Introduce Comparator interface (#88016)

* Introduce Comparator interface

* Add compare implementation everywhere

* Add comment explaining what Compare should do

* Lint

go.work.sum

@@ -573,6 +573,8 @@ github.com/grafana/grafana-plugin-sdk-go v0.230.0 h1:Y4IL+eT1jXqTCctlNzdCvxAozpB
 github.com/grafana/grafana-plugin-sdk-go v0.230.0/go.mod h1:6V6ikT4ryva8MrAp7Bdz5fTJx3/ztzKvpMJFfpzr4CI=
 github.com/grafana/grafana-plugin-sdk-go v0.231.1-0.20240523124942-62dae9836284/go.mod h1:bNgmNmub1I7Mc8dzIncgNqHC5jTgSZPPHlZ3aG8HKJQ=
 github.com/grafana/grafana/pkg/promlib v0.0.3/go.mod h1:3El4NlsfALz8QQCbEGHGFvJUG+538QLMuALRhZ3pcoo=
+github.com/grafana/saml v0.4.15-0.20231025143828-a6c0e9b86a4c h1:1pHLC1ZTz7N5QI3jzCs5sqmVvAKe+JwGnpp9lQ+iUjY=
+github.com/grafana/saml v0.4.15-0.20231025143828-a6c0e9b86a4c/go.mod h1:S4+611dxnKt8z/ulbvaJzcgSHsuhjVc1QHNTcr1R7Fw=
 github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7 h1:pdN6V1QBWetyv/0+wjACpqVH+eVULgEjkurDLq3goeM=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.18.1/go.mod h1:YvJ2f6MplWDhfxiUC3KpyTy76kYUZA4W3pTv/wdKQ9Y=
 github.com/grpc-ecosystem/grpc-opentracing v0.0.0-20180507213350-8e809c8a8645 h1:MJG/KsmcqMwFAkh8mTnAwhyKoB+sTAnY4CACC110tbU=

pkg/apiserver/rest/dualwriter.go

@@ -35,6 +35,8 @@ type Storage interface {
 	rest.CreaterUpdater
 	rest.GracefulDeleter
 	rest.CollectionDeleter
+	// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+	Compare(storageObj, legacyObj runtime.Object) bool
 }
 
 // LegacyStorage is a storage implementation that writes to the Grafana SQL database.
@@ -91,18 +93,18 @@ func NewDualWriter(mode DualWriterMode, legacy LegacyStorage, storage Storage) D
 	switch mode {
 	case Mode1:
 		// read and write only from legacy storage
-		return NewDualWriterMode1(legacy, storage)
+		return newDualWriterMode1(legacy, storage)
 	case Mode2:
 		// write to both, read from storage but use legacy as backup
-		return NewDualWriterMode2(legacy, storage)
+		return newDualWriterMode2(legacy, storage)
 	case Mode3:
 		// write to both, read from storage only
-		return NewDualWriterMode3(legacy, storage)
+		return newDualWriterMode3(legacy, storage)
 	case Mode4:
 		// read and write only from storage
-		return NewDualWriterMode4(legacy, storage)
+		return newDualWriterMode4(legacy, storage)
 	default:
-		return NewDualWriterMode1(legacy, storage)
+		return newDualWriterMode1(legacy, storage)
 	}
 }
 

pkg/apiserver/rest/dualwriter_mode1.go

@@ -23,7 +23,7 @@ const mode1Str = "1"
 
 // NewDualWriterMode1 returns a new DualWriter in mode 1.
 // Mode 1 represents writing to and reading from LegacyStorage.
-func NewDualWriterMode1(legacy LegacyStorage, storage Storage) *DualWriterMode1 {
+func newDualWriterMode1(legacy LegacyStorage, storage Storage) *DualWriterMode1 {
 	metrics := &dualWriterMetrics{}
 	metrics.init()
 	return &DualWriterMode1{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode1"), dualWriterMetrics: metrics}
@@ -236,3 +236,7 @@ func (d *DualWriterMode1) NewList() runtime.Object {
 func (d *DualWriterMode1) ConvertToTable(ctx context.Context, object runtime.Object, tableOptions runtime.Object) (*metav1.Table, error) {
 	return d.Legacy.ConvertToTable(ctx, object, tableOptions)
 }
+
+func (d *DualWriterMode1) Compare(storageObj, legacyObj runtime.Object) bool {
+	return d.Storage.Compare(storageObj, legacyObj)
+}

pkg/apiserver/rest/dualwriter_mode2.go

@@ -27,7 +27,7 @@ const mode2Str = "2"
 
 // NewDualWriterMode2 returns a new DualWriter in mode 2.
 // Mode 2 represents writing to LegacyStorage and Storage and reading from LegacyStorage.
-func NewDualWriterMode2(legacy LegacyStorage, storage Storage) *DualWriterMode2 {
+func newDualWriterMode2(legacy LegacyStorage, storage Storage) *DualWriterMode2 {
 	metrics := &dualWriterMetrics{}
 	metrics.init()
 	return &DualWriterMode2{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode2"), dualWriterMetrics: metrics}
@@ -310,6 +310,10 @@ func (d *DualWriterMode2) ConvertToTable(ctx context.Context, object runtime.Obj
 	return d.Storage.ConvertToTable(ctx, object, tableOptions)
 }
 
+func (d *DualWriterMode2) Compare(storageObj, legacyObj runtime.Object) bool {
+	return d.Storage.Compare(storageObj, legacyObj)
+}
+
 func parseList(legacyList []runtime.Object) (metainternalversion.ListOptions, map[string]int, error) {
 	options := metainternalversion.ListOptions{}
 	originKeys := []string{}

pkg/apiserver/rest/dualwriter_mode3.go

@@ -18,9 +18,9 @@ type DualWriterMode3 struct {
 	Log klog.Logger
 }
 
-// NewDualWriterMode3 returns a new DualWriter in mode 3.
+// newDualWriterMode3 returns a new DualWriter in mode 3.
 // Mode 3 represents writing to LegacyStorage and Storage and reading from Storage.
-func NewDualWriterMode3(legacy LegacyStorage, storage Storage) *DualWriterMode3 {
+func newDualWriterMode3(legacy LegacyStorage, storage Storage) *DualWriterMode3 {
 	metrics := &dualWriterMetrics{}
 	metrics.init()
 	return &DualWriterMode3{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode3"), dualWriterMetrics: metrics}
@@ -157,3 +157,7 @@ func (d *DualWriterMode3) NewList() runtime.Object {
 func (d *DualWriterMode3) ConvertToTable(ctx context.Context, object runtime.Object, tableOptions runtime.Object) (*metav1.Table, error) {
 	return d.Storage.ConvertToTable(ctx, object, tableOptions)
 }
+
+func (d *DualWriterMode3) Compare(storageObj, legacyObj runtime.Object) bool {
+	return d.Storage.Compare(storageObj, legacyObj)
+}

pkg/apiserver/rest/dualwriter_mode4.go

@@ -17,9 +17,9 @@ type DualWriterMode4 struct {
 	Log klog.Logger
 }
 
-// NewDualWriterMode4 returns a new DualWriter in mode 4.
+// newDualWriterMode4 returns a new DualWriter in mode 4.
 // Mode 4 represents writing and reading from Storage.
-func NewDualWriterMode4(legacy LegacyStorage, storage Storage) *DualWriterMode4 {
+func newDualWriterMode4(legacy LegacyStorage, storage Storage) *DualWriterMode4 {
 	metrics := &dualWriterMetrics{}
 	metrics.init()
 	return &DualWriterMode4{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode4"), dualWriterMetrics: metrics}
@@ -85,3 +85,7 @@ func (d *DualWriterMode4) NewList() runtime.Object {
 func (d *DualWriterMode4) ConvertToTable(ctx context.Context, object runtime.Object, tableOptions runtime.Object) (*metav1.Table, error) {
 	return d.Storage.ConvertToTable(ctx, object, tableOptions)
 }
+
+func (d *DualWriterMode4) Compare(storageObj, legacyObj runtime.Object) bool {
+	return d.Storage.Compare(storageObj, legacyObj)
+}

pkg/registry/apis/dashboard/register.go

@@ -1,15 +1,11 @@
 package dashboard
 
 import (
-	"fmt"
-	"time"
-
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
 	"k8s.io/apiserver/pkg/registry/generic"
-	genericregistry "k8s.io/apiserver/pkg/registry/generic/registry"
 	"k8s.io/apiserver/pkg/registry/rest"
 	genericapiserver "k8s.io/apiserver/pkg/server"
 	common "k8s.io/kube-openapi/pkg/common"
@@ -24,7 +20,6 @@ import (
 	"github.com/grafana/grafana/pkg/registry/apis/dashboard/access"
 	"github.com/grafana/grafana/pkg/services/accesscontrol"
 	"github.com/grafana/grafana/pkg/services/apiserver/endpoints/request"
-	"github.com/grafana/grafana/pkg/services/apiserver/utils"
 	"github.com/grafana/grafana/pkg/services/dashboards"
 	dashver "github.com/grafana/grafana/pkg/services/dashboardversion"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
@@ -119,43 +114,10 @@ func (b *DashboardsAPIBuilder) GetAPIGroupInfo(
 	apiGroupInfo := genericapiserver.NewDefaultAPIGroupInfo(v0alpha1.GROUP, scheme, metav1.ParameterCodec, codecs)
 
 	resourceInfo := v0alpha1.DashboardResourceInfo
-	strategy := grafanaregistry.NewStrategy(scheme)
+	store, err := newStorage(scheme)
-	store := &genericregistry.Store{
+	if err != nil {
-		NewFunc:                   resourceInfo.NewFunc,
+		return nil, err
-		NewListFunc:               resourceInfo.NewListFunc,
-		PredicateFunc:             grafanaregistry.Matcher,
-		DefaultQualifiedResource:  resourceInfo.GroupResource(),
-		SingularQualifiedResource: resourceInfo.SingularGroupResource(),
-		CreateStrategy:            strategy,
-		UpdateStrategy:            strategy,
-		DeleteStrategy:            strategy,
 	}
-	store.TableConvertor = utils.NewTableConverter(
-		store.DefaultQualifiedResource,
-		[]metav1.TableColumnDefinition{
-			{Name: "Name", Type: "string", Format: "name"},
-			{Name: "Title", Type: "string", Format: "string", Description: "The dashboard name"},
-			{Name: "Created At", Type: "date"},
-		},
-		func(obj any) ([]interface{}, error) {
-			dash, ok := obj.(*v0alpha1.Dashboard)
-			if ok {
-				return []interface{}{
-					dash.Name,
-					dash.Spec.GetNestedString("title"),
-					dash.CreationTimestamp.UTC().Format(time.RFC3339),
-				}, nil
-			}
-			summary, ok := obj.(*v0alpha1.DashboardSummary)
-			if ok {
-				return []interface{}{
-					dash.Name,
-					summary.Spec.Title,
-					dash.CreationTimestamp.UTC().Format(time.RFC3339),
-				}, nil
-			}
-			return nil, fmt.Errorf("expected dashboard or summary")
-		})
 
 	legacyStore := &dashboardStorage{
 		resource:       resourceInfo,

pkg/registry/apis/dashboard/storage.go

@@ -0,0 +1,72 @@
+package dashboard
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/grafana/grafana/pkg/apis/dashboard/v0alpha1"
+	"github.com/grafana/grafana/pkg/services/apiserver/utils"
+	"k8s.io/apimachinery/pkg/runtime"
+
+	grafanaregistry "github.com/grafana/grafana/pkg/apiserver/registry/generic"
+	grafanarest "github.com/grafana/grafana/pkg/apiserver/rest"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	genericregistry "k8s.io/apiserver/pkg/registry/generic/registry"
+)
+
+var _ grafanarest.Storage = (*storage)(nil)
+
+type storage struct {
+	*genericregistry.Store
+}
+
+func newStorage(scheme *runtime.Scheme) (*storage, error) {
+	strategy := grafanaregistry.NewStrategy(scheme)
+	resourceInfo := v0alpha1.DashboardResourceInfo
+	store := &genericregistry.Store{
+		NewFunc:                   resourceInfo.NewFunc,
+		NewListFunc:               resourceInfo.NewListFunc,
+		PredicateFunc:             grafanaregistry.Matcher,
+		DefaultQualifiedResource:  resourceInfo.GroupResource(),
+		SingularQualifiedResource: resourceInfo.SingularGroupResource(),
+		CreateStrategy:            strategy,
+		UpdateStrategy:            strategy,
+		DeleteStrategy:            strategy,
+	}
+
+	store.TableConvertor = utils.NewTableConverter(
+		store.DefaultQualifiedResource,
+		[]metav1.TableColumnDefinition{
+			{Name: "Name", Type: "string", Format: "name"},
+			{Name: "Title", Type: "string", Format: "string", Description: "The dashboard name"},
+			{Name: "Created At", Type: "date"},
+		},
+		func(obj any) ([]interface{}, error) {
+			dash, ok := obj.(*v0alpha1.Dashboard)
+			if ok {
+				if dash != nil {
+					return []interface{}{
+						dash.Name,
+						dash.Spec.GetNestedString("title"),
+						dash.CreationTimestamp.UTC().Format(time.RFC3339),
+					}, nil
+				}
+			}
+			summary, ok := obj.(*v0alpha1.DashboardSummary)
+			if ok {
+				return []interface{}{
+					dash.Name,
+					summary.Spec.Title,
+					dash.CreationTimestamp.UTC().Format(time.RFC3339),
+				}, nil
+			}
+			return nil, fmt.Errorf("expected dashboard or summary")
+		})
+	return &storage{Store: store}, nil
+}
+
+// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+func (s *storage) Compare(storageObj, legacyObj runtime.Object) bool {
+	//TODO: define the comparison logic between a dashboard returned by the storage and a dashboard returned by the legacy storage
+	return false
+}

pkg/registry/apis/folders/storage.go

@@ -38,3 +38,9 @@ func newStorage(scheme *runtime.Scheme, optsGetter generic.RESTOptionsGetter, le
 	}
 	return &storage{Store: store}, nil
 }
+
+// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+func (s *storage) Compare(storageObj, legacyObj runtime.Object) bool {
+	//TODO: define the comparison logic between a folder returned by the storage and a folder returned by the legacy storage
+	return false
+}

pkg/registry/apis/peakq/storage.go

@@ -60,3 +60,9 @@ func newStorage(scheme *runtime.Scheme, optsGetter generic.RESTOptionsGetter) (*
 	}
 	return &storage{Store: store}, nil
 }
+
+// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+func (s *storage) Compare(storageObj, legacyObj runtime.Object) bool {
+	//TODO: define the comparison logic between a query template returned by the storage and a query template returned by the legacy storage
+	return false
+}

pkg/registry/apis/playlist/storage.go

@@ -38,3 +38,9 @@ func newStorage(scheme *runtime.Scheme, optsGetter generic.RESTOptionsGetter, le
 	}
 	return &storage{Store: store}, nil
 }
+
+// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+func (s *storage) Compare(storageObj, legacyObj runtime.Object) bool {
+	//TODO: define the comparison logic between a playlist returned by the storage and a playlist returned by the legacy storage
+	return false
+}

pkg/registry/apis/scope/storage.go

@@ -184,3 +184,9 @@ func SelectableScopeNodeFields(obj *scope.ScopeNode) fields.Set {
 		"spec.parentName": parentName,
 	})
 }
+
+// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+func (s *storage) Compare(storageObj, legacyObj runtime.Object) bool {
+	//TODO: define the comparison logic between a scope returned by the storage and a scope returned by the legacy storage
+	return false
+}

pkg/registry/apis/service/storage.go

@@ -60,3 +60,9 @@ func newStorage(scheme *runtime.Scheme, optsGetter generic.RESTOptionsGetter) (*
 	}
 	return &storage{Store: store}, nil
 }
+
+// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+func (s *storage) Compare(storageObj, legacyObj runtime.Object) bool {
+	//TODO: define the comparison logic between a generic object returned by the storage and a generic object returned by the legacy storage
+	return false
+}