Chore: Ignore duplicate process_* metrics in MultiRegistry (grafana#9…

…7857)

pkg/infra/metrics/service.go

@@ -144,10 +144,10 @@ func (r *multiRegistry) Gather() (mfs []*dto.MetricFamily, err error) {
 			_, exists := names[*m.Name]
 			// prevent duplicate metric names
 			if exists {
-				// we can skip go_ metrics without returning an error
+				// we can skip go_ and process_ metrics without returning an error
 				// because they are known to be duplicates in both
 				// the k8s and prometheus gatherers.
-				if strings.HasPrefix(*m.Name, "go_") {
+				if strings.HasPrefix(*m.Name, "go_") || strings.HasPrefix(*m.Name, "process_") {
 					continue
 				}
 				errs = append(errs, fmt.Errorf("duplicate metric name: %s", *m.Name))

pkg/infra/metrics/service_test.go

@@ -99,12 +99,13 @@ func TestMultiRegistry_Gather(t *testing.T) {
 		require.Error(t, err)
 	})
 
-	t.Run("duplicate go_ prefixed metrics do not result in an error", func(t *testing.T) {
+	t.Run("duplicate go_ or process_ prefixed metrics do not result in an error", func(t *testing.T) {
 		one.GatherFunc = func() ([]*dto.MetricFamily, error) {
 			return []*dto.MetricFamily{
 				{Name: strptr("b")},
 				{Name: strptr("a")},
 				{Name: strptr("go_a")},
+				{Name: strptr("process_a")},
 			}, nil
 		}
 
@@ -113,6 +114,7 @@ func TestMultiRegistry_Gather(t *testing.T) {
 				{Name: strptr("d")},
 				{Name: strptr("c")},
 				{Name: strptr("go_a")},
+				{Name: strptr("process_a")},
 			}, nil
 		}
 
@@ -122,6 +124,7 @@ func TestMultiRegistry_Gather(t *testing.T) {
 			{Name: strptr("c")},
 			{Name: strptr("d")},
 			{Name: strptr("go_a")},
+			{Name: strptr("process_a")},
 		}
 
 		mf, err := g.Gather()