feat: add streaming for orchestrator

.env

@@ -32,4 +32,4 @@ TOP_K=3
 EXAMPLE_TYPE=workflow
 
 # Set it to true to start FastAPI endpoint
-FAST_API=true
+FAST_API=false

app/agents/planner.py

@@ -1,7 +1,7 @@
 import asyncio
 import uuid
 from enum import Enum
-from typing import Any, Dict, List, Optional, Tuple, Union
+from typing import Any, AsyncGenerator, Dict, List, Optional, Tuple, Union
 
 from llama_index.core.agent.runner.planner import (
     DEFAULT_INITIAL_PLAN_PROMPT,
@@ -37,7 +37,7 @@ class SubTaskEvent(Event):
 
 class SubTaskResultEvent(Event):
     sub_task: SubTask
-    result: AgentRunResult
+    result: AgentRunResult | AsyncGenerator
 
 
 class PlanEventType(Enum):
@@ -87,9 +87,13 @@ class StructuredPlannerAgent(Workflow):
     async def create_plan(
         self, ctx: Context, ev: StartEvent
     ) -> ExecutePlanEvent | StopEvent:
-        plan_id, plan = await self.planner.create_plan(input=ev.input)
+        # set streaming
+        ctx.data["streaming"] = getattr(ev, "streaming", False)
         ctx.data["task"] = ev.input
+
+        plan_id, plan = await self.planner.create_plan(input=ev.input)
         ctx.data["act_plan_id"] = plan_id
+
         # inform about the new plan
         ctx.write_event_to_stream(
             PlanEvent(name=self.name, event_type=PlanEventType.CREATED, plan=plan)
@@ -118,11 +122,19 @@ class StructuredPlannerAgent(Workflow):
     ) -> SubTaskResultEvent:
         if self._verbose:
             print(f"=== Executing sub task: {ev.sub_task.name} ===")
-        task = asyncio.create_task(self.executor.run(input=ev.sub_task.input))
+        is_last_tasks = ctx.data["num_sub_tasks"] == self.get_remaining_subtasks(ctx)
+        # TODO: streaming only works without plan refining
+        streaming = is_last_tasks and ctx.data["streaming"] and not self.refine_plan
+        task = asyncio.create_task(
+            self.executor.run(
+                input=ev.sub_task.input,
+                streaming=streaming,
+            )
+        )
         # bubble all events while running the executor to the planner
         async for event in self.executor.stream_events():
             ctx.write_event_to_stream(event)
-        result: AgentRunResult = await task
+        result = await task
         if self._verbose:
             print("=== Done executing sub task ===\n")
         self.planner.state.add_completed_sub_task(ctx.data["act_plan_id"], ev.sub_task)
@@ -138,19 +150,17 @@ class StructuredPlannerAgent(Workflow):
         if results is None:
             return None
 
-        # store all results for refining the plan
-        ctx.data["results"] = ctx.data.get("results", {})
-        for result in results:
-            ctx.data["results"][result.sub_task.name] = result.result
-
-        upcoming_sub_tasks = self.planner.state.get_next_sub_tasks(
-            ctx.data["act_plan_id"]
-        )
+        upcoming_sub_tasks = self.get_upcoming_sub_tasks(ctx)
         # if no more tasks to do, stop workflow and send result of last step
-        if len(upcoming_sub_tasks) == 0:
+        if upcoming_sub_tasks == 0:
             return StopEvent(result=results[-1].result)
 
         if self.refine_plan:
+            # store all results for refining the plan
+            ctx.data["results"] = ctx.data.get("results", {})
+            for result in results:
+                ctx.data["results"][result.sub_task.name] = result.result
+
             new_plan = await self.planner.refine_plan(
                 ctx.data["task"], ctx.data["act_plan_id"], ctx.data["results"]
             )
@@ -165,6 +175,18 @@ class StructuredPlannerAgent(Workflow):
         # continue executing plan
         return ExecutePlanEvent()
 
+    def get_upcoming_sub_tasks(self, ctx: Context):
+        upcoming_sub_tasks = self.planner.state.get_next_sub_tasks(
+            ctx.data["act_plan_id"]
+        )
+        return len(upcoming_sub_tasks)
+
+    def get_remaining_subtasks(self, ctx: Context):
+        remaining_subtasks = self.planner.state.get_remaining_subtasks(
+            ctx.data["act_plan_id"]
+        )
+        return len(remaining_subtasks)
+
 
 # Concern dealing with creating and refining a plan, extracted from https://github.com/run-llama/llama_index/blob/main/llama-index-core/llama_index/core/agent/runner/planner.py#L138
 class Planner:

app/examples/orchestrator.py

@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 from app.agents.single import FunctionCallingAgent
 from app.agents.multi import AgentOrchestrator
 from app.examples.researcher import create_researcher
@@ -6,7 +6,7 @@ from app.examples.researcher import create_researcher
 from llama_index.core.chat_engine.types import ChatMessage
 
 
-def create_orchestrator(chat_history: List[ChatMessage]):
+def create_orchestrator(chat_history: Optional[List[ChatMessage]] = None):
     researcher = create_researcher(chat_history)
     writer = FunctionCallingAgent(
         name="writer",