修复：weblive 协程 panic 防护、Mongo 空指针防护、直播状态轮询退避

Made-with: Cursor

server/pkg/weblive/hub.go

@@ -154,7 +154,7 @@ func (h *Hub) onPublisherTrack(track *webrtc.TrackRemote) {
 	h.mu.Lock()
 	h.forwarders = append(h.forwarders, tf)
 	h.mu.Unlock()
-	go tf.runReadLoop()
+	goSafe("trackRead", tf.runReadLoop)
 	// 观众仅在「已开播」后拉流：首次协商时 attachForwardersToViewerPC 会带上当前全部轨，无需在此重协商
 }
 
@@ -173,14 +173,14 @@ func (h *Hub) attachForwardersToViewerPC(v *viewerSession) {
 			continue
 		}
 		// Drain RTCP feedback to keep interceptors/senders healthy.
-		go func() {
+		goSafe("viewerRTCP", func() {
 			rtcpBuf := make([]byte, 1500)
 			for {
 				if _, _, e := rtpSender.Read(rtcpBuf); e != nil {
 					return
 				}
 			}
-		}()
+		})
 		tf.addViewer(v.id, lt)
 	}
 }

server/pkg/weblive/safe.go

@@ -0,0 +1,15 @@
+package weblive
+
+import "log"
+
+// goSafe 在独立 goroutine 中运行 fn；panic 只记录日志，避免拖垮整个 HTTP 进程（否则 Nginx 会看到 502）。
+func goSafe(label string, fn func()) {
+	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				log.Printf("weblive: panic in %s: %v", label, r)
+			}
+		}()
+		fn()
+	}()
+}

server/pkg/weblive/ws.go

@@ -120,7 +120,8 @@ func handlePublisherWS(c *gin.Context, h *Hub) {
 		log.Printf("weblive: publisher track kind=%s", track.Kind().String())
 		h.onPublisherTrack(track)
 		if track.Kind() == webrtc.RTPCodecTypeVideo {
-			go func(ssrc uint32) {
+			ssrc := uint32(track.SSRC())
+			goSafe("publisherPLI", func() {
 				_ = pc.WriteRTCP([]rtcp.Packet{&rtcp.PictureLossIndication{MediaSSRC: ssrc}})
 				ticker := time.NewTicker(2 * time.Second)
 				defer ticker.Stop()
@@ -131,7 +132,7 @@ func handlePublisherWS(c *gin.Context, h *Hub) {
 					}
 					_ = pc.WriteRTCP([]rtcp.Packet{&rtcp.PictureLossIndication{MediaSSRC: ssrc}})
 				}
-			}(uint32(track.SSRC()))
+			})
 		}
 	})