fixup! fixup! fix: add readyz endpoint

pkg/app/server.go

@@ -42,7 +42,6 @@ import (
 	versionCollector "github.com/prometheus/client_golang/prometheus/collectors/version"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"github.com/prometheus/client_golang/prometheus/testutil"
 	"github.com/prometheus/common/version"
 	"github.com/prometheus/exporter-toolkit/web"
 
@@ -380,7 +379,7 @@ func buildTelemetryServer(registry prometheus.Gatherer) *http.ServeMux {
 
 	// Add readyzPath
 	mux.Handle(readyzPath, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-		count, err := testutil.GatherAndCount(registry)
+		count, err := util.GatherAndCount(registry)
 		if err != nil || count == 0 {
 			w.WriteHeader(http.StatusServiceUnavailable)
 			w.Write([]byte(http.StatusText(http.StatusServiceUnavailable)))

pkg/util/utils.go

@@ -21,7 +21,6 @@ import (
 	"runtime"
 	"strings"
 
-	"github.com/prometheus/common/version"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/client-go/discovery"
@@ -32,6 +31,9 @@ import (
 	"k8s.io/klog/v2"
 	testUnstructuredMock "k8s.io/sample-controller/pkg/apis/samplecontroller/v1alpha1"
 
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/version"
+
 	"k8s.io/kube-state-metrics/v2/pkg/customresource"
 )
 
@@ -154,3 +156,19 @@ func GVRFromType(resourceName string, expectedType interface{}) *schema.GroupVer
 		Resource: r,
 	}
 }
+
+// GatherAndCount gathers all metrics from the provided Gatherer and counts
+// them. It returns the number of metric children in all gathered metric
+// families together.
+func GatherAndCount(g prometheus.Gatherer) (int, error) {
+	got, err := g.Gather()
+	if err != nil {
+		return 0, fmt.Errorf("gathering metrics failed: %w", err)
+	}
+
+	result := 0
+	for _, mf := range got {
+		result += len(mf.GetMetric())
+	}
+	return result, nil
+}