feat: 支持 agent 运行取消功能

backend/src/v1/agent/dependencies.py

@@ -1,6 +1,8 @@
 from __future__ import annotations
 
 import asyncio
+from datetime import datetime, timezone
+import json
 from typing import Any
 
 from fastapi import Depends
@@ -22,6 +24,7 @@ DEDUP_WAIT_RETRIES = 20
 DEDUP_WAIT_SECONDS = 0.05
 DEDUP_LOCK_SECONDS = 300
 DEDUP_INFLIGHT_MARKER = "__inflight__"
+RUN_CANCEL_SIGNAL_TTL_SECONDS = 1800
 
 
 def _event_stream_block_ms() -> int:
@@ -87,6 +90,29 @@ class TaskiqQueueClient:
                 await redis_client.delete(redis_key)
             raise
 
+    async def request_cancel(
+        self,
+        *,
+        thread_id: str,
+        run_id: str,
+        requested_by: str,
+    ) -> None:
+        redis_client = await self._get_redis()
+        cancel_key = f"agent:cancel:{thread_id}:{run_id}"
+        payload = json.dumps(
+            {
+                "requested_by": requested_by,
+                "requested_at": datetime.now(timezone.utc).isoformat(),
+            },
+            ensure_ascii=True,
+            separators=(",", ":"),
+        )
+        await redis_client.set(
+            cancel_key,
+            payload,
+            ex=RUN_CANCEL_SIGNAL_TTL_SECONDS,
+        )
+
 
 class RedisEventStream:
     def __init__(self) -> None:

backend/src/v1/agent/router.py

@@ -37,6 +37,7 @@ from v1.agent.schemas import (
     AttachmentReference,
     AttachmentSignedUrlResponse,
     AttachmentUploadResponse,
+    CancelRunResponse,
     HistorySnapshotResponse,
     TaskAcceptedResponse,
 )
@@ -147,6 +148,34 @@ async def enqueue_run(
     )
 
 
+@router.post(
+    "/runs/{thread_id}/cancel",
+    response_model=CancelRunResponse,
+    status_code=status.HTTP_202_ACCEPTED,
+)
+async def cancel_run(
+    thread_id: str,
+    service: Annotated[AgentService, Depends(get_agent_service)],
+    current_user: Annotated[CurrentUser, Depends(get_current_user)],
+    run_id: str = Query(
+        alias="runId",
+        min_length=1,
+        max_length=128,
+        pattern=r"^[A-Za-z0-9_-]+$",
+    ),
+) -> CancelRunResponse:
+    canceled = await service.cancel_run(
+        thread_id=thread_id,
+        run_id=run_id,
+        current_user=current_user,
+    )
+    return CancelRunResponse(
+        threadId=canceled.thread_id,
+        runId=canceled.run_id,
+        accepted=canceled.accepted,
+    )
+
+
 @router.get("/runs/{thread_id}/events")
 async def stream_events(
     request: Request,

backend/src/v1/agent/schemas.py

@@ -49,6 +49,14 @@ class QueueClientLike(Protocol):
         self, *, command: dict[str, object], dedup_key: str | None
     ) -> str: ...
 
+    async def request_cancel(
+        self,
+        *,
+        thread_id: str,
+        run_id: str,
+        requested_by: str,
+    ) -> None: ...
+
 
 class EventStreamLike(Protocol):
     async def read(
@@ -90,6 +98,13 @@ class TaskAccepted:
     created: bool
 
 
+@dataclass(frozen=True)
+class CancelRequested:
+    thread_id: str
+    run_id: str
+    accepted: bool
+
+
 class TaskAcceptedResponse(BaseModel):
     model_config = ConfigDict(populate_by_name=True, serialize_by_alias=True)
 
@@ -99,6 +114,14 @@ class TaskAcceptedResponse(BaseModel):
     created: bool
 
 
+class CancelRunResponse(BaseModel):
+    model_config = ConfigDict(populate_by_name=True, serialize_by_alias=True)
+
+    thread_id: str = Field(alias="threadId")
+    run_id: str = Field(alias="runId")
+    accepted: bool
+
+
 class AsrTranscribeResponse(BaseModel):
     transcript: str = Field(description="Transcribed text from audio")
 

backend/src/v1/agent/service.py

@@ -30,6 +30,7 @@ from schemas.domain.chat_message import (
 from v1.agent.schemas import (
     AgentRepositoryLike,
     AttachmentStorageLike,
+    CancelRequested,
     EventStreamLike,
     HistorySnapshotResponse,
     QueueClientLike,
@@ -157,6 +158,26 @@ class AgentService:
             created=created,
         )
 
+    async def cancel_run(
+        self,
+        *,
+        thread_id: str,
+        run_id: str,
+        current_user: CurrentUser,
+    ) -> CancelRequested:
+        owner = await self._repository.get_session_owner(session_id=thread_id)
+        ensure_session_owner(owner_id=owner, current_user=current_user)
+        await self._queue.request_cancel(
+            thread_id=thread_id,
+            run_id=run_id,
+            requested_by=str(current_user.id),
+        )
+        return CancelRequested(
+            thread_id=thread_id,
+            run_id=run_id,
+            accepted=True,
+        )
+
     async def _append_context_cache_user_message(
         self,
         *,