feat: 接入fastapi

app/services/agent.py

@@ -0,0 +1,85 @@
+"""异步执行与恢复大屏任务，当前使用单进程内存检查点"""
+
+from uuid import uuid4
+
+from langgraph.types import Command
+
+from app.core.exceptions import BizException
+from app.observability.tracing import ainvoke_screen
+from app.schemas.agent import AgentResult, ResumeRequest
+from app.schemas.request import DesignRequest
+
+
+class AgentService:
+    def __init__(self, graph):
+        self.graph = graph
+        self._active: set[str] = set()
+
+    async def run(self, request: DesignRequest) -> AgentResult:
+        # 新请求始终独立建任务，不用 conversation_id 充当检查点 ID
+        thread_id = str(uuid4())
+        return await self._invoke(
+            thread_id,
+            {"request": request.model_dump(mode="json")},
+            request.context.conversation_id,
+        )
+
+    async def resume(self, request: ResumeRequest) -> AgentResult:
+        thread_id = str(request.thread_id)
+        # 检查和占用之间没有 await，同一事件循环内不会重复进入
+        self._claim(thread_id)
+        try:
+            snapshot = await self.graph.aget_state(
+                {"configurable": {"thread_id": thread_id}}
+            )
+            if not snapshot.values:
+                raise BizException(404, "任务不存在或已过期")
+            if not any(task.interrupts for task in snapshot.tasks):
+                raise BizException(409, "任务当前未等待用户补充")
+            # 恢复前校验选项，避免无效回答消耗一次 interrupt 恢复
+            clarification = snapshot.values["clarification"]
+            reply = request.reply
+            if (
+                not reply.cancel
+                and reply.option_id is not None
+                and reply.option_id not in {item.id for item in clarification.options}
+            ):
+                raise BizException(422, "请选择当前问题的有效选项")
+            session_id = (
+                snapshot.values["request"].get("context", {}).get("conversation_id")
+            )
+            return await self._execute(
+                thread_id, Command(resume=reply.model_dump(mode="json")), session_id
+            )
+        finally:
+            self._active.discard(thread_id)
+
+    def _claim(self, thread_id: str) -> None:
+        if thread_id in self._active:
+            raise BizException(409, "任务正在执行，请勿重复提交")
+        self._active.add(thread_id)
+
+    async def _invoke(self, thread_id, payload, session_id) -> AgentResult:
+        self._claim(thread_id)
+        try:
+            return await self._execute(thread_id, payload, session_id)
+        finally:
+            # 异常和取消也必须释放占用，不阻塞后续请求
+            self._active.discard(thread_id)
+
+    async def _execute(self, thread_id, payload, session_id) -> AgentResult:
+        state = await ainvoke_screen(
+            self.graph, payload, thread_id=thread_id, session_id=session_id
+        )
+        waiting = bool(state.get("__interrupt__"))
+        # 只交付校验通过的完整动作批次，失败草稿留在后端
+        return AgentResult(
+            thread_id=thread_id,
+            status="waiting_for_input" if waiting else state["status"],
+            actions=state.get("actions") or []
+            if state.get("validation_passed") is True and state["status"] == "completed"
+            else [],
+            answer=state.get("answer"),
+            clarification=state.get("clarification") if waiting else None,
+            failure_reason=state.get("failure_reason"),
+        )