*: fix pending events metrics

etcdserver/api/v3rpc/watch.go

@@ -214,7 +214,19 @@ func (sws *serverWatchStream) sendLoop() {
 
 	interval := GetProgressReportInterval()
 	progressTicker := time.NewTicker(interval)
-	defer progressTicker.Stop()
+
+	defer func() {
+		progressTicker.Stop()
+		// drain the chan to clean up pending events
+		for ws := range sws.watchStream.Chan() {
+			mvcc.ReportEventReceived(len(ws.Events))
+		}
+		for _, wrs := range pending {
+			for _, ws := range wrs {
+				mvcc.ReportEventReceived(len(ws.Events))
+			}
+		}
+	}()
 
 	for {
 		select {
@@ -246,7 +258,7 @@ func (sws *serverWatchStream) sendLoop() {
 				continue
 			}
 
-			mvcc.ReportEventReceived()
+			mvcc.ReportEventReceived(len(evs))
 			if err := sws.gRPCStream.Send(wr); err != nil {
 				return
 			}
@@ -276,7 +288,7 @@ func (sws *serverWatchStream) sendLoop() {
 				// flush buffered events
 				ids[wid] = struct{}{}
 				for _, v := range pending[wid] {
-					mvcc.ReportEventReceived()
+					mvcc.ReportEventReceived(len(v.Events))
 					if err := sws.gRPCStream.Send(v); err != nil {
 						return
 					}
@@ -291,15 +303,7 @@ func (sws *serverWatchStream) sendLoop() {
 				sws.progress[id] = true
 			}
 		case <-sws.closec:
-			// drain the chan to clean up pending events
-			for range sws.watchStream.Chan() {
-				mvcc.ReportEventReceived()
-			}
-			for _, wrs := range pending {
-				for range wrs {
-					mvcc.ReportEventReceived()
-				}
-			}
+			return
 		}
 	}
 }

mvcc/metrics.go

@@ -157,7 +157,7 @@ func init() {
 // ReportEventReceived reports that an event is received.
 // This function should be called when the external systems received an
 // event from mvcc.Watcher.
-func ReportEventReceived() {
-	pendingEventsGauge.Dec()
-	totalEventsCounter.Inc()
+func ReportEventReceived(n int) {
+	pendingEventsGauge.Sub(float64(n))
+	totalEventsCounter.Add(float64(n))
 }