Add support for converting Crossplane Configurations

- Add the migration.Executor interface

Signed-off-by: Alper Rifat Ulucinar <ulucinar@users.noreply.github.com>

pkg/migration/converter.go

@@ -16,7 +16,9 @@ package migration
 
 import (
 	"github.com/crossplane/crossplane-runtime/pkg/fieldpath"
+	"github.com/crossplane/crossplane-runtime/pkg/resource"
 	xpv1 "github.com/crossplane/crossplane/apis/apiextensions/v1"
+	xpmetav1 "github.com/crossplane/crossplane/apis/pkg/meta/v1"
 	"github.com/pkg/errors"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -27,6 +29,7 @@ import (
 
 const (
 	errFromUnstructured      = "failed to convert from unstructured.Unstructured to the managed resource type"
+	errFromUnstructuredConf  = "failed to convert from unstructured.Unstructured to Crossplane Configuration metadata"
 	errToUnstructured        = "failed to convert from the managed resource type to unstructured.Unstructured"
 	errRawExtensionUnmarshal = "failed to unmarshal runtime.RawExtension"
 
@@ -165,3 +168,27 @@ func addNameGVK(u unstructured.Unstructured, target map[string]any) map[string]a
 	target["metadata"] = m
 	return target
 }
+
+func toManagedResource(c runtime.ObjectCreater, u unstructured.Unstructured) (resource.Managed, bool, error) {
+	gvk := u.GroupVersionKind()
+	if gvk == xpv1.CompositionGroupVersionKind {
+		return nil, false, nil
+	}
+	obj, err := c.New(gvk)
+	if err != nil {
+		return nil, false, errors.Wrapf(err, errFmtNewObject, gvk)
+	}
+	if err := runtime.DefaultUnstructuredConverter.FromUnstructured(u.Object, obj); err != nil {
+		return nil, false, errors.Wrap(err, errFromUnstructured)
+	}
+	mg, ok := obj.(resource.Managed)
+	return mg, ok, nil
+}
+
+func toConfiguration(u unstructured.Unstructured) (*xpmetav1.Configuration, error) {
+	conf := &xpmetav1.Configuration{}
+	if err := runtime.DefaultUnstructuredConverter.FromUnstructured(u.Object, conf); err != nil {
+		return nil, errors.Wrap(err, errFromUnstructuredConf)
+	}
+	return conf, nil
+}

pkg/migration/errors.go

@@ -0,0 +1,31 @@
+// Copyright 2023 Upbound Inc.
+//
+// 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 migration
+
+import "fmt"
+
+type errUnsupportedStepType struct {
+	planStep Step
+}
+
+func (e errUnsupportedStepType) Error() string {
+	return fmt.Sprintf("executor does not support steps of type %q in step: %s", e.planStep.Type, e.planStep.Name)
+}
+
+func NewUnsupportedStepTypeError(s Step) error {
+	return errUnsupportedStepType{
+		planStep: s,
+	}
+}

pkg/migration/interfaces.go

@@ -17,6 +17,7 @@ package migration
 import (
 	"github.com/crossplane/crossplane-runtime/pkg/resource"
 	xpv1 "github.com/crossplane/crossplane/apis/apiextensions/v1"
+	xpmetav1 "github.com/crossplane/crossplane/apis/pkg/meta/v1"
 )
 
 // ResourceConverter converts a managed resource from
@@ -69,6 +70,14 @@ type PatchSetConverter interface {
 	PatchSets(psMap map[string]*xpv1.PatchSet) error
 }
 
+// ConfigurationConverter converts a Crossplane Configuration's metadata.
+type ConfigurationConverter interface {
+	// Configuration takes a Crossplane Configuration metadata, converts it,
+	// and stores the converted metadata in its argument. Returns any errors
+	// encountered during the conversion.
+	Configuration(configuration *xpmetav1.Configuration) error
+}
+
 // Source is a source for reading resource manifests
 type Source interface {
 	// HasNext returns `true` if the Source implementation has a next manifest
@@ -88,3 +97,18 @@ type Target interface {
 	// Delete deletes a resource manifest from this Target
 	Delete(o UnstructuredWithMetadata) error
 }
+
+// Executor is a migration plan executor.
+type Executor interface {
+	// Init initializes an executor using the supplied executor specific
+	// configuration data.
+	Init(config any) error
+	// Step asks the executor to execute the next step passing any available
+	// context from the previous step, and returns any new context to be passed
+	// to the next step if there exists one.
+	Step(s Step, ctx any) (any, error)
+	// Destroy is called when all the steps have been executed,
+	// or a step has returned an error, and we would like to stop
+	// executing the plan.
+	Destroy() error
+}

pkg/migration/plan_generator.go

@@ -28,6 +28,7 @@ import (
 	"github.com/crossplane/crossplane-runtime/pkg/resource/unstructured/claim"
 	"github.com/crossplane/crossplane-runtime/pkg/resource/unstructured/composite"
 	xpv1 "github.com/crossplane/crossplane/apis/apiextensions/v1"
+	xpmetav1 "github.com/crossplane/crossplane/apis/pkg/meta/v1"
 	"github.com/pkg/errors"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
@@ -45,7 +46,8 @@ const (
 	errCompositePause          = "failed to pause composite resource"
 	errCompositesEdit          = "failed to edit composite resources"
 	errCompositesStart         = "failed to start composite resources"
-	errCompositionMigrate      = "failed to migrate the composition"
+	errCompositionMigrateFmt   = "failed to migrate the composition: %s"
+	errConfigurationMigrateFmt = "failed to migrate the configuration: %s"
 	errComposedTemplateBase    = "failed to migrate the base of a composed template"
 	errComposedTemplateMigrate = "failed to migrate the composed templates of the composition"
 	errResourceOutput          = "failed to output migrated resource"
@@ -197,17 +199,25 @@ func (pg *PlanGenerator) convert() error { //nolint: gocyclo
 			return errors.Wrap(err, errSourceNext)
 		}
 		switch gvk := o.Object.GroupVersionKind(); gvk {
+		case xpmetav1.ConfigurationGroupVersionKind:
+			target, converted, err := pg.convertConfiguration(o)
+			if err != nil {
+				return errors.Wrapf(err, errConfigurationMigrateFmt, o.Object.GetName())
+			}
+			if converted {
+				fmt.Printf("converted configuration: %v\n", target)
+			}
 		case xpv1.CompositionGroupVersionKind:
 			target, converted, err := pg.convertComposition(o)
 			if err != nil {
-				return errors.Wrap(err, errCompositionMigrate)
+				return errors.Wrapf(err, errCompositionMigrateFmt, o.Object.GetName())
 			}
 			if converted {
 				migratedName := fmt.Sprintf("%s-migrated", o.Object.GetName())
 				convertedComposition[o.Object.GetName()] = migratedName
 				target.Object.SetName(migratedName)
 				if err := pg.stepNewComposition(target); err != nil {
-					return errors.Wrap(err, errCompositionMigrate)
+					return errors.Wrapf(err, errCompositionMigrateFmt, o.Object.GetName())
 				}
 			}
 		default:
@@ -314,20 +324,25 @@ func assertMetadataName(parentName string, resources []resource.Managed) {
 	}
 }
 
-func toManagedResource(c runtime.ObjectCreater, u unstructured.Unstructured) (resource.Managed, bool, error) {
-	gvk := u.GroupVersionKind()
-	if gvk == xpv1.CompositionGroupVersionKind {
-		return nil, false, nil
-	}
-	obj, err := c.New(gvk)
+func (pg *PlanGenerator) convertConfiguration(o UnstructuredWithMetadata) (*UnstructuredWithMetadata, bool, error) {
+	conf, err := toConfiguration(o.Object)
 	if err != nil {
-		return nil, false, errors.Wrapf(err, errFmtNewObject, gvk)
+		return nil, false, err
 	}
-	if err := runtime.DefaultUnstructuredConverter.FromUnstructured(u.Object, obj); err != nil {
-		return nil, false, errors.Wrap(err, errFromUnstructured)
+	isConverted := false
+	for _, confConv := range pg.registry.configurationConverters {
+		if confConv.re == nil || confConv.converter == nil || !confConv.re.MatchString(o.Object.GetName()) {
+			continue
+		}
+		if err := confConv.converter.Configuration(conf); err != nil {
+			return nil, false, errors.Wrapf(err, "failed to call converter on Configuration: %s", conf.GetName())
+		}
+		isConverted = true
 	}
-	mg, ok := obj.(resource.Managed)
-	return mg, ok, nil
+	return &UnstructuredWithMetadata{
+		Object:   ToSanitizedUnstructured(conf),
+		Metadata: o.Metadata,
+	}, isConverted, nil
 }
 
 func (pg *PlanGenerator) convertComposition(o UnstructuredWithMetadata) (*UnstructuredWithMetadata, bool, error) { // nolint:gocyclo
@@ -344,7 +359,7 @@ func (pg *PlanGenerator) convertComposition(o UnstructuredWithMetadata) (*Unstru
 	for _, cmp := range comp.Spec.Resources {
 		u, err := FromRawExtension(cmp.Base)
 		if err != nil {
-			return nil, false, errors.Wrap(err, errCompositionMigrate)
+			return nil, false, errors.Wrapf(err, errCompositionMigrateFmt, o.Object.GetName())
 		}
 		gvk := u.GroupVersionKind()
 		converted, ok, err := pg.convertResource(UnstructuredWithMetadata{

pkg/migration/plan_generator_test.go

@@ -23,6 +23,7 @@ import (
 	xpresource "github.com/crossplane/crossplane-runtime/pkg/resource"
 	"github.com/crossplane/crossplane-runtime/pkg/test"
 	v1 "github.com/crossplane/crossplane/apis/apiextensions/v1"
+	xpmetav1 "github.com/crossplane/crossplane/apis/pkg/meta/v1"
 	"github.com/google/go-cmp/cmp"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -95,7 +96,7 @@ func TestGeneratePlan(t *testing.T) {
 						re:        AllCompositions,
 						converter: &testConverter{},
 					},
-				}),
+				}, nil),
 			},
 			want: want{
 				migrationPlanPath: "testdata/plan/generated/migration_plan.yaml",
@@ -112,6 +113,20 @@ func TestGeneratePlan(t *testing.T) {
 				},
 			},
 		},
+		"PlanWithConfiguration": {
+			fields: fields{
+				source: newTestSource(map[string]Metadata{
+					"testdata/plan/configuration.yaml": {}}),
+				target: newTestTarget(),
+				registry: getRegistryWithConverters(nil, nil, []configurationConverter{
+					{
+						re:        AllConfigurations,
+						converter: &testConverter{},
+					},
+				}),
+			},
+			want: want{},
+		},
 	}
 	for name, tt := range tests {
 		t.Run(name, func(t *testing.T) {
@@ -239,6 +254,16 @@ func (f *testTarget) Delete(o UnstructuredWithMetadata) error {
 
 type testConverter struct{}
 
+func (f *testConverter) Configuration(c *xpmetav1.Configuration) error {
+	c.Spec.DependsOn = []xpmetav1.Dependency{
+		{
+			Provider: ptrFromString("xpkg.upbound.io/upbound/provider-aws-eks"),
+			Version:  ">=v0.17.0",
+		},
+	}
+	return nil
+}
+
 func (f *testConverter) PatchSets(psMap map[string]*v1.PatchSet) error {
 	psMap["ps1"].Patches[0].ToFieldPath = ptrFromString(`spec.forProvider.tags["key3"]`)
 	psMap["ps6"].Patches[0].ToFieldPath = ptrFromString(`spec.forProvider.tags["key4"]`)
@@ -249,14 +274,17 @@ func ptrFromString(s string) *string {
 	return &s
 }
 
-func getRegistryWithConverters(converters map[schema.GroupVersionKind]delegatingConverter, psConverters []patchSetConverter) *Registry {
+func getRegistryWithConverters(converters map[schema.GroupVersionKind]delegatingConverter, psConverters []patchSetConverter, confConverters []configurationConverter) *Registry {
 	scheme := runtime.NewScheme()
 	scheme.AddKnownTypeWithName(fake.MigrationSourceGVK, &fake.MigrationSourceObject{})
 	scheme.AddKnownTypeWithName(fake.MigrationTargetGVK, &fake.MigrationTargetObject{})
 	r := NewRegistry(scheme)
 	for _, c := range psConverters {
 		r.RegisterPatchSetConverter(c.re, c.converter)
 	}
+	for _, c := range confConverters {
+		r.RegisterConfigurationConverter(c.re, c.converter)
+	}
 	for gvk, d := range converters {
 		r.RegisterConversionFunctions(gvk, d.rFn, d.cmpFn, nil)
 	}