chore: funcs to create kustomize plugins (opendatahub-io#1062)

The actual use with resMap is inlined and moved to the caller.

This way we can construct plugins on demand and use them as building blocks instead.

pkg/deploy/deploy.go

@@ -165,14 +165,14 @@ func DeployManifestsFromPath(cli client.Client, owner metav1.Object, manifestPat
 		return err
 	}
 
-	// Apply NamespaceTransformer Plugin
-	if err := plugins.ApplyNamespacePlugin(namespace, resMap); err != nil {
-		return err
+	nsPlugin := plugins.CreateNamespaceApplierPlugin(namespace)
+	if err := nsPlugin.Transform(resMap); err != nil {
+		return fmt.Errorf("failed applying namespace plugin when preparing Kustomize resources. %w", err)
 	}
 
-	// Apply LabelTransformer Plugin
-	if err := plugins.ApplyAddLabelsPlugin(componentName, resMap); err != nil {
-		return err
+	labelsPlugin := plugins.CreateAddLabelsPlugin(componentName)
+	if err := labelsPlugin.Transform(resMap); err != nil {
+		return fmt.Errorf("failed applying labels plugin when preparing Kustomize resources. %w", err)
 	}
 
 	objs, err := GetResources(resMap)

pkg/plugins/addLabelsplugin.go

@@ -2,15 +2,21 @@ package plugins
 
 import (
 	"sigs.k8s.io/kustomize/api/builtins" //nolint:staticcheck //Remove after package update
-	"sigs.k8s.io/kustomize/api/resmap"
 	"sigs.k8s.io/kustomize/api/types"
 	"sigs.k8s.io/kustomize/kyaml/resid"
 
 	"github.com/opendatahub-io/opendatahub-operator/v2/pkg/metadata/labels"
 )
 
-func ApplyAddLabelsPlugin(componentName string, resMap resmap.ResMap) error {
-	nsplug := builtins.LabelTransformerPlugin{
+// CreateAddLabelsPlugin creates a label transformer plugin that ensures resources
+// to which this plugin is applied will have the Open Data Hub common labels included.
+//
+// It has a following characteristics:
+//   - It adds labels to the "metadata/labels" path for all resource kinds.
+//   - It adds labels to the "spec/template/metadata/labels" and "spec/selector/matchLabels" paths
+//     for resources of kind "Deployment".
+func CreateAddLabelsPlugin(componentName string) builtins.LabelTransformerPlugin {
+	return builtins.LabelTransformerPlugin{
 		Labels: map[string]string{
 			labels.ODH.Component(componentName): "true",
 			labels.K8SCommon.PartOf:             componentName,
@@ -33,6 +39,4 @@ func ApplyAddLabelsPlugin(componentName string, resMap resmap.ResMap) error {
 			},
 		},
 	}
-
-	return nsplug.Transform(resMap)
 }

pkg/plugins/namespacePlugin.go

@@ -3,16 +3,16 @@ package plugins
 import (
 	"sigs.k8s.io/kustomize/api/builtins" //nolint:staticcheck // Remove after package update
 	"sigs.k8s.io/kustomize/api/filters/namespace"
-	"sigs.k8s.io/kustomize/api/resmap"
 	"sigs.k8s.io/kustomize/api/types"
 	"sigs.k8s.io/kustomize/kyaml/resid"
 )
 
-func ApplyNamespacePlugin(manifestNamespace string, resMap resmap.ResMap) error {
-	nsplug := builtins.NamespaceTransformerPlugin{
+// CreateNamespaceApplierPlugin creates a plugin to ensure resources have the specified target namespace.
+func CreateNamespaceApplierPlugin(targetNamespace string) builtins.NamespaceTransformerPlugin {
+	return builtins.NamespaceTransformerPlugin{
 		ObjectMeta: types.ObjectMeta{
 			Name:      "odh-namespace-plugin",
-			Namespace: manifestNamespace,
+			Namespace: targetNamespace,
 		},
 		FieldSpecs: []types.FieldSpec{
 			{
@@ -64,6 +64,4 @@ func ApplyNamespacePlugin(manifestNamespace string, resMap resmap.ResMap) error
 		UnsetOnly:              false,
 		SetRoleBindingSubjects: namespace.AllServiceAccountSubjects,
 	}
-
-	return nsplug.Transform(resMap)
 }