[Core] Tracing: update parent run_tree's child_runs (#21049)

libs/core/langchain_core/callbacks/manager.py

@@ -41,6 +41,7 @@ from langchain_core.callbacks.base import (
 )
 from langchain_core.callbacks.stdout import StdOutCallbackHandler
 from langchain_core.messages import BaseMessage, get_buffer_string
+from langchain_core.tracers.schemas import Run
 from langchain_core.utils.env import env_var_is_set
 
 if TYPE_CHECKING:
@@ -1994,15 +1995,22 @@ def _configure(
                 callback_manager.add_handler(tracer_v2, True)
             else:
                 try:
-                    handler = LangChainTracer(project_name=tracer_project)
+                    handler = LangChainTracer(
+                        project_name=tracer_project,
+                        client=run_tree.client if run_tree is not None else None,
+                    )
                     callback_manager.add_handler(handler, True)
                 except Exception as e:
                     logger.warning(
                         "Unable to load requested LangChainTracer."
                         " To disable this warning,"
                         " unset the LANGCHAIN_TRACING_V2 environment variables.",
-                        e,
+                        f"{repr(e)}",
                     )
+        if run_tree is not None:
+            for handler in callback_manager.handlers:
+                if isinstance(handler, LangChainTracer):
+                    handler.run_map[str(run_tree.id)] = cast(Run, run_tree)
     for var, inheritable, handler_class, env_var in _configure_hooks:
         create_one = (
             env_var is not None

libs/core/langchain_core/tracers/base.py

@@ -1,4 +1,5 @@
 """Base interfaces for tracing runs."""
+
 from __future__ import annotations
 
 import logging
@@ -102,9 +103,10 @@ class BaseTracer(BaseCallbackHandler, ABC):
             parent_run = self.run_map.get(str(run.parent_run_id))
             if parent_run:
                 self._add_child_run(parent_run, run)
-                parent_run.child_execution_order = max(
-                    parent_run.child_execution_order, run.child_execution_order
-                )
+                if hasattr(parent_run, "child_execution_order"):
+                    parent_run.child_execution_order = max(
+                        parent_run.child_execution_order, run.child_execution_order
+                    )
                 run.trace_id = parent_run.trace_id
                 if parent_run.dotted_order:
                     run.dotted_order = (
@@ -135,7 +137,7 @@ class BaseTracer(BaseCallbackHandler, ABC):
                 logger.debug(f"Parent run with UUID {run.parent_run_id} not found.")
             elif (
                 run.child_execution_order is not None
-                and parent_run.child_execution_order is not None
+                and getattr(parent_run, "child_execution_order", None) is not None
                 and run.child_execution_order > parent_run.child_execution_order
             ):
                 parent_run.child_execution_order = run.child_execution_order
@@ -151,10 +153,11 @@ class BaseTracer(BaseCallbackHandler, ABC):
         if parent_run is None:
             logger.debug(f"Parent run with UUID {parent_run_id} not found.")
             return 1
-        if parent_run.child_execution_order is None:
-            raise TracerException(
-                f"Parent run with UUID {parent_run_id} has no child execution order."
+        if getattr(parent_run, "child_execution_order", None) is None:
+            logger.debug(
+                f"Parent run with UUID {parent_run_id} has no child_execution_order."
             )
+            return 1
 
         return parent_run.child_execution_order + 1
 

libs/core/tests/unit_tests/tracers/test_base_tracer.py

@@ -1,16 +1,21 @@
 """Test Tracer classes."""
+
 from __future__ import annotations
 
 from datetime import datetime, timezone
 from typing import Any, List
+from unittest.mock import MagicMock
 from uuid import uuid4
 
+import langsmith
 import pytest
 from freezegun import freeze_time
+from langsmith import Client, traceable
 
 from langchain_core.callbacks import CallbackManager
 from langchain_core.messages import HumanMessage
 from langchain_core.outputs import LLMResult
+from langchain_core.runnables import chain as as_runnable
 from langchain_core.tracers.base import BaseTracer, TracerException
 from langchain_core.tracers.schemas import Run
 
@@ -627,3 +632,33 @@ def test_tracer_nested_runs_on_error() -> None:
     assert len(tracer.runs) == 3
     for run in tracer.runs:
         _compare_run_with_error(run, compare_run)
+
+
+def _get_mock_client() -> Client:
+    mock_session = MagicMock()
+    client = Client(session=mock_session, api_key="test")
+    return client
+
+
+def test_traceable_to_tracing() -> None:
+    has_children = False
+
+    def _collect_run(run: Any) -> None:
+        nonlocal has_children
+        has_children = bool(run.child_runs)
+
+    @as_runnable
+    def foo(x: int) -> int:
+        return x + 1
+
+    @traceable
+    def some_parent(a: int, b: int) -> int:
+        return foo.invoke(a) + foo.invoke(b)
+
+    mock_client_ = _get_mock_client()
+    with langsmith.run_helpers.tracing_context(enabled=True):
+        result = some_parent(
+            1, 2, langsmith_extra={"client": mock_client_, "on_end": _collect_run}
+        )
+    assert result == 5
+    assert has_children, "Child run not collected"

libs/core/tests/unit_tests/tracers/test_langchain.py

@@ -2,11 +2,13 @@ import threading
 import time
 import unittest
 import unittest.mock
+import uuid
 from typing import Any, Dict
 from uuid import UUID
 
 import pytest
 from langsmith import Client
+from langsmith.run_trees import RunTree
 
 from langchain_core.outputs import LLMResult
 from langchain_core.tracers.langchain import LangChainTracer
@@ -59,6 +61,24 @@ def test_example_id_assignment_threadsafe() -> None:
         assert example_ids == expected_example_ids
 
 
+def test_tracer_with_run_tree_parent() -> None:
+    mock_session = unittest.mock.MagicMock()
+    client = Client(session=mock_session, api_key="test")
+    parent = RunTree(name="parent", inputs={"input": "foo"}, client=client)
+    run_id = uuid.uuid4()
+    tracer = LangChainTracer(client=client)
+    tracer.run_map[str(parent.id)] = parent  # type: ignore
+    tracer.on_chain_start(
+        {"name": "child"}, {"input": "bar"}, run_id=run_id, parent_run_id=parent.id
+    )
+    tracer.on_chain_end({}, run_id=run_id)
+    assert parent.child_runs
+    assert len(parent.child_runs) == 1
+    assert parent.child_runs[0].id == run_id
+    assert parent.child_runs[0].trace_id == parent.id
+    assert parent.child_runs[0].parent_run_id == parent.id
+
+
 def test_log_lock() -> None:
     """Test that example assigned at callback start/end is honored."""