langchain[patch[: Add async methods to TimeWeightedVectorStoreRetriever (#19606)

libs/langchain/langchain/retrievers/time_weighted_retriever.py

@@ -2,7 +2,10 @@ import datetime
 from copy import deepcopy
 from typing import Any, Dict, List, Optional, Tuple
 
-from langchain_core.callbacks import CallbackManagerForRetrieverRun
+from langchain_core.callbacks import (
+    AsyncCallbackManagerForRetrieverRun,
+    CallbackManagerForRetrieverRun,
+)
 from langchain_core.documents import Document
 from langchain_core.pydantic_v1 import Field
 from langchain_core.retrievers import BaseRetriever
@@ -89,17 +92,26 @@ class TimeWeightedVectorStoreRetriever(BaseRetriever):
                 results[buffer_idx] = (doc, relevance)
         return results
 
-    def _get_relevant_documents(
-        self, query: str, *, run_manager: CallbackManagerForRetrieverRun
+    async def aget_salient_docs(self, query: str) -> Dict[int, Tuple[Document, float]]:
+        """Return documents that are salient to the query."""
+        docs_and_scores: List[Tuple[Document, float]]
+        docs_and_scores = (
+            await self.vectorstore.asimilarity_search_with_relevance_scores(
+                query, **self.search_kwargs
+            )
+        )
+        results = {}
+        for fetched_doc, relevance in docs_and_scores:
+            if "buffer_idx" in fetched_doc.metadata:
+                buffer_idx = fetched_doc.metadata["buffer_idx"]
+                doc = self.memory_stream[buffer_idx]
+                results[buffer_idx] = (doc, relevance)
+        return results
+
+    def _get_rescored_docs(
+        self, docs_and_scores: Dict[Any, Tuple[Document, Optional[float]]]
     ) -> List[Document]:
-        """Return documents that are relevant to the query."""
         current_time = datetime.datetime.now()
-        docs_and_scores = {
-            doc.metadata["buffer_idx"]: (doc, self.default_salience)
-            for doc in self.memory_stream[-self.k :]
-        }
-        # If a doc is considered salient, update the salience score
-        docs_and_scores.update(self.get_salient_docs(query))
         rescored_docs = [
             (doc, self._get_combined_score(doc, relevance, current_time))
             for doc, relevance in docs_and_scores.values()
@@ -114,6 +126,28 @@ class TimeWeightedVectorStoreRetriever(BaseRetriever):
             result.append(buffered_doc)
         return result
 
+    def _get_relevant_documents(
+        self, query: str, *, run_manager: CallbackManagerForRetrieverRun
+    ) -> List[Document]:
+        docs_and_scores = {
+            doc.metadata["buffer_idx"]: (doc, self.default_salience)
+            for doc in self.memory_stream[-self.k :]
+        }
+        # If a doc is considered salient, update the salience score
+        docs_and_scores.update(self.get_salient_docs(query))
+        return self._get_rescored_docs(docs_and_scores)
+
+    async def _aget_relevant_documents(
+        self, query: str, *, run_manager: AsyncCallbackManagerForRetrieverRun
+    ) -> List[Document]:
+        docs_and_scores = {
+            doc.metadata["buffer_idx"]: (doc, self.default_salience)
+            for doc in self.memory_stream[-self.k :]
+        }
+        # If a doc is considered salient, update the salience score
+        docs_and_scores.update(await self.aget_salient_docs(query))
+        return self._get_rescored_docs(docs_and_scores)
+
     def add_documents(self, documents: List[Document], **kwargs: Any) -> List[str]:
         """Add documents to vectorstore."""
         current_time = kwargs.get("current_time")

libs/langchain/tests/unit_tests/retrievers/test_time_weighted_retriever.py

@@ -36,45 +36,13 @@ class MockVectorStore(VectorStore):
         metadatas: Optional[List[dict]] = None,
         **kwargs: Any,
     ) -> List[str]:
-        """Run more texts through the embeddings and add to the vectorstore.
-
-        Args:
-            texts: Iterable of strings to add to the vectorstore.
-            metadatas: Optional list of metadatas associated with the texts.
-            kwargs: vectorstore specific parameters
-
-        Returns:
-            List of ids from adding the texts into the vectorstore.
-        """
         return list(texts)
 
-    async def aadd_texts(
-        self,
-        texts: Iterable[str],
-        metadatas: Optional[List[dict]] = None,
-        **kwargs: Any,
-    ) -> List[str]:
-        """Run more texts through the embeddings and add to the vectorstore."""
-        raise NotImplementedError
-
     def similarity_search(
         self, query: str, k: int = 4, **kwargs: Any
     ) -> List[Document]:
-        """Return docs most similar to query."""
         return []
 
-    @classmethod
-    def from_documents(
-        cls: Type["MockVectorStore"],
-        documents: List[Document],
-        embedding: Embeddings,
-        **kwargs: Any,
-    ) -> "MockVectorStore":
-        """Return VectorStore initialized from documents and embeddings."""
-        texts = [d.page_content for d in documents]
-        metadatas = [d.metadata for d in documents]
-        return cls.from_texts(texts, embedding, metadatas=metadatas, **kwargs)
-
     @classmethod
     def from_texts(
         cls: Type["MockVectorStore"],
@@ -83,7 +51,6 @@ class MockVectorStore(VectorStore):
         metadatas: Optional[List[dict]] = None,
         **kwargs: Any,
     ) -> "MockVectorStore":
-        """Return VectorStore initialized from texts and embeddings."""
         return cls()
 
     def _similarity_search_with_relevance_scores(
@@ -92,12 +59,16 @@ class MockVectorStore(VectorStore):
         k: int = 4,
         **kwargs: Any,
     ) -> List[Tuple[Document, float]]:
-        """Return docs and similarity scores, normalized on a scale from 0 to 1.
-
-        0 is dissimilar, 1 is most similar.
-        """
         return [(doc, 0.5) for doc in _get_example_memories()]
 
+    async def _asimilarity_search_with_relevance_scores(
+        self,
+        query: str,
+        k: int = 4,
+        **kwargs: Any,
+    ) -> List[Tuple[Document, float]]:
+        return self._similarity_search_with_relevance_scores(query, k, **kwargs)
+
 
 @pytest.fixture
 def time_weighted_retriever() -> TimeWeightedVectorStoreRetriever:
@@ -146,6 +117,18 @@ def test_get_salient_docs(
         assert doc in want
 
 
+async def test_aget_salient_docs(
+    time_weighted_retriever: TimeWeightedVectorStoreRetriever,
+) -> None:
+    query = "Test query"
+    docs_and_scores = await time_weighted_retriever.aget_salient_docs(query)
+    want = [(doc, 0.5) for doc in _get_example_memories()]
+    assert isinstance(docs_and_scores, dict)
+    assert len(docs_and_scores) == len(want)
+    for k, doc in docs_and_scores.items():
+        assert doc in want
+
+
 def test_get_relevant_documents(
     time_weighted_retriever: TimeWeightedVectorStoreRetriever,
 ) -> None:
@@ -164,6 +147,24 @@ def test_get_relevant_documents(
         assert now - timedelta(hours=1) < d.metadata["last_accessed_at"] <= now
 
 
+async def test_aget_relevant_documents(
+    time_weighted_retriever: TimeWeightedVectorStoreRetriever,
+) -> None:
+    query = "Test query"
+    relevant_documents = await time_weighted_retriever.aget_relevant_documents(query)
+    want = [(doc, 0.5) for doc in _get_example_memories()]
+    assert isinstance(relevant_documents, list)
+    assert len(relevant_documents) == len(want)
+    now = datetime.now()
+    for doc in relevant_documents:
+        # assert that the last_accessed_at is close to now.
+        assert now - timedelta(hours=1) < doc.metadata["last_accessed_at"] <= now
+
+    # assert that the last_accessed_at in the memory stream is updated.
+    for d in time_weighted_retriever.memory_stream:
+        assert now - timedelta(hours=1) < d.metadata["last_accessed_at"] <= now
+
+
 def test_add_documents(
     time_weighted_retriever: TimeWeightedVectorStoreRetriever,
 ) -> None:
@@ -175,3 +176,16 @@ def test_add_documents(
         time_weighted_retriever.memory_stream[-1].page_content
         == documents[0].page_content
     )
+
+
+async def test_aadd_documents(
+    time_weighted_retriever: TimeWeightedVectorStoreRetriever,
+) -> None:
+    documents = [Document(page_content="test_add_documents document")]
+    added_documents = await time_weighted_retriever.aadd_documents(documents)
+    assert isinstance(added_documents, list)
+    assert len(added_documents) == 1
+    assert (
+        time_weighted_retriever.memory_stream[-1].page_content
+        == documents[0].page_content
+    )