[Core] Feat: update config CVar in tool.invoke (#20808)

libs/core/langchain_core/tools.py

@@ -19,10 +19,12 @@ tool for the job.
 
 from __future__ import annotations
 
+import asyncio
 import inspect
 import uuid
 import warnings
 from abc import ABC, abstractmethod
+from contextvars import copy_context
 from functools import partial
 from inspect import signature
 from typing import Any, Awaitable, Callable, Dict, List, Optional, Tuple, Type, Union
@@ -60,7 +62,12 @@ from langchain_core.runnables import (
     RunnableSerializable,
     ensure_config,
 )
-from langchain_core.runnables.config import run_in_executor
+from langchain_core.runnables.config import (
+    patch_config,
+    run_in_executor,
+    var_child_runnable_config,
+)
+from langchain_core.runnables.utils import accepts_context
 
 
 class SchemaAnnotationError(TypeError):
@@ -255,6 +262,7 @@ class ChildTool(BaseTool):
             metadata=config.get("metadata"),
             run_name=config.get("run_name"),
             run_id=config.pop("run_id", None),
+            config=config,
             **kwargs,
         )
 
@@ -272,6 +280,7 @@ class ChildTool(BaseTool):
             metadata=config.get("metadata"),
             run_name=config.get("run_name"),
             run_id=config.pop("run_id", None),
+            config=config,
             **kwargs,
         )
 
@@ -353,6 +362,7 @@ class ChildTool(BaseTool):
         metadata: Optional[Dict[str, Any]] = None,
         run_name: Optional[str] = None,
         run_id: Optional[uuid.UUID] = None,
+        config: Optional[RunnableConfig] = None,
         **kwargs: Any,
     ) -> Any:
         """Run the tool."""
@@ -385,12 +395,20 @@ class ChildTool(BaseTool):
             **kwargs,
         )
         try:
+            child_config = patch_config(
+                config,
+                callbacks=run_manager.get_child(),
+            )
+            context = copy_context()
+            context.run(var_child_runnable_config.set, child_config)
             parsed_input = self._parse_input(tool_input)
             tool_args, tool_kwargs = self._to_args_and_kwargs(parsed_input)
             observation = (
-                self._run(*tool_args, run_manager=run_manager, **tool_kwargs)
+                context.run(
+                    self._run, *tool_args, run_manager=run_manager, **tool_kwargs
+                )
                 if new_arg_supported
-                else self._run(*tool_args, **tool_kwargs)
+                else context.run(self._run, *tool_args, **tool_kwargs)
             )
         except ValidationError as e:
             if not self.handle_validation_error:
@@ -446,6 +464,7 @@ class ChildTool(BaseTool):
         metadata: Optional[Dict[str, Any]] = None,
         run_name: Optional[str] = None,
         run_id: Optional[uuid.UUID] = None,
+        config: Optional[RunnableConfig] = None,
         **kwargs: Any,
     ) -> Any:
         """Run the tool asynchronously."""
@@ -476,11 +495,24 @@ class ChildTool(BaseTool):
             parsed_input = self._parse_input(tool_input)
             # We then call the tool on the tool input to get an observation
             tool_args, tool_kwargs = self._to_args_and_kwargs(parsed_input)
-            observation = (
+            child_config = patch_config(
-                await self._arun(*tool_args, run_manager=run_manager, **tool_kwargs)
+                config,
-                if new_arg_supported
+                callbacks=run_manager.get_child(),
-                else await self._arun(*tool_args, **tool_kwargs)
             )
+            context = copy_context()
+            context.run(var_child_runnable_config.set, child_config)
+            coro = (
+                context.run(
+                    self._arun, *tool_args, run_manager=run_manager, **tool_kwargs
+                )
+                if new_arg_supported
+                else context.run(self._arun, *tool_args, **tool_kwargs)
+            )
+            if accepts_context(asyncio.create_task):
+                observation = await asyncio.create_task(coro, context=context)  # type: ignore
+            else:
+                observation = await coro
+
         except ValidationError as e:
             if not self.handle_validation_error:
                 raise e

libs/core/tests/unit_tests/test_tools.py

@@ -1,6 +1,8 @@
 """Test the base tool implementation."""
 
+import asyncio
 import json
+import sys
 from datetime import datetime
 from enum import Enum
 from functools import partial
@@ -13,6 +15,7 @@ from langchain_core.callbacks import (
     CallbackManagerForToolRun,
 )
 from langchain_core.pydantic_v1 import BaseModel, ValidationError
+from langchain_core.runnables import ensure_config
 from langchain_core.tools import (
     BaseTool,
     SchemaAnnotationError,
@@ -871,3 +874,34 @@ def test_tool_invoke_optional_args(inputs: dict, expected: Optional[dict]) -> No
     else:
         with pytest.raises(ValidationError):
             foo.invoke(inputs)  # type: ignore
+
+
+def test_tool_pass_context() -> None:
+    @tool
+    def foo(bar: str) -> str:
+        """The foo."""
+        config = ensure_config()
+        assert config["configurable"]["foo"] == "not-bar"
+        assert bar == "baz"
+        return bar
+
+    assert foo.invoke({"bar": "baz"}, {"configurable": {"foo": "not-bar"}}) == "baz"  # type: ignore
+
+
+@pytest.mark.skipif(
+    sys.version_info < (3, 11),
+    reason="requires python3.11 or higher",
+)
+async def test_async_tool_pass_context() -> None:
+    @tool
+    async def foo(bar: str) -> str:
+        """The foo."""
+        await asyncio.sleep(0.0001)
+        config = ensure_config()
+        assert config["configurable"]["foo"] == "not-bar"
+        assert bar == "baz"
+        return bar
+
+    assert (
+        await foo.ainvoke({"bar": "baz"}, {"configurable": {"foo": "not-bar"}}) == "baz"  # type: ignore
+    )