community[minor]: Relax constraints on Cassandra VectorStore constructors (#21209)

If Session and/or keyspace are not provided, they are resolved from
cassio's context. So they are not required.
This change is fully backward compatible.

libs/community/langchain_community/vectorstores/cassandra.py

@@ -31,8 +31,6 @@ from langchain_community.vectorstores.utils import maximal_marginal_relevance
 
 CVST = TypeVar("CVST", bound="Cassandra")
 
-_NOT_SET = object()
-
 
 class Cassandra(VectorStore):
     """Apache Cassandra(R) for vector-store workloads.
@@ -56,9 +54,9 @@ class Cassandra(VectorStore):
 
     Args:
         embedding: Embedding function to use.
-        session: Cassandra driver session.
-        keyspace: Cassandra key space.
-        table_name: Cassandra table.
+        session: Cassandra driver session. If not provided, it is resolved from cassio.
+        keyspace: Cassandra key space. If not provided, it is resolved from cassio.
+        table_name: Cassandra table (required).
         ttl_seconds: Optional time-to-live for the added texts.
         body_index_options: Optional options used to create the body index.
             Eg. body_index_options = [cassio.table.cql.STANDARD_ANALYZER]
@@ -83,9 +81,9 @@ class Cassandra(VectorStore):
     def __init__(
         self,
         embedding: Embeddings,
-        session: Session,
-        keyspace: str,
-        table_name: str,
+        session: Optional[Session] = None,
+        keyspace: Optional[str] = None,
+        table_name: str = "",
         ttl_seconds: Optional[int] = None,
         *,
         body_index_options: Optional[List[Tuple[str, Any]]] = None,
@@ -98,7 +96,8 @@ class Cassandra(VectorStore):
                 "Could not import cassio python package. "
                 "Please install it with `pip install cassio`."
             )
-        """Create a vector table."""
+        if not table_name:
+            raise ValueError("Missing required parameter 'table_name'.")
         self.embedding = embedding
         self.session = session
         self.keyspace = keyspace
@@ -779,8 +778,8 @@ class Cassandra(VectorStore):
         embedding: Embeddings,
         metadatas: Optional[List[dict]] = None,
         *,
-        session: Session = _NOT_SET,
-        keyspace: str = "",
+        session: Optional[Session] = None,
+        keyspace: Optional[str] = None,
         table_name: str = "",
         ids: Optional[List[str]] = None,
         batch_size: int = 16,
@@ -794,8 +793,10 @@ class Cassandra(VectorStore):
             texts: Texts to add to the vectorstore.
             embedding: Embedding function to use.
             metadatas: Optional list of metadatas associated with the texts.
-            session: Cassandra driver session (required).
-            keyspace: Cassandra key space (required).
+            session: Cassandra driver session.
+                If not provided, it is resolved from cassio.
+            keyspace: Cassandra key space.
+                If not provided, it is resolved from cassio.
             table_name: Cassandra table (required).
             ids: Optional list of IDs associated with the texts.
             batch_size: Number of concurrent requests to send to the server.
@@ -807,12 +808,6 @@ class Cassandra(VectorStore):
         Returns:
             a Cassandra vectorstore.
         """
-        if session is _NOT_SET:
-            raise ValueError("session parameter is required")
-        if not keyspace:
-            raise ValueError("keyspace parameter is required")
-        if not table_name:
-            raise ValueError("table_name parameter is required")
         store = cls(
             embedding=embedding,
             session=session,
@@ -833,8 +828,8 @@ class Cassandra(VectorStore):
         embedding: Embeddings,
         metadatas: Optional[List[dict]] = None,
         *,
-        session: Session = _NOT_SET,
-        keyspace: str = "",
+        session: Optional[Session] = None,
+        keyspace: Optional[str] = None,
         table_name: str = "",
         ids: Optional[List[str]] = None,
         concurrency: int = 16,
@@ -848,8 +843,10 @@ class Cassandra(VectorStore):
             texts: Texts to add to the vectorstore.
             embedding: Embedding function to use.
             metadatas: Optional list of metadatas associated with the texts.
-            session: Cassandra driver session (required).
-            keyspace: Cassandra key space (required).
+            session: Cassandra driver session.
+                If not provided, it is resolved from cassio.
+            keyspace: Cassandra key space.
+                If not provided, it is resolved from cassio.
             table_name: Cassandra table (required).
             ids: Optional list of IDs associated with the texts.
             concurrency: Number of concurrent queries to send to the database.
@@ -861,12 +858,6 @@ class Cassandra(VectorStore):
         Returns:
             a Cassandra vectorstore.
         """
-        if session is _NOT_SET:
-            raise ValueError("session parameter is required")
-        if not keyspace:
-            raise ValueError("keyspace parameter is required")
-        if not table_name:
-            raise ValueError("table_name parameter is required")
         store = cls(
             embedding=embedding,
             session=session,
@@ -887,8 +878,8 @@ class Cassandra(VectorStore):
         documents: List[Document],
         embedding: Embeddings,
         *,
-        session: Session = _NOT_SET,
-        keyspace: str = "",
+        session: Optional[Session] = None,
+        keyspace: Optional[str] = None,
         table_name: str = "",
         ids: Optional[List[str]] = None,
         batch_size: int = 16,
@@ -901,8 +892,10 @@ class Cassandra(VectorStore):
         Args:
             documents: Documents to add to the vectorstore.
             embedding: Embedding function to use.
-            session: Cassandra driver session (required).
-            keyspace: Cassandra key space (required).
+            session: Cassandra driver session.
+                If not provided, it is resolved from cassio.
+            keyspace: Cassandra key space.
+                If not provided, it is resolved from cassio.
             table_name: Cassandra table (required).
             ids: Optional list of IDs associated with the documents.
             batch_size: Number of concurrent requests to send to the server.
@@ -936,8 +929,8 @@ class Cassandra(VectorStore):
         documents: List[Document],
         embedding: Embeddings,
         *,
-        session: Session = _NOT_SET,
-        keyspace: str = "",
+        session: Optional[Session] = None,
+        keyspace: Optional[str] = None,
         table_name: str = "",
         ids: Optional[List[str]] = None,
         concurrency: int = 16,
@@ -950,8 +943,10 @@ class Cassandra(VectorStore):
         Args:
             documents: Documents to add to the vectorstore.
             embedding: Embedding function to use.
-            session: Cassandra driver session (required).
-            keyspace: Cassandra key space (required).
+            session: Cassandra driver session.
+                If not provided, it is resolved from cassio.
+            keyspace: Cassandra key space.
+                If not provided, it is resolved from cassio.
             table_name: Cassandra table (required).
             ids: Optional list of IDs associated with the documents.
             concurrency: Number of concurrent queries to send to the database.