feat(metrics): Add method to reset label allow lists

Adds a new method `ResetLabelAllowLists` to various metric types,
allowing for the reset of label allow lists. This is intended
specifically for use in testing scenarios.

Author: yongruilin

staging/src/k8s.io/component-base/metrics/counter.go

@@ -18,6 +18,7 @@ package metrics
 
 import (
 	"context"
+	"sync"
 
 	"github.com/blang/semver/v4"
 	"github.com/prometheus/client_golang/prometheus"
@@ -249,6 +250,13 @@ func (v *CounterVec) Reset() {
 	v.CounterVec.Reset()
 }
 
+// ResetLabelAllowLists resets the label allow list for the CounterVec.
+// NOTE: This should only be used in test.
+func (v *CounterVec) ResetLabelAllowLists() {
+	v.initializeLabelAllowListsOnce = sync.Once{}
+	v.LabelValueAllowLists = nil
+}
+
 // WithContext returns wrapped CounterVec with context
 func (v *CounterVec) WithContext(ctx context.Context) *CounterVecWithContext {
 	return &CounterVecWithContext{

staging/src/k8s.io/component-base/metrics/gauge.go

@@ -18,6 +18,7 @@ package metrics
 
 import (
 	"context"
+	"sync"
 
 	"github.com/blang/semver/v4"
 	"github.com/prometheus/client_golang/prometheus"
@@ -239,6 +240,13 @@ func (v *GaugeVec) Reset() {
 	v.GaugeVec.Reset()
 }
 
+// ResetLabelAllowLists resets the label allow list for the GaugeVec.
+// NOTE: This should only be used in test.
+func (v *GaugeVec) ResetLabelAllowLists() {
+	v.initializeLabelAllowListsOnce = sync.Once{}
+	v.LabelValueAllowLists = nil
+}
+
 func newGaugeFunc(opts *GaugeOpts, function func() float64, v semver.Version) GaugeFunc {
 	g := NewGauge(opts)
 

staging/src/k8s.io/component-base/metrics/histogram.go

@@ -18,6 +18,7 @@ package metrics
 
 import (
 	"context"
+	"sync"
 
 	"github.com/blang/semver/v4"
 	"github.com/prometheus/client_golang/prometheus"
@@ -202,6 +203,13 @@ func (v *HistogramVec) Reset() {
 	v.HistogramVec.Reset()
 }
 
+// ResetLabelAllowLists resets the label allow list for the HistogramVec.
+// NOTE: This should only be used in test.
+func (v *HistogramVec) ResetLabelAllowLists() {
+	v.initializeLabelAllowListsOnce = sync.Once{}
+	v.LabelValueAllowLists = nil
+}
+
 // WithContext returns wrapped HistogramVec with context
 func (v *HistogramVec) WithContext(ctx context.Context) *HistogramVecWithContext {
 	return &HistogramVecWithContext{

staging/src/k8s.io/component-base/metrics/summary.go

@@ -18,6 +18,7 @@ package metrics
 
 import (
 	"context"
+	"sync"
 
 	"github.com/blang/semver/v4"
 	"github.com/prometheus/client_golang/prometheus"
@@ -214,6 +215,13 @@ func (v *SummaryVec) Reset() {
 	v.SummaryVec.Reset()
 }
 
+// ResetLabelAllowLists resets the label allow list for the SummaryVec.
+// NOTE: This should only be used in test.
+func (v *SummaryVec) ResetLabelAllowLists() {
+	v.initializeLabelAllowListsOnce = sync.Once{}
+	v.LabelValueAllowLists = nil
+}
+
 // WithContext returns wrapped SummaryVec with context
 func (v *SummaryVec) WithContext(ctx context.Context) *SummaryVecWithContext {
 	return &SummaryVecWithContext{

staging/src/k8s.io/component-base/metrics/timing_histogram.go

@@ -18,6 +18,7 @@ package metrics
 
 import (
 	"context"
+	"sync"
 	"time"
 
 	"github.com/blang/semver/v4"
@@ -267,6 +268,13 @@ func (v *TimingHistogramVec) Reset() {
 	v.TimingHistogramVec.Reset()
 }
 
+// ResetLabelAllowLists resets the label allow list for the TimingHistogramVec.
+// NOTE: This should only be used in test.
+func (v *TimingHistogramVec) ResetLabelAllowLists() {
+	v.initializeLabelAllowListsOnce = sync.Once{}
+	v.LabelValueAllowLists = nil
+}
+
 // WithContext returns wrapped TimingHistogramVec with context
 func (v *TimingHistogramVec) InterfaceWithContext(ctx context.Context) GaugeVecMetric {
 	return &TimingHistogramVecWithContext{