Only send counts every second if there is a change

pkg/resources/counts/buffer.go

@@ -0,0 +1,40 @@
+package counts
+
+import (
+	"time"
+
+	"github.com/rancher/apiserver/pkg/types"
+)
+
+func buffer(c chan types.APIEvent) chan types.APIEvent {
+	result := make(chan types.APIEvent)
+	go func() {
+		defer close(result)
+		debounce(result, c)
+	}()
+	return result
+}
+
+func debounce(result, input chan types.APIEvent) {
+	t := time.NewTicker(time.Second)
+	defer t.Stop()
+
+	var (
+		lastEvent *types.APIEvent
+	)
+	for {
+		select {
+		case event, ok := <-input:
+			if ok {
+				lastEvent = &event
+			} else {
+				return
+			}
+		case <-t.C:
+			if lastEvent != nil {
+				result <- *lastEvent
+				lastEvent = nil
+			}
+		}
+	}
+}