fix: traces inputs and outputs not being sent to tracing services (#4669)

* Fix node inputs not being captured, add runtime inputs as well to be captured by the tracers properly

* Fix outputs missing on traces due to them being reset before ending the traces because of race conditions

* Fallback to project name if none

* Remove 'dynamic inputs' to stop sending the component code every time

* fix: Add async flow name retrieval in graph building process

* fix: Retrieve flow name from database when building graph from data

* Fix: make session.exec call awaitable in chat API

* Refactor `_get_flow_name` to manage session internally

* Refactor session handling to use `async_session_scope` in chat API

* Refactor test cases to remove unnecessary async usage in mock functions

* [autofix.ci] apply automated fixes

---------

Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

src/backend/base/langflow/api/utils.py

@@ -17,7 +17,7 @@ from langflow.services.database.models import User
 from langflow.services.database.models.flow import Flow
 from langflow.services.database.models.transactions.model import TransactionTable
 from langflow.services.database.models.vertex_builds.model import VertexBuildTable
-from langflow.services.deps import get_async_session, get_session
+from langflow.services.deps import async_session_scope, get_async_session, get_session
 from langflow.services.store.utils import get_lf_version_from_pypi
 
 if TYPE_CHECKING:
@@ -142,8 +142,21 @@ def format_elapsed_time(elapsed_time: float) -> str:
     return f"{minutes} {minutes_unit}, {seconds} {seconds_unit}"
 
 
+async def _get_flow_name(flow_id: str) -> str:
+    async with async_session_scope() as session:
+        flow = await session.get(Flow, flow_id)
+        if flow is None:
+            msg = f"Flow {flow_id} not found"
+            raise ValueError(msg)
+    return flow.name
+
+
 async def build_graph_from_data(flow_id: str, payload: dict, **kwargs):
     """Build and cache the graph."""
+    # Get flow name
+    if "flow_name" not in kwargs:
+        flow_name = await _get_flow_name(flow_id)
+        kwargs["flow_name"] = flow_name
     graph = Graph.from_payload(payload, flow_id, **kwargs)
     for vertex_id in graph.has_session_id_vertices:
         vertex = graph.get_vertex(vertex_id)

src/backend/base/langflow/api/v1/chat.py

@@ -11,6 +11,7 @@ from typing import TYPE_CHECKING, Annotated
 from fastapi import APIRouter, BackgroundTasks, Body, HTTPException
 from fastapi.responses import StreamingResponse
 from loguru import logger
+from sqlmodel import select
 from starlette.background import BackgroundTask
 from starlette.responses import ContentStream
 from starlette.types import Receive
@@ -42,7 +43,8 @@ from langflow.graph.utils import log_vertex_build
 from langflow.schema.schema import OutputValue
 from langflow.services.cache.utils import CacheMiss
 from langflow.services.chat.service import ChatService
-from langflow.services.deps import get_async_session, get_chat_service, get_telemetry_service
+from langflow.services.database.models.flow.model import Flow
+from langflow.services.deps import async_session_scope, get_async_session, get_chat_service, get_telemetry_service
 from langflow.services.telemetry.schema import ComponentPayload, PlaygroundPayload
 
 if TYPE_CHECKING:
@@ -166,7 +168,12 @@ async def build_flow(
             if not data:
                 graph = await build_graph_from_db_no_cache(flow_id=flow_id_str, session=session)
             else:
-                graph = await build_graph_from_data(flow_id_str, data.model_dump(), user_id=str(current_user.id))
+                async with async_session_scope() as new_session:
+                    result = await new_session.exec(select(Flow.name).where(Flow.id == flow_id_str))
+                    flow_name = result.first()
+                graph = await build_graph_from_data(
+                    flow_id_str, data.model_dump(), user_id=str(current_user.id), flow_name=flow_name
+                )
             graph.validate_stream()
             if stop_component_id or start_component_id:
                 try:

src/backend/base/langflow/custom/custom_component/component.py

@@ -801,9 +801,9 @@ class Component(CustomComponent):
             for input_ in self.inputs
             if hasattr(input_, "trace_as_input") and input_.trace_as_input
         }
-        # Dynamic inputs
-        dynamic_inputs = {key: value for key, value in self._attributes.items() if key not in predefined_inputs}
-        return {**predefined_inputs, **dynamic_inputs}
+        # Runtime inputs
+        runtime_inputs = {name: input_.value for name, input_ in self._inputs.items() if hasattr(input_, "value")}
+        return {**predefined_inputs, **runtime_inputs}
 
     def get_trace_as_metadata(self):
         return {

src/backend/base/langflow/services/tracing/langwatch.py

@@ -41,6 +41,7 @@ class LangWatchTracer(BaseTracer):
             self.spans: dict[str, ContextSpan] = {}
 
             name_without_id = " - ".join(trace_name.split(" - ")[0:-1])
+            name_without_id = project_name if name_without_id == "None" else name_without_id
             self.trace.root_span.update(
                 # nanoid to make the span_id globally unique, which is required for LangWatch for now
                 span_id=f"{self.flow_id}-{nanoid.generate(size=6)}",

src/backend/base/langflow/services/tracing/service.py

@@ -184,6 +184,7 @@ class TracingService(Service):
                     )
                 except Exception:  # noqa: BLE001
                     logger.exception(f"Error ending trace {trace_name}")
+        self._reset_io()
 
     def _end_all_traces(self, outputs: dict, error: Exception | None = None) -> None:
         for tracer in self._tracers.values():
@@ -192,10 +193,10 @@ class TracingService(Service):
                     tracer.end(self.inputs, outputs=self.outputs, error=error, metadata=outputs)
                 except Exception:  # noqa: BLE001
                     logger.exception("Error ending all traces")
+        self._reset_io()
 
     async def end(self, outputs: dict, error: Exception | None = None) -> None:
         await asyncio.to_thread(self._end_all_traces, outputs, error)
-        self._reset_io()
         await self.stop()
 
     def add_log(self, trace_name: str, log: Log) -> None:
@@ -236,7 +237,6 @@ class TracingService(Service):
         task = asyncio.create_task(asyncio.to_thread(self._end_traces, trace_id, trace_name, error))
         self.end_trace_tasks.add(task)
         task.add_done_callback(self.end_trace_tasks.discard)
-        self._reset_io()
 
     def set_outputs(
         self,