fix: Agent execution time duration display in streaming mode (#7852)

* Update events.py

* timer compotation update

* clean up

* add time elapsed for streaming

* [autofix.ci] apply automated fixes

* Update events.py

* preliminary fix

* Update src/backend/base/langflow/schema/message.py

Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>

* Update src/backend/base/langflow/schema/message.py

Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>

---------

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

src/backend/base/langflow/base/agents/events.py

@@ -231,7 +231,8 @@ async def handle_on_chain_stream(
             agent_message.text += output_text
             agent_message.properties.state = "partial"
             agent_message = await send_message_method(message=agent_message)
-        start_time = perf_counter()
+        if not agent_message.text:
+            start_time = perf_counter()
     return agent_message, start_time
 
 

src/backend/base/langflow/schema/message.py

@@ -51,6 +51,7 @@ class Message(Data):
     properties: Properties = Field(default_factory=Properties)
     category: Literal["message", "error", "warning", "info"] | None = "message"
     content_blocks: list[ContentBlock] = Field(default_factory=list)
+    duration: int | None = None
 
     @field_validator("flow_id", mode="before")
     @classmethod
@@ -306,6 +307,7 @@ class MessageResponse(DefaultModel):
     text: str
     files: list[str] = []
     edit: bool
+    duration: float | None = None
 
     properties: Properties | None = None
     category: str | None = None

src/frontend/src/modals/IOModal/components/chatView/chatMessage/chat-message.tsx

@@ -327,7 +327,6 @@ export default function ChatMessage({
                 playgroundPage={playgroundPage}
                 contentBlocks={chat.content_blocks}
                 isLoading={
-                  chatMessage === "" &&
                   chat.properties?.state === "partial" &&
                   isBuilding &&
                   lastMessage