use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

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

@@ -0,0 +1,12 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+approvers:
+- piosz
+- brancz
+- logicalhan
+reviewers:
+- piosz
+- brancz
+- logicalhan
+labels:
+- sig/instrumentation

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

@@ -0,0 +1,165 @@
+/*
+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 (
+	"github.com/blang/semver"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Counter is our internal representation for our wrapping struct around prometheus
+// counters. Counter implements both kubeCollector and CounterMetric.
+type Counter struct {
+	CounterMetric
+	*CounterOpts
+	lazyMetric
+	selfCollector
+}
+
+// NewCounter returns an object which satisfies the kubeCollector and CounterMetric interfaces.
+// However, the object returned will not measure anything unless the collector is first
+// registered, since the metric is lazily instantiated.
+func NewCounter(opts *CounterOpts) *Counter {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	kc := &Counter{
+		CounterOpts: opts,
+		lazyMetric:  lazyMetric{},
+	}
+	kc.setPrometheusCounter(noop)
+	kc.lazyInit(kc)
+	return kc
+}
+
+// setPrometheusCounter sets the underlying CounterMetric object, i.e. the thing that does the measurement.
+func (c *Counter) setPrometheusCounter(counter prometheus.Counter) {
+	c.CounterMetric = counter
+	c.initSelfCollection(counter)
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (c *Counter) DeprecatedVersion() *semver.Version {
+	return parseSemver(c.CounterOpts.DeprecatedVersion)
+}
+
+// initializeMetric invocation creates the actual underlying Counter. Until this method is called
+// the underlying counter is a no-op.
+func (c *Counter) initializeMetric() {
+	c.CounterOpts.annotateStabilityLevel()
+	// this actually creates the underlying prometheus counter.
+	c.setPrometheusCounter(prometheus.NewCounter(c.CounterOpts.toPromCounterOpts()))
+}
+
+// initializeDeprecatedMetric invocation creates the actual (but deprecated) Counter. Until this method
+// is called the underlying counter is a no-op.
+func (c *Counter) initializeDeprecatedMetric() {
+	c.CounterOpts.markDeprecated()
+	c.initializeMetric()
+}
+
+// CounterVec is the internal representation of our wrapping struct around prometheus
+// counterVecs. CounterVec implements both kubeCollector and CounterVecMetric.
+type CounterVec struct {
+	*prometheus.CounterVec
+	*CounterOpts
+	lazyMetric
+	originalLabels []string
+}
+
+// NewCounterVec returns an object which satisfies the kubeCollector and CounterVecMetric interfaces.
+// However, the object returned will not measure anything unless the collector is first
+// registered, since the metric is lazily instantiated.
+func NewCounterVec(opts *CounterOpts, labels []string) *CounterVec {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	cv := &CounterVec{
+		CounterVec:     noopCounterVec,
+		CounterOpts:    opts,
+		originalLabels: labels,
+		lazyMetric:     lazyMetric{},
+	}
+	cv.lazyInit(cv)
+	return cv
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (v *CounterVec) DeprecatedVersion() *semver.Version {
+	return parseSemver(v.CounterOpts.DeprecatedVersion)
+
+}
+
+// initializeMetric invocation creates the actual underlying CounterVec. Until this method is called
+// the underlying counterVec is a no-op.
+func (v *CounterVec) initializeMetric() {
+	v.CounterOpts.annotateStabilityLevel()
+	v.CounterVec = prometheus.NewCounterVec(v.CounterOpts.toPromCounterOpts(), v.originalLabels)
+}
+
+// initializeDeprecatedMetric invocation creates the actual (but deprecated) CounterVec. Until this method is called
+// the underlying counterVec is a no-op.
+func (v *CounterVec) initializeDeprecatedMetric() {
+	v.CounterOpts.markDeprecated()
+	v.initializeMetric()
+}
+
+// Default Prometheus behavior actually results in the creation of a new metric
+// if a metric with the unique label values is not found in the underlying stored metricMap.
+// This means  that if this function is called but the underlying metric is not registered
+// (which means it will never be exposed externally nor consumed), the metric will exist in memory
+// for perpetuity (i.e. throughout application lifecycle).
+//
+// For reference: https://github.com/prometheus/client_golang/blob/v0.9.2/prometheus/counter.go#L179-L197
+
+// WithLabelValues returns the Counter for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Counter is created IFF the counterVec
+// has been registered to a metrics registry.
+func (v *CounterVec) WithLabelValues(lvs ...string) CounterMetric {
+	if !v.IsCreated() {
+		return noop // return no-op counter
+	}
+	return v.CounterVec.WithLabelValues(lvs...)
+}
+
+// With returns the Counter for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Counter is created IFF the counterVec has
+// been registered to a metrics registry.
+func (v *CounterVec) With(labels prometheus.Labels) CounterMetric {
+	if !v.IsCreated() {
+		return noop // return no-op counter
+	}
+	return v.CounterVec.With(labels)
+}
+
+// Delete deletes the metric where the variable labels are the same as those
+// passed in as labels. It returns true if a metric was deleted.
+//
+// It is not an error if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc. However, such inconsistent Labels
+// can never match an actual metric, so the method will always return false in
+// that case.
+func (v *CounterVec) Delete(labels prometheus.Labels) bool {
+	if !v.IsCreated() {
+		return false // since we haven't created the metric, we haven't deleted a metric with the passed in values
+	}
+	return v.CounterVec.Delete(labels)
+}

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

@@ -0,0 +1,164 @@
+/*
+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 (
+	"github.com/blang/semver"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Gauge is our internal representation for our wrapping struct around prometheus
+// gauges. kubeGauge implements both kubeCollector and KubeGauge.
+type Gauge struct {
+	GaugeMetric
+	*GaugeOpts
+	lazyMetric
+	selfCollector
+}
+
+// NewGauge returns an object which satisfies the kubeCollector and KubeGauge interfaces.
+// However, the object returned will not measure anything unless the collector is first
+// registered, since the metric is lazily instantiated.
+func NewGauge(opts *GaugeOpts) *Gauge {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	kc := &Gauge{
+		GaugeOpts:  opts,
+		lazyMetric: lazyMetric{},
+	}
+	kc.setPrometheusGauge(noop)
+	kc.lazyInit(kc)
+	return kc
+}
+
+// setPrometheusGauge sets the underlying KubeGauge object, i.e. the thing that does the measurement.
+func (g *Gauge) setPrometheusGauge(gauge prometheus.Gauge) {
+	g.GaugeMetric = gauge
+	g.initSelfCollection(gauge)
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (g *Gauge) DeprecatedVersion() *semver.Version {
+	return parseSemver(g.GaugeOpts.DeprecatedVersion)
+}
+
+// initializeMetric invocation creates the actual underlying Gauge. Until this method is called
+// the underlying gauge is a no-op.
+func (g *Gauge) initializeMetric() {
+	g.GaugeOpts.annotateStabilityLevel()
+	// this actually creates the underlying prometheus gauge.
+	g.setPrometheusGauge(prometheus.NewGauge(g.GaugeOpts.toPromGaugeOpts()))
+}
+
+// initializeDeprecatedMetric invocation creates the actual (but deprecated) Gauge. Until this method
+// is called the underlying gauge is a no-op.
+func (g *Gauge) initializeDeprecatedMetric() {
+	g.GaugeOpts.markDeprecated()
+	g.initializeMetric()
+}
+
+// GaugeVec is the internal representation of our wrapping struct around prometheus
+// gaugeVecs. kubeGaugeVec implements both kubeCollector and KubeGaugeVec.
+type GaugeVec struct {
+	*prometheus.GaugeVec
+	*GaugeOpts
+	lazyMetric
+	originalLabels []string
+}
+
+// NewGaugeVec returns an object which satisfies the kubeCollector and KubeGaugeVec interfaces.
+// However, the object returned will not measure anything unless the collector is first
+// registered, since the metric is lazily instantiated.
+func NewGaugeVec(opts *GaugeOpts, labels []string) *GaugeVec {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	cv := &GaugeVec{
+		GaugeVec:       noopGaugeVec,
+		GaugeOpts:      opts,
+		originalLabels: labels,
+		lazyMetric:     lazyMetric{},
+	}
+	cv.lazyInit(cv)
+	return cv
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (v *GaugeVec) DeprecatedVersion() *semver.Version {
+	return parseSemver(v.GaugeOpts.DeprecatedVersion)
+}
+
+// initializeMetric invocation creates the actual underlying GaugeVec. Until this method is called
+// the underlying gaugeVec is a no-op.
+func (v *GaugeVec) initializeMetric() {
+	v.GaugeOpts.annotateStabilityLevel()
+	v.GaugeVec = prometheus.NewGaugeVec(v.GaugeOpts.toPromGaugeOpts(), v.originalLabels)
+}
+
+// initializeDeprecatedMetric invocation creates the actual (but deprecated) GaugeVec. Until this method is called
+// the underlying gaugeVec is a no-op.
+func (v *GaugeVec) initializeDeprecatedMetric() {
+	v.GaugeOpts.markDeprecated()
+	v.initializeMetric()
+}
+
+// Default Prometheus behavior actually results in the creation of a new metric
+// if a metric with the unique label values is not found in the underlying stored metricMap.
+// This means  that if this function is called but the underlying metric is not registered
+// (which means it will never be exposed externally nor consumed), the metric will exist in memory
+// for perpetuity (i.e. throughout application lifecycle).
+//
+// For reference: https://github.com/prometheus/client_golang/blob/v0.9.2/prometheus/gauge.go#L190-L208
+
+// WithLabelValues returns the GaugeMetric for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new GaugeMetric is created IFF the gaugeVec
+// has been registered to a metrics registry.
+func (v *GaugeVec) WithLabelValues(lvs ...string) GaugeMetric {
+	if !v.IsCreated() {
+		return noop // return no-op gauge
+	}
+	return v.GaugeVec.WithLabelValues(lvs...)
+}
+
+// With returns the GaugeMetric for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new GaugeMetric is created IFF the gaugeVec has
+// been registered to a metrics registry.
+func (v *GaugeVec) With(labels prometheus.Labels) GaugeMetric {
+	if !v.IsCreated() {
+		return noop // return no-op gauge
+	}
+	return v.GaugeVec.With(labels)
+}
+
+// Delete deletes the metric where the variable labels are the same as those
+// passed in as labels. It returns true if a metric was deleted.
+//
+// It is not an error if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc. However, such inconsistent Labels
+// can never match an actual metric, so the method will always return false in
+// that case.
+func (v *GaugeVec) Delete(labels prometheus.Labels) bool {
+	if !v.IsCreated() {
+		return false // since we haven't created the metric, we haven't deleted a metric with the passed in values
+	}
+	return v.GaugeVec.Delete(labels)
+}

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

@@ -0,0 +1,159 @@
+/*
+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 (
+	"github.com/blang/semver"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Histogram is our internal representation for our wrapping struct around prometheus
+// histograms. Summary implements both kubeCollector and ObserverMetric
+type Histogram struct {
+	ObserverMetric
+	*HistogramOpts
+	lazyMetric
+	selfCollector
+}
+
+// NewHistogram returns an object which is Histogram-like. However, nothing
+// will be measured until the histogram is registered somewhere.
+func NewHistogram(opts *HistogramOpts) *Histogram {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	h := &Histogram{
+		HistogramOpts: opts,
+		lazyMetric:    lazyMetric{},
+	}
+	h.setPrometheusHistogram(noopMetric{})
+	h.lazyInit(h)
+	return h
+}
+
+// setPrometheusHistogram sets the underlying KubeGauge object, i.e. the thing that does the measurement.
+func (h *Histogram) setPrometheusHistogram(histogram prometheus.Histogram) {
+	h.ObserverMetric = histogram
+	h.initSelfCollection(histogram)
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (h *Histogram) DeprecatedVersion() *semver.Version {
+	return parseSemver(h.HistogramOpts.DeprecatedVersion)
+}
+
+// initializeMetric invokes the actual prometheus.Histogram object instantiation
+// and stores a reference to it
+func (h *Histogram) initializeMetric() {
+	h.HistogramOpts.annotateStabilityLevel()
+	// this actually creates the underlying prometheus gauge.
+	h.setPrometheusHistogram(prometheus.NewHistogram(h.HistogramOpts.toPromHistogramOpts()))
+}
+
+// initializeDeprecatedMetric invokes the actual prometheus.Histogram object instantiation
+// but modifies the Help description prior to object instantiation.
+func (h *Histogram) initializeDeprecatedMetric() {
+	h.HistogramOpts.markDeprecated()
+	h.initializeMetric()
+}
+
+// HistogramVec is the internal representation of our wrapping struct around prometheus
+// histogramVecs.
+type HistogramVec struct {
+	*prometheus.HistogramVec
+	*HistogramOpts
+	lazyMetric
+	originalLabels []string
+}
+
+// NewHistogramVec returns an object which satisfies kubeCollector and wraps the
+// prometheus.HistogramVec object. However, the object returned will not measure
+// anything unless the collector is first registered, since the metric is lazily instantiated.
+func NewHistogramVec(opts *HistogramOpts, labels []string) *HistogramVec {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	v := &HistogramVec{
+		HistogramVec:   noopHistogramVec,
+		HistogramOpts:  opts,
+		originalLabels: labels,
+		lazyMetric:     lazyMetric{},
+	}
+	v.lazyInit(v)
+	return v
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (v *HistogramVec) DeprecatedVersion() *semver.Version {
+	return parseSemver(v.HistogramOpts.DeprecatedVersion)
+}
+
+func (v *HistogramVec) initializeMetric() {
+	v.HistogramOpts.annotateStabilityLevel()
+	v.HistogramVec = prometheus.NewHistogramVec(v.HistogramOpts.toPromHistogramOpts(), v.originalLabels)
+}
+
+func (v *HistogramVec) initializeDeprecatedMetric() {
+	v.HistogramOpts.markDeprecated()
+	v.initializeMetric()
+}
+
+// Default Prometheus behavior actually results in the creation of a new metric
+// if a metric with the unique label values is not found in the underlying stored metricMap.
+// This means  that if this function is called but the underlying metric is not registered
+// (which means it will never be exposed externally nor consumed), the metric will exist in memory
+// for perpetuity (i.e. throughout application lifecycle).
+//
+// For reference: https://github.com/prometheus/client_golang/blob/v0.9.2/prometheus/histogram.go#L460-L470
+
+// WithLabelValues returns the ObserverMetric for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new ObserverMetric is created IFF the HistogramVec
+// has been registered to a metrics registry.
+func (v *HistogramVec) WithLabelValues(lvs ...string) ObserverMetric {
+	if !v.IsCreated() {
+		return noop
+	}
+	return v.HistogramVec.WithLabelValues(lvs...)
+}
+
+// With returns the ObserverMetric for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new ObserverMetric is created IFF the HistogramVec has
+// been registered to a metrics registry.
+func (v *HistogramVec) With(labels prometheus.Labels) ObserverMetric {
+	if !v.IsCreated() {
+		return noop
+	}
+	return v.HistogramVec.With(labels)
+}
+
+// Delete deletes the metric where the variable labels are the same as those
+// passed in as labels. It returns true if a metric was deleted.
+//
+// It is not an error if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc. However, such inconsistent Labels
+// can never match an actual metric, so the method will always return false in
+// that case.
+func (v *HistogramVec) Delete(labels prometheus.Labels) bool {
+	if !v.IsCreated() {
+		return false // since we haven't created the metric, we haven't deleted a metric with the passed in values
+	}
+	return v.HistogramVec.Delete(labels)
+}

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

@@ -0,0 +1,85 @@
+/*
+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 legacyregistry
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"k8s.io/component-base/metrics"
+	"net/http"
+)
+
+var (
+	defaultRegistry = metrics.NewKubeRegistry()
+	// DefaultGatherer exposes the global registry gatherer
+	DefaultGatherer prometheus.Gatherer = defaultRegistry
+)
+
+func init() {
+	RawMustRegister(prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{}))
+	RawMustRegister(prometheus.NewGoCollector())
+}
+
+// Handler returns an HTTP handler for the DefaultGatherer. It is
+// already instrumented with InstrumentHandler (using "prometheus" as handler
+// name).
+//
+// Deprecated: Please note the issues described in the doc comment of
+// InstrumentHandler. You might want to consider using promhttp.Handler instead.
+func Handler() http.Handler {
+	return prometheus.InstrumentHandler("prometheus", 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)
+	// sideload global prom registry as fallback
+	prometheus.Register(c)
+	return err
+}
+
+// MustRegister registers registerable metrics but uses the global registry.
+func MustRegister(cs ...metrics.Registerable) {
+	defaultRegistry.MustRegister(cs...)
+	// sideload global prom registry as fallback
+	for _, c := range cs {
+		prometheus.Register(c)
+	}
+}
+
+// RawMustRegister registers prometheus collectors but uses the global registry, this
+// bypasses the metric stability framework
+//
+// Deprecated
+func RawMustRegister(cs ...prometheus.Collector) {
+	defaultRegistry.RawMustRegister(cs...)
+	// sideload global prom registry as fallback
+	for _, c := range cs {
+		prometheus.Register(c)
+	}
+}
+
+// RawRegister registers a prometheus collector but uses the global registry, this
+// bypasses the metric stability framework
+//
+// Deprecated
+func RawRegister(c prometheus.Collector) error {
+	err := defaultRegistry.RawRegister(c)
+	// sideload global prom registry as fallback
+	prometheus.Register(c)
+	return err
+}

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

@@ -0,0 +1,206 @@
+/*
+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 (
+	"github.com/blang/semver"
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+	"k8s.io/klog"
+	"sync"
+)
+
+/*
+kubeCollector extends the prometheus.Collector interface to allow customization of the metric
+registration process. Defer metric initialization until Create() is called, which then
+delegates to the underlying metric's initializeMetric or initializeDeprecatedMetric
+method call depending on whether the metric is deprecated or not.
+*/
+type kubeCollector interface {
+	Collector
+	lazyKubeMetric
+	DeprecatedVersion() *semver.Version
+	// Each collector metric should provide an initialization function
+	// for both deprecated and non-deprecated variants of a metric. This
+	// is necessary since metric instantiation will be deferred
+	// until the metric is actually registered somewhere.
+	initializeMetric()
+	initializeDeprecatedMetric()
+}
+
+/*
+lazyKubeMetric defines our metric registration interface. lazyKubeMetric objects are expected
+to lazily instantiate metrics (i.e defer metric instantiation until when
+the Create() function is explicitly called).
+*/
+type lazyKubeMetric interface {
+	Create(*semver.Version) bool
+	IsCreated() bool
+	IsHidden() bool
+	IsDeprecated() bool
+}
+
+/*
+lazyMetric implements lazyKubeMetric. A lazy metric is lazy because it waits until metric
+registration time before instantiation. Add it as an anonymous field to a struct that
+implements kubeCollector to get deferred registration behavior. You must call lazyInit
+with the kubeCollector itself as an argument.
+*/
+type lazyMetric struct {
+	isDeprecated        bool
+	isHidden            bool
+	isCreated           bool
+	createLock          sync.RWMutex
+	markDeprecationOnce sync.Once
+	createOnce          sync.Once
+	self                kubeCollector
+}
+
+func (r *lazyMetric) IsCreated() bool {
+	r.createLock.RLock()
+	defer r.createLock.RUnlock()
+	return r.isCreated
+}
+
+// lazyInit provides the lazyMetric with a reference to the kubeCollector it is supposed
+// to allow lazy initialization for. It should be invoked in the factory function which creates new
+// kubeCollector type objects.
+func (r *lazyMetric) lazyInit(self kubeCollector) {
+	r.self = self
+}
+
+// determineDeprecationStatus figures out whether the lazy metric should be deprecated or not.
+// This method takes a Version argument which should be the version of the binary in which
+// this code is currently being executed.
+func (r *lazyMetric) determineDeprecationStatus(version semver.Version) {
+	selfVersion := r.self.DeprecatedVersion()
+	if selfVersion == nil {
+		return
+	}
+	r.markDeprecationOnce.Do(func() {
+		if selfVersion.LTE(version) {
+			r.isDeprecated = true
+		}
+		if ShouldShowHidden() {
+			klog.Warningf("Hidden metrics have been manually overridden, showing this very deprecated metric.")
+			return
+		}
+		if selfVersion.LT(version) {
+			klog.Warningf("This metric has been deprecated for more than one release, hiding.")
+			r.isHidden = true
+		}
+	})
+}
+
+func (r *lazyMetric) IsHidden() bool {
+	return r.isHidden
+}
+
+func (r *lazyMetric) IsDeprecated() bool {
+	return r.isDeprecated
+}
+
+// Create forces the initialization of metric which has been deferred until
+// the point at which this method is invoked. This method will determine whether
+// the metric is deprecated or hidden, no-opting if the metric should be considered
+// hidden. Furthermore, this function no-opts and returns true if metric is already
+// created.
+func (r *lazyMetric) Create(version *semver.Version) bool {
+	if version != nil {
+		r.determineDeprecationStatus(*version)
+	}
+	// let's not create if this metric is slated to be hidden
+	if r.IsHidden() {
+		return false
+	}
+	r.createOnce.Do(func() {
+		r.createLock.Lock()
+		defer r.createLock.Unlock()
+		r.isCreated = true
+		if r.IsDeprecated() {
+			r.self.initializeDeprecatedMetric()
+		} else {
+			r.self.initializeMetric()
+		}
+	})
+	return r.IsCreated()
+}
+
+/*
+This code is directly lifted from the prometheus codebase. It's a convenience struct which
+allows you satisfy the Collector interface automatically if you already satisfy the Metric interface.
+
+For reference: https://github.com/prometheus/client_golang/blob/v0.9.2/prometheus/collector.go#L98-L120
+*/
+type selfCollector struct {
+	metric prometheus.Metric
+}
+
+func (c *selfCollector) initSelfCollection(m prometheus.Metric) {
+	c.metric = m
+}
+
+func (c *selfCollector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- c.metric.Desc()
+}
+
+func (c *selfCollector) Collect(ch chan<- prometheus.Metric) {
+	ch <- c.metric
+}
+
+// no-op vecs for convenience
+var noopCounterVec = &prometheus.CounterVec{}
+var noopHistogramVec = &prometheus.HistogramVec{}
+var noopSummaryVec = &prometheus.SummaryVec{}
+var noopGaugeVec = &prometheus.GaugeVec{}
+var noopObserverVec = &noopObserverVector{}
+
+// just use a convenience struct for all the no-ops
+var noop = &noopMetric{}
+
+type noopMetric struct{}
+
+func (noopMetric) Inc()                             {}
+func (noopMetric) Add(float64)                      {}
+func (noopMetric) Dec()                             {}
+func (noopMetric) Set(float64)                      {}
+func (noopMetric) Sub(float64)                      {}
+func (noopMetric) Observe(float64)                  {}
+func (noopMetric) SetToCurrentTime()                {}
+func (noopMetric) Desc() *prometheus.Desc           { return nil }
+func (noopMetric) Write(*dto.Metric) error          { return nil }
+func (noopMetric) Describe(chan<- *prometheus.Desc) {}
+func (noopMetric) Collect(chan<- prometheus.Metric) {}
+
+type noopObserverVector struct{}
+
+func (noopObserverVector) GetMetricWith(prometheus.Labels) (prometheus.Observer, error) {
+	return noop, nil
+}
+func (noopObserverVector) GetMetricWithLabelValues(...string) (prometheus.Observer, error) {
+	return noop, nil
+}
+func (noopObserverVector) With(prometheus.Labels) prometheus.Observer    { return noop }
+func (noopObserverVector) WithLabelValues(...string) prometheus.Observer { return noop }
+func (noopObserverVector) CurryWith(prometheus.Labels) (prometheus.ObserverVec, error) {
+	return noopObserverVec, nil
+}
+func (noopObserverVector) MustCurryWith(prometheus.Labels) prometheus.ObserverVec {
+	return noopObserverVec
+}
+func (noopObserverVector) Describe(chan<- *prometheus.Desc) {}
+func (noopObserverVector) Collect(chan<- prometheus.Metric) {}

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

@@ -0,0 +1,211 @@
+/*
+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/prometheus/client_golang/prometheus"
+	"sync"
+	"time"
+)
+
+// KubeOpts is superset struct for prometheus.Opts. The prometheus Opts structure
+// is purposefully not embedded here because that would change struct initialization
+// in the manner which people are currently accustomed.
+//
+// Name must be set to a non-empty string. DeprecatedVersion is defined only
+// if the metric for which this options applies is, in fact, deprecated.
+type KubeOpts struct {
+	Namespace         string
+	Subsystem         string
+	Name              string
+	Help              string
+	ConstLabels       prometheus.Labels
+	DeprecatedVersion string
+	deprecateOnce     sync.Once
+	annotateOnce      sync.Once
+	StabilityLevel    StabilityLevel
+}
+
+// StabilityLevel represents the API guarantees for a given defined metric.
+type StabilityLevel string
+
+const (
+	// ALPHA metrics have no stability guarantees, as such, labels may
+	// be arbitrarily added/removed and the metric may be deleted at any time.
+	ALPHA StabilityLevel = "ALPHA"
+	// STABLE metrics are guaranteed not be mutated and removal is governed by
+	// the deprecation policy outlined in by the control plane metrics stability KEP.
+	STABLE StabilityLevel = "STABLE"
+)
+
+// CounterOpts is an alias for Opts. See there for doc comments.
+type CounterOpts KubeOpts
+
+// Modify help description on the metric description.
+func (o *CounterOpts) markDeprecated() {
+	o.deprecateOnce.Do(func() {
+		o.Help = fmt.Sprintf("(Deprecated since %v) %v", o.DeprecatedVersion, o.Help)
+	})
+}
+
+// annotateStabilityLevel annotates help description on the metric description with the stability level
+// of the metric
+func (o *CounterOpts) annotateStabilityLevel() {
+	o.annotateOnce.Do(func() {
+		o.Help = fmt.Sprintf("[%v] %v", o.StabilityLevel, o.Help)
+	})
+}
+
+// convenience function to allow easy transformation to the prometheus
+// counterpart. This will do more once we have a proper label abstraction
+func (o *CounterOpts) toPromCounterOpts() prometheus.CounterOpts {
+	return prometheus.CounterOpts{
+		Namespace:   o.Namespace,
+		Subsystem:   o.Subsystem,
+		Name:        o.Name,
+		Help:        o.Help,
+		ConstLabels: o.ConstLabels,
+	}
+}
+
+// GaugeOpts is an alias for Opts. See there for doc comments.
+type GaugeOpts KubeOpts
+
+// Modify help description on the metric description.
+func (o *GaugeOpts) markDeprecated() {
+	o.deprecateOnce.Do(func() {
+		o.Help = fmt.Sprintf("(Deprecated since %v) %v", o.DeprecatedVersion, o.Help)
+	})
+}
+
+// annotateStabilityLevel annotates help description on the metric description with the stability level
+// of the metric
+func (o *GaugeOpts) annotateStabilityLevel() {
+	o.annotateOnce.Do(func() {
+		o.Help = fmt.Sprintf("[%v] %v", o.StabilityLevel, o.Help)
+	})
+}
+
+// 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 {
+	return prometheus.GaugeOpts{
+		Namespace:   o.Namespace,
+		Subsystem:   o.Subsystem,
+		Name:        o.Name,
+		Help:        o.Help,
+		ConstLabels: o.ConstLabels,
+	}
+}
+
+// HistogramOpts bundles the options for creating a Histogram metric. It is
+// mandatory to set Name to a non-empty string. All other fields are optional
+// and can safely be left at their zero value, although it is strongly
+// encouraged to set a Help string.
+type HistogramOpts struct {
+	Namespace         string
+	Subsystem         string
+	Name              string
+	Help              string
+	ConstLabels       prometheus.Labels
+	Buckets           []float64
+	DeprecatedVersion string
+	deprecateOnce     sync.Once
+	annotateOnce      sync.Once
+	StabilityLevel    StabilityLevel
+}
+
+// Modify help description on the metric description.
+func (o *HistogramOpts) markDeprecated() {
+	o.deprecateOnce.Do(func() {
+		o.Help = fmt.Sprintf("(Deprecated since %v) %v", o.DeprecatedVersion, o.Help)
+	})
+}
+
+// annotateStabilityLevel annotates help description on the metric description with the stability level
+// of the metric
+func (o *HistogramOpts) annotateStabilityLevel() {
+	o.annotateOnce.Do(func() {
+		o.Help = fmt.Sprintf("[%v] %v", o.StabilityLevel, o.Help)
+	})
+}
+
+// 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 {
+	return prometheus.HistogramOpts{
+		Namespace:   o.Namespace,
+		Subsystem:   o.Subsystem,
+		Name:        o.Name,
+		Help:        o.Help,
+		ConstLabels: o.ConstLabels,
+		Buckets:     o.Buckets,
+	}
+}
+
+// SummaryOpts bundles the options for creating a Summary metric. It is
+// mandatory to set Name to a non-empty string. While all other fields are
+// optional and can safely be left at their zero value, it is recommended to set
+// a help string and to explicitly set the Objectives field to the desired value
+// as the default value will change in the upcoming v0.10 of the library.
+type SummaryOpts struct {
+	Namespace         string
+	Subsystem         string
+	Name              string
+	Help              string
+	ConstLabels       prometheus.Labels
+	Objectives        map[float64]float64
+	MaxAge            time.Duration
+	AgeBuckets        uint32
+	BufCap            uint32
+	DeprecatedVersion string
+	deprecateOnce     sync.Once
+	annotateOnce      sync.Once
+	StabilityLevel    StabilityLevel
+}
+
+// Modify help description on the metric description.
+func (o *SummaryOpts) markDeprecated() {
+	o.deprecateOnce.Do(func() {
+		o.Help = fmt.Sprintf("(Deprecated since %v) %v", o.DeprecatedVersion, o.Help)
+	})
+}
+
+// annotateStabilityLevel annotates help description on the metric description with the stability level
+// of the metric
+func (o *SummaryOpts) annotateStabilityLevel() {
+	o.annotateOnce.Do(func() {
+		o.Help = fmt.Sprintf("[%v] %v", o.StabilityLevel, o.Help)
+	})
+}
+
+// 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 {
+	return prometheus.SummaryOpts{
+		Namespace:   o.Namespace,
+		Subsystem:   o.Subsystem,
+		Name:        o.Name,
+		Help:        o.Help,
+		ConstLabels: o.ConstLabels,
+		Objectives:  o.Objectives,
+		MaxAge:      o.MaxAge,
+		AgeBuckets:  o.AgeBuckets,
+		BufCap:      o.BufCap,
+	}
+}

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

@@ -0,0 +1,64 @@
+/*
+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 (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/procfs"
+	"k8s.io/klog"
+	"os"
+	"time"
+)
+
+var processStartTime = prometheus.NewGaugeVec(
+	prometheus.GaugeOpts{
+		Name: "process_start_time_seconds",
+		Help: "Start time of the process since unix epoch in seconds.",
+	},
+	[]string{},
+)
+
+// Registerer is an interface expected by RegisterProcessStartTime in order to register the metric
+type Registerer interface {
+	Register(prometheus.Collector) error
+}
+
+// RegisterProcessStartTime registers the process_start_time_seconds to
+// a prometheus registry. This metric needs to be included to ensure counter
+// data fidelity.
+func RegisterProcessStartTime(registrationFunc func(prometheus.Collector) error) error {
+	start, err := getProcessStart()
+	if err != nil {
+		klog.Errorf("Could not get process start time, %v", err)
+		start = float64(time.Now().Unix())
+	}
+	processStartTime.WithLabelValues().Set(start)
+	return registrationFunc(processStartTime)
+}
+
+func getProcessStart() (float64, error) {
+	pid := os.Getpid()
+	p, err := procfs.NewProc(pid)
+	if err != nil {
+		return 0, err
+	}
+
+	if stat, err := p.NewStat(); err == nil {
+		return stat.StartTime()
+	}
+	return 0, err
+}

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

@@ -0,0 +1,161 @@
+/*
+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 (
+	"sync"
+	"sync/atomic"
+
+	"github.com/blang/semver"
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+
+	apimachineryversion "k8s.io/apimachinery/pkg/version"
+	"k8s.io/component-base/version"
+)
+
+var (
+	showHiddenOnce sync.Once
+	showHidden     atomic.Value
+)
+
+// SetShowHidden will enable showing hidden metrics. This will no-opt
+// after the initial call
+func SetShowHidden() {
+	showHiddenOnce.Do(func() {
+		showHidden.Store(true)
+	})
+}
+
+// ShouldShowHidden returns whether showing hidden deprecated metrics
+// is enabled. While the primary usecase for this is internal (to determine
+// registration behavior) this can also be used to introspect
+func ShouldShowHidden() bool {
+	return showHidden.Load() != nil && showHidden.Load().(bool)
+}
+
+// Registerable is an interface for a collector metric which we
+// will register with KubeRegistry.
+type Registerable interface {
+	prometheus.Collector
+	Create(version *semver.Version) bool
+}
+
+// KubeRegistry is an interface which implements a subset of prometheus.Registerer and
+// prometheus.Gatherer interfaces
+type KubeRegistry interface {
+	// Deprecated
+	RawRegister(prometheus.Collector) error
+	// Deprecated
+	RawMustRegister(...prometheus.Collector)
+	Register(Registerable) error
+	MustRegister(...Registerable)
+	Unregister(Registerable) bool
+	Gather() ([]*dto.MetricFamily, error)
+}
+
+// kubeRegistry is a wrapper around a prometheus registry-type object. Upon initialization
+// the kubernetes binary version information is loaded into the registry object, so that
+// automatic behavior can be configured for metric versioning.
+type kubeRegistry struct {
+	PromRegistry
+	version semver.Version
+}
+
+// Register registers a new Collector to be included in metrics
+// collection. It returns an error if the descriptors provided by the
+// Collector are invalid or if they — in combination with descriptors of
+// already registered Collectors — do not fulfill the consistency and
+// uniqueness criteria described in the documentation of metric.Desc.
+func (kr *kubeRegistry) Register(c Registerable) error {
+	if c.Create(&kr.version) {
+		return kr.PromRegistry.Register(c)
+	}
+	return nil
+}
+
+// MustRegister works like Register but registers any number of
+// Collectors and panics upon the first registration that causes an
+// error.
+func (kr *kubeRegistry) MustRegister(cs ...Registerable) {
+	metrics := make([]prometheus.Collector, 0, len(cs))
+	for _, c := range cs {
+		if c.Create(&kr.version) {
+			metrics = append(metrics, c)
+		}
+	}
+	kr.PromRegistry.MustRegister(metrics...)
+}
+
+// RawRegister takes a native prometheus.Collector and registers the collector
+// to the registry. This bypasses metrics safety checks, so should only be used
+// to register custom prometheus collectors.
+//
+// Deprecated
+func (kr *kubeRegistry) RawRegister(c prometheus.Collector) error {
+	return kr.PromRegistry.Register(c)
+}
+
+// RawMustRegister takes a native prometheus.Collector and registers the collector
+// to the registry. This bypasses metrics safety checks, so should only be used
+// to register custom prometheus collectors.
+//
+// Deprecated
+func (kr *kubeRegistry) RawMustRegister(cs ...prometheus.Collector) {
+	kr.PromRegistry.MustRegister(cs...)
+}
+
+// Unregister unregisters the Collector that equals the Collector passed
+// in as an argument.  (Two Collectors are considered equal if their
+// Describe method yields the same set of descriptors.) The function
+// returns whether a Collector was unregistered. Note that an unchecked
+// Collector cannot be unregistered (as its Describe method does not
+// yield any descriptor).
+func (kr *kubeRegistry) Unregister(collector Registerable) bool {
+	return kr.PromRegistry.Unregister(collector)
+}
+
+// Gather calls the Collect method of the registered Collectors and then
+// gathers the collected metrics into a lexicographically sorted slice
+// of uniquely named MetricFamily protobufs. Gather ensures that the
+// returned slice is valid and self-consistent so that it can be used
+// for valid exposition. As an exception to the strict consistency
+// requirements described for metric.Desc, Gather will tolerate
+// different sets of label names for metrics of the same metric family.
+func (kr *kubeRegistry) Gather() ([]*dto.MetricFamily, error) {
+	return kr.PromRegistry.Gather()
+}
+
+func newKubeRegistry(v apimachineryversion.Info) *kubeRegistry {
+	r := &kubeRegistry{
+		PromRegistry: prometheus.NewRegistry(),
+		version:      parseVersion(v),
+	}
+	return r
+}
+
+func registerMetadataMetrics(r *kubeRegistry) {
+	RegisterBuildInfo(r)
+}
+
+// NewKubeRegistry creates a new vanilla Registry without any Collectors
+// pre-registered.
+func NewKubeRegistry() KubeRegistry {
+	r := newKubeRegistry(version.Get())
+	registerMetadataMetrics(r)
+	return r
+}

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

@@ -0,0 +1,166 @@
+/*
+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 (
+	"github.com/blang/semver"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Summary is our internal representation for our wrapping struct around prometheus
+// summaries. Summary implements both kubeCollector and ObserverMetric
+//
+// DEPRECATED: as per the metrics overhaul KEP
+type Summary struct {
+	ObserverMetric
+	*SummaryOpts
+	lazyMetric
+	selfCollector
+}
+
+// NewSummary returns an object which is Summary-like. However, nothing
+// will be measured until the summary is registered somewhere.
+//
+// DEPRECATED: as per the metrics overhaul KEP
+func NewSummary(opts *SummaryOpts) *Summary {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	s := &Summary{
+		SummaryOpts: opts,
+		lazyMetric:  lazyMetric{},
+	}
+	s.setPrometheusSummary(noopMetric{})
+	s.lazyInit(s)
+	return s
+}
+
+// setPrometheusSummary sets the underlying KubeGauge object, i.e. the thing that does the measurement.
+func (s *Summary) setPrometheusSummary(summary prometheus.Summary) {
+	s.ObserverMetric = summary
+	s.initSelfCollection(summary)
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (s *Summary) DeprecatedVersion() *semver.Version {
+	return parseSemver(s.SummaryOpts.DeprecatedVersion)
+}
+
+// initializeMetric invokes the actual prometheus.Summary object instantiation
+// and stores a reference to it
+func (s *Summary) initializeMetric() {
+	s.SummaryOpts.annotateStabilityLevel()
+	// this actually creates the underlying prometheus gauge.
+	s.setPrometheusSummary(prometheus.NewSummary(s.SummaryOpts.toPromSummaryOpts()))
+}
+
+// initializeDeprecatedMetric invokes the actual prometheus.Summary object instantiation
+// but modifies the Help description prior to object instantiation.
+func (s *Summary) initializeDeprecatedMetric() {
+	s.SummaryOpts.markDeprecated()
+	s.initializeMetric()
+}
+
+// SummaryVec is the internal representation of our wrapping struct around prometheus
+// summaryVecs.
+//
+// DEPRECATED: as per the metrics overhaul KEP
+type SummaryVec struct {
+	*prometheus.SummaryVec
+	*SummaryOpts
+	lazyMetric
+	originalLabels []string
+}
+
+// NewSummaryVec returns an object which satisfies kubeCollector and wraps the
+// prometheus.SummaryVec object. However, the object returned will not measure
+// anything unless the collector is first registered, since the metric is lazily instantiated.
+//
+// DEPRECATED: as per the metrics overhaul KEP
+func NewSummaryVec(opts *SummaryOpts, labels []string) *SummaryVec {
+	// todo: handle defaulting better
+	if opts.StabilityLevel == "" {
+		opts.StabilityLevel = ALPHA
+	}
+	v := &SummaryVec{
+		SummaryOpts:    opts,
+		originalLabels: labels,
+		lazyMetric:     lazyMetric{},
+	}
+	v.lazyInit(v)
+	return v
+}
+
+// DeprecatedVersion returns a pointer to the Version or nil
+func (v *SummaryVec) DeprecatedVersion() *semver.Version {
+	return parseSemver(v.SummaryOpts.DeprecatedVersion)
+}
+
+func (v *SummaryVec) initializeMetric() {
+	v.SummaryOpts.annotateStabilityLevel()
+	v.SummaryVec = prometheus.NewSummaryVec(v.SummaryOpts.toPromSummaryOpts(), v.originalLabels)
+}
+
+func (v *SummaryVec) initializeDeprecatedMetric() {
+	v.SummaryOpts.markDeprecated()
+	v.initializeMetric()
+}
+
+// Default Prometheus behavior actually results in the creation of a new metric
+// if a metric with the unique label values is not found in the underlying stored metricMap.
+// This means  that if this function is called but the underlying metric is not registered
+// (which means it will never be exposed externally nor consumed), the metric will exist in memory
+// for perpetuity (i.e. throughout application lifecycle).
+//
+// For reference: https://github.com/prometheus/client_golang/blob/v0.9.2/prometheus/summary.go#L485-L495
+
+// WithLabelValues returns the ObserverMetric for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new ObserverMetric is created IFF the summaryVec
+// has been registered to a metrics registry.
+func (v *SummaryVec) WithLabelValues(lvs ...string) ObserverMetric {
+	if !v.IsCreated() {
+		return noop
+	}
+	return v.SummaryVec.WithLabelValues(lvs...)
+}
+
+// With returns the ObserverMetric for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new ObserverMetric is created IFF the summaryVec has
+// been registered to a metrics registry.
+func (v *SummaryVec) With(labels prometheus.Labels) ObserverMetric {
+	if !v.IsCreated() {
+		return noop
+	}
+	return v.SummaryVec.With(labels)
+}
+
+// Delete deletes the metric where the variable labels are the same as those
+// passed in as labels. It returns true if a metric was deleted.
+//
+// It is not an error if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc. However, such inconsistent Labels
+// can never match an actual metric, so the method will always return false in
+// that case.
+func (v *SummaryVec) Delete(labels prometheus.Labels) bool {
+	if !v.IsCreated() {
+		return false // since we haven't created the metric, we haven't deleted a metric with the passed in values
+	}
+	return v.SummaryVec.Delete(labels)
+}

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

@@ -0,0 +1,37 @@
+/*
+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 "k8s.io/component-base/version"
+
+var (
+	buildInfo = NewGaugeVec(
+		&GaugeOpts{
+			Name:           "kubernetes_build_info",
+			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"},
+	)
+)
+
+// RegisterBuildInfo registers the build and version info in a metadata metric in prometheus
+func RegisterBuildInfo(r KubeRegistry) {
+	info := version.Get()
+	r.MustRegister(buildInfo)
+	buildInfo.WithLabelValues(info.Major, info.Minor, info.GitVersion, info.GitCommit, info.GitTreeState, info.BuildDate, info.GoVersion, info.Compiler, info.Platform).Set(1)
+}

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

@@ -0,0 +1,48 @@
+/*
+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"
+	apimachineryversion "k8s.io/apimachinery/pkg/version"
+	"regexp"
+)
+
+const (
+	versionRegexpString = `^v(\d+\.\d+\.\d+)`
+)
+
+var (
+	versionRe = regexp.MustCompile(versionRegexpString)
+)
+
+func parseSemver(s string) *semver.Version {
+	if s != "" {
+		sv := semver.MustParse(s)
+		return &sv
+	}
+	return nil
+}
+func parseVersion(ver apimachineryversion.Info) semver.Version {
+	matches := versionRe.FindAllStringSubmatch(ver.String(), -1)
+
+	if len(matches) != 1 {
+		panic(fmt.Sprintf("version string \"%v\" doesn't match expected regular expression: \"%v\"", ver.String(), versionRe.String()))
+	}
+	return semver.MustParse(matches[0][1])
+}

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

@@ -0,0 +1,81 @@
+/*
+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 (
+	"github.com/prometheus/client_golang/prometheus"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// This file contains a series of interfaces which we explicitly define for
+// integrating with prometheus. We redefine the interfaces explicitly here
+// so that we can prevent breakage if methods are ever added to prometheus
+// variants of them.
+
+// Collector defines a subset of prometheus.Collector interface methods
+type Collector interface {
+	Describe(chan<- *prometheus.Desc)
+	Collect(chan<- prometheus.Metric)
+}
+
+// Metric defines a subset of prometheus.Metric interface methods
+type Metric interface {
+	Desc() *prometheus.Desc
+	Write(*dto.Metric) error
+}
+
+// CounterMetric is a Metric that represents a single numerical value that only ever
+// goes up. That implies that it cannot be used to count items whose number can
+// also go down, e.g. the number of currently running goroutines. Those
+// "counters" are represented by Gauges.
+
+// CounterMetric is an interface which defines a subset of the interface provided by prometheus.Counter
+type CounterMetric interface {
+	Inc()
+	Add(float64)
+}
+
+// CounterVecMetric is an interface which prometheus.CounterVec satisfies.
+type CounterVecMetric interface {
+	WithLabelValues(...string) CounterMetric
+	With(prometheus.Labels) CounterMetric
+}
+
+// GaugeMetric is an interface which defines a subset of the interface provided by prometheus.Gauge
+type GaugeMetric interface {
+	Set(float64)
+	Inc()
+	Dec()
+	Add(float64)
+	Write(out *dto.Metric) error
+	SetToCurrentTime()
+}
+
+// ObserverMetric captures individual observations.
+type ObserverMetric interface {
+	Observe(float64)
+}
+
+// PromRegistry is an interface which implements a subset of prometheus.Registerer and
+// prometheus.Gatherer interfaces
+type PromRegistry interface {
+	Register(prometheus.Collector) error
+	MustRegister(...prometheus.Collector)
+	Unregister(prometheus.Collector) bool
+	Gather() ([]*dto.MetricFamily, error)
+}