mv base cache to schema (#9953)

if you remove all other imports from langchain.init it exposes a
circular dep

libs/langchain/langchain/__init__.py

@@ -4,7 +4,6 @@ from importlib import metadata
 from typing import Optional
 
 from langchain.agents import MRKLChain, ReActChain, SelfAskWithSearchChain
-from langchain.cache import BaseCache
 from langchain.chains import (
     ConversationChain,
     LLMBashChain,
@@ -40,6 +39,7 @@ from langchain.prompts import (
     Prompt,
     PromptTemplate,
 )
+from langchain.schema.cache import BaseCache
 from langchain.schema.prompt_template import BasePromptTemplate
 from langchain.utilities.arxiv import ArxivAPIWrapper
 from langchain.utilities.golden_query import GoldenQueryAPIWrapper

libs/langchain/langchain/cache.py

@@ -26,7 +26,6 @@ import inspect
 import json
 import logging
 import warnings
-from abc import ABC, abstractmethod
 from datetime import timedelta
 from typing import (
     TYPE_CHECKING,
@@ -35,7 +34,6 @@ from typing import (
     Dict,
     List,
     Optional,
-    Sequence,
     Tuple,
     Type,
     Union,
@@ -46,17 +44,18 @@ from sqlalchemy import Column, Integer, String, create_engine, select
 from sqlalchemy.engine.base import Engine
 from sqlalchemy.orm import Session
 
-from langchain.utils import get_from_env
-
 try:
     from sqlalchemy.orm import declarative_base
 except ImportError:
     from sqlalchemy.ext.declarative import declarative_base
 
+
 from langchain.embeddings.base import Embeddings
 from langchain.load.dump import dumps
 from langchain.load.load import loads
 from langchain.schema import ChatGeneration, Generation
+from langchain.schema.cache import RETURN_VAL_TYPE, BaseCache
+from langchain.utils import get_from_env
 from langchain.vectorstores.redis import Redis as RedisVectorstore
 
 logger = logging.getLogger(__file__)
@@ -64,8 +63,6 @@ logger = logging.getLogger(__file__)
 if TYPE_CHECKING:
     import momento
 
-RETURN_VAL_TYPE = Sequence[Generation]
-
 
 def _hash(_input: str) -> str:
     """Use a deterministic hashing approach."""
@@ -105,22 +102,6 @@ def _load_generations_from_json(generations_json: str) -> RETURN_VAL_TYPE:
         )
 
 
-class BaseCache(ABC):
-    """Base interface for cache."""
-
-    @abstractmethod
-    def lookup(self, prompt: str, llm_string: str) -> Optional[RETURN_VAL_TYPE]:
-        """Look up based on prompt and llm_string."""
-
-    @abstractmethod
-    def update(self, prompt: str, llm_string: str, return_val: RETURN_VAL_TYPE) -> None:
-        """Update cache based on prompt and llm_string."""
-
-    @abstractmethod
-    def clear(self, **kwargs: Any) -> None:
-        """Clear cache that can take additional keyword arguments."""
-
-
 class InMemoryCache(BaseCache):
     """Cache that stores things in memory."""
 

libs/langchain/langchain/schema/__init__.py

@@ -1,5 +1,6 @@
 """**Schemas** are the LangChain Base Classes and Interfaces."""
 from langchain.schema.agent import AgentAction, AgentFinish
+from langchain.schema.cache import BaseCache
 from langchain.schema.chat_history import BaseChatMessageHistory
 from langchain.schema.document import BaseDocumentTransformer, Document
 from langchain.schema.exceptions import LangChainException
@@ -39,6 +40,7 @@ RUN_KEY = "__run"
 Memory = BaseMemory
 
 __all__ = [
+    "BaseCache",
     "BaseMemory",
     "BaseStore",
     "AgentFinish",

libs/langchain/langchain/schema/cache.py

@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any, Optional, Sequence
+
+from langchain.schema.output import Generation
+
+RETURN_VAL_TYPE = Sequence[Generation]
+
+
+class BaseCache(ABC):
+    """Base interface for cache."""
+
+    @abstractmethod
+    def lookup(self, prompt: str, llm_string: str) -> Optional[RETURN_VAL_TYPE]:
+        """Look up based on prompt and llm_string."""
+
+    @abstractmethod
+    def update(self, prompt: str, llm_string: str, return_val: RETURN_VAL_TYPE) -> None:
+        """Update cache based on prompt and llm_string."""
+
+    @abstractmethod
+    def clear(self, **kwargs: Any) -> None:
+        """Clear cache that can take additional keyword arguments."""