INTPYTHON-838 Allow additional arguments to vector_search_index_definition (#267)

This pull request adds support for passing custom vector index options
throughout the vector search index creation and update workflows in the
MongoDB integration. This enhancement allows users to specify additional
parameters for vector index configuration, increasing flexibility and
control over index behavior.

Enhancements to vector index configuration:

* Added a new `vector_index_options` parameter to the
`_vector_search_index_definition`, `create_vector_search_index`, and
`update_vector_search_index` functions in `index.py`, enabling custom
options to be merged into the index definition.
[[1]](diffhunk://#diff-ded4d757aa6ceaa72da4d733902d2754b87d8e30294ac133b52d93345a2a6492R18-R29)
[[2]](diffhunk://#diff-ded4d757aa6ceaa72da4d733902d2754b87d8e30294ac133b52d93345a2a6492R47)
[[3]](diffhunk://#diff-ded4d757aa6ceaa72da4d733902d2754b87d8e30294ac133b52d93345a2a6492R79)
[[4]](diffhunk://#diff-ded4d757aa6ceaa72da4d733902d2754b87d8e30294ac133b52d93345a2a6492R130)
[[5]](diffhunk://#diff-ded4d757aa6ceaa72da4d733902d2754b87d8e30294ac133b52d93345a2a6492R160)
* Updated the `MongoDBAtlasVectorSearch` class in `vectorstores.py` to
accept and forward the `vector_index_options` parameter during
initialization and index creation, ensuring consistent propagation of
custom options.
[[1]](diffhunk://#diff-6dc2a6cf887e0d19be789087d31e249730d5f33112e0f784defb71eb92ad2a4eR215)
[[2]](diffhunk://#diff-6dc2a6cf887e0d19be789087d31e249730d5f33112e0f784defb71eb92ad2a4eR260)
[[3]](diffhunk://#diff-6dc2a6cf887e0d19be789087d31e249730d5f33112e0f784defb71eb92ad2a4eR846)
[[4]](diffhunk://#diff-6dc2a6cf887e0d19be789087d31e249730d5f33112e0f784defb71eb92ad2a4eR885)[Issue
Key](https://jira.mongodb.org/browse/{ISSUE_KEY})

Author: barnuri

libs/langchain-mongodb/langchain_mongodb/index.py

@@ -20,15 +20,18 @@ def _vector_search_index_definition(
     path: str,
     similarity: str,
     filters: Optional[List[str]] = None,
+    vector_index_options: dict | None = None,
     **kwargs: Any,
 ) -> Dict[str, Any]:
     # https://www.mongodb.com/docs/atlas/atlas-vector-search/vector-search-type/
+    vector_index_options = vector_index_options or {}
     fields = [
         {
             "numDimensions": dimensions,
             "path": path,
             "similarity": similarity,
             "type": "vector",
+            **vector_index_options,
         },
     ]
     if filters:

libs/langchain-mongodb/langchain_mongodb/vectorstores.py

@@ -213,6 +213,7 @@ def __init__(
         dimensions: int = -1,
         auto_create_index: bool | None = None,
         auto_index_timeout: int = 15,
+        vector_index_options: dict | None = None,
         **kwargs: Any,
     ):
         """
@@ -257,6 +258,7 @@ def __init__(
                 path=embedding_key,
                 similarity=relevance_score_fn,
                 wait_until_complete=auto_index_timeout,
+                vector_index_options=vector_index_options,
             )
 
     @property
@@ -829,6 +831,7 @@ def create_vector_search_index(
         filters: Optional[List[str]] = None,
         update: bool = False,
         wait_until_complete: Optional[float] = None,
+        vector_index_options: dict | None = None,
         **kwargs: Any,
     ) -> None:
         """Creates a MongoDB Atlas vectorSearch index for the VectorStore
@@ -867,6 +870,7 @@ def create_vector_search_index(
             path=self._embedding_key,
             similarity=self._relevance_score_fn,
             filters=filters or [],
+            vector_index_options=vector_index_options,
             wait_until_complete=wait_until_complete,
             **kwargs,
         )  # type: ignore [operator]