refactor: Defer metrics label value allow list initialization

Defer the initialization of label value allow lists until the first invocation of `WithLabelValues` or `With`. This fixes the issue that metrics initialized before flag applied which results in label value allow list is not honored.
2025-09-14 13:45:06 +00:00 · 2024-10-15 10:26:46 -07:00
parent 55b83c92b3
commit 67f3128cb9
6 changed files with 142 additions and 72 deletions
--- a/staging/src/k8s.io/component-base/metrics/counter.go
+++ b/staging/src/k8s.io/component-base/metrics/counter.go
@@ -119,11 +119,6 @@ func NewCounterVec(opts *CounterOpts, labels []string) *CounterVec {
 	opts.StabilityLevel.setDefaults()

 	fqName := BuildFQName(opts.Namespace, opts.Subsystem, opts.Name)
-	allowListLock.RLock()
-	if allowList, ok := labelValueAllowLists[fqName]; ok {
-		opts.LabelValueAllowLists = allowList
-	}
-	allowListLock.RUnlock()

 	cv := &CounterVec{
 		CounterVec:     noopCounterVec,
@@ -176,7 +171,17 @@ func (v *CounterVec) WithLabelValues(lvs ...string) CounterMetric {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainToAllowedList(v.originalLabels, lvs)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainToAllowedList(v.originalLabels, lvs)
+			}
+			allowListLock.RUnlock()
+		})
 	}
+
 	return v.CounterVec.WithLabelValues(lvs...)
 }

@@ -190,6 +195,15 @@ func (v *CounterVec) With(labels map[string]string) CounterMetric {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainLabelMap(labels)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainLabelMap(labels)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	return v.CounterVec.With(labels)
 }
--- a/staging/src/k8s.io/component-base/metrics/gauge.go
+++ b/staging/src/k8s.io/component-base/metrics/gauge.go
@@ -105,11 +105,6 @@ func NewGaugeVec(opts *GaugeOpts, labels []string) *GaugeVec {
 	opts.StabilityLevel.setDefaults()

 	fqName := BuildFQName(opts.Namespace, opts.Subsystem, opts.Name)
-	allowListLock.RLock()
-	if allowList, ok := labelValueAllowLists[fqName]; ok {
-		opts.LabelValueAllowLists = allowList
-	}
-	allowListLock.RUnlock()

 	cv := &GaugeVec{
 		GaugeVec:       noopGaugeVec,
@@ -149,6 +144,15 @@ func (v *GaugeVec) WithLabelValuesChecked(lvs ...string) (GaugeMetric, error) {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainToAllowedList(v.originalLabels, lvs)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainToAllowedList(v.originalLabels, lvs)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	elt, err := v.GaugeVec.GetMetricWithLabelValues(lvs...)
 	return elt, err
@@ -186,6 +190,15 @@ func (v *GaugeVec) WithChecked(labels map[string]string) (GaugeMetric, error) {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainLabelMap(labels)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainLabelMap(labels)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	elt, err := v.GaugeVec.GetMetricWith(labels)
 	return elt, err
--- a/staging/src/k8s.io/component-base/metrics/histogram.go
+++ b/staging/src/k8s.io/component-base/metrics/histogram.go
@@ -96,11 +96,6 @@ func NewHistogramVec(opts *HistogramOpts, labels []string) *HistogramVec {
 	opts.StabilityLevel.setDefaults()

 	fqName := BuildFQName(opts.Namespace, opts.Subsystem, opts.Name)
-	allowListLock.RLock()
-	if allowList, ok := labelValueAllowLists[fqName]; ok {
-		opts.LabelValueAllowLists = allowList
-	}
-	allowListLock.RUnlock()

 	v := &HistogramVec{
 		HistogramVec:   noopHistogramVec,
@@ -148,6 +143,15 @@ func (v *HistogramVec) WithLabelValues(lvs ...string) ObserverMetric {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainToAllowedList(v.originalLabels, lvs)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainToAllowedList(v.originalLabels, lvs)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	return v.HistogramVec.WithLabelValues(lvs...)
 }
@@ -162,6 +166,15 @@ func (v *HistogramVec) With(labels map[string]string) ObserverMetric {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainLabelMap(labels)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainLabelMap(labels)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	return v.HistogramVec.With(labels)
 }
--- a/staging/src/k8s.io/component-base/metrics/opts.go
+++ b/staging/src/k8s.io/component-base/metrics/opts.go
@@ -44,16 +44,17 @@ var (
 // 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          map[string]string
-	DeprecatedVersion    string
-	deprecateOnce        sync.Once
-	annotateOnce         sync.Once
-	StabilityLevel       StabilityLevel
-	LabelValueAllowLists *MetricLabelAllowList
+	Namespace                     string
+	Subsystem                     string
+	Name                          string
+	Help                          string
+	ConstLabels                   map[string]string
+	DeprecatedVersion             string
+	deprecateOnce                 sync.Once
+	annotateOnce                  sync.Once
+	StabilityLevel                StabilityLevel
+	initializeLabelAllowListsOnce sync.Once
+	LabelValueAllowLists          *MetricLabelAllowList
 }

 // BuildFQName joins the given three name components by "_". Empty name
@@ -160,17 +161,18 @@ func (o *GaugeOpts) toPromGaugeOpts() prometheus.GaugeOpts {
 // 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          map[string]string
-	Buckets              []float64
-	DeprecatedVersion    string
-	deprecateOnce        sync.Once
-	annotateOnce         sync.Once
-	StabilityLevel       StabilityLevel
-	LabelValueAllowLists *MetricLabelAllowList
+	Namespace                     string
+	Subsystem                     string
+	Name                          string
+	Help                          string
+	ConstLabels                   map[string]string
+	Buckets                       []float64
+	DeprecatedVersion             string
+	deprecateOnce                 sync.Once
+	annotateOnce                  sync.Once
+	StabilityLevel                StabilityLevel
+	initializeLabelAllowListsOnce sync.Once
+	LabelValueAllowLists          *MetricLabelAllowList
 }

 // Modify help description on the metric description.
@@ -206,18 +208,19 @@ func (o *HistogramOpts) toPromHistogramOpts() prometheus.HistogramOpts {
 // and can safely be left at their zero value, although it is strongly
 // encouraged to set a Help string.
 type TimingHistogramOpts struct {
-	Namespace            string
-	Subsystem            string
-	Name                 string
-	Help                 string
-	ConstLabels          map[string]string
-	Buckets              []float64
-	InitialValue         float64
-	DeprecatedVersion    string
-	deprecateOnce        sync.Once
-	annotateOnce         sync.Once
-	StabilityLevel       StabilityLevel
-	LabelValueAllowLists *MetricLabelAllowList
+	Namespace                     string
+	Subsystem                     string
+	Name                          string
+	Help                          string
+	ConstLabels                   map[string]string
+	Buckets                       []float64
+	InitialValue                  float64
+	DeprecatedVersion             string
+	deprecateOnce                 sync.Once
+	annotateOnce                  sync.Once
+	StabilityLevel                StabilityLevel
+	initializeLabelAllowListsOnce sync.Once
+	LabelValueAllowLists          *MetricLabelAllowList
 }

 // Modify help description on the metric description.
@@ -255,20 +258,21 @@ func (o *TimingHistogramOpts) toPromHistogramOpts() promext.TimingHistogramOpts
 // 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          map[string]string
-	Objectives           map[float64]float64
-	MaxAge               time.Duration
-	AgeBuckets           uint32
-	BufCap               uint32
-	DeprecatedVersion    string
-	deprecateOnce        sync.Once
-	annotateOnce         sync.Once
-	StabilityLevel       StabilityLevel
-	LabelValueAllowLists *MetricLabelAllowList
+	Namespace                     string
+	Subsystem                     string
+	Name                          string
+	Help                          string
+	ConstLabels                   map[string]string
+	Objectives                    map[float64]float64
+	MaxAge                        time.Duration
+	AgeBuckets                    uint32
+	BufCap                        uint32
+	DeprecatedVersion             string
+	deprecateOnce                 sync.Once
+	annotateOnce                  sync.Once
+	StabilityLevel                StabilityLevel
+	initializeLabelAllowListsOnce sync.Once
+	LabelValueAllowLists          *MetricLabelAllowList
 }

 // Modify help description on the metric description.
--- a/staging/src/k8s.io/component-base/metrics/summary.go
+++ b/staging/src/k8s.io/component-base/metrics/summary.go
@@ -109,11 +109,6 @@ func NewSummaryVec(opts *SummaryOpts, labels []string) *SummaryVec {
 	opts.StabilityLevel.setDefaults()

 	fqName := BuildFQName(opts.Namespace, opts.Subsystem, opts.Name)
-	allowListLock.RLock()
-	if allowList, ok := labelValueAllowLists[fqName]; ok {
-		opts.LabelValueAllowLists = allowList
-	}
-	allowListLock.RUnlock()

 	v := &SummaryVec{
 		SummaryOpts:    opts,
@@ -160,6 +155,15 @@ func (v *SummaryVec) WithLabelValues(lvs ...string) ObserverMetric {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainToAllowedList(v.originalLabels, lvs)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainToAllowedList(v.originalLabels, lvs)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	return v.SummaryVec.WithLabelValues(lvs...)
 }
@@ -174,6 +178,15 @@ func (v *SummaryVec) With(labels map[string]string) ObserverMetric {
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainLabelMap(labels)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainLabelMap(labels)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	return v.SummaryVec.With(labels)
 }
--- a/staging/src/k8s.io/component-base/metrics/timing_histogram.go
+++ b/staging/src/k8s.io/component-base/metrics/timing_histogram.go
@@ -125,11 +125,6 @@ func NewTestableTimingHistogramVec(nowFunc func() time.Time, opts *TimingHistogr
 	opts.StabilityLevel.setDefaults()

 	fqName := BuildFQName(opts.Namespace, opts.Subsystem, opts.Name)
-	allowListLock.RLock()
-	if allowList, ok := labelValueAllowLists[fqName]; ok {
-		opts.LabelValueAllowLists = allowList
-	}
-	allowListLock.RUnlock()

 	v := &TimingHistogramVec{
 		TimingHistogramVec:  noopTimingHistogramVec,
@@ -175,6 +170,15 @@ func (v *TimingHistogramVec) WithLabelValuesChecked(lvs ...string) (GaugeMetric,
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainToAllowedList(v.originalLabels, lvs)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainToAllowedList(v.originalLabels, lvs)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	ops, err := v.TimingHistogramVec.GetMetricWithLabelValues(lvs...)
 	if err != nil {
@@ -214,6 +218,15 @@ func (v *TimingHistogramVec) WithChecked(labels map[string]string) (GaugeMetric,
 	}
 	if v.LabelValueAllowLists != nil {
 		v.LabelValueAllowLists.ConstrainLabelMap(labels)
+	} else {
+		v.initializeLabelAllowListsOnce.Do(func() {
+			allowListLock.RLock()
+			if allowList, ok := labelValueAllowLists[v.FQName()]; ok {
+				v.LabelValueAllowLists = allowList
+				allowList.ConstrainLabelMap(labels)
+			}
+			allowListLock.RUnlock()
+		})
 	}
 	ops, err := v.TimingHistogramVec.GetMetricWith(labels)
 	return ops.(GaugeMetric), err