rfc zep search mem

libs/langchain/langchain/memory/zep_memory.py

@@ -1,12 +1,14 @@
 from __future__ import annotations
 
-from typing import Any, Dict, Optional
+from typing import Any, Dict, List, Optional
 
 from langchain.memory import ConversationBufferMemory
+from langchain.memory.chat_memory import BaseChatMemory
 from langchain.memory.chat_message_histories import ZepChatMessageHistory
+from langchain.memory.utils import get_prompt_input_key
 
 
-class ZepMemory(ConversationBufferMemory):
+class _ZepMemory(BaseChatMemory):
     """Persist your chain history to the Zep Memory Server.
 
     The number of messages returned by Zep and when the Zep server summarizes chat
@@ -51,6 +53,7 @@ class ZepMemory(ConversationBufferMemory):
     """
 
     chat_memory: ZepChatMessageHistory
+    memory_key: str = "history"  #: :meta private:
 
     def __init__(
         self,
@@ -102,6 +105,14 @@ def __init__(
             memory_key=memory_key,
         )
 
+    @property
+    def memory_variables(self) -> List[str]:
+        """Will always return list of memory variables.
+
+        :meta private:
+        """
+        return [self.memory_key]
+
     def save_context(
         self,
         inputs: Dict[str, Any],
@@ -122,3 +133,25 @@ def save_context(
         input_str, output_str = self._get_input_output(inputs, outputs)
         self.chat_memory.add_user_message(input_str, metadata=metadata)
         self.chat_memory.add_ai_message(output_str, metadata=metadata)
+
+
+class ZepSearchMemory(_ZepMemory):
+    top_k: int = 4
+
+    def _get_prompt_input_key(self, inputs: Dict[str, Any]) -> str:
+        """Get the input key for the prompt."""
+        if self.input_key is None:
+            return get_prompt_input_key(inputs, self.memory_variables)
+        return self.input_key
+
+    def load_memory_variables(self, inputs: Dict[str, Any]) -> Dict[str, str]:
+        """Return history buffer."""
+        input_key = self._get_prompt_input_key(inputs)
+        query = inputs[input_key]
+        results = self.chat_memory.search(query, limit=self.top_k)
+        result = "\n".join([r.message.pop("content") for r in results])
+        return {self.memory_key: result}
+
+
+class ZepBufferMemory(_ZepMemory, ConversationBufferMemory):
+    """"""

libs/langchain/langchain/retrievers/zep.py

@@ -42,7 +42,7 @@ def create_client(cls, values: dict) -> dict:
         try:
             from zep_python import ZepClient
         except ImportError:
-            raise ValueError(
+            raise ImportError(
                 "Could not import zep-python package. "
                 "Please install it with `pip install zep-python`."
             )