rebase: update kubernetes to v1.20.0

updated kubernetes packages to latest
release.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

vendor/k8s.io/component-base/metrics/registry.go

@@ -51,19 +51,6 @@ func shouldHide(currentVersion *semver.Version, deprecatedVersion *semver.Versio
 	return false
 }
 
-func validateShowHiddenMetricsVersion(currentVersion semver.Version, targetVersionStr string) error {
-	if targetVersionStr == "" {
-		return nil
-	}
-
-	validVersionStr := fmt.Sprintf("%d.%d", currentVersion.Major, currentVersion.Minor-1)
-	if targetVersionStr != validVersionStr {
-		return fmt.Errorf("--show-hidden-metrics-for-version must be omitted or have the value '%v'. Only the previous minor version is allowed", validVersionStr)
-	}
-
-	return nil
-}
-
 // ValidateShowHiddenMetricsVersion checks invalid version for which show hidden metrics.
 func ValidateShowHiddenMetricsVersion(v string) []error {
 	err := validateShowHiddenMetricsVersion(parseVersion(version.Get()), v)
@@ -110,17 +97,30 @@ type Registerable interface {
 	FQName() string
 }
 
+type resettable interface {
+	Reset()
+}
+
 // KubeRegistry is an interface which implements a subset of prometheus.Registerer and
 // prometheus.Gatherer interfaces
 type KubeRegistry interface {
 	// Deprecated
 	RawMustRegister(...prometheus.Collector)
+	// CustomRegister is our internal variant of Prometheus registry.Register
 	CustomRegister(c StableCollector) error
+	// CustomMustRegister is our internal variant of Prometheus registry.MustRegister
 	CustomMustRegister(cs ...StableCollector)
+	// Register conforms to Prometheus registry.Register
 	Register(Registerable) error
+	// MustRegister conforms to Prometheus registry.MustRegister
 	MustRegister(...Registerable)
+	// Unregister conforms to Prometheus registry.Unregister
 	Unregister(collector Collector) bool
+	// Gather conforms to Prometheus gatherer.Gather
 	Gather() ([]*dto.MetricFamily, error)
+	// Reset invokes the Reset() function on all items in the registry
+	// which are added as resettables.
+	Reset()
 }
 
 // kubeRegistry is a wrapper around a prometheus registry-type object. Upon initialization
@@ -133,6 +133,8 @@ type kubeRegistry struct {
 	stableCollectors     []StableCollector       // stores all stable collector
 	hiddenCollectorsLock sync.RWMutex
 	stableCollectorsLock sync.RWMutex
+	resetLock            sync.RWMutex
+	resettables          []resettable
 }
 
 // Register registers a new Collector to be included in metrics
@@ -142,11 +144,11 @@ type kubeRegistry struct {
 // uniqueness criteria described in the documentation of metric.Desc.
 func (kr *kubeRegistry) Register(c Registerable) error {
 	if c.Create(&kr.version) {
+		defer kr.addResettable(c)
 		return kr.PromRegistry.Register(c)
 	}
 
 	kr.trackHiddenCollector(c)
-
 	return nil
 }
 
@@ -158,6 +160,7 @@ func (kr *kubeRegistry) MustRegister(cs ...Registerable) {
 	for _, c := range cs {
 		if c.Create(&kr.version) {
 			metrics = append(metrics, c)
+			kr.addResettable(c)
 		} else {
 			kr.trackHiddenCollector(c)
 		}
@@ -168,7 +171,7 @@ func (kr *kubeRegistry) MustRegister(cs ...Registerable) {
 // CustomRegister registers a new custom collector.
 func (kr *kubeRegistry) CustomRegister(c StableCollector) error {
 	kr.trackStableCollectors(c)
-
+	defer kr.addResettable(c)
 	if c.Create(&kr.version, c) {
 		return kr.PromRegistry.Register(c)
 	}
@@ -180,14 +183,13 @@ func (kr *kubeRegistry) CustomRegister(c StableCollector) error {
 // error.
 func (kr *kubeRegistry) CustomMustRegister(cs ...StableCollector) {
 	kr.trackStableCollectors(cs...)
-
 	collectors := make([]prometheus.Collector, 0, len(cs))
 	for _, c := range cs {
 		if c.Create(&kr.version, c) {
+			kr.addResettable(c)
 			collectors = append(collectors, c)
 		}
 	}
-
 	kr.PromRegistry.MustRegister(collectors...)
 }
 
@@ -198,6 +200,19 @@ func (kr *kubeRegistry) CustomMustRegister(cs ...StableCollector) {
 // Deprecated
 func (kr *kubeRegistry) RawMustRegister(cs ...prometheus.Collector) {
 	kr.PromRegistry.MustRegister(cs...)
+	for _, c := range cs {
+		kr.addResettable(c)
+	}
+}
+
+// addResettable will automatically add our metric to our reset
+// list if it satisfies the interface
+func (kr *kubeRegistry) addResettable(i interface{}) {
+	kr.resetLock.Lock()
+	defer kr.resetLock.Unlock()
+	if resettable, ok := i.(resettable); ok {
+		kr.resettables = append(kr.resettables, resettable)
+	}
 }
 
 // Unregister unregisters the Collector that equals the Collector passed
@@ -279,6 +294,15 @@ func (kr *kubeRegistry) enableHiddenStableCollectors() {
 	kr.CustomMustRegister(cs...)
 }
 
+// Reset invokes Reset on all metrics that are resettable.
+func (kr *kubeRegistry) Reset() {
+	kr.resetLock.RLock()
+	defer kr.resetLock.RUnlock()
+	for _, r := range kr.resettables {
+		r.Reset()
+	}
+}
+
 // BuildVersion is a helper function that can be easily mocked.
 var BuildVersion = version.Get
 
@@ -287,6 +311,7 @@ func newKubeRegistry(v apimachineryversion.Info) *kubeRegistry {
 		PromRegistry:     prometheus.NewRegistry(),
 		version:          parseVersion(v),
 		hiddenCollectors: make(map[string]Registerable),
+		resettables:      make([]resettable, 0),
 	}
 
 	registriesLock.Lock()
@@ -300,6 +325,5 @@ func newKubeRegistry(v apimachineryversion.Info) *kubeRegistry {
 // pre-registered.
 func NewKubeRegistry() KubeRegistry {
 	r := newKubeRegistry(BuildVersion())
-
 	return r
 }