless Scripting.
 
+        Optional Args:
+            vector_field: Document field embeddings are stored in. Defaults to
+            "vector_field".
+
+            text_field: Document field the text of the document is stored in. Defaults
+            to "text".
+
         Optional Keyword Args for Approximate Search:
             engine: "nmslib", "faiss", "hnsw"; default: "nmslib"
 
@@ -402,6 +438,8 @@ class OpenSearchVectorSearch(VectorStore):
             kwargs, "index_name", "OPENSEARCH_INDEX_NAME", default=uuid.uuid4().hex
         )
         is_appx_search = _get_kwargs_value(kwargs, "is_appx_search", True)
+        vector_field = _get_kwargs_value(kwargs, "vector_field", "vector_field")
+        text_field = _get_kwargs_value(kwargs, "text_field", "text")
         if is_appx_search:
             engine = _get_kwargs_value(kwargs, "engine", "nmslib")
             space_type = _get_kwargs_value(kwargs, "space_type", "l2")
@@ -410,11 +448,13 @@ class OpenSearchVectorSearch(VectorStore):
             m = _get_kwargs_value(kwargs, "m", 16)
 
             mapping = _default_text_mapping(
-                dim, engine, space_type, ef_search, ef_construction, m
+                dim, engine, space_type, ef_search, ef_construction, m, vector_field
             )
         else:
             mapping = _default_scripting_text_mapping(dim)
 
         client.indices.create(index=index_name, body=mapping)
-        _bulk_ingest_embeddings(client, index_name, embeddings, texts, metadatas)
+        _bulk_ingest_embeddings(
+            client, index_name, embeddings, texts, metadatas, vector_field, text_field
+        )
         return cls(opensearch_url, index_name, embedding)

tests/integration_tests/vectorstores/test_opensearch.py

@@ -23,6 +23,30 @@ def test_opensearch() -> None:
     assert output == [Document(page_content="foo")]
 
 
+def test_opensearch_with_custom_field_name() -> None:
+    """Test indexing and search using custom vector field and text field name."""
+    docsearch = OpenSearchVectorSearch.from_texts(
+        texts,
+        FakeEmbeddings(),
+        opensearch_url=DEFAULT_OPENSEARCH_URL,
+        vector_field="my_vector",
+        text_field="custom_text",
+    )
+    output = docsearch.similarity_search(
+        "foo", k=1, vector_field="my_vector", text_field="custom_text"
+    )
+    assert output == [Document(page_content="foo")]
+
+    text_input = ["test", "add", "text", "method"]
+    OpenSearchVectorSearch.add_texts(
+        docsearch, text_input, vector_field="my_vector", text_field="custom_text"
+    )
+    output = docsearch.similarity_search(
+        "add", k=1, vector_field="my_vector", text_field="custom_text"
+    )
+    assert output == [Document(page_content="foo")]
+
+
 def test_opensearch_with_metadatas() -> None:
     """Test end to end indexing and search with metadata."""
     metadatas = [{"page": i} for i in range(len(texts))]