Merge pull request #82957 from RainbowMango/pr_handle_stability_level_default_better

Handle stability level default better

staging/src/k8s.io/component-base/metrics/BUILD

@@ -42,6 +42,7 @@ go_test(
         "counter_test.go",
         "gauge_test.go",
         "histogram_test.go",
+        "opts_test.go",
         "registry_test.go",
         "summary_test.go",
         "version_parser_test.go",

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

@@ -34,10 +34,8 @@ type Counter struct {
 // 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
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	kc := &Counter{
 		CounterOpts: opts,
 		lazyMetric:  lazyMetric{},
@@ -86,10 +84,8 @@ type CounterVec struct {
 // 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
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	cv := &CounterVec{
 		CounterVec:     noopCounterVec,
 		CounterOpts:    opts,

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

@@ -34,10 +34,8 @@ type Gauge struct {
 // 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
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	kc := &Gauge{
 		GaugeOpts:  opts,
 		lazyMetric: lazyMetric{},
@@ -86,10 +84,8 @@ type GaugeVec struct {
 // 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
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	cv := &GaugeVec{
 		GaugeVec:       noopGaugeVec,
 		GaugeOpts:      opts,

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

@@ -46,10 +46,8 @@ type Histogram struct {
 // 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
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	h := &Histogram{
 		HistogramOpts: opts,
 		lazyMetric:    lazyMetric{},
@@ -98,10 +96,8 @@ type HistogramVec struct {
 // 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
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	v := &HistogramVec{
 		HistogramVec:   noopHistogramVec,
 		HistogramOpts:  opts,

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

@@ -53,6 +53,16 @@ const (
 	STABLE StabilityLevel = "STABLE"
 )
 
+// setDefaults takes 'ALPHA' in case of empty.
+func (sl *StabilityLevel) setDefaults() {
+	switch *sl {
+	case "":
+		*sl = ALPHA
+	default:
+		// no-op, since we have a StabilityLevel already
+	}
+}
+
 // CounterOpts is an alias for Opts. See there for doc comments.
 type CounterOpts KubeOpts
 

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

@@ -0,0 +1,61 @@
+/*
+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 (
+	"testing"
+)
+
+func TestDefaultStabilityLevel(t *testing.T) {
+	var tests = []struct {
+		name        string
+		inputValue  StabilityLevel
+		expectValue StabilityLevel
+		expectPanic bool
+	}{
+		{
+			name:        "empty should take ALPHA by default",
+			inputValue:  "",
+			expectValue: ALPHA,
+			expectPanic: false,
+		},
+		{
+			name:        "ALPHA remain unchanged",
+			inputValue:  ALPHA,
+			expectValue: ALPHA,
+			expectPanic: false,
+		},
+		{
+			name:        "STABLE remain unchanged",
+			inputValue:  STABLE,
+			expectValue: STABLE,
+			expectPanic: false,
+		},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			var stability = tc.inputValue
+
+			stability.setDefaults()
+			if stability != tc.expectValue {
+				t.Errorf("Got %s, expected: %v ", stability, tc.expectValue)
+			}
+		})
+	}
+}

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

@@ -37,10 +37,8 @@ type Summary struct {
 //
 // DEPRECATED: as per the metrics overhaul KEP
 func NewSummary(opts *SummaryOpts) *Summary {
-	// todo: handle defaulting better
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	s := &Summary{
 		SummaryOpts: opts,
 		lazyMetric:  lazyMetric{},
@@ -93,10 +91,8 @@ type SummaryVec struct {
 //
 // DEPRECATED: as per the metrics overhaul KEP
 func NewSummaryVec(opts *SummaryOpts, labels []string) *SummaryVec {
-	// todo: handle defaulting better
+	opts.StabilityLevel.setDefaults()
-	if opts.StabilityLevel == "" {
+
-		opts.StabilityLevel = ALPHA
-	}
 	v := &SummaryVec{
 		SummaryOpts:    opts,
 		originalLabels: labels,