chore: modernize using slices, min builtin, and %w error wrapping

internal/store/utils.go

@@ -19,7 +19,7 @@ package store
 import (
 	"fmt"
 	"regexp"
-	"sort"
+	"slices"
 	"strconv"
 	"strings"
 
@@ -87,7 +87,7 @@ func mapToPrometheusLabels(labels map[string]string, prefix string) ([]string, [
 	for key := range labels {
 		sortedKeys = append(sortedKeys, key)
 	}
-	sort.Strings(sortedKeys)
+	slices.Sort(sortedKeys)
 
 	// conflictDesc holds some metadata for resolving potential label conflicts
 	type conflictDesc struct {

pkg/app/server.go

@@ -143,7 +143,7 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 		} else {
 			configFile, err := os.ReadFile(filepath.Clean(got))
 			if err != nil {
-				return fmt.Errorf("failed to read opts config file: %v", err)
+				return fmt.Errorf("failed to read opts config file: %w", err)
 			}
 			// NOTE: Config value will override default values of intersecting options.
 			err = yaml.Unmarshal(configFile, opts)
@@ -184,7 +184,7 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 
 	kubeConfig, err := clientcmd.BuildConfigFromFlags(opts.Apiserver, opts.Kubeconfig)
 	if err != nil {
-		return fmt.Errorf("failed to build config from flags: %v", err)
+		return fmt.Errorf("failed to build config from flags: %w", err)
 	}
 
 	// Loading custom resource state configuration from cli argument or config file
@@ -199,7 +199,7 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 		} else {
 			crcFile, err := os.ReadFile(filepath.Clean(opts.CustomResourceConfigFile))
 			if err != nil {
-				return fmt.Errorf("failed to read custom resource config file: %v", err)
+				return fmt.Errorf("failed to read custom resource config file: %w", err)
 			}
 			configSuccess.WithLabelValues("customresourceconfig", filepath.Clean(opts.CustomResourceConfigFile)).Set(1)
 			configSuccessTime.WithLabelValues("customresourceconfig", filepath.Clean(opts.CustomResourceConfigFile)).SetToCurrentTime()
@@ -223,7 +223,7 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 	}
 
 	if err := storeBuilder.WithEnabledResources(resources); err != nil {
-		return fmt.Errorf("failed to set up resources: %v", err)
+		return fmt.Errorf("failed to set up resources: %w", err)
 	}
 
 	namespaces := opts.Namespaces.GetNamespaces()
@@ -249,14 +249,14 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 
 	err = allowDenyList.Parse()
 	if err != nil {
-		return fmt.Errorf("error initializing the allowdeny list: %v", err)
+		return fmt.Errorf("error initializing the allowdeny list: %w", err)
 	}
 
 	klog.InfoS("Metric allow-denylisting", "allowDenyStatus", allowDenyList.Status())
 
 	optInMetricFamilyFilter, err := optin.NewMetricFamilyFilter(opts.MetricOptInList)
 	if err != nil {
-		return fmt.Errorf("error initializing the opt-in metric list: %v", err)
+		return fmt.Errorf("error initializing the opt-in metric list: %w", err)
 	}
 
 	if optInMetricFamilyFilter.Count() > 0 {
@@ -276,18 +276,18 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 	storeBuilder.WithUtilOptions(opts)
 	kubeClient, err := util.CreateKubeClient(opts.Apiserver, opts.Kubeconfig)
 	if err != nil {
-		return fmt.Errorf("failed to create client: %v", err)
+		return fmt.Errorf("failed to create client: %w", err)
 	}
 	storeBuilder.WithKubeClient(kubeClient)
 
 	storeBuilder.WithSharding(opts.Shard, opts.TotalShards)
 	if err := storeBuilder.WithAllowAnnotations(opts.AnnotationsAllowList); err != nil {
-		return fmt.Errorf("failed to set up annotations allowlist: %v", err)
+		return fmt.Errorf("failed to set up annotations allowlist: %w", err)
 	}
 	klog.InfoS("Using annotations allowlist", "annotationsAllowList", opts.AnnotationsAllowList)
 
 	if err := storeBuilder.WithAllowLabels(opts.LabelsAllowList); err != nil {
-		return fmt.Errorf("failed to set up labels allowlist: %v", err)
+		return fmt.Errorf("failed to set up labels allowlist: %w", err)
 	}
 	klog.InfoS("Using labels allowlist", "labelsAllowList", opts.LabelsAllowList)
 
@@ -396,7 +396,7 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
 	}
 
 	if err := g.Run(); err != nil {
-		return fmt.Errorf("run server group error: %v", err)
+		return fmt.Errorf("run server group error: %w", err)
 	}
 
 	klog.InfoS("Exited")
@@ -628,7 +628,7 @@ func resolveCustomResourceConfig(opts *options.Options) (customresourcestate.Con
 		} else {
 			f, err := os.Open(filepath.Clean(file))
 			if err != nil {
-				return nil, fmt.Errorf("unable to open Custom Resource State Metrics file: %v", err)
+				return nil, fmt.Errorf("unable to open Custom Resource State Metrics file: %w", err)
 			}
 			return yaml.NewDecoder(f), nil
 		}

pkg/customresourcestate/registry_factory.go

@@ -19,8 +19,7 @@ package customresourcestate
 import (
 	"errors"
 	"fmt"
-	"math"
-	"sort"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -220,7 +219,7 @@ type compiledGauge struct {
 
 func (c *compiledGauge) Values(v interface{}) (result []eachValue, errs []error) {
 	onError := func(err error) {
-		errs = append(errs, fmt.Errorf("%s: %v", c.Path(), err))
+		errs = append(errs, fmt.Errorf("%s: %w", c.Path(), err))
 	}
 
 	switch iter := v.(type) {
@@ -312,7 +311,7 @@ type compiledInfo struct {
 
 func (c *compiledInfo) Values(v interface{}) (result []eachValue, errs []error) {
 	onError := func(err ...error) {
-		errs = append(errs, fmt.Errorf("%s: %v", c.Path(), err))
+		errs = append(errs, fmt.Errorf("%s: %w", c.Path(), errors.Join(err...)))
 	}
 
 	switch iter := v.(type) {
@@ -418,30 +417,27 @@ func (c *compiledStateSet) values(v interface{}) (result []eachValue, errs []err
 	return
 }
 
-// less compares two maps of labels by keys and values
-func less(a, b map[string]string) bool {
-	var aKeys, bKeys sort.StringSlice
+// compareLabels compares two maps of labels by keys and values, returning
+// a negative, zero, or positive int for use with slices.SortFunc.
+func compareLabels(a, b map[string]string) int {
+	var aKeys, bKeys []string
 	for k := range a {
 		aKeys = append(aKeys, k)
 	}
 	for k := range b {
 		bKeys = append(bKeys, k)
 	}
-	aKeys.Sort()
-	bKeys.Sort()
-	for i := 0; i < int(math.Min(float64(len(aKeys)), float64(len(bKeys)))); i++ {
-		if aKeys[i] != bKeys[i] {
-			return aKeys[i] < bKeys[i]
+	slices.Sort(aKeys)
+	slices.Sort(bKeys)
+	for i := 0; i < min(len(aKeys), len(bKeys)); i++ {
+		if c := strings.Compare(aKeys[i], bKeys[i]); c != 0 {
+			return c
 		}
-
-		va := a[aKeys[i]]
-		vb := b[bKeys[i]]
-		if va == vb {
-			continue
+		if c := strings.Compare(a[aKeys[i]], b[bKeys[i]]); c != 0 {
+			return c
 		}
-		return va < vb
 	}
-	return len(aKeys) < len(bKeys)
+	return len(aKeys) - len(bKeys)
 }
 
 func (c compiledGauge) value(it interface{}) (*eachValue, error) {
@@ -486,7 +482,7 @@ func (e eachValue) ToMetric() *metric.Metric {
 		keys = append(keys, k)
 	}
 	// make it deterministic
-	sort.Strings(keys)
+	slices.Sort(keys)
 	for _, key := range keys {
 		values = append(values, e.Labels[key])
 	}
@@ -524,7 +520,7 @@ func addPathLabels(obj interface{}, labels map[string]valuePath, result map[stri
 			stars = append(stars, k)
 		}
 	}
-	sort.Strings(stars)
+	slices.Sort(stars)
 	for _, star := range stars {
 		m := labels[star].Get(obj)
 		if kv, ok := m.(map[string]interface{}); ok {
@@ -704,8 +700,8 @@ func scrapeValuesFor(e compiledEach, obj map[string]interface{}) ([]eachValue, [
 	result, errs := e.Values(v)
 
 	// return results in a consistent order (simplifies testing)
-	sort.Slice(result, func(i, j int) bool {
-		return less(result[i].Labels, result[j].Labels)
+	slices.SortFunc(result, func(a, b eachValue) int {
+		return compareLabels(a.Labels, b.Labels)
 	})
 	return result, errs
 }

pkg/customresourcestate/registry_factory_test.go

@@ -366,7 +366,13 @@ func Test_values(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			gotResult, gotErrors := scrapeValuesFor(tt.each, cr)
 			assert.Equal(t, tt.wantResult, gotResult)
-			assert.Equal(t, tt.wantErrors, gotErrors)
+			if tt.wantErrors == nil {
+				assert.Nil(t, gotErrors)
+			} else if assert.Len(t, gotErrors, len(tt.wantErrors)) {
+				for i, wantErr := range tt.wantErrors {
+					assert.EqualError(t, gotErrors[i], wantErr.Error())
+				}
+			}
 		})
 	}
 }

pkg/metrics_store/metrics_writer.go

@@ -67,7 +67,7 @@ func (m MetricsWriter) WriteAll(w io.Writer) error {
 		m.stores[0].metrics.Range(func(_ interface{}, _ interface{}) bool {
 			_, err = w.Write([]byte(help))
 			if err != nil {
-				err = fmt.Errorf("failed to write help text: %v", err)
+				err = fmt.Errorf("failed to write help text: %w", err)
 			}
 			return false
 		})
@@ -80,7 +80,7 @@ func (m MetricsWriter) WriteAll(w io.Writer) error {
 				metricFamilies := value.([][]byte)
 				_, err = w.Write(metricFamilies[i])
 				if err != nil {
-					err = fmt.Errorf("failed to write metrics family: %v", err)
+					err = fmt.Errorf("failed to write metrics family: %w", err)
 					return false
 				}
 				return true

pkg/optin/optin.go

@@ -18,7 +18,7 @@ package optin
 
 import (
 	"regexp"
-	"sort"
+	"slices"
 	"strings"
 
 	generator "k8s.io/kube-state-metrics/v2/pkg/metric_generator"
@@ -49,7 +49,7 @@ func (filter MetricFamilyFilter) Status() string {
 		asStrings = append(asStrings, metric.String())
 	}
 	// sort the strings for the sake of ux such that the resulting status is consistent
-	sort.Strings(asStrings)
+	slices.Sort(asStrings)
 	return strings.Join(asStrings, ", ")
 }
 

pkg/options/types.go

@@ -18,7 +18,7 @@ package options
 
 import (
 	"errors"
-	"sort"
+	"slices"
 	"strings"
 
 	"k8s.io/apimachinery/pkg/fields"
@@ -36,7 +36,7 @@ type MetricSet map[string]struct{}
 func (ms *MetricSet) String() string {
 	s := *ms
 	ss := s.asSlice()
-	sort.Strings(ss)
+	slices.Sort(ss)
 	return strings.Join(ss, ",")
 }
 
@@ -73,7 +73,7 @@ type ResourceSet map[string]struct{}
 func (r *ResourceSet) String() string {
 	s := *r
 	ss := s.AsSlice()
-	sort.Strings(ss)
+	slices.Sort(ss)
 	return strings.Join(ss, ",")
 }
 
@@ -307,7 +307,7 @@ func (l LabelsAllowList) asSlice() []string {
 func (l *LabelsAllowList) String() string {
 	s := *l
 	ss := s.asSlice()
-	sort.Strings(ss)
+	slices.Sort(ss)
 	return strings.Join(ss, ",")
 }