feat(wecom-aibot): add context management for stream tasks to improve agent cancellation

pkg/channels/wecom/aibot.go

@@ -48,7 +48,9 @@ type streamTask struct {
 	StreamClosed bool      // stream returned finish:true; waiting for agent to reply via response_url
 	Finished     bool      // fully done
 	mu           sync.Mutex
-	answerCh     chan string // receives agent reply from Send()
+	answerCh     chan string        // receives agent reply from Send()
+	ctx          context.Context    // canceled when task is removed; used to interrupt the agent goroutine
+	cancel       context.CancelFunc // call on task removal to cancel ctx
 }
 
 // WeComAIBotMessage represents the decrypted JSON message from WeCom AI Bot
@@ -109,7 +111,7 @@ type WeComAIBotStreamInfo struct {
 
 // WeComAIBotStreamResponse represents the streaming response format
 type WeComAIBotStreamResponse struct {
-	MsgType string              `json:"msgtype"`
+	MsgType string               `json:"msgtype"`
 	Stream  WeComAIBotStreamInfo `json:"stream"`
 }
 
@@ -237,6 +239,9 @@ func (c *WeComAIBotChannel) Send(ctx context.Context, msg bus.OutboundMessage) e
 	// Stream still open: deliver via answerCh for the next poll response.
 	select {
 	case task.answerCh <- msg.Content:
+	case <-task.ctx.Done():
+		// Task was canceled (cleanup removed it); silently drop the reply.
+		return nil
 	case <-ctx.Done():
 		return ctx.Err()
 	}
@@ -490,6 +495,10 @@ func (c *WeComAIBotChannel) handleTextMessage(
 	// Set a slightly shorter deadline so we can send a timeout notice before it gives up.
 	deadline := time.Now().Add(30 * time.Second)
 
+	// Each task gets its own context derived from the channel lifetime context.
+	// Canceling taskCancel interrupts the agent goroutine when the task is removed.
+	taskCtx, taskCancel := context.WithCancel(c.ctx)
+
 	task := &streamTask{
 		StreamID:    streamID,
 		ChatID:      chatID,
@@ -499,6 +508,8 @@ func (c *WeComAIBotChannel) handleTextMessage(
 		Deadline:    deadline,
 		Finished:    false,
 		answerCh:    make(chan string, 1),
+		ctx:         taskCtx,
+		cancel:      taskCancel,
 	}
 
 	c.taskMu.Lock()
@@ -506,8 +517,8 @@ func (c *WeComAIBotChannel) handleTextMessage(
 	c.chatTasks[chatID] = append(c.chatTasks[chatID], task)
 	c.taskMu.Unlock()
 
-	// Publish to agent asynchronously; agent will call Send() with reply
-	// Use c.ctx (channel lifetime) instead of r.Context() which is canceled when the HTTP handler returns.
+	// Publish to agent asynchronously; agent will call Send() with reply.
+	// Use task.ctx (not c.ctx) so the agent goroutine is canceled when the task is removed.
 	go func() {
 		sender := bus.SenderInfo{
 			Platform:    "wecom_aibot",
@@ -529,7 +540,7 @@ func (c *WeComAIBotChannel) handleTextMessage(
 			"stream_id":    streamID,
 			"response_url": msg.ResponseURL,
 		}
-		c.HandleMessage(c.ctx, peer, msg.MsgID, userID, chatID,
+		c.HandleMessage(task.ctx, peer, msg.MsgID, userID, chatID,
 			content, nil, metadata, sender)
 	}()
 
@@ -800,11 +811,13 @@ func (c *WeComAIBotChannel) getStreamResponse(task *streamTask, timestamp, nonce
 	return c.encryptResponse(task.StreamID, timestamp, nonce, response)
 }
 
-// removeTask removes a task from both streamTasks and chatTasks and marks it finished.
+// removeTask removes a task from both streamTasks and chatTasks, marks it finished,
+// and cancels its context to interrupt the associated agent goroutine.
 func (c *WeComAIBotChannel) removeTask(task *streamTask) {
 	task.mu.Lock()
 	task.Finished = true
 	task.mu.Unlock()
+	task.cancel() // interrupt agent goroutine bound to this task
 
 	c.taskMu.Lock()
 	delete(c.streamTasks, task.StreamID)
@@ -1114,6 +1127,7 @@ func (c *WeComAIBotChannel) cleanupOldTasks() {
 	for id, task := range c.streamTasks {
 		if task.CreatedTime.Before(cutoff) {
 			delete(c.streamTasks, id)
+			task.cancel() // interrupt agent goroutine still waiting for LLM
 			queue := c.chatTasks[task.ChatID]
 			for i, t := range queue {
 				if t == task {
@@ -1130,11 +1144,14 @@ func (c *WeComAIBotChannel) cleanupOldTasks() {
 		}
 	}
 	// Also clean up StreamClosed tasks from chatTasks that are older than 1 hour.
+	// These were removed from streamTasks earlier but kept alive for response_url delivery.
 	for chatID, queue := range c.chatTasks {
 		filtered := queue[:0]
 		for _, t := range queue {
 			if !t.Finished && t.CreatedTime.After(cutoff) {
 				filtered = append(filtered, t)
+			} else if !t.Finished {
+				t.cancel() // cancel any lingering agent goroutine
 			}
 		}
 		if len(filtered) == 0 {