feat: support labels key in transformer configuration (#5556)

* feat: support labels key in transformer configuration

Allow the usage of a separate transformer configuration for the labels key,
similar to what is currently available for commonLabels and commonAnnotations.
This aims to provide the same functionality that commonLabels currently provide
for labels, since commonLabels is deprecated and slated for removal in a future
release.

* chore(transformerconfig): add nolint hint

Add a nolint hint to the new method so the returns can stay consistent with
one another.

* fix: changes from code review

* Rename methods `AddCommonLabelFieldSpec` and `AddLabelFieldSpec` to
  `AddCommonLabelsFieldSpec` and `AddLabelsFieldSpec`.
* Add extra test to verify scenarios applying labels to Custom Resource Definitions.

api/internal/accumulator/loadconfigfromcrds.go

@@ -144,7 +144,7 @@ func loadCrdIntoConfig(
 		}
 		_, label := property.Extensions.GetString(xLabelSelector)
 		if label {
-			err = theConfig.AddLabelFieldSpec(
+			err = theConfig.AddCommonLabelsFieldSpec(
 				makeFs(theGvk, append(path, propName)))
 			if err != nil {
 				return

api/internal/plugins/builtinconfig/loaddefaultconfig_test.go

@@ -70,30 +70,3 @@ namoPrefix:
 		t.Fatalf("expected error %s, but got %s", errMsg, err)
 	}
 }
-
-// please remove this failing test after implements the labels support
-func TestLoadDefaultConfigsFromFilesWithMissingFieldsLabels(t *testing.T) {
-	fSys := filesys.MakeFsInMemory()
-	filePathContainsTypo := "config_contains_typo.yaml"
-	if err := fSys.WriteFile(filePathContainsTypo, []byte(`
-labels:
-  - path: spec/podTemplate/metadata/labels
-    create: true
-    kind: FlinkDeployment
-`)); err != nil {
-		t.Fatal(err)
-	}
-	ldr, err := loader.NewLoader(
-		loader.RestrictionRootOnly, filesys.Separator, fSys)
-	if err != nil {
-		t.Fatal(err)
-	}
-	errMsg := "error unmarshaling JSON: while decoding JSON: json: unknown field"
-	_, err = loadDefaultConfig(ldr, []string{filePathContainsTypo})
-	if err == nil {
-		t.Fatalf("expected to fail unmarshal yaml, but got nil %s", filePathContainsTypo)
-	}
-	if !strings.Contains(err.Error(), errMsg) {
-		t.Fatalf("expected error %s, but got %s", errMsg, err)
-	}
-}

api/internal/plugins/builtinconfig/transformerconfig.go

@@ -21,6 +21,7 @@ type TransformerConfig struct {
 	NameSuffix        types.FsSlice `json:"nameSuffix,omitempty" yaml:"nameSuffix,omitempty"`
 	NameSpace         types.FsSlice `json:"namespace,omitempty" yaml:"namespace,omitempty"`
 	CommonLabels      types.FsSlice `json:"commonLabels,omitempty" yaml:"commonLabels,omitempty"`
+	Labels            types.FsSlice `json:"labels,omitempty" yaml:"labels,omitempty"`
 	TemplateLabels    types.FsSlice `json:"templateLabels,omitempty" yaml:"templateLabels,omitempty"`
 	CommonAnnotations types.FsSlice `json:"commonAnnotations,omitempty" yaml:"commonAnnotations,omitempty"`
 	NameReference     nbrSlice      `json:"nameReference,omitempty" yaml:"nameReference,omitempty"`
@@ -41,6 +42,7 @@ func (t *TransformerConfig) DeepCopy() *TransformerConfig {
 		NameSuffix:        t.NameSuffix.DeepCopy(),
 		NameSpace:         t.NameSpace.DeepCopy(),
 		CommonLabels:      t.CommonLabels.DeepCopy(),
+		Labels:            t.Labels.DeepCopy(),
 		TemplateLabels:    t.TemplateLabels.DeepCopy(),
 		CommonAnnotations: t.CommonAnnotations.DeepCopy(),
 		NameReference:     t.NameReference.DeepCopy(),
@@ -94,6 +96,7 @@ func (t *TransformerConfig) sortFields() {
 	sort.Sort(t.NameSuffix)
 	sort.Sort(t.NameSpace)
 	sort.Sort(t.CommonLabels)
+	sort.Sort(t.Labels)
 	sort.Sort(t.TemplateLabels)
 	sort.Sort(t.CommonAnnotations)
 	sort.Sort(t.NameReference)
@@ -114,12 +117,18 @@ func (t *TransformerConfig) AddSuffixFieldSpec(fs types.FieldSpec) (err error) {
 	return err
 }
 
-// AddLabelFieldSpec adds a FieldSpec to CommonLabels
-func (t *TransformerConfig) AddLabelFieldSpec(fs types.FieldSpec) (err error) {
+// AddCommonLabelsFieldSpec adds a FieldSpec to CommonLabels
+func (t *TransformerConfig) AddCommonLabelsFieldSpec(fs types.FieldSpec) (err error) {
 	t.CommonLabels, err = t.CommonLabels.MergeOne(fs)
 	return err
 }
 
+// AddLabelsFieldSpec adds a FieldSpec to Labels
+func (t *TransformerConfig) AddLabelsFieldSpec(fs types.FieldSpec) (err error) {
+	t.Labels, err = t.Labels.MergeOne(fs)
+	return err //nolint:wrapcheck
+}
+
 // AddAnnotationFieldSpec adds a FieldSpec to CommonAnnotations
 func (t *TransformerConfig) AddAnnotationFieldSpec(fs types.FieldSpec) (err error) {
 	t.CommonAnnotations, err = t.CommonAnnotations.MergeOne(fs)
@@ -162,6 +171,10 @@ func (t *TransformerConfig) Merge(input *TransformerConfig) (
 	if err != nil {
 		return nil, errors.WrapPrefixf(err, "failed to merge CommonLabels fieldSpec")
 	}
+	merged.Labels, err = t.Labels.MergeAll(input.Labels)
+	if err != nil {
+		return nil, errors.WrapPrefixf(err, "failed to merge Labels fieldSpec")
+	}
 	merged.TemplateLabels, err = t.TemplateLabels.MergeAll(input.TemplateLabels)
 	if err != nil {
 		return nil, errors.WrapPrefixf(err, "failed to merge TemplateLabels fieldSpec")

api/internal/plugins/builtinconfig/transformerconfig_test.go

@@ -4,9 +4,10 @@
 package builtinconfig_test
 
 import (
-	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	. "sigs.k8s.io/kustomize/api/internal/plugins/builtinconfig"
 	"sigs.k8s.io/kustomize/api/types"
 	"sigs.k8s.io/kustomize/kyaml/resid"
@@ -35,13 +36,8 @@ func TestAddNamereferenceFieldSpec(t *testing.T) {
 		},
 	}
 
-	err := cfg.AddNamereferenceFieldSpec(nbrs)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
-	if len(cfg.NameReference) != 1 {
-		t.Fatal("failed to add namereference FieldSpec")
-	}
+	require.NoError(t, cfg.AddNamereferenceFieldSpec(nbrs))
+	require.Len(t, cfg.NameReference, 1, "failed to add namereference FieldSpec")
 }
 
 func TestAddFieldSpecs(t *testing.T) {
@@ -53,34 +49,14 @@ func TestAddFieldSpecs(t *testing.T) {
 		CreateIfNotPresent: true,
 	}
 
-	err := cfg.AddPrefixFieldSpec(fieldSpec)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
-	if len(cfg.NamePrefix) != 1 {
-		t.Fatalf("failed to add nameprefix FieldSpec")
-	}
-	err = cfg.AddSuffixFieldSpec(fieldSpec)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
-	if len(cfg.NameSuffix) != 1 {
-		t.Fatalf("failed to add namesuffix FieldSpec")
-	}
-	err = cfg.AddLabelFieldSpec(fieldSpec)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
-	if len(cfg.CommonLabels) != 1 {
-		t.Fatalf("failed to add nameprefix FieldSpec")
-	}
-	err = cfg.AddAnnotationFieldSpec(fieldSpec)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
-	if len(cfg.CommonAnnotations) != 1 {
-		t.Fatalf("failed to add nameprefix FieldSpec")
-	}
+	require.NoError(t, cfg.AddPrefixFieldSpec(fieldSpec))
+	require.Len(t, cfg.NamePrefix, 1, "failed to add nameprefix FieldSpec")
+	require.NoError(t, cfg.AddSuffixFieldSpec(fieldSpec))
+	require.Len(t, cfg.NameSuffix, 1, "failed to add namesuffix FieldSpec")
+	require.NoError(t, cfg.AddCommonLabelsFieldSpec(fieldSpec))
+	require.Len(t, cfg.CommonLabels, 1, "failed to add labels FieldSpec")
+	require.NoError(t, cfg.AddAnnotationFieldSpec(fieldSpec))
+	require.Len(t, cfg.CommonAnnotations, 1, "failed to add nameprefix FieldSpec")
 }
 
 func TestMerge(t *testing.T) {
@@ -127,51 +103,43 @@ func TestMerge(t *testing.T) {
 		},
 	}
 	cfga := &TransformerConfig{}
-	cfga.AddNamereferenceFieldSpec(nameReference[0])
-	cfga.AddPrefixFieldSpec(fieldSpecs[0])
-	cfga.AddSuffixFieldSpec(fieldSpecs[0])
+	require.NoError(t, cfga.AddNamereferenceFieldSpec(nameReference[0]))
+	require.NoError(t, cfga.AddPrefixFieldSpec(fieldSpecs[0]))
+	require.NoError(t, cfga.AddSuffixFieldSpec(fieldSpecs[0]))
+	require.NoError(t, cfga.AddCommonLabelsFieldSpec(fieldSpecs[0]))
+	require.NoError(t, cfga.AddLabelsFieldSpec(fieldSpecs[0]))
 
 	cfgb := &TransformerConfig{}
-	cfgb.AddNamereferenceFieldSpec(nameReference[1])
-	cfgb.AddPrefixFieldSpec(fieldSpecs[1])
-	cfga.AddSuffixFieldSpec(fieldSpecs[1])
+	require.NoError(t, cfgb.AddNamereferenceFieldSpec(nameReference[1]))
+	require.NoError(t, cfgb.AddPrefixFieldSpec(fieldSpecs[1]))
+	require.NoError(t, cfgb.AddSuffixFieldSpec(fieldSpecs[1]))
+	require.NoError(t, cfgb.AddCommonLabelsFieldSpec(fieldSpecs[1]))
+	require.NoError(t, cfgb.AddLabelsFieldSpec(fieldSpecs[1]))
 
 	actual, err := cfga.Merge(cfgb)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
-
-	if len(actual.NamePrefix) != 2 {
-		t.Fatal("merge failed for namePrefix FieldSpec")
-	}
-
-	if len(actual.NameSuffix) != 2 {
-		t.Fatal("merge failed for nameSuffix FieldSpec")
-	}
-
-	if len(actual.NameReference) != 1 {
-		t.Fatal("merge failed for namereference FieldSpec")
-	}
+	require.NoError(t, err)
+	require.Len(t, actual.NamePrefix, 2, "merge failed for namePrefix FieldSpec")
+	require.Len(t, actual.NameSuffix, 2, "merge failed for nameSuffix FieldSpec")
+	require.Len(t, actual.NameReference, 1, "merge failed for nameReference FieldSpec")
+	require.Len(t, actual.Labels, 2, "merge failed for labels FieldSpec")
+	require.Len(t, actual.CommonLabels, 2, "merge failed for commonLabels FieldSpec")
 
 	expected := &TransformerConfig{}
-	expected.AddNamereferenceFieldSpec(nameReference[0])
-	expected.AddNamereferenceFieldSpec(nameReference[1])
-	expected.AddPrefixFieldSpec(fieldSpecs[0])
-	expected.AddPrefixFieldSpec(fieldSpecs[1])
-	expected.AddSuffixFieldSpec(fieldSpecs[0])
-	expected.AddSuffixFieldSpec(fieldSpecs[1])
-
-	if !reflect.DeepEqual(actual, expected) {
-		t.Fatalf("expected: %v\n but got: %v\n", expected, actual)
-	}
+	require.NoError(t, expected.AddNamereferenceFieldSpec(nameReference[0]))
+	require.NoError(t, expected.AddNamereferenceFieldSpec(nameReference[1]))
+	require.NoError(t, expected.AddPrefixFieldSpec(fieldSpecs[0]))
+	require.NoError(t, expected.AddPrefixFieldSpec(fieldSpecs[1]))
+	require.NoError(t, expected.AddSuffixFieldSpec(fieldSpecs[0]))
+	require.NoError(t, expected.AddSuffixFieldSpec(fieldSpecs[1]))
+	require.NoError(t, expected.AddCommonLabelsFieldSpec(fieldSpecs[0]))
+	require.NoError(t, expected.AddCommonLabelsFieldSpec(fieldSpecs[1]))
+	require.NoError(t, expected.AddLabelsFieldSpec(fieldSpecs[0]))
+	require.NoError(t, expected.AddLabelsFieldSpec(fieldSpecs[1]))
+	require.Equal(t, expected, actual)
 
 	actual, err = cfga.Merge(nil)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
-	if !reflect.DeepEqual(actual, cfga) {
-		t.Fatalf("expected: %v\n but got: %v\n", cfga, actual)
-	}
+	require.NoError(t, err)
+	require.Equal(t, cfga, actual)
 }
 
 func TestMakeDefaultConfig_mutation(t *testing.T) {
@@ -182,9 +150,7 @@ func TestMakeDefaultConfig_mutation(t *testing.T) {
 	a.NameReference = a.NameReference[:1]
 
 	clean := MakeDefaultConfig()
-	if clean.NameReference[0].Kind == "mutated" {
-		t.Errorf("MakeDefaultConfig() did not return a clean copy: %+v", clean.NameReference)
-	}
+	assert.NotEqualf(t, "mutated", clean.NameReference[0].Kind, "MakeDefaultConfig() did not return a clean copy: %+v", clean.NameReference)
 }
 
 func BenchmarkMakeDefaultConfig(b *testing.B) {

api/internal/target/kusttarget_configplugin.go

@@ -275,13 +275,25 @@ var transformerConfigurators = map[builtinhelpers.BuiltinPluginType]func(
 		if len(kt.kustomization.Labels) == 0 && len(kt.kustomization.CommonLabels) == 0 {
 			return
 		}
+
+		type labelStruct struct {
+			Labels     map[string]string
+			FieldSpecs []types.FieldSpec
+		}
+
 		for _, label := range kt.kustomization.Labels {
-			var c struct {
-				Labels     map[string]string
-				FieldSpecs []types.FieldSpec
-			}
+			var c labelStruct
+
 			c.Labels = label.Pairs
 			fss := types.FsSlice(label.FieldSpecs)
+
+			// merge labels specified in the label section of transformer configs
+			// these apply to selectors and templates
+			fss, err := fss.MergeAll(tc.Labels)
+			if err != nil {
+				return nil, fmt.Errorf("failed to merge labels: %w", err)
+			}
+
 			// merge the custom fieldSpecs with the default
 			if label.IncludeSelectors {
 				fss, err = fss.MergeAll(tc.CommonLabels)
@@ -297,7 +309,7 @@ var transformerConfigurators = map[builtinhelpers.BuiltinPluginType]func(
 				fss, err = fss.MergeOne(types.FieldSpec{Path: "metadata/labels", CreateIfNotPresent: true})
 			}
 			if err != nil {
-				return nil, err
+				return nil, fmt.Errorf("failed to merge labels: %w", err)
 			}
 			c.FieldSpecs = fss
 			p := f()
@@ -307,10 +319,9 @@ var transformerConfigurators = map[builtinhelpers.BuiltinPluginType]func(
 			}
 			result = append(result, p)
 		}
-		var c struct {
-			Labels     map[string]string
-			FieldSpecs []types.FieldSpec
-		}
+
+		var c labelStruct
+
 		c.Labels = kt.kustomization.CommonLabels
 		c.FieldSpecs = tc.CommonLabels
 		p := f()

api/internal/target/kusttarget_test.go

@@ -295,9 +295,7 @@ metadata:
 
 	expected := resmap.New()
 	for _, r := range resources {
-		if err := expected.Append(r); err != nil {
-			t.Fatalf("failed to append resource: %v", err)
-		}
+		require.NoError(t, expected.Append(r), "failed to append resource: %v")
 	}
 	expected.RemoveBuildAnnotations()
 	expYaml, err := expected.AsYaml()