feat: register the metrics with manager

internal/webserver/middleware/metrics.go

@@ -10,11 +10,11 @@ import (
 	"github.com/gorilla/mux"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
 )
 
 func init() {
-	_ = prometheus.Register(totalRequests)
-	_ = prometheus.Register(httpDuration)
+	metrics.Registry.MustRegister(totalRequests, httpDuration)
 }
 
 type httpResponseWriter struct {

internal/webserver/middleware/metrics_test.go

@@ -20,18 +20,20 @@ func dummyHandler(w http.ResponseWriter, r *http.Request) {
 
 func newRequest(method, url string) (*http.Request, error) {
 	req, err := http.NewRequest(method, url, nil)
+
 	return req, err
 }
 
 func Test_MetricsMiddleware_RequestCount(t *testing.T) {
+	t.Parallel()
+
 	testCases := []struct {
 		name         string
 		requestCount int
 		path         string
 		output       float64
 	}{
 		{
-
 			name:         "single request count",
 			requestCount: 1,
 			path:         "/test",
@@ -51,6 +53,7 @@ func Test_MetricsMiddleware_RequestCount(t *testing.T) {
 			if err != nil {
 				t.Errorf("failed to create HTTP request object")
 			}
+
 			router.ServeHTTP(rw, req)
 		}
 
@@ -76,6 +79,7 @@ func labels2Map(labels []*model.LabelPair) map[string]string {
 	for _, l := range labels {
 		res[l.GetName()] = l.GetValue()
 	}
+
 	return res
 }
 

internal/webserver/webserver.go

@@ -19,7 +19,6 @@ import (
 	"github.com/gorilla/handlers"
 	"github.com/gorilla/mux"
 	"github.com/pkg/errors"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"golang.org/x/net/http/httpguts"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/util/sets"
@@ -265,7 +264,6 @@ func (n kubeFilter) Start(ctx context.Context) error {
 		writer.WriteHeader(200)
 		_, _ = writer.Write([]byte("ok"))
 	})
-	r.Path("/_metrics").Subrouter().Handle("", promhttp.Handler())
 
 	root := r.PathPrefix("").Subrouter()
 	n.registerModules(ctx, root)