feat: Use PartialObjectMetadata for Configmaps

internal/store/builder.go

@@ -38,7 +38,9 @@ import (
 	policyv1 "k8s.io/api/policy/v1"
 	rbacv1 "k8s.io/api/rbac/v1"
 	storagev1 "k8s.io/api/storage/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/metadata"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/klog/v2"
 
@@ -65,9 +67,10 @@ var _ ksmtypes.BuilderInterface = &Builder{}
 // Builder helps to build store. It follows the builder pattern
 // (https://en.wikipedia.org/wiki/Builder_pattern).
 type Builder struct {
-	kubeClient            clientset.Interface
-	customResourceClients map[string]interface{}
-	namespaces            options.NamespaceList
+	kubeClient             clientset.Interface
+	metadataOnlyKubeClient metadata.Interface
+	customResourceClients  map[string]interface{}
+	namespaces             options.NamespaceList
 	// namespaceFilter is inside fieldSelectorFilter
 	fieldSelectorFilter           string
 	ctx                           context.Context
@@ -78,6 +81,7 @@ type Builder struct {
 	shard                         int32
 	totalShards                   int
 	buildStoresFunc               ksmtypes.BuildStoresFunc
+	buildMetadataOnlyStoresFunc   ksmtypes.BuildMetadataOnlyStoresFunc
 	buildCustomResourceStoresFunc ksmtypes.BuildCustomResourceStoresFunc
 	allowAnnotationsList          map[string][]string
 	allowLabelsList               map[string][]string
@@ -157,6 +161,11 @@ func (b *Builder) WithKubeClient(c clientset.Interface) {
 	b.kubeClient = c
 }
 
+// WithMetadataOnlyKubeClient sets the metadataOnlyKubeClient property of a Builder.
+func (b *Builder) WithMetadataOnlyKubeClient(c metadata.Interface) {
+	b.metadataOnlyKubeClient = c
+}
+
 // WithCustomResourceClients sets the customResourceClients property of a Builder.
 func (b *Builder) WithCustomResourceClients(cs map[string]interface{}) {
 	b.customResourceClients = cs
@@ -178,6 +187,11 @@ func (b *Builder) WithGenerateStoresFunc(f ksmtypes.BuildStoresFunc) {
 	b.buildStoresFunc = f
 }
 
+// WithGenerateMetadataOnlyStoresFunc configures a custom generate custom resource store function
+func (b *Builder) WithGenerateMetadataOnlyStoresFunc(f ksmtypes.BuildMetadataOnlyStoresFunc) {
+	b.buildMetadataOnlyStoresFunc = f
+}
+
 // WithGenerateCustomResourceStoresFunc configures a custom generate custom resource store function
 func (b *Builder) WithGenerateCustomResourceStoresFunc(f ksmtypes.BuildCustomResourceStoresFunc) {
 	b.buildCustomResourceStoresFunc = f
@@ -188,6 +202,11 @@ func (b *Builder) DefaultGenerateStoresFunc() ksmtypes.BuildStoresFunc {
 	return b.buildStores
 }
 
+// DefaultGenerateMetadataOnlyStoresFunc returns default buildStores function
+func (b *Builder) DefaultGenerateMetadataOnlyStoresFunc() ksmtypes.BuildMetadataOnlyStoresFunc {
+	return b.buildMetadataOnlyStores
+}
+
 // DefaultGenerateCustomResourceStoresFunc returns default buildCustomResourceStores function
 func (b *Builder) DefaultGenerateCustomResourceStoresFunc() ksmtypes.BuildCustomResourceStoresFunc {
 	return b.buildCustomResourceStores
@@ -362,7 +381,7 @@ func availableResources() []string {
 }
 
 func (b *Builder) buildConfigMapStores() []cache.Store {
-	return b.buildStoresFunc(configMapMetricFamilies(b.allowAnnotationsList["configmaps"], b.allowLabelsList["configmaps"]), &v1.ConfigMap{}, createConfigMapListWatch, b.useAPIServerCache)
+	return b.buildMetadataOnlyStoresFunc(configMapMetricFamilies(b.allowAnnotationsList["configmaps"], b.allowLabelsList["configmaps"]), &metav1.PartialObjectMetadata{}, createConfigMapListWatch, b.useAPIServerCache)
 }
 
 func (b *Builder) buildCronJobStores() []cache.Store {
@@ -519,7 +538,8 @@ func (b *Builder) buildStores(
 		if b.fieldSelectorFilter != "" {
 			klog.InfoS("FieldSelector is used", "fieldSelector", b.fieldSelectorFilter)
 		}
-		listWatcher := listWatchFunc(b.kubeClient, v1.NamespaceAll, b.fieldSelectorFilter)
+		kubeClient := b.kubeClient
+		listWatcher := listWatchFunc(kubeClient, v1.NamespaceAll, b.fieldSelectorFilter)
 		b.startReflector(expectedType, store, listWatcher, useAPIServerCache)
 		return []cache.Store{store}
 	}
@@ -541,6 +561,46 @@ func (b *Builder) buildStores(
 	return stores
 }
 
+func (b *Builder) buildMetadataOnlyStores(
+	metricFamilies []generator.FamilyGenerator,
+	expectedType interface{},
+	listWatchFunc func(kubeClient metadata.Interface, ns string, fieldSelector string) cache.ListerWatcher,
+	useAPIServerCache bool,
+) []cache.Store {
+	metricFamilies = generator.FilterFamilyGenerators(b.familyGeneratorFilter, metricFamilies)
+	composedMetricGenFuncs := generator.ComposeMetricGenFuncs(metricFamilies)
+	familyHeaders := generator.ExtractMetricFamilyHeaders(metricFamilies)
+
+	if b.namespaces.IsAllNamespaces() {
+		store := metricsstore.NewMetricsStore(
+			familyHeaders,
+			composedMetricGenFuncs,
+		)
+		if b.fieldSelectorFilter != "" {
+			klog.InfoS("FieldSelector is used", "fieldSelector", b.fieldSelectorFilter)
+		}
+		listWatcher := listWatchFunc(b.metadataOnlyKubeClient, v1.NamespaceAll, b.fieldSelectorFilter)
+		b.startReflector(expectedType, store, listWatcher, useAPIServerCache)
+		return []cache.Store{store}
+	}
+
+	stores := make([]cache.Store, 0, len(b.namespaces))
+	for _, ns := range b.namespaces {
+		store := metricsstore.NewMetricsStore(
+			familyHeaders,
+			composedMetricGenFuncs,
+		)
+		if b.fieldSelectorFilter != "" {
+			klog.InfoS("FieldSelector is used", "fieldSelector", b.fieldSelectorFilter)
+		}
+		listWatcher := listWatchFunc(b.metadataOnlyKubeClient, ns, b.fieldSelectorFilter)
+		b.startReflector(expectedType, store, listWatcher, useAPIServerCache)
+		stores = append(stores, store)
+	}
+
+	return stores
+}
+
 // TODO(Garrybest): Merge `buildStores` and `buildCustomResourceStores`
 func (b *Builder) buildCustomResourceStores(resourceName string,
 	metricFamilies []generator.FamilyGenerator,

internal/store/configmap.go

@@ -19,11 +19,11 @@ package store
 import (
 	"context"
 
-	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/watch"
-	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/metadata"
 	"k8s.io/client-go/tools/cache"
 	basemetrics "k8s.io/component-base/metrics"
 
@@ -43,7 +43,7 @@ func configMapMetricFamilies(allowAnnotationsList, allowLabelsList []string) []g
 			metric.Gauge,
 			basemetrics.ALPHA,
 			"",
-			wrapConfigMapFunc(func(c *v1.ConfigMap) *metric.Family {
+			wrapConfigMapFunc(func(c *metav1.PartialObjectMetadata) *metric.Family {
 				if len(allowAnnotationsList) == 0 {
 					return &metric.Family{}
 				}
@@ -65,7 +65,7 @@ func configMapMetricFamilies(allowAnnotationsList, allowLabelsList []string) []g
 			metric.Gauge,
 			basemetrics.STABLE,
 			"",
-			wrapConfigMapFunc(func(c *v1.ConfigMap) *metric.Family {
+			wrapConfigMapFunc(func(c *metav1.PartialObjectMetadata) *metric.Family {
 				if len(allowLabelsList) == 0 {
 					return &metric.Family{}
 				}
@@ -87,7 +87,7 @@ func configMapMetricFamilies(allowAnnotationsList, allowLabelsList []string) []g
 			metric.Gauge,
 			basemetrics.STABLE,
 			"",
-			wrapConfigMapFunc(func(_ *v1.ConfigMap) *metric.Family {
+			wrapConfigMapFunc(func(_ *metav1.PartialObjectMetadata) *metric.Family {
 				return &metric.Family{
 					Metrics: []*metric.Metric{{
 						LabelKeys:   []string{},
@@ -103,7 +103,7 @@ func configMapMetricFamilies(allowAnnotationsList, allowLabelsList []string) []g
 			metric.Gauge,
 			basemetrics.STABLE,
 			"",
-			wrapConfigMapFunc(func(c *v1.ConfigMap) *metric.Family {
+			wrapConfigMapFunc(func(c *metav1.PartialObjectMetadata) *metric.Family {
 				ms := []*metric.Metric{}
 
 				if !c.CreationTimestamp.IsZero() {
@@ -125,7 +125,7 @@ func configMapMetricFamilies(allowAnnotationsList, allowLabelsList []string) []g
 			metric.Gauge,
 			basemetrics.ALPHA,
 			"",
-			wrapConfigMapFunc(func(c *v1.ConfigMap) *metric.Family {
+			wrapConfigMapFunc(func(c *metav1.PartialObjectMetadata) *metric.Family {
 				return &metric.Family{
 					Metrics: resourceVersionMetric(c.ObjectMeta.ResourceVersion),
 				}
@@ -134,22 +134,22 @@ func configMapMetricFamilies(allowAnnotationsList, allowLabelsList []string) []g
 	}
 }
 
-func createConfigMapListWatch(kubeClient clientset.Interface, ns string, fieldSelector string) cache.ListerWatcher {
+func createConfigMapListWatch(kubeClient metadata.Interface, ns string, fieldSelector string) cache.ListerWatcher {
 	return &cache.ListWatch{
 		ListFunc: func(opts metav1.ListOptions) (runtime.Object, error) {
 			opts.FieldSelector = fieldSelector
-			return kubeClient.CoreV1().ConfigMaps(ns).List(context.TODO(), opts)
+			return kubeClient.Resource(schema.GroupVersionResource{Group: "", Version: "v1", Resource: "configmaps"}).Namespace(ns).List(context.TODO(), opts)
 		},
 		WatchFunc: func(opts metav1.ListOptions) (watch.Interface, error) {
 			opts.FieldSelector = fieldSelector
-			return kubeClient.CoreV1().ConfigMaps(ns).Watch(context.TODO(), opts)
+			return kubeClient.Resource(schema.GroupVersionResource{Group: "", Version: "v1", Resource: "configmaps"}).Namespace(ns).Watch(context.TODO(), opts)
 		},
 	}
 }
 
-func wrapConfigMapFunc(f func(*v1.ConfigMap) *metric.Family) func(interface{}) *metric.Family {
+func wrapConfigMapFunc(f func(*metav1.PartialObjectMetadata) *metric.Family) func(interface{}) *metric.Family {
 	return func(obj interface{}) *metric.Family {
-		configMap := obj.(*v1.ConfigMap)
+		configMap := obj.(*metav1.PartialObjectMetadata)
 
 		metricFamily := f(configMap)
 

internal/store/configmap_test.go

@@ -19,7 +19,6 @@ package store
 import (
 	"testing"
 
-	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	generator "k8s.io/kube-state-metrics/v2/pkg/metric_generator"
@@ -37,7 +36,7 @@ func TestConfigMapStore(t *testing.T) {
 			AllowLabelsList: []string{
 				"app",
 			},
-			Obj: &v1.ConfigMap{
+			Obj: &metav1.PartialObjectMetadata{
 				ObjectMeta: metav1.ObjectMeta{
 					Name:            "configmap1",
 					Namespace:       "ns1",
@@ -73,7 +72,7 @@ func TestConfigMapStore(t *testing.T) {
 			},
 		},
 		{
-			Obj: &v1.ConfigMap{
+			Obj: &metav1.PartialObjectMetadata{
 				ObjectMeta: metav1.ObjectMeta{
 					Name:              "configmap2",
 					Namespace:         "ns2",

pkg/app/server.go

@@ -266,6 +266,7 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 
 	storeBuilder.WithUsingAPIServerCache(opts.UseAPIServerCache)
 	storeBuilder.WithGenerateStoresFunc(storeBuilder.DefaultGenerateStoresFunc())
+	storeBuilder.WithGenerateMetadataOnlyStoresFunc(storeBuilder.DefaultGenerateMetadataOnlyStoresFunc())
 	proc.StartReaper()
 
 	storeBuilder.WithUtilOptions(opts)
@@ -275,6 +276,12 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 	}
 	storeBuilder.WithKubeClient(kubeClient)
 
+	metadataOnlyKubeClient, err := util.CreateMetadataOnlyKubeClient(opts.Apiserver, opts.Kubeconfig)
+	if err != nil {
+		return fmt.Errorf("failed to create metadata-only client: %v", err)
+	}
+	storeBuilder.WithMetadataOnlyKubeClient(metadataOnlyKubeClient)
+
 	storeBuilder.WithSharding(opts.Shard, opts.TotalShards)
 	if err := storeBuilder.WithAllowAnnotations(opts.AnnotationsAllowList); err != nil {
 		return fmt.Errorf("failed to set up annotations allowlist: %v", err)

pkg/app/server_test.go

@@ -84,6 +84,7 @@ func BenchmarkKubeStateMetrics(b *testing.B) {
 	builder.WithContext(ctx)
 	builder.WithNamespaces(options.DefaultNamespaces)
 	builder.WithGenerateStoresFunc(builder.DefaultGenerateStoresFunc())
+	builder.WithGenerateMetadataOnlyStoresFunc(builder.DefaultGenerateMetadataOnlyStoresFunc())
 
 	allowDenyListFilter, err := allowdenylist.New(map[string]struct{}{}, map[string]struct{}{})
 	if err != nil {
@@ -159,6 +160,7 @@ func TestFullScrapeCycle(t *testing.T) {
 	builder.WithKubeClient(kubeClient)
 	builder.WithNamespaces(options.DefaultNamespaces)
 	builder.WithGenerateStoresFunc(builder.DefaultGenerateStoresFunc())
+	builder.WithGenerateMetadataOnlyStoresFunc(builder.DefaultGenerateMetadataOnlyStoresFunc())
 
 	l, err := allowdenylist.New(map[string]struct{}{}, map[string]struct{}{})
 	if err != nil {
@@ -463,6 +465,7 @@ func TestShardingEquivalenceScrapeCycle(t *testing.T) {
 	unshardedBuilder.WithFamilyGeneratorFilter(l)
 	unshardedBuilder.WithAllowLabels(map[string][]string{})
 	unshardedBuilder.WithGenerateStoresFunc(unshardedBuilder.DefaultGenerateStoresFunc())
+	unshardedBuilder.WithGenerateMetadataOnlyStoresFunc(unshardedBuilder.DefaultGenerateMetadataOnlyStoresFunc())
 
 	unshardedHandler := metricshandler.New(&options.Options{}, kubeClient, unshardedBuilder, false)
 	unshardedHandler.ConfigureSharding(ctx, 0, 1)
@@ -479,6 +482,7 @@ func TestShardingEquivalenceScrapeCycle(t *testing.T) {
 	shardedBuilder1.WithFamilyGeneratorFilter(l)
 	shardedBuilder1.WithAllowLabels(map[string][]string{})
 	shardedBuilder1.WithGenerateStoresFunc(shardedBuilder1.DefaultGenerateStoresFunc())
+	shardedBuilder1.WithGenerateMetadataOnlyStoresFunc(shardedBuilder1.DefaultGenerateMetadataOnlyStoresFunc())
 
 	shardedHandler1 := metricshandler.New(&options.Options{}, kubeClient, shardedBuilder1, false)
 	shardedHandler1.ConfigureSharding(ctx, 0, 2)
@@ -495,6 +499,7 @@ func TestShardingEquivalenceScrapeCycle(t *testing.T) {
 	shardedBuilder2.WithFamilyGeneratorFilter(l)
 	shardedBuilder2.WithAllowLabels(map[string][]string{})
 	shardedBuilder2.WithGenerateStoresFunc(shardedBuilder2.DefaultGenerateStoresFunc())
+	shardedBuilder2.WithGenerateMetadataOnlyStoresFunc(shardedBuilder2.DefaultGenerateMetadataOnlyStoresFunc())
 
 	shardedHandler2 := metricshandler.New(&options.Options{}, kubeClient, shardedBuilder2, false)
 	shardedHandler2.ConfigureSharding(ctx, 1, 2)
@@ -635,6 +640,7 @@ func TestCustomResourceExtension(t *testing.T) {
 	builder.WithCustomResourceClients(customResourceClients)
 	builder.WithNamespaces(options.DefaultNamespaces)
 	builder.WithGenerateStoresFunc(builder.DefaultGenerateStoresFunc())
+	builder.WithGenerateMetadataOnlyStoresFunc(builder.DefaultGenerateMetadataOnlyStoresFunc())
 	builder.WithGenerateCustomResourceStoresFunc(builder.DefaultGenerateCustomResourceStoresFunc())
 
 	l, err := allowdenylist.New(map[string]struct{}{}, map[string]struct{}{})

pkg/builder/builder.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/metadata"
 	"k8s.io/client-go/tools/cache"
 
 	internalstore "k8s.io/kube-state-metrics/v2/internal/store"
@@ -84,6 +85,11 @@ func (b *Builder) WithKubeClient(c clientset.Interface) {
 	b.internal.WithKubeClient(c)
 }
 
+// WithMetadataOnlyKubeClient sets the metadataOnlyKubeClient property of a Builder.
+func (b *Builder) WithMetadataOnlyKubeClient(c metadata.Interface) {
+	b.internal.WithMetadataOnlyKubeClient(c)
+}
+
 // WithCustomResourceClients sets the customResourceClients property of a Builder.
 func (b *Builder) WithCustomResourceClients(cs map[string]interface{}) {
 	b.internal.WithCustomResourceClients(cs)
@@ -120,6 +126,16 @@ func (b *Builder) DefaultGenerateStoresFunc() ksmtypes.BuildStoresFunc {
 	return b.internal.DefaultGenerateStoresFunc()
 }
 
+// WithGenerateMetadataOnlyStoresFunc configures a custom generate metadataonly store function
+func (b *Builder) WithGenerateMetadataOnlyStoresFunc(f ksmtypes.BuildMetadataOnlyStoresFunc) {
+	b.internal.WithGenerateMetadataOnlyStoresFunc(f)
+}
+
+// DefaultGenerateMetadataOnlyStoresFunc returns default buildMetadataOnlyStore function
+func (b *Builder) DefaultGenerateMetadataOnlyStoresFunc() ksmtypes.BuildMetadataOnlyStoresFunc {
+	return b.internal.DefaultGenerateMetadataOnlyStoresFunc()
+}
+
 // DefaultGenerateCustomResourceStoresFunc returns default buildStores function
 func (b *Builder) DefaultGenerateCustomResourceStoresFunc() ksmtypes.BuildCustomResourceStoresFunc {
 	return b.internal.DefaultGenerateCustomResourceStoresFunc()

pkg/builder/types/interfaces.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/metadata"
 	"k8s.io/client-go/tools/cache"
 
 	"k8s.io/kube-state-metrics/v2/pkg/customresource"
@@ -38,6 +39,7 @@ type BuilderInterface interface {
 	WithFieldSelectorFilter(fieldSelectors string)
 	WithSharding(shard int32, totalShards int)
 	WithContext(ctx context.Context)
+	WithMetadataOnlyKubeClient(c metadata.Interface)
 	WithKubeClient(c clientset.Interface)
 	WithCustomResourceClients(cs map[string]interface{})
 	WithUsingAPIServerCache(u bool)
@@ -46,6 +48,8 @@ type BuilderInterface interface {
 	WithAllowLabels(l map[string][]string) error
 	WithGenerateStoresFunc(f BuildStoresFunc)
 	DefaultGenerateStoresFunc() BuildStoresFunc
+	WithGenerateMetadataOnlyStoresFunc(f BuildMetadataOnlyStoresFunc)
+	DefaultGenerateMetadataOnlyStoresFunc() BuildMetadataOnlyStoresFunc
 	DefaultGenerateCustomResourceStoresFunc() BuildCustomResourceStoresFunc
 	WithCustomResourceStoreFactories(fs ...customresource.RegistryFactory)
 	Build() metricsstore.MetricsWriterList
@@ -60,6 +64,13 @@ type BuildStoresFunc func(metricFamilies []generator.FamilyGenerator,
 	useAPIServerCache bool,
 ) []cache.Store
 
+// BuildMetadataOnlyStoresFunc function signature that is used to return a list of cache.Store
+type BuildMetadataOnlyStoresFunc func(metricFamilies []generator.FamilyGenerator,
+	expectedType interface{},
+	listWatchFunc func(kubeClient metadata.Interface, ns string, fieldSelector string) cache.ListerWatcher,
+	useAPIServerCache bool,
+) []cache.Store
+
 // BuildCustomResourceStoresFunc function signature that is used to return a list of custom resource cache.Store
 type BuildCustomResourceStoresFunc func(resourceName string,
 	metricFamilies []generator.FamilyGenerator,