Default On Retry (#9230)

Base callbacks don't have a default on retry event

Fix #8542

---------

Co-authored-by: landonsilla <landon.silla@stepstone.com>

libs/langchain/langchain/callbacks/base.py

@@ -4,6 +4,8 @@ from __future__ import annotations
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Sequence, Union
 from uuid import UUID
 
+from tenacity import RetryCallState
+
 if TYPE_CHECKING:
     from langchain.schema.agent import AgentAction, AgentFinish
     from langchain.schema.document import Document
@@ -222,6 +224,16 @@ class RunManagerMixin:
     ) -> Any:
         """Run on arbitrary text."""
 
+    def on_retry(
+        self,
+        retry_state: RetryCallState,
+        *,
+        run_id: UUID,
+        parent_run_id: Optional[UUID] = None,
+        **kwargs: Any,
+    ) -> Any:
+        """Run on a retry event."""
+
 
 class BaseCallbackHandler(
     LLMManagerMixin,
@@ -414,6 +426,16 @@ class AsyncCallbackHandler(BaseCallbackHandler):
     ) -> None:
         """Run on arbitrary text."""
 
+    async def on_retry(
+        self,
+        retry_state: RetryCallState,
+        *,
+        run_id: UUID,
+        parent_run_id: Optional[UUID] = None,
+        **kwargs: Any,
+    ) -> Any:
+        """Run on a retry event."""
+
     async def on_agent_action(
         self,
         action: AgentAction,

libs/langchain/tests/unit_tests/callbacks/test_openai_info.py

@@ -1,3 +1,6 @@
+from unittest.mock import MagicMock
+from uuid import uuid4
+
 import pytest
 
 from langchain.callbacks import OpenAICallbackHandler
@@ -124,3 +127,7 @@ def test_on_llm_end_no_cost_invalid_model(
     )
     handler.on_llm_end(response)
     assert handler.total_cost == 0
+
+
+def test_on_retry_works(handler: OpenAICallbackHandler) -> None:
+    handler.on_retry(MagicMock(), run_id=uuid4())