metrics: fixes panic when using WithLabels without passing in labels …

…through ObserveDuration
puppetlabs-toy-chest · Nov 14, 2019 · 9965640 · 9965640
1 parent afda647
commit 9965640
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Showing 2 changed files with 7 additions and 3 deletions.
diff --git a/instrumentation/examples/metrics_server/server.go b/instrumentation/examples/metrics_server/server.go
@@ -99,13 +99,15 @@ func main() {
 	mux := http.NewServeMux()
 	mux.Handle("/", mw.Wrap(testApp{m}))
 
+	log.Println("example server running at: http://localhost:2399/")
 	go http.ListenAndServe("localhost:2399", mux)
 
 	server := server.New(m, server.Options{
-		BindAddr: "localhost:2398",
-		Path:     "/metrics",
+		BindAddr: "localhost:3050",
+		Path:     "/",
 	})
 
+	log.Println("metrics server running at: http://localhost:3050/")
 	if err := server.Run(context.Background()); err != nil {
 		log.Fatal(err)
 	}

diff --git a/instrumentation/metrics/internal/prometheus/timer.go b/instrumentation/metrics/internal/prometheus/timer.go
@@ -44,7 +44,9 @@ func (t *Timer) ObserveDuration(h *collectors.TimerHandle, labels ...collectors.
 	t.RLock()
 	defer t.RUnlock()
 
-	t.labels = labels
+	if len(labels) > 0 {
+		t.labels = labels
+	}
 
 	if promt, ok := t.timers[h]; ok {
 		promt.ObserveDuration()