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/counter.go

@@ -45,6 +45,14 @@ func NewCounter(opts *CounterOpts) *Counter {
 	return kc
 }
 
+// Reset resets the underlying prometheus Counter to start counting from 0 again
+func (c *Counter) Reset() {
+	if !c.IsCreated() {
+		return
+	}
+	c.setPrometheusCounter(prometheus.NewCounter(c.CounterOpts.toPromCounterOpts()))
+}
+
 // setPrometheusCounter sets the underlying CounterMetric object, i.e. the thing that does the measurement.
 func (c *Counter) setPrometheusCounter(counter prometheus.Counter) {
 	c.CounterMetric = counter

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

@@ -23,7 +23,7 @@ import (
 	"github.com/blang/semver"
 	"github.com/prometheus/client_golang/prometheus"
 
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 )
 
 // Desc is a prometheus.Desc extension.

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

@@ -17,6 +17,7 @@ limitations under the License.
 package metrics
 
 import (
+	"io"
 	"net/http"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -61,3 +62,16 @@ func (ho *HandlerOpts) toPromhttpHandlerOpts() promhttp.HandlerOpts {
 func HandlerFor(reg Gatherer, opts HandlerOpts) http.Handler {
 	return promhttp.HandlerFor(reg, opts.toPromhttpHandlerOpts())
 }
+
+// HandlerWithReset return an http.Handler with Reset
+func HandlerWithReset(reg KubeRegistry, opts HandlerOpts) http.Handler {
+	defaultHandler := promhttp.HandlerFor(reg, opts.toPromhttpHandlerOpts())
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodDelete {
+			reg.Reset()
+			io.WriteString(w, "metrics reset\n")
+			return
+		}
+		defaultHandler.ServeHTTP(w, r)
+	})
+}

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

@@ -29,6 +29,18 @@ var (
 	defaultRegistry = metrics.NewKubeRegistry()
 	// DefaultGatherer exposes the global registry gatherer
 	DefaultGatherer metrics.Gatherer = defaultRegistry
+	// Reset calls reset on the global registry
+	Reset = defaultRegistry.Reset
+	// MustRegister registers registerable metrics but uses the global registry.
+	MustRegister = defaultRegistry.MustRegister
+	// RawMustRegister registers prometheus collectors but uses the global registry, this
+	// bypasses the metric stability framework
+	//
+	// Deprecated
+	RawMustRegister = defaultRegistry.RawMustRegister
+
+	// Register registers a collectable metric but uses the global registry
+	Register = defaultRegistry.Register
 )
 
 func init() {
@@ -46,23 +58,12 @@ func Handler() http.Handler {
 	return promhttp.InstrumentMetricHandler(prometheus.DefaultRegisterer, promhttp.HandlerFor(defaultRegistry, promhttp.HandlerOpts{}))
 }
 
-// Register registers a collectable metric but uses the global registry
-func Register(c metrics.Registerable) error {
-	err := defaultRegistry.Register(c)
-	return err
-}
-
-// MustRegister registers registerable metrics but uses the global registry.
-func MustRegister(cs ...metrics.Registerable) {
-	defaultRegistry.MustRegister(cs...)
-}
-
-// RawMustRegister registers prometheus collectors but uses the global registry, this
-// bypasses the metric stability framework
-//
-// Deprecated
-func RawMustRegister(cs ...prometheus.Collector) {
-	defaultRegistry.RawMustRegister(cs...)
+// HandlerWithReset returns an HTTP handler for the DefaultGatherer but invokes
+// registry reset if the http method is DELETE.
+func HandlerWithReset() http.Handler {
+	return promhttp.InstrumentMetricHandler(
+		prometheus.DefaultRegisterer,
+		metrics.HandlerWithReset(defaultRegistry, metrics.HandlerOpts{}))
 }
 
 // CustomRegister registers a custom collector but uses the global registry.

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

@@ -23,7 +23,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	dto "github.com/prometheus/client_model/go"
 
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 )
 
 /*
@@ -188,9 +188,6 @@ func (c *selfCollector) Collect(ch chan<- prometheus.Metric) {
 // no-op vecs for convenience
 var noopCounterVec = &prometheus.CounterVec{}
 var noopHistogramVec = &prometheus.HistogramVec{}
-
-// lint:ignore U1000 Keep it for future use
-var noopSummaryVec = &prometheus.SummaryVec{}
 var noopGaugeVec = &prometheus.GaugeVec{}
 var noopObserverVec = &noopObserverVector{}
 

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

@@ -0,0 +1,79 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package metrics
+
+import (
+	"fmt"
+
+	"github.com/blang/semver"
+	"github.com/spf13/pflag"
+
+	"k8s.io/component-base/version"
+)
+
+// Options has all parameters needed for exposing metrics from components
+type Options struct {
+	ShowHiddenMetricsForVersion string
+}
+
+// NewOptions returns default metrics options
+func NewOptions() *Options {
+	return &Options{}
+}
+
+// Validate validates metrics flags options.
+func (o *Options) Validate() []error {
+	err := validateShowHiddenMetricsVersion(parseVersion(version.Get()), o.ShowHiddenMetricsForVersion)
+	if err != nil {
+		return []error{err}
+	}
+
+	return nil
+}
+
+// AddFlags adds flags for exposing component metrics.
+func (o *Options) AddFlags(fs *pflag.FlagSet) {
+	if o != nil {
+		o = NewOptions()
+	}
+	fs.StringVar(&o.ShowHiddenMetricsForVersion, "show-hidden-metrics-for-version", o.ShowHiddenMetricsForVersion,
+		"The previous version for which you want to show hidden metrics. "+
+			"Only the previous minor version is meaningful, other values will not be allowed. "+
+			"The format is <major>.<minor>, e.g.: '1.16'. "+
+			"The purpose of this format is make sure you have the opportunity to notice if the next release hides additional metrics, "+
+			"rather than being surprised when they are permanently removed in the release after that.")
+}
+
+// Apply applies parameters into global configuration of metrics.
+func (o *Options) Apply() {
+	if o != nil && len(o.ShowHiddenMetricsForVersion) > 0 {
+		SetShowHidden()
+	}
+}
+
+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
+}

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

@@ -125,7 +125,7 @@ func (o *GaugeOpts) annotateStabilityLevel() {
 
 // convenience function to allow easy transformation to the prometheus
 // counterpart. This will do more once we have a proper label abstraction
-func (o GaugeOpts) toPromGaugeOpts() prometheus.GaugeOpts {
+func (o *GaugeOpts) toPromGaugeOpts() prometheus.GaugeOpts {
 	return prometheus.GaugeOpts{
 		Namespace:   o.Namespace,
 		Subsystem:   o.Subsystem,
@@ -169,7 +169,7 @@ func (o *HistogramOpts) annotateStabilityLevel() {
 
 // convenience function to allow easy transformation to the prometheus
 // counterpart. This will do more once we have a proper label abstraction
-func (o HistogramOpts) toPromHistogramOpts() prometheus.HistogramOpts {
+func (o *HistogramOpts) toPromHistogramOpts() prometheus.HistogramOpts {
 	return prometheus.HistogramOpts{
 		Namespace:   o.Namespace,
 		Subsystem:   o.Subsystem,
@@ -224,7 +224,7 @@ var (
 
 // convenience function to allow easy transformation to the prometheus
 // counterpart. This will do more once we have a proper label abstraction
-func (o SummaryOpts) toPromSummaryOpts() prometheus.SummaryOpts {
+func (o *SummaryOpts) toPromSummaryOpts() prometheus.SummaryOpts {
 	// we need to retain existing quantile behavior for backwards compatibility,
 	// so let's do what prometheus used to do prior to v1.
 	objectives := o.Objectives

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

@@ -22,7 +22,7 @@ import (
 
 	"github.com/prometheus/procfs"
 
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 )
 
 var processStartTime = NewGaugeVec(
@@ -43,6 +43,12 @@ func RegisterProcessStartTime(registrationFunc func(Registerable) error) error {
 		klog.Errorf("Could not get process start time, %v", err)
 		start = float64(time.Now().Unix())
 	}
+	// processStartTime is a lazy metric which only get initialized after registered.
+	// so we have to explicitly create it before setting the label value. Otherwise
+	// it is a noop.
+	if !processStartTime.IsCreated() {
+		processStartTime.initializeMetric()
+	}
 	processStartTime.WithLabelValues().Set(start)
 	return registrationFunc(processStartTime)
 }
@@ -54,7 +60,7 @@ func getProcessStart() (float64, error) {
 		return 0, err
 	}
 
-	if stat, err := p.NewStat(); err == nil {
+	if stat, err := p.Stat(); err == nil {
 		return stat.StartTime()
 	}
 	return 0, err

vendor/k8s.io/component-base/metrics/prometheus/ratelimiter/OWNERS

@@ -1,9 +0,0 @@
-# See the OWNERS docs at https://go.k8s.io/owners
-
-approvers:
-- sig-instrumentation-approvers
-- logicalhan
-reviewers:
-- sig-instrumentation-reviewers
-labels:
-- sig/instrumentation

vendor/k8s.io/component-base/metrics/prometheus/ratelimiter/rate_limiter.go

@@ -1,77 +0,0 @@
-/*
-Copyright 2015 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package ratelimiter
-
-import (
-	"fmt"
-	"sync"
-
-	"k8s.io/client-go/util/flowcontrol"
-	"k8s.io/component-base/metrics"
-	"k8s.io/component-base/metrics/legacyregistry"
-)
-
-var (
-	metricsLock        sync.Mutex
-	rateLimiterMetrics = make(map[string]*rateLimiterMetric)
-)
-
-type rateLimiterMetric struct {
-	metric metrics.GaugeMetric
-	stopCh chan struct{}
-}
-
-func registerRateLimiterMetric(ownerName string) error {
-	metricsLock.Lock()
-	defer metricsLock.Unlock()
-
-	if _, ok := rateLimiterMetrics[ownerName]; ok {
-		// only register once in Prometheus. We happen to see an ownerName reused in parallel integration tests.
-		return nil
-	}
-	metric := metrics.NewGauge(&metrics.GaugeOpts{
-		Name:           "rate_limiter_use",
-		Subsystem:      ownerName,
-		Help:           fmt.Sprintf("A metric measuring the saturation of the rate limiter for %v", ownerName),
-		StabilityLevel: metrics.ALPHA,
-	})
-	if err := legacyregistry.Register(metric); err != nil {
-		return fmt.Errorf("error registering rate limiter usage metric: %v", err)
-	}
-	stopCh := make(chan struct{})
-	rateLimiterMetrics[ownerName] = &rateLimiterMetric{
-		metric: metric,
-		stopCh: stopCh,
-	}
-	return nil
-}
-
-// RegisterMetricAndTrackRateLimiterUsage registers a metric ownerName_rate_limiter_use in prometheus to track
-// how much used rateLimiter is and starts a goroutine that updates this metric every updatePeriod
-func RegisterMetricAndTrackRateLimiterUsage(ownerName string, rateLimiter flowcontrol.RateLimiter) error {
-	if err := registerRateLimiterMetric(ownerName); err != nil {
-		return err
-	}
-	// TODO: determine how to track rate limiter saturation
-	// See discussion at https://go-review.googlesource.com/c/time/+/29958#message-4caffc11669cadd90e2da4c05122cfec50ea6a22
-	// go wait.Until(func() {
-	//   metricsLock.Lock()
-	//   defer metricsLock.Unlock()
-	//   rateLimiterMetrics[ownerName].metric.Set()
-	// }, updatePeriod, rateLimiterMetrics[ownerName].stopCh)
-	return nil
-}

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
 }

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

@@ -43,8 +43,8 @@ type Metrics map[string]model.Samples
 
 // Equal returns true if all metrics are the same as the arguments.
 func (m *Metrics) Equal(o Metrics) bool {
-	leftKeySet := []string{}
-	rightKeySet := []string{}
+	var leftKeySet []string
+	var rightKeySet []string
 	for k := range *m {
 		leftKeySet = append(leftKeySet, k)
 	}
@@ -86,35 +86,22 @@ func ParseMetrics(data string, output *Metrics) error {
 			continue
 		}
 		for _, metric := range v {
-			name := string(metric.Metric[model.MetricNameLabel])
+			name := string(metric.Metric[MetricNameLabel])
 			(*output)[name] = append((*output)[name], metric)
 		}
 	}
 }
 
-// ExtractMetricSamples parses the prometheus metric samples from the input string.
-func ExtractMetricSamples(metricsBlob string) ([]*model.Sample, error) {
-	dec := expfmt.NewDecoder(strings.NewReader(metricsBlob), expfmt.FmtText)
-	decoder := expfmt.SampleDecoder{
-		Dec:  dec,
-		Opts: &expfmt.DecodeOptions{},
-	}
-
-	var samples []*model.Sample
-	for {
-		var v model.Vector
-		if err := decoder.Decode(&v); err != nil {
-			if err == io.EOF {
-				// Expected loop termination condition.
-				return samples, nil
-			}
-			return nil, err
-		}
-		samples = append(samples, v...)
-	}
+// TextToMetricFamilies reads 'in' as the simple and flat text-based exchange
+// format and creates MetricFamily proto messages. It returns the MetricFamily
+// proto messages in a map where the metric names are the keys, along with any
+// error encountered.
+func TextToMetricFamilies(in io.Reader) (map[string]*dto.MetricFamily, error) {
+	var textParser expfmt.TextParser
+	return textParser.TextToMetricFamilies(in)
 }
 
-// PrintSample returns formated representation of metric Sample
+// PrintSample returns formatted representation of metric Sample
 func PrintSample(sample *model.Sample) string {
 	buf := make([]string, 0)
 	// Id is a VERY special label. For 'normal' container it's useless, but it's necessary
@@ -198,22 +185,22 @@ func GetHistogramFromGatherer(gatherer metrics.Gatherer, metricName string) (His
 		return Histogram{}, err
 	}
 	for _, mFamily := range m {
-		if mFamily.Name != nil && *mFamily.Name == metricName {
+		if mFamily.GetName() == metricName {
 			metricFamily = mFamily
 			break
 		}
 	}
 
 	if metricFamily == nil {
-		return Histogram{}, fmt.Errorf("Metric %q not found", metricName)
+		return Histogram{}, fmt.Errorf("metric %q not found", metricName)
 	}
 
 	if metricFamily.GetMetric() == nil {
-		return Histogram{}, fmt.Errorf("Metric %q is empty", metricName)
+		return Histogram{}, fmt.Errorf("metric %q is empty", metricName)
 	}
 
 	if len(metricFamily.GetMetric()) == 0 {
-		return Histogram{}, fmt.Errorf("Metric %q is empty", metricName)
+		return Histogram{}, fmt.Errorf("metric %q is empty", metricName)
 	}
 
 	return Histogram{
@@ -253,6 +240,10 @@ func bucketQuantile(q float64, buckets []bucket) float64 {
 		return buckets[0].upperBound * (rank / buckets[0].count)
 	}
 
+	if b == len(buckets)-1 && math.IsInf(buckets[b].upperBound, 1) {
+		return buckets[len(buckets)-2].upperBound
+	}
+
 	// linear approximation of b-th bucket
 	brank := rank - buckets[b-1].count
 	bSize := buckets[b].upperBound - buckets[b-1].upperBound
@@ -264,24 +255,30 @@ func bucketQuantile(q float64, buckets []bucket) float64 {
 // Quantile computes q-th quantile of a cumulative histogram.
 // It's expected the histogram is valid (by calling Validate)
 func (hist *Histogram) Quantile(q float64) float64 {
-	buckets := []bucket{}
+	var buckets []bucket
 
 	for _, bckt := range hist.Bucket {
 		buckets = append(buckets, bucket{
-			count:      float64(*bckt.CumulativeCount),
-			upperBound: *bckt.UpperBound,
+			count:      float64(bckt.GetCumulativeCount()),
+			upperBound: bckt.GetUpperBound(),
 		})
 	}
 
-	// bucketQuantile expects the upper bound of the last bucket to be +inf
-	// buckets[len(buckets)-1].upperBound = math.Inf(+1)
+	if len(buckets) == 0 || buckets[len(buckets)-1].upperBound != math.Inf(+1) {
+		// The list of buckets in dto.Histogram doesn't include the final +Inf bucket, so we
+		// add it here for the reset of the samples.
+		buckets = append(buckets, bucket{
+			count:      float64(hist.GetSampleCount()),
+			upperBound: math.Inf(+1),
+		})
+	}
 
 	return bucketQuantile(q, buckets)
 }
 
 // Average computes histogram's average value
 func (hist *Histogram) Average() float64 {
-	return *hist.SampleSum / float64(*hist.SampleCount)
+	return hist.GetSampleSum() / float64(hist.GetSampleCount())
 }
 
 // Clear clears all fields of the wrapped histogram
@@ -301,11 +298,11 @@ func (hist *Histogram) Clear() {
 
 // Validate makes sure the wrapped histogram has all necessary fields set and with valid values.
 func (hist *Histogram) Validate() error {
-	if hist.SampleCount == nil || *hist.SampleCount == 0 {
+	if hist.SampleCount == nil || hist.GetSampleCount() == 0 {
 		return fmt.Errorf("nil or empty histogram SampleCount")
 	}
 
-	if hist.SampleSum == nil || *hist.SampleSum == 0 {
+	if hist.SampleSum == nil || hist.GetSampleSum() == 0 {
 		return fmt.Errorf("nil or empty histogram SampleSum")
 	}
 
@@ -313,7 +310,7 @@ func (hist *Histogram) Validate() error {
 		if bckt == nil {
 			return fmt.Errorf("empty histogram bucket")
 		}
-		if bckt.UpperBound == nil || *bckt.UpperBound < 0 {
+		if bckt.UpperBound == nil || bckt.GetUpperBound() < 0 {
 			return fmt.Errorf("nil or negative histogram bucket UpperBound")
 		}
 	}
@@ -325,7 +322,7 @@ func (hist *Histogram) Validate() error {
 func GetGaugeMetricValue(m metrics.GaugeMetric) (float64, error) {
 	metricProto := &dto.Metric{}
 	if err := m.Write(metricProto); err != nil {
-		return 0, fmt.Errorf("Error writing m: %v", err)
+		return 0, fmt.Errorf("error writing m: %v", err)
 	}
 	return metricProto.Gauge.GetValue(), nil
 }
@@ -334,7 +331,7 @@ func GetGaugeMetricValue(m metrics.GaugeMetric) (float64, error) {
 func GetCounterMetricValue(m metrics.CounterMetric) (float64, error) {
 	metricProto := &dto.Metric{}
 	if err := m.(metrics.Metric).Write(metricProto); err != nil {
-		return 0, fmt.Errorf("Error writing m: %v", err)
+		return 0, fmt.Errorf("error writing m: %v", err)
 	}
 	return metricProto.Counter.GetValue(), nil
 }
@@ -343,7 +340,29 @@ func GetCounterMetricValue(m metrics.CounterMetric) (float64, error) {
 func GetHistogramMetricValue(m metrics.ObserverMetric) (float64, error) {
 	metricProto := &dto.Metric{}
 	if err := m.(metrics.Metric).Write(metricProto); err != nil {
-		return 0, fmt.Errorf("Error writing m: %v", err)
+		return 0, fmt.Errorf("error writing m: %v", err)
 	}
 	return metricProto.Histogram.GetSampleSum(), nil
 }
+
+// LabelsMatch returns true if metric has all expected labels otherwise false
+func LabelsMatch(metric *dto.Metric, labelFilter map[string]string) bool {
+	metricLabels := map[string]string{}
+
+	for _, labelPair := range metric.Label {
+		metricLabels[labelPair.GetName()] = labelPair.GetValue()
+	}
+
+	// length comparison then match key to values in the maps
+	if len(labelFilter) > len(metricLabels) {
+		return false
+	}
+
+	for labelName, labelValue := range labelFilter {
+		if value, ok := metricLabels[labelName]; !ok || value != labelValue {
+			return false
+		}
+	}
+
+	return true
+}

vendor/k8s.io/component-base/metrics/testutil/promlint.go

@@ -0,0 +1,156 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package testutil
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus/testutil/promlint"
+)
+
+// exceptionMetrics is an exception list of metrics which violates promlint rules.
+//
+// The original entries come from the existing metrics when we introduce promlint.
+// We setup this list for allow and not fail on the current violations.
+// Generally speaking, you need to fix the problem for a new metric rather than add it into the list.
+var exceptionMetrics = []string{
+	// k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/server/egressselector
+	"apiserver_egress_dialer_dial_failure_count", // counter metrics should have "_total" suffix
+
+	// k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/server/healthz
+	"apiserver_request_total", // label names should be written in 'snake_case' not 'camelCase'
+
+	// k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/filters
+	"authenticated_user_requests", // counter metrics should have "_total" suffix
+	"authentication_attempts",     // counter metrics should have "_total" suffix
+
+	// kube-apiserver
+	"aggregator_openapi_v2_regeneration_count",
+	"apiserver_admission_step_admission_duration_seconds_summary",
+	"apiserver_current_inflight_requests",
+	"apiserver_longrunning_gauge",
+	"get_token_count",
+	"get_token_fail_count",
+	"ssh_tunnel_open_count",
+	"ssh_tunnel_open_fail_count",
+
+	// kube-controller-manager
+	"attachdetach_controller_forced_detaches",
+	"authenticated_user_requests",
+	"authentication_attempts",
+	"get_token_count",
+	"get_token_fail_count",
+	"node_collector_evictions_number",
+
+	// k8s.io/kubernetes/pkg/kubelet/server/stats
+	// The two metrics have been deprecated and will be removed in release v1.20+.
+	"container_cpu_usage_seconds_total", // non-counter metrics should not have "_total" suffix
+	"node_cpu_usage_seconds_total",      // non-counter metrics should not have "_total" suffix
+}
+
+// A Problem is an issue detected by a Linter.
+type Problem promlint.Problem
+
+func (p *Problem) String() string {
+	return fmt.Sprintf("%s:%s", p.Metric, p.Text)
+}
+
+// A Linter is a Prometheus metrics linter.  It identifies issues with metric
+// names, types, and metadata, and reports them to the caller.
+type Linter struct {
+	promLinter *promlint.Linter
+}
+
+// Lint performs a linting pass, returning a slice of Problems indicating any
+// issues found in the metrics stream.  The slice is sorted by metric name
+// and issue description.
+func (l *Linter) Lint() ([]Problem, error) {
+	promProblems, err := l.promLinter.Lint()
+	if err != nil {
+		return nil, err
+	}
+
+	// Ignore problems those in exception list
+	problems := make([]Problem, 0, len(promProblems))
+	for i := range promProblems {
+		if !l.shouldIgnore(promProblems[i].Metric) {
+			problems = append(problems, Problem(promProblems[i]))
+		}
+	}
+
+	return problems, nil
+}
+
+// shouldIgnore returns true if metric in the exception list, otherwise returns false.
+func (l *Linter) shouldIgnore(metricName string) bool {
+	for i := range exceptionMetrics {
+		if metricName == exceptionMetrics[i] {
+			return true
+		}
+	}
+
+	return false
+}
+
+// NewPromLinter creates a new Linter that reads an input stream of Prometheus metrics.
+// Only the text exposition format is supported.
+func NewPromLinter(r io.Reader) *Linter {
+	return &Linter{
+		promLinter: promlint.New(r),
+	}
+}
+
+func mergeProblems(problems []Problem) string {
+	var problemsMsg []string
+
+	for index := range problems {
+		problemsMsg = append(problemsMsg, problems[index].String())
+	}
+
+	return strings.Join(problemsMsg, ",")
+}
+
+// shouldIgnore returns true if metric in the exception list, otherwise returns false.
+func shouldIgnore(metricName string) bool {
+	for i := range exceptionMetrics {
+		if metricName == exceptionMetrics[i] {
+			return true
+		}
+	}
+
+	return false
+}
+
+// getLintError will ignore the metrics in exception list and converts lint problem to error.
+func getLintError(problems []promlint.Problem) error {
+	var filteredProblems []Problem
+	for _, problem := range problems {
+		if shouldIgnore(problem.Metric) {
+			continue
+		}
+
+		filteredProblems = append(filteredProblems, Problem(problem))
+	}
+
+	if len(filteredProblems) == 0 {
+		return nil
+	}
+
+	return fmt.Errorf("lint error: %s", mergeProblems(filteredProblems))
+}

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

@@ -30,6 +30,14 @@ import (
 // pedantic Registry. It then does the same as GatherAndCompare, gathering the
 // metrics from the pedantic Registry.
 func CollectAndCompare(c metrics.Collector, expected io.Reader, metricNames ...string) error {
+	lintProblems, err := testutil.CollectAndLint(c, metricNames...)
+	if err != nil {
+		return err
+	}
+	if err := getLintError(lintProblems); err != nil {
+		return err
+	}
+
 	return testutil.CollectAndCompare(c, expected, metricNames...)
 }
 
@@ -38,6 +46,14 @@ func CollectAndCompare(c metrics.Collector, expected io.Reader, metricNames ...s
 // exposition format. If any metricNames are provided, only metrics with those
 // names are compared.
 func GatherAndCompare(g metrics.Gatherer, expected io.Reader, metricNames ...string) error {
+	lintProblems, err := testutil.GatherAndLint(g, metricNames...)
+	if err != nil {
+		return err
+	}
+	if err := getLintError(lintProblems); err != nil {
+		return err
+	}
+
 	return testutil.GatherAndCompare(g, expected, metricNames...)
 }
 

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

@@ -25,7 +25,7 @@ var (
 			Help:           "A metric with a constant '1' value labeled by major, minor, git version, git commit, git tree state, build date, Go version, and compiler from which Kubernetes was built, and platform on which it is running.",
 			StabilityLevel: ALPHA,
 		},
-		[]string{"major", "minor", "gitVersion", "gitCommit", "gitTreeState", "buildDate", "goVersion", "compiler", "platform"},
+		[]string{"major", "minor", "git_version", "git_commit", "git_tree_state", "build_date", "go_version", "compiler", "platform"},
 	)
 )