Merge pull request #890 from zalando-incubator/dependabot/go_modules/all-go-mod-patch-and-minor-27074441d2

Bump the all-go-mod-patch-and-minor group with 9 updates

.github/workflows/ci.yaml

@@ -10,10 +10,10 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v6.0.1
-    - uses: actions/setup-go@v6.1.0
+    - uses: actions/checkout@v6.0.2
+    - uses: actions/setup-go@v6.4.0
       with:
-        go-version: '^1.25'
+        go-version: '^1.26'
     - run: go version
     - run: go install github.com/mattn/goveralls@latest
     - run: go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest

.github/workflows/codeql-analysis.yml

@@ -38,12 +38,12 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v6.0.1
+      uses: actions/checkout@v6.0.2
 
     - name: setup go
-      uses: actions/setup-go@v6.1.0
+      uses: actions/setup-go@v6.4.0
       with:
-        go-version: '1.25'
+        go-version: '1.26'
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/gh-packages.yaml

@@ -25,15 +25,15 @@ jobs:
       packages: write # to push packages
     steps:
       - name: Checkout
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8
+        uses: actions/checkout@0c366fd6a839edf440554fa01a7085ccba70ac98
 
-      - uses: actions/setup-go@4dc6199c7b1a012772edbd06daecab0f50c9053c
+      - uses: actions/setup-go@4a3601121dd01d1626a1e23e37211e3254c1c06c
         with:
           # https://www.npmjs.com/package/semver#caret-ranges-123-025-004
-          go-version: '^1.25'
+          go-version: '^1.26'
 
       - name: Login to Github Container Registry
-        uses: docker/login-action@5e57cd118135c172c3672efd75eb46360885c0ef
+        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
@@ -47,21 +47,21 @@ jobs:
           make build.linux.amd64 build.linux.arm64
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130
+        uses: docker/setup-qemu-action@ce360397dd3f832beb865e1373c09c0e9f86d70a
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f
+        uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd
 
       - name: Login to GitHub Container Registry
         if: github.event_name != 'pull_request'
-        uses: docker/login-action@5e57cd118135c172c3672efd75eb46360885c0ef
+        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Docker meta
-        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051
+        uses: docker/metadata-action@030e881283bb7a6894de51c315a6bfe6a94e05cf
         id: meta
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
@@ -70,7 +70,7 @@ jobs:
             type=semver,pattern=v{{major}}.{{minor}}
 
       - name: Build and push
-        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83
+        uses: docker/build-push-action@d08e5c354a6adb9ed34480a06d141179aa583294
         with:
           context: .
           build-args: BASE_IMAGE=gcr.io/distroless/static-debian12
@@ -81,7 +81,7 @@ jobs:
 
       # Build and push latest tag
       - name: Build and push latest
-        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83
+        uses: docker/build-push-action@d08e5c354a6adb9ed34480a06d141179aa583294
         with:
           context: .
           build-args: BASE_IMAGE=gcr.io/distroless/static-debian12

.github/workflows/release-chart.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.1
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
 

docs/helm/templates/custom-metrics-apiservice.yaml

@@ -3,6 +3,13 @@ apiVersion: apiregistration.k8s.io/v1
 kind: APIService
 metadata:
   name: v1beta1.custom.metrics.k8s.io
+  {{- with .Values.customMetricsApi.annotations }}
+  annotations:
+    {{- range $k, $v := . }}
+      {{- $value := $v | quote }}
+      {{- printf "%s: %s" (tpl $k $) (tpl $value $) | nindent 4 }}
+    {{- end }}
+  {{- end }}
 spec:
   service:
     name: kube-metrics-adapter

docs/helm/templates/external-metrics-apiservice.yaml

@@ -3,6 +3,13 @@ apiVersion: apiregistration.k8s.io/v1
 kind: APIService
 metadata:
   name: v1beta1.external.metrics.k8s.io
+  {{- with .Values.externalMetricsApi.annotations }}
+  annotations:
+    {{- range $k, $v := . }}
+      {{- $value := $v | quote }}
+      {{- printf "%s: %s" (tpl $k $) (tpl $value $) | nindent 4 }}
+    {{- end }}
+  {{- end }}
 spec:
   service:
     name: kube-metrics-adapter

docs/helm/values.yaml

@@ -15,7 +15,19 @@ addDirectoryHeader:
 contentionProfiling:
 profiling:
 enableCustomMetricsApi: true
+
+# -- add annotations to the custom metrics apiservice resource, e.g.
+# cert-manager.io/inject-ca-from: {{.Release.Namespace}}/kube-metrics-adapter to inject the CA certificate form a cert-manager-issued cert used for the deployment
+customMetricsApi:
+  annotations: {}
+
 enableExternalMetricsApi: true
+
+# -- add annotations to the custom metrics apiservice resource, e.g.
+# cert-manager.io/inject-ca-from: {{.Release.Namespace}}/kube-metrics-adapter to inject the CA certificate form a cert-manager-issued cert used for the deployment
+externalMetricsApi:
+  annotations: {}
+
 credentialsDirectory:
 disregardIncompatibleHPAs:
 http2MaxStreamsPerConnection:

example/main.go

@@ -10,7 +10,7 @@ import (
 
 func metricsHandler(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(200)
-	_, err := w.Write([]byte(fmt.Sprintf(`{"queue": {"length": %d}}`, size)))
+	_, err := fmt.Fprintf(w, `{"queue": {"length": %d}}`, size)
 	if err != nil {
 		log.Fatalf("failed to write: %v", err)
 	}

pkg/apis/zalando.org/v1/types.go

@@ -35,7 +35,7 @@ type ScalingSchedule struct {
 // Identifier returns the namespaced scalingScale Identifier in the format
 // `<namespace>/<name>`.
 func (s *ScalingSchedule) Identifier() string {
-	return s.ObjectMeta.Namespace + "/" + s.ObjectMeta.Name
+	return s.Namespace + "/" + s.Name
 }
 
 // ResourceSpec returns the ScalingScheduleSpec of the ScalingSchedule.
@@ -66,7 +66,7 @@ type ClusterScalingSchedule struct {
 // Identifier returns the cluster scalingScale Identifier in the format
 // `<name>`.
 func (s *ClusterScalingSchedule) Identifier() string {
-	return s.ObjectMeta.Name
+	return s.Name
 }
 
 // ResourceSpec returns the ScalingScheduleSpec of the ClusterScalingSchedule.

pkg/client/clientset/versioned/fake/clientset_generated.go

@@ -34,10 +34,6 @@ import (
 // It's backed by a very simple object tracker that processes creates, updates and deletions as-is,
 // without applying any field management, validations and/or defaults. It shouldn't be considered a replacement
 // for a real clientset and is mostly useful in simple unit tests.
-//
-// DEPRECATED: NewClientset replaces this with support for field management, which significantly improves
-// server side apply testing. NewClientset is only available when apply configurations are generated (e.g.
-// via --with-applyconfig).
 func NewSimpleClientset(objects ...runtime.Object) *Clientset {
 	o := testing.NewObjectTracker(scheme, codecs.UniversalDecoder())
 	for _, obj := range objects {
@@ -51,8 +47,8 @@ func NewSimpleClientset(objects ...runtime.Object) *Clientset {
 	cs.AddReactor("*", "*", testing.ObjectReaction(o))
 	cs.AddWatchReactor("*", func(action testing.Action) (handled bool, ret watch.Interface, err error) {
 		var opts metav1.ListOptions
-		if watchActcion, ok := action.(testing.WatchActionImpl); ok {
-			opts = watchActcion.ListOptions
+		if watchAction, ok := action.(testing.WatchActionImpl); ok {
+			opts = watchAction.ListOptions
 		}
 		gvr := action.GetResource()
 		ns := action.GetNamespace()
@@ -83,6 +79,17 @@ func (c *Clientset) Tracker() testing.ObjectTracker {
 	return c.tracker
 }
 
+// IsWatchListSemanticsSupported informs the reflector that this client
+// doesn't support WatchList semantics.
+//
+// This is a synthetic method whose sole purpose is to satisfy the optional
+// interface check performed by the reflector.
+// Returning true signals that WatchList can NOT be used.
+// No additional logic is implemented here.
+func (c *Clientset) IsWatchListSemanticsUnSupported() bool {
+	return true
+}
+
 var (
 	_ clientset.Interface = &Clientset{}
 	_ testing.FakeClient  = &Clientset{}

pkg/client/informers/externalversions/factory.go

@@ -97,6 +97,7 @@ func NewSharedInformerFactory(client versioned.Interface, defaultResync time.Dur
 // NewFilteredSharedInformerFactory constructs a new instance of sharedInformerFactory.
 // Listers obtained via this SharedInformerFactory will be subject to the same filters
 // as specified here.
+//
 // Deprecated: Please use NewSharedInformerFactoryWithOptions instead
 func NewFilteredSharedInformerFactory(client versioned.Interface, defaultResync time.Duration, namespace string, tweakListOptions internalinterfaces.TweakListOptionsFunc) SharedInformerFactory {
 	return NewSharedInformerFactoryWithOptions(client, defaultResync, WithNamespace(namespace), WithTweakListOptions(tweakListOptions))
@@ -204,7 +205,7 @@ func (f *sharedInformerFactory) InformerFor(obj runtime.Object, newFunc internal
 //
 // It is typically used like this:
 //
-//	ctx, cancel := context.Background()
+//	ctx, cancel := context.WithCancel(context.Background())
 //	defer cancel()
 //	factory := NewSharedInformerFactory(client, resyncPeriod)
 //	defer factory.WaitForStop()    // Returns immediately if nothing was started.

pkg/client/informers/externalversions/zalando.org/v1/clusterscalingschedule.go

@@ -56,7 +56,7 @@ func NewClusterScalingScheduleInformer(client versioned.Interface, resyncPeriod
 // one. This reduces memory footprint and number of connections to the server.
 func NewFilteredClusterScalingScheduleInformer(client versioned.Interface, resyncPeriod time.Duration, indexers cache.Indexers, tweakListOptions internalinterfaces.TweakListOptionsFunc) cache.SharedIndexInformer {
 	return cache.NewSharedIndexInformer(
-		&cache.ListWatch{
+		cache.ToListWatcherWithWatchListSemantics(&cache.ListWatch{
 			ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
 				if tweakListOptions != nil {
 					tweakListOptions(&options)
@@ -81,7 +81,7 @@ func NewFilteredClusterScalingScheduleInformer(client versioned.Interface, resyn
 				}
 				return client.ZalandoV1().ClusterScalingSchedules().Watch(ctx, options)
 			},
-		},
+		}, client),
 		&apiszalandoorgv1.ClusterScalingSchedule{},
 		resyncPeriod,
 		indexers,

pkg/client/informers/externalversions/zalando.org/v1/scalingschedule.go

@@ -57,7 +57,7 @@ func NewScalingScheduleInformer(client versioned.Interface, namespace string, re
 // one. This reduces memory footprint and number of connections to the server.
 func NewFilteredScalingScheduleInformer(client versioned.Interface, namespace string, resyncPeriod time.Duration, indexers cache.Indexers, tweakListOptions internalinterfaces.TweakListOptionsFunc) cache.SharedIndexInformer {
 	return cache.NewSharedIndexInformer(
-		&cache.ListWatch{
+		cache.ToListWatcherWithWatchListSemantics(&cache.ListWatch{
 			ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
 				if tweakListOptions != nil {
 					tweakListOptions(&options)
@@ -82,7 +82,7 @@ func NewFilteredScalingScheduleInformer(client versioned.Interface, namespace st
 				}
 				return client.ZalandoV1().ScalingSchedules(namespace).Watch(ctx, options)
 			},
-		},
+		}, client),
 		&apiszalandoorgv1.ScalingSchedule{},
 		resyncPeriod,
 		indexers,

pkg/collector/collector.go

@@ -185,7 +185,7 @@ type MetricTypeName struct {
 
 func (m MetricTypeName) String() string {
 	str := fmt.Sprintf("%s/%s", m.Type, m.Metric.Name)
-	if len(m.Metric.Selector.MatchLabels) > 0 {
+	if m.Metric.Selector != nil && len(m.Metric.Selector.MatchLabels) > 0 {
 		str += " " + mapToString(m.Metric.Selector.MatchLabels)
 	}
 	return str

pkg/collector/collector_test.go

@@ -30,6 +30,88 @@ func (c *mockCollector) Interval() time.Duration {
 	return 0
 }
 
+func TestMetricTypeName_String(t *testing.T) {
+	for _, tc := range []struct {
+		name          string
+		metricType    autoscalingv2.MetricSourceType
+		metricName    string
+		selector      *metav1.LabelSelector
+		expectedStr   string
+		shouldContain []string
+	}{
+		{
+			name:        "nil selector with PodsMetricSourceType",
+			metricType:  autoscalingv2.PodsMetricSourceType,
+			metricName:  "metric-name",
+			selector:    nil,
+			expectedStr: "Pods/metric-name",
+		},
+		{
+			name:        "nil selector with ObjectMetricSourceType",
+			metricType:  autoscalingv2.ObjectMetricSourceType,
+			metricName:  "metric-name",
+			selector:    nil,
+			expectedStr: "Object/metric-name",
+		},
+		{
+			name:        "nil selector with ExternalMetricSourceType",
+			metricType:  autoscalingv2.ExternalMetricSourceType,
+			metricName:  "metric-name",
+			selector:    nil,
+			expectedStr: "External/metric-name",
+		},
+		{
+			name:       "empty selector (non-nil but empty MatchLabels)",
+			metricType: autoscalingv2.ExternalMetricSourceType,
+			metricName: "metric-name",
+			selector: &metav1.LabelSelector{
+				MatchLabels: map[string]string{},
+			},
+			expectedStr: "External/metric-name",
+		},
+		{
+			name:       "selector with single MatchLabel",
+			metricType: autoscalingv2.ExternalMetricSourceType,
+			metricName: "metric-name",
+			selector: &metav1.LabelSelector{
+				MatchLabels: map[string]string{"key": "value"},
+			},
+			shouldContain: []string{"External/metric-name", "key=value"},
+		},
+		{
+			name:       "selector with multiple MatchLabels",
+			metricType: autoscalingv2.ExternalMetricSourceType,
+			metricName: "metric-name",
+			selector: &metav1.LabelSelector{
+				MatchLabels: map[string]string{"key1": "val1", "key2": "val2"},
+			},
+			shouldContain: []string{"External/metric-name", "key1=val1", "key2=val2"},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			mtn := MetricTypeName{
+				Type: tc.metricType,
+				Metric: autoscalingv2.MetricIdentifier{
+					Name:     tc.metricName,
+					Selector: tc.selector,
+				},
+			}
+
+			result := mtn.String()
+
+			if tc.expectedStr != "" {
+				require.Equal(t, tc.expectedStr, result)
+			}
+
+			if len(tc.shouldContain) > 0 {
+				for _, substring := range tc.shouldContain {
+					require.Contains(t, result, substring, "result should contain %q", substring)
+				}
+			}
+		})
+	}
+}
+
 func TestNewCollector(t *testing.T) {
 	for _, tc := range []struct {
 		msg               string

pkg/collector/external_rps_collector.go

@@ -63,7 +63,7 @@ func (p *ExternalRPSCollectorPlugin) NewCollector(
 	confCopy := *config
 
 	if _, ok := config.Config["hostnames"]; !ok {
-		return nil, fmt.Errorf("Hostname is not specified, unable to create collector")
+		return nil, fmt.Errorf("hostname is not specified, unable to create collector")
 	}
 
 	hostnames := strings.Split(config.Config["hostnames"], ",")

pkg/collector/http_collector_test.go

@@ -10,7 +10,6 @@ import (
 	"github.com/stretchr/testify/require"
 	autoscalingv2 "k8s.io/api/autoscaling/v2"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
 type testExternalMetricsHandler struct {
@@ -84,7 +83,7 @@ func makeTestHTTPCollectorConfig(endpoint, aggregator string) *MetricConfig {
 			Type: autoscalingv2.ExternalMetricSourceType,
 			Metric: autoscalingv2.MetricIdentifier{
 				Name: "test-metric",
-				Selector: &v1.LabelSelector{
+				Selector: &metav1.LabelSelector{
 					MatchLabels: map[string]string{"type": HTTPJSONPathType},
 				},
 			},

pkg/collector/httpmetrics/pod_metrics.go

@@ -2,6 +2,7 @@ package httpmetrics
 
 import (
 	"fmt"
+	"net"
 	"net/url"
 	"strconv"
 	"time"
@@ -88,7 +89,7 @@ func NewPodMetricsJSONPathGetter(config map[string]string) (*PodMetricsJSONPathG
 			return nil, err
 		}
 		if d < 0 {
-			return nil, fmt.Errorf("Invalid request-timeout config value: %s", v)
+			return nil, fmt.Errorf("invalid request-timeout config value: %s", v)
 		}
 		requestTimeout = d
 	}
@@ -99,7 +100,7 @@ func NewPodMetricsJSONPathGetter(config map[string]string) (*PodMetricsJSONPathG
 			return nil, err
 		}
 		if d < 0 {
-			return nil, fmt.Errorf("Invalid connect-timeout config value: %s", v)
+			return nil, fmt.Errorf("invalid connect-timeout config value: %s", v)
 		}
 		connectTimeout = d
 	}
@@ -122,7 +123,7 @@ func (g *PodMetricsJSONPathGetter) buildMetricsURL(podIP string) url.URL {
 
 	return url.URL{
 		Scheme:   scheme,
-		Host:     fmt.Sprintf("%s:%d", podIP, g.port),
+		Host:     net.JoinHostPort(podIP, strconv.Itoa(g.port)),
 		Path:     g.path,
 		RawQuery: g.rawQuery,
 	}

pkg/collector/influxdb_collector_test.go

@@ -8,7 +8,6 @@ import (
 
 	autoscalingv2 "k8s.io/api/autoscaling/v2"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
 func TestInfluxDBCollector_New(t *testing.T) {
@@ -24,7 +23,7 @@ func TestInfluxDBCollector_New(t *testing.T) {
 				Metric: autoscalingv2.MetricIdentifier{
 					Name: "flux-query",
 					// This is actually useless, because the selector should be flattened in Config when parsing.
-					Selector: &v1.LabelSelector{
+					Selector: &metav1.LabelSelector{
 						MatchLabels: map[string]string{
 							"query-name": "range2m",
 						},
@@ -62,7 +61,7 @@ func TestInfluxDBCollector_New(t *testing.T) {
 				Type: autoscalingv2.ExternalMetricSourceType,
 				Metric: autoscalingv2.MetricIdentifier{
 					Name: "flux-query",
-					Selector: &v1.LabelSelector{
+					Selector: &metav1.LabelSelector{
 						MatchLabels: map[string]string{
 							"query-name": "range2m",
 						},

pkg/collector/pod_collector.go

@@ -135,7 +135,7 @@ func (c *PodCollector) Interval() time.Duration {
 func (c *PodCollector) getPodMetric(pod corev1.Pod, ch chan CollectedMetric, errCh chan error) {
 	value, err := c.Getter.GetMetric(&pod)
 	if err != nil {
-		errCh <- fmt.Errorf("Failed to get metrics from pod '%s/%s': %v", pod.Namespace, pod.Name, err)
+		errCh <- fmt.Errorf("failed to get metrics from pod '%s/%s': %v", pod.Namespace, pod.Name, err)
 		return
 	}
 

pkg/collector/pod_collector_test.go

@@ -289,9 +289,9 @@ func makeTestPods(t *testing.T, testServer string, metricName string, port strin
 		}
 
 		if podDeletionTimestamp.IsZero() {
-			testPod.ObjectMeta.DeletionTimestamp = nil
+			testPod.DeletionTimestamp = nil
 		} else {
-			testPod.ObjectMeta.DeletionTimestamp = &v1.Time{Time: podDeletionTimestamp}
+			testPod.DeletionTimestamp = &v1.Time{Time: podDeletionTimestamp}
 		}
 		_, err := client.CoreV1().Pods(testNamespace).Create(context.Background(), testPod, v1.CreateOptions{})
 		require.NoError(t, err)

pkg/collector/scaling_schedule_collector_test.go

@@ -654,7 +654,7 @@ func TestScalingScheduleCollector(t *testing.T) {
 					require.EqualValues(t, namespace, collected[0].Custom.DescribedObject.Namespace)
 					require.EqualValues(t, "zalando.org/v1", collected[0].Custom.DescribedObject.APIVersion)
 					require.EqualValues(t, resourceType, collected[0].Custom.DescribedObject.Kind)
-					require.EqualValues(t, uTCNowRFC3339, collected[0].Custom.Timestamp.Time.Format(time.RFC3339))
+					require.EqualValues(t, uTCNowRFC3339, collected[0].Custom.Timestamp.Format(time.RFC3339))
 					require.EqualValues(t, collected[0].Custom.Metric.Name, scalingScheduleName)
 					require.EqualValues(t, namespace, collected[0].Namespace)
 				}

pkg/collector/skipper_collector.go

@@ -173,7 +173,7 @@ func (c *SkipperCollector) getCollector(ctx context.Context) (Collector, error)
 		}
 
 		for _, rule := range ingress.Spec.Rules {
-			escapedHostnames = append(escapedHostnames, regexp.QuoteMeta(strings.Replace(rule.Host, ".", "_", -1)))
+			escapedHostnames = append(escapedHostnames, regexp.QuoteMeta(strings.ReplaceAll(rule.Host, ".", "_")))
 		}
 	case "RouteGroup":
 		routegroup, err := c.rgClient.ZalandoV1().RouteGroups(c.objectReference.Namespace).Get(ctx, c.objectReference.Name, metav1.GetOptions{})
@@ -187,7 +187,7 @@ func (c *SkipperCollector) getCollector(ctx context.Context) (Collector, error)
 		}
 
 		for _, host := range routegroup.Spec.Hosts {
-			escapedHostnames = append(escapedHostnames, regexp.QuoteMeta(strings.Replace(host, ".", "_", -1)))
+			escapedHostnames = append(escapedHostnames, regexp.QuoteMeta(strings.ReplaceAll(host, ".", "_")))
 		}
 	default:
 		return nil, fmt.Errorf("unknown skipper resource kind %s for resource %s/%s", c.objectReference.Kind, c.objectReference.Namespace, c.objectReference.Name)

pkg/controller/scheduledscaling/scaler.go

@@ -16,7 +16,6 @@ import (
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/restmapper"
-	"k8s.io/client-go/scale"
 	scaleclient "k8s.io/client-go/scale"
 )
 
@@ -41,8 +40,8 @@ func NewHPATargetScaler(ctx context.Context, kubeClient kubernetes.Interface, cf
 		restMapper.Reset()
 	}, 30*time.Second, ctx.Done())
 
-	scaleKindResolver := scale.NewDiscoveryScaleKindResolver(kubeClient.Discovery())
-	scaleClient, err := scale.NewForConfig(cfg, restMapper, dynamic.LegacyAPIPathResolverFunc, scaleKindResolver)
+	scaleKindResolver := scaleclient.NewDiscoveryScaleKindResolver(kubeClient.Discovery())
+	scaleClient, err := scaleclient.NewForConfig(cfg, restMapper, dynamic.LegacyAPIPathResolverFunc, scaleKindResolver)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create scale client: %w", err)
 	}

pkg/controller/scheduledscaling/scheduled_scaling_test.go

@@ -8,12 +8,10 @@ import (
 
 	"github.com/stretchr/testify/require"
 	v1 "github.com/zalando-incubator/kube-metrics-adapter/pkg/apis/zalando.org/v1"
-	scalingschedulefake "github.com/zalando-incubator/kube-metrics-adapter/pkg/client/clientset/versioned/fake"
 	zfake "github.com/zalando-incubator/kube-metrics-adapter/pkg/client/clientset/versioned/fake"
 	zalandov1 "github.com/zalando-incubator/kube-metrics-adapter/pkg/client/clientset/versioned/typed/zalando.org/v1"
 	appsv1 "k8s.io/api/apps/v1"
 	autoscalingv2 "k8s.io/api/autoscaling/v2"
-	v2 "k8s.io/api/autoscaling/v2"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -217,7 +215,7 @@ func TestRunOnce(t *testing.T) {
 	} {
 		t.Run(tc.msg, func(t *testing.T) {
 			// setup fake client and cache
-			client := scalingschedulefake.NewSimpleClientset()
+			client := zfake.NewSimpleClientset()
 
 			clusterScalingSchedulesStore := fakeClusterScalingScheduleStore{
 				client: client.ZalandoV1(),
@@ -425,25 +423,25 @@ func TestAdjustScaling(t *testing.T) {
 				ObjectMeta: metav1.ObjectMeta{
 					Name: "hpa-1",
 				},
-				Spec: v2.HorizontalPodAutoscalerSpec{
-					ScaleTargetRef: v2.CrossVersionObjectReference{
+				Spec: autoscalingv2.HorizontalPodAutoscalerSpec{
+					ScaleTargetRef: autoscalingv2.CrossVersionObjectReference{
 						APIVersion: "apps/v1",
 						Kind:       "Deployment",
 						Name:       "deployment-1",
 					},
 					MinReplicas: ptr.To(int32(1)),
 					MaxReplicas: 1000,
-					Metrics: []v2.MetricSpec{
+					Metrics: []autoscalingv2.MetricSpec{
 						{
-							Type: v2.ObjectMetricSourceType,
-							Object: &v2.ObjectMetricSource{
-								DescribedObject: v2.CrossVersionObjectReference{
+							Type: autoscalingv2.ObjectMetricSourceType,
+							Object: &autoscalingv2.ObjectMetricSource{
+								DescribedObject: autoscalingv2.CrossVersionObjectReference{
 									APIVersion: "zalando.org/v1",
 									Kind:       "ClusterScalingSchedule",
 									Name:       "schedule-1",
 								},
-								Target: v2.MetricTarget{
-									Type: v2.AverageValueMetricType,
+								Target: autoscalingv2.MetricTarget{
+									Type: autoscalingv2.AverageValueMetricType,
 								},
 							},
 						},

pkg/nakadi/nakadi.go

@@ -8,6 +8,10 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"strconv"
+	"time"
+
+	"github.com/cenkalti/backoff/v5"
 )
 
 // Nakadi defines an interface for talking to the Nakadi API.
@@ -95,26 +99,40 @@ func (c *Client) subscriptions(ctx context.Context, filter *SubscriptionFilter,
 		endpoint.RawQuery = q.Encode()
 	}
 
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
-	if err != nil {
-		return nil, fmt.Errorf("[nakadi subscriptions] failed to create request: %w", err)
+	op := func() ([]byte, error) {
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
+		if err != nil {
+			return nil, fmt.Errorf("[nakadi subscriptions] failed to create request: %w", err)
+		}
+
+		resp, err := c.http.Do(req)
+		if err != nil {
+			return nil, fmt.Errorf("[nakadi subscriptions] failed to make request: %w", err)
+		}
+		defer resp.Body.Close()
+
+		b, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return nil, err
+		}
+
+		if err := checkResponseStatus(resp, b); err != nil {
+			return nil, fmt.Errorf("[nakadi subscriptions] %w", err)
+		}
+
+		return b, nil
 	}
 
-	resp, err := c.http.Do(req)
-	if err != nil {
-		return nil, fmt.Errorf("[nakadi subscriptions] failed to make request: %w", err)
-	}
-	defer resp.Body.Close()
-
-	d, err := io.ReadAll(resp.Body)
+	d, err := backoff.Retry(
+		ctx,
+		op,
+		backoff.WithBackOff(exponentialBackoff()),
+		backoff.WithMaxTries(3),
+	)
 	if err != nil {
 		return nil, err
 	}
 
-	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("[nakadi subscriptions] unexpected response code: %d (%s)", resp.StatusCode, string(d))
-	}
-
 	var subscriptionsResp struct {
 		Items []struct {
 			ID string `json:"id"`
@@ -194,26 +212,40 @@ func (c *Client) stats(ctx context.Context, filter *SubscriptionFilter) ([]stats
 		q.Set("show_time_lag", "true")
 		endpoint.RawQuery = q.Encode()
 
-		req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
-		if err != nil {
-			return nil, fmt.Errorf("[nakadi stats] failed to create request: %w", err)
+		op := func() ([]byte, error) {
+			req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
+			if err != nil {
+				return nil, fmt.Errorf("[nakadi stats] failed to create request: %w", err)
+			}
+
+			resp, err := c.http.Do(req)
+			if err != nil {
+				return nil, fmt.Errorf("[nakadi stats] failed to make request: %w", err)
+			}
+			defer resp.Body.Close()
+
+			b, err := io.ReadAll(resp.Body)
+			if err != nil {
+				return nil, err
+			}
+
+			if err := checkResponseStatus(resp, b); err != nil {
+				return nil, fmt.Errorf("[nakadi stats] %w", err)
+			}
+
+			return b, nil
 		}
 
-		resp, err := c.http.Do(req)
-		if err != nil {
-			return nil, fmt.Errorf("[nakadi stats] failed to make request: %w", err)
-		}
-		defer resp.Body.Close()
-
-		d, err := io.ReadAll(resp.Body)
+		d, err := backoff.Retry(
+			ctx,
+			op,
+			backoff.WithBackOff(exponentialBackoff()),
+			backoff.WithMaxTries(3),
+		)
 		if err != nil {
 			return nil, err
 		}
 
-		if resp.StatusCode != http.StatusOK {
-			return nil, fmt.Errorf("[nakadi stats] unexpected response code: %d (%s)", resp.StatusCode, string(d))
-		}
-
 		var result statsResp
 		err = json.Unmarshal(d, &result)
 		if err != nil {
@@ -229,3 +261,35 @@ func (c *Client) stats(ctx context.Context, filter *SubscriptionFilter) ([]stats
 
 	return stats, nil
 }
+
+func checkResponseStatus(resp *http.Response, b []byte) error {
+	if resp.StatusCode == http.StatusTooManyRequests {
+		h := resp.Header.Get("Retry-After")
+		if h == "" {
+			return fmt.Errorf("unexpected response code: %d (%s)", resp.StatusCode, string(b))
+
+		}
+		sec, err := strconv.ParseInt(h, 10, 32)
+		if err != nil {
+			return backoff.Permanent(err)
+		}
+		return backoff.RetryAfter(int(sec))
+	}
+	if resp.StatusCode >= http.StatusBadRequest &&
+		resp.StatusCode < http.StatusInternalServerError {
+		return backoff.Permanent(
+			fmt.Errorf("non-retryable response code: %d (%s)", resp.StatusCode, string(b)),
+		)
+	}
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("unexpected response code: %d (%s)", resp.StatusCode, string(b))
+	}
+	return nil
+}
+
+func exponentialBackoff() backoff.BackOff {
+	b := backoff.NewExponentialBackOff()
+	b.MaxInterval = time.Second * 30
+	b.InitialInterval = time.Millisecond * 100
+	return b
+}

pkg/nakadi/nakadi_test.go

@@ -5,8 +5,10 @@ import (
 	"errors"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 
+	"github.com/cenkalti/backoff/v5"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -210,11 +212,70 @@ func TestQuery(tt *testing.T) {
 
 			nakadiClient := NewNakadiClient(ts.URL, client)
 			consumerLagSeconds, err := nakadiClient.ConsumerLagSeconds(context.Background(), ti.subscriptionFilter)
-			assert.Equal(t, ti.err, err)
+			assertErrorMessage(t, ti.err, err)
 			assert.Equal(t, ti.consumerLagSeconds, consumerLagSeconds)
 			unconsumedEvents, err := nakadiClient.UnconsumedEvents(context.Background(), ti.subscriptionFilter)
-			assert.Equal(t, ti.err, err)
+			assertErrorMessage(t, ti.err, err)
 			assert.Equal(t, ti.unconsumedEvents, unconsumedEvents)
 		})
 	}
 }
+
+func Test_checkResponseStatus(tt *testing.T) {
+	for _, ti := range []struct {
+		msg      string
+		resp     *http.Response
+		errCheck func(error) bool
+	}{
+		{
+			msg:  "nil when 200",
+			resp: &http.Response{StatusCode: http.StatusOK},
+		},
+		{
+			msg:  "backoff.Permanent when 4xx",
+			resp: &http.Response{StatusCode: http.StatusBadRequest},
+			errCheck: func(err error) bool {
+				var permanentErr *backoff.PermanentError
+				return errors.As(err, &permanentErr)
+			},
+		},
+		{
+			msg:  "unexpected error when 422 without Retry-After header",
+			resp: &http.Response{StatusCode: http.StatusTooManyRequests},
+			errCheck: func(err error) bool {
+				return strings.Contains(err.Error(), "unexpected response code")
+			},
+		},
+		{
+			msg: "backoff.RetryAfter when 422 with Retry-After header",
+			resp: &http.Response{
+				StatusCode: http.StatusTooManyRequests,
+				Header: http.Header{
+					"Retry-After": []string{"120"},
+				},
+			},
+			errCheck: func(err error) bool {
+				var retryAfterErr *backoff.RetryAfterError
+				return errors.As(err, &retryAfterErr)
+			},
+		},
+	} {
+		tt.Run(ti.msg, func(t *testing.T) {
+			err := checkResponseStatus(ti.resp, nil)
+			if ti.errCheck == nil {
+				assert.NoError(t, err)
+			} else {
+				assert.True(t, ti.errCheck(err))
+			}
+		})
+	}
+}
+
+func assertErrorMessage(t *testing.T, expected, actual error) {
+	t.Helper()
+	if expected != nil {
+		assert.EqualError(t, actual, expected.Error())
+	} else {
+		assert.NoError(t, actual)
+	}
+}