unified-storage: apply backwards compatibility changes outside sqlkv (#115954)

pkg/storage/unified/resource/datastore.go

@@ -12,6 +12,9 @@ import (
 	"time"
 
 	"github.com/grafana/grafana/pkg/apimachinery/validation"
+	"github.com/grafana/grafana/pkg/storage/unified/sql/db"
+	"github.com/grafana/grafana/pkg/storage/unified/sql/dbutil"
+	"github.com/grafana/grafana/pkg/storage/unified/sql/sqltemplate"
 	gocache "github.com/patrickmn/go-cache"
 )
 
@@ -306,10 +309,6 @@ func (d *dataStore) GetResourceKeyAtRevision(ctx context.Context, key GetRequest
 		return DataKey{}, fmt.Errorf("invalid get request key: %w", err)
 	}
 
-	if rv == 0 {
-		rv = math.MaxInt64
-	}
-
 	listKey := ListRequestKey(key)
 
 	iter := d.ListResourceKeysAtRevision(ctx, ListRequestOptions{Key: listKey, ResourceVersion: rv})
@@ -598,7 +597,7 @@ func ParseKey(key string) (DataKey, error) {
 	}, nil
 }
 
-// Temporary while we need to support unified/sql/backend compatibility
+// Temporary while we need to support unified/sql/backend compatibility.
 // Remove once we stop using RvManager in storage_backend.go
 func ParseKeyWithGUID(key string) (DataKey, error) {
 	parts := strings.Split(key, "/")
@@ -815,3 +814,121 @@ func (d *dataStore) getGroupResources(ctx context.Context) ([]GroupResource, err
 
 	return results, nil
 }
+
+// TODO: remove when backwards compatibility is no longer needed.
+var (
+	sqlKVUpdateLegacyResourceHistory = mustTemplate("sqlkv_update_legacy_resource_history.sql")
+	sqlKVInsertLegacyResource        = mustTemplate("sqlkv_insert_legacy_resource.sql")
+	sqlKVUpdateLegacyResource        = mustTemplate("sqlkv_update_legacy_resource.sql")
+)
+
+// TODO: remove when backwards compatibility is no longer needed.
+type sqlKVLegacySaveRequest struct {
+	sqltemplate.SQLTemplate
+	GUID       string
+	Group      string
+	Resource   string
+	Namespace  string
+	Name       string
+	Action     int64
+	Folder     string
+	PreviousRV int64
+}
+
+func (req sqlKVLegacySaveRequest) Validate() error {
+	return nil
+}
+
+// TODO: remove when backwards compatibility is no longer needed.
+type sqlKVLegacyUpdateHistoryRequest struct {
+	sqltemplate.SQLTemplate
+	GUID       string
+	PreviousRV int64
+	Generation int64
+}
+
+func (req sqlKVLegacyUpdateHistoryRequest) Validate() error {
+	return nil
+}
+
+// applyBackwardsCompatibleChanges updates the `resource` and `resource_history` tables
+// to make sure the sqlkv implementation is backwards-compatible with the existing sql backend.
+// Specifically, it will update the `resource_history` table to include the previous resource version
+// and generation, which come from the `WriteEvent`, and also make the corresponding change on the
+// `resource` table, no longer used in the storage backend.
+//
+// TODO: remove when backwards compatibility is no longer needed.
+func (d *dataStore) applyBackwardsCompatibleChanges(ctx context.Context, tx db.Tx, event WriteEvent, key DataKey) error {
+	kv, isSQLKV := d.kv.(*sqlKV)
+	if !isSQLKV {
+		return nil
+	}
+
+	_, err := dbutil.Exec(ctx, tx, sqlKVUpdateLegacyResourceHistory, sqlKVLegacyUpdateHistoryRequest{
+		SQLTemplate: sqltemplate.New(kv.dialect),
+		GUID:        key.GUID,
+		PreviousRV:  event.PreviousRV,
+		Generation:  event.Object.GetGeneration(),
+	})
+
+	if err != nil {
+		return fmt.Errorf("compatibility layer: failed to insert to resource: %w", err)
+	}
+
+	var action int64
+	switch key.Action {
+	case DataActionCreated:
+		action = 1
+	case DataActionUpdated:
+		action = 2
+	case DataActionDeleted:
+		action = 3
+	}
+
+	switch key.Action {
+	case DataActionCreated:
+		_, err := dbutil.Exec(ctx, tx, sqlKVInsertLegacyResource, sqlKVLegacySaveRequest{
+			SQLTemplate: sqltemplate.New(kv.dialect),
+			GUID:        key.GUID,
+			Group:       key.Group,
+			Resource:    key.Resource,
+			Namespace:   key.Namespace,
+			Name:        key.Name,
+			Action:      action,
+			Folder:      key.Folder,
+			PreviousRV:  event.PreviousRV,
+		})
+
+		if err != nil {
+			return fmt.Errorf("compatibility layer: failed to insert to resource: %w", err)
+		}
+	case DataActionUpdated:
+		_, err := dbutil.Exec(ctx, tx, sqlKVUpdateLegacyResource, sqlKVLegacySaveRequest{
+			SQLTemplate: sqltemplate.New(kv.dialect),
+			GUID:        key.GUID,
+			Group:       key.Group,
+			Resource:    key.Resource,
+			Namespace:   key.Namespace,
+			Name:        key.Name,
+			Folder:      key.Folder,
+			PreviousRV:  event.PreviousRV,
+		})
+
+		if err != nil {
+			return fmt.Errorf("compatibility layer: failed to update resource: %w", err)
+		}
+	case DataActionDeleted:
+		_, err := dbutil.Exec(ctx, tx, sqlKVDeleteLegacyResource, sqlKVLegacySaveRequest{
+			SQLTemplate: sqltemplate.New(kv.dialect),
+			Resource:    key.Resource,
+			Namespace:   key.Namespace,
+			Name:        key.Name,
+		})
+
+		if err != nil {
+			return fmt.Errorf("compatibility layer: failed to delete from resource: %w", err)
+		}
+	}
+
+	return nil
+}