Consolidate run collector. Add link helper (#11269)

Instead of:

```
client = Client()
with collect_runs() as cb:
    chain.invoke()
    run = cb.traced_runs[0]
    client.get_run_url(run)
```

it's
```
with tracing_v2_enabled() as cb:
    chain.invoke()
    cb.get_run_url()
```

libs/langchain/langchain/callbacks/manager.py

@@ -41,7 +41,9 @@ from langchain.callbacks.base import (
 from langchain.callbacks.openai_info import OpenAICallbackHandler
 from langchain.callbacks.stdout import StdOutCallbackHandler
 from langchain.callbacks.tracers import run_collector
-from langchain.callbacks.tracers.langchain import LangChainTracer
+from langchain.callbacks.tracers.langchain import (
+    LangChainTracer,
+)
 from langchain.callbacks.tracers.langchain_v1 import LangChainTracerV1, TracerSessionV1
 from langchain.callbacks.tracers.stdout import ConsoleCallbackHandler
 from langchain.callbacks.tracers.wandb import WandbTracer
@@ -161,7 +163,7 @@ def tracing_v2_enabled(
     example_id: Optional[Union[str, UUID]] = None,
     tags: Optional[List[str]] = None,
     client: Optional[LangSmithClient] = None,
-) -> Generator[None, None, None]:
+) -> Generator[LangChainTracer, None, None]:
     """Instruct LangChain to log all runs in context to LangSmith.
 
     Args:
@@ -178,6 +180,12 @@ def tracing_v2_enabled(
     Example:
         >>> with tracing_v2_enabled():
         ...     # LangChain code will automatically be traced
+
+        You can use this to fetch the LangSmith run URL:
+
+        >>> with tracing_v2_enabled() as cb:
+        ...     chain.invoke("foo")
+        ...     run_url = cb.get_run_url()
     """
     if isinstance(example_id, str):
         example_id = UUID(example_id)
@@ -188,7 +196,7 @@ def tracing_v2_enabled(
         client=client,
     )
     tracing_v2_callback_var.set(cb)
-    yield
+    yield cb
     tracing_v2_callback_var.set(None)
 
 

libs/langchain/langchain/callbacks/tracers/langchain.py

@@ -10,9 +10,16 @@ from typing import Any, Callable, Dict, List, Optional, Union
 from uuid import UUID
 
 from langsmith import Client
+from langsmith.utils import LangSmithError
+from tenacity import (
+    Retrying,
+    retry_if_exception_type,
+    stop_after_attempt,
+    wait_exponential_jitter,
+)
 
 from langchain.callbacks.tracers.base import BaseTracer
-from langchain.callbacks.tracers.schemas import Run, TracerSession
+from langchain.callbacks.tracers.schemas import Run
 from langchain.env import get_runtime_environment
 from langchain.load.dump import dumpd
 from langchain.schema.messages import BaseMessage
@@ -71,7 +78,6 @@ class LangChainTracer(BaseTracer):
     ) -> None:
         """Initialize the LangChain tracer."""
         super().__init__(**kwargs)
-        self.session: Optional[TracerSession] = None
         self.example_id = (
             UUID(example_id) if isinstance(example_id, str) else example_id
         )
@@ -82,6 +88,7 @@ class LangChainTracer(BaseTracer):
         self._futures: weakref.WeakSet[Future] = weakref.WeakSet()
         self.tags = tags or []
         self.executor = _get_executor() if use_threading else None
+        self.latest_run: Optional[Run] = None
         global _TRACERS
         _TRACERS.add(self)
 
@@ -121,7 +128,27 @@ class LangChainTracer(BaseTracer):
         self._on_chat_model_start(chat_model_run)
 
     def _persist_run(self, run: Run) -> None:
-        """The Langchain Tracer uses Post/Patch rather than persist."""
+        run_ = run.copy()
+        run_.reference_example_id = self.example_id
+        self.latest_run = run_
+
+    def get_run_url(self) -> str:
+        """Get the LangSmith root run URL"""
+        if not self.latest_run:
+            raise ValueError("No traced run found.")
+        # If this is the first run in a project, the project may not yet be created.
+        # This method is only really useful for debugging flows, so we will assume
+        # there is some tolerace for latency.
+        for attempt in Retrying(
+            stop=stop_after_attempt(5),
+            wait=wait_exponential_jitter(),
+            retry=retry_if_exception_type(LangSmithError),
+        ):
+            with attempt:
+                return self.client.get_run_url(
+                    run=self.latest_run, project_name=self.project_name
+                )
+        raise ValueError("Failed to get run URL.")
 
     def _get_tags(self, run: Run) -> List[str]:
         """Get combined tags for a run."""

libs/langchain/poetry.lock

@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 1.6.1 and should not be changed by hand.
+# This file is automatically @generated by Poetry 1.5.1 and should not be changed by hand.
 
 [[package]]
 name = "absl-py"
@@ -3671,7 +3671,6 @@ optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*, !=3.6.*"
 files = [
     {file = "jsonpointer-2.4-py2.py3-none-any.whl", hash = "sha256:15d51bba20eea3165644553647711d150376234112651b4f1811022aecad7d7a"},
-    {file = "jsonpointer-2.4.tar.gz", hash = "sha256:585cee82b70211fa9e6043b7bb89db6e1aa49524340dde8ad6b63206ea689d88"},
 ]
 
 [[package]]
@@ -5843,7 +5842,7 @@ files = [
 [package.dependencies]
 numpy = [
     {version = ">=1.20.3", markers = "python_version < \"3.10\""},
-    {version = ">=1.21.0", markers = "python_version >= \"3.10\" and python_version < \"3.11\""},
+    {version = ">=1.21.0", markers = "python_version >= \"3.10\""},
     {version = ">=1.23.2", markers = "python_version >= \"3.11\""},
 ]
 python-dateutil = ">=2.8.2"
@@ -8803,7 +8802,7 @@ files = [
 ]
 
 [package.dependencies]
-greenlet = {version = "!=0.4.17", markers = "platform_machine == \"aarch64\" or platform_machine == \"ppc64le\" or platform_machine == \"x86_64\" or platform_machine == \"amd64\" or platform_machine == \"AMD64\" or platform_machine == \"win32\" or platform_machine == \"WIN32\""}
+greenlet = {version = "!=0.4.17", markers = "platform_machine == \"win32\" or platform_machine == \"WIN32\" or platform_machine == \"AMD64\" or platform_machine == \"amd64\" or platform_machine == \"x86_64\" or platform_machine == \"ppc64le\" or platform_machine == \"aarch64\""}
 typing-extensions = ">=4.2.0"
 
 [package.extras]
@@ -10616,4 +10615,4 @@ text-helpers = ["chardet"]
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.8.1,<4.0"
-content-hash = "5dbafef78ce5d6eb643885038ee5f95c95684c4097cad3d00e8bacb7e668e950"
+content-hash = "cd1e7089bf95e9eb885c392790b2afa85168b3af8ee8227727f8a95a4b60419b"

libs/langchain/pyproject.toml

@@ -113,7 +113,7 @@ cassio = {version = "^0.1.0", optional = true}
 rdflib = {version = "^6.3.2", optional = true}
 sympy = {version = "^1.12", optional = true}
 rapidfuzz = {version = "^3.1.1", optional = true}
-langsmith = "~0.0.38"
+langsmith = "~0.0.40"
 rank-bm25 = {version = "^0.2.2", optional = true}
 amadeus = {version = ">=8.1.0", optional = true}
 geopandas = {version = "^0.13.1", optional = true}