fix: always register beats registries (#15439)

* fix: always recreate libbeat beats registry

match the logic we had before the otel translation

* ok then

* always register beats registries

* cleanup fix

* test: fix race condition in TestLibbeatMetrics

use atomic in http handler

* test: clear output and apm-server beats registry

before starting a beat, also clear output and apm-server registry

(cherry picked from commit cd0bc2d)

internal/beatcmd/beat.go

@@ -491,10 +491,6 @@ func (b *Beat) registerStateMetrics() {
 }
 
 func (b *Beat) registerStatsMetrics() {
-	if b.Config.Output.Name() != "elasticsearch" {
-		return
-	}
-
 	libbeatRegistry := monitoring.Default.GetRegistry("libbeat")
 	monitoring.NewFunc(libbeatRegistry, "output", func(_ monitoring.Mode, v monitoring.Visitor) {
 		var rm metricdata.ResourceMetrics
@@ -503,10 +499,10 @@ func (b *Beat) registerStatsMetrics() {
 		}
 		v.OnRegistryStart()
 		defer v.OnRegistryFinished()
-		monitoring.ReportString(v, "type", "elasticsearch")
 		for _, sm := range rm.ScopeMetrics {
 			switch {
 			case sm.Scope.Name == "github.com/elastic/go-docappender":
+				monitoring.ReportString(v, "type", "elasticsearch")
 				addDocappenderLibbeatOutputMetrics(context.Background(), v, sm)
 			}
 		}

internal/beatcmd/beat_test.go

@@ -146,7 +146,7 @@ func TestLibbeatMetrics(t *testing.T) {
 	defer func() { assert.NoError(t, stop()) }()
 	args := <-runnerParamsChan
 
-	var requestIndex int
+	var requestIndex atomic.Int64
 	requestsChan := make(chan chan struct{})
 	defer close(requestsChan)
 	esClient := docappendertest.NewMockElasticsearchClient(t, func(w http.ResponseWriter, r *http.Request) {
@@ -161,17 +161,16 @@ func TestLibbeatMetrics(t *testing.T) {
 			}
 		}
 		_, result := docappendertest.DecodeBulkRequest(r)
-		switch requestIndex {
-		case 1:
+		switch requestIndex.Add(1) {
+		case 2:
 			result.HasErrors = true
 			result.Items[0]["create"] = esutil.BulkIndexerResponseItem{Status: 400}
-		case 3:
+		case 4:
 			result.HasErrors = true
 			result.Items[0]["create"] = esutil.BulkIndexerResponseItem{Status: 429}
 		default:
 			// success
 		}
-		requestIndex++
 		json.NewEncoder(w).Encode(result)
 	})
 	appender, err := docappender.New(esClient, docappender.Config{
@@ -603,7 +602,7 @@ func resetGlobals() {
 	// Clear monitoring registries to allow the new Beat to populate them.
 	monitoring.GetNamespace("info").SetRegistry(nil)
 	monitoring.GetNamespace("state").SetRegistry(nil)
-	for _, name := range []string{"system", "beat", "libbeat"} {
+	for _, name := range []string{"system", "beat", "libbeat", "apm-server", "output"} {
 		registry := monitoring.Default.GetRegistry(name)
 		if registry != nil {
 			registry.Clear()