removed redundant temp slice from apm-server monitoring func

Author: isaacaflores2

internal/beatcmd/beat.go

@@ -549,22 +549,20 @@ func (b *Beat) registerStatsMetrics() {
 		defer v.OnRegistryFinished()
 
 		// first collect all apm-server metrics
-		apmServerMetrics := make([]metricdata.Metrics, 0)
+		beatsMetrics := make(map[string]any)
 		for _, sm := range rm.ScopeMetrics {
 			switch {
 			case strings.HasPrefix(sm.Scope.Name, "github.com/elastic/apm-server"):
 				// All simple scalar metrics that begin with the name "apm-server."
 				// in github.com/elastic/apm-server/... scopes are mapped directly.
-				apmServerMetrics = append(apmServerMetrics, sm.Metrics...)
+				addAPMServerMetricsToMap(beatsMetrics, sm.Metrics)
 			}
 		}
 
-		// add all metrics once
+		// register all metrics once
 		// this prevents metrics with the same prefix in the name
 		// from different scoped meters from overwriting each other
-		if len(apmServerMetrics) > 0 {
-			addAPMServerMetrics(v, apmServerMetrics)
-		}
+		reportOnKey(v, beatsMetrics)
 	})
 }
 
@@ -587,8 +585,9 @@ func getScalarInt64(data metricdata.Aggregation) (int64, bool) {
 	return 0, false
 }
 
-func addAPMServerMetrics(v monitoring.Visitor, metrics []metricdata.Metrics) {
-	beatsMetrics := make(map[string]any)
+// addAPMServerMetricsToMap adds simple scalar metrics with the "apm-server." prefix
+// to the map.
+func addAPMServerMetricsToMap(beatsMetrics map[string]any, metrics []metricdata.Metrics) {
 	for _, m := range metrics {
 		if suffix, ok := strings.CutPrefix(m.Name, "apm-server."); ok {
 			if value, ok := getScalarInt64(m.Data); ok {
@@ -607,8 +606,6 @@ func addAPMServerMetrics(v monitoring.Visitor, metrics []metricdata.Metrics) {
 			}
 		}
 	}
-
-	reportOnKey(v, beatsMetrics)
 }
 
 func reportOnKey(v monitoring.Visitor, m map[string]any) {

internal/beatcmd/beat_test.go

@@ -268,7 +268,7 @@ func TestLibbeatMetrics(t *testing.T) {
 	}, snapshot)
 }
 
-// TestAddAPMServerMetrics tests basic functionality of the addAPMServerMetrics
+// TestAddAPMServerMetrics tests basic functionality of the metrics collection and reporting
 func TestAddAPMServerMetrics(t *testing.T) {
 	r := monitoring.NewRegistry()
 	sm := metricdata.ScopeMetrics{
@@ -297,7 +297,12 @@ func TestAddAPMServerMetrics(t *testing.T) {
 	}
 
 	monitoring.NewFunc(r, "apm-server", func(m monitoring.Mode, v monitoring.Visitor) {
-		addAPMServerMetrics(v, sm.Metrics)
+		v.OnRegistryStart()
+		defer v.OnRegistryFinished()
+
+		beatsMetrics := make(map[string]any)
+		addAPMServerMetricsToMap(beatsMetrics, sm.Metrics)
+		reportOnKey(v, beatsMetrics)
 	})
 
 	snapshot := monitoring.CollectStructSnapshot(r, monitoring.Full, false)
@@ -306,7 +311,7 @@ func TestAddAPMServerMetrics(t *testing.T) {
 			"request":  int64(1),
 			"response": int64(1),
 		},
-	}, snapshot)
+	}, snapshot["apm-server"])
 }
 
 func TestMonitoringApmServer(t *testing.T) {