community[patch]: Add driver config param for neo4j graph (#20772)

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/community/langchain_community/graphs/neo4j_graph.py

@@ -151,6 +151,7 @@ class Neo4jGraph(GraphStore):
             embedding-like properties from database responses. Default is False.
     refresh_schema (bool): A flag whether to refresh schema information
             at initialization. Default is True.
+    driver_config (Dict): Configuration passed to Neo4j Driver.
 
     *Security note*: Make sure that the database connection uses credentials
         that are narrowly-scoped to only include necessary permissions.
@@ -173,6 +174,8 @@ class Neo4jGraph(GraphStore):
         timeout: Optional[float] = None,
         sanitize: bool = False,
         refresh_schema: bool = True,
+        *,
+        driver_config: Optional[Dict] = None,
     ) -> None:
         """Create a new Neo4j graph wrapper instance."""
         try:
@@ -194,7 +197,9 @@ class Neo4jGraph(GraphStore):
             {"database": database}, "database", "NEO4J_DATABASE", "neo4j"
         )
 
-        self._driver = neo4j.GraphDatabase.driver(url, auth=(username, password))
+        self._driver = neo4j.GraphDatabase.driver(
+            url, auth=(username, password), **(driver_config or {})
+        )
         self._database = database
         self.timeout = timeout
         self.sanitize = sanitize

libs/community/tests/integration_tests/graphs/test_neo4j.py

@@ -273,3 +273,21 @@ def test_neo4j_filtering_labels() -> None:
     # Assert both are empty
     assert graph.structured_schema["node_props"] == {}
     assert graph.structured_schema["relationships"] == []
+
+
+def test_driver_config() -> None:
+    """Test that neo4j works with driver config."""
+    url = os.environ.get("NEO4J_URI")
+    username = os.environ.get("NEO4J_USERNAME")
+    password = os.environ.get("NEO4J_PASSWORD")
+    assert url is not None
+    assert username is not None
+    assert password is not None
+
+    graph = Neo4jGraph(
+        url=url,
+        username=username,
+        password=password,
+        driver_config={"max_connection_pool_size": 1},
+    )
+    graph.query("RETURN 'foo'")