support deletion of snapshots after restore from backup

When a user requests a restore from an off-site backup, they might want the
local snapshot to be deleted after the restore.

We already have this option when creating the snapshot by using a special
parameter on the snapshot class. However, we do not have that information
available directly.

To support this, we need to lookup the snapshot content and snapshot class
ourselfes, then parse the parameters. This is all optional, as LINSTOR CSI
still needs to work outside kubernetes, or inside Kubernetes with incomplete
information.

Signed-off-by: Moritz "WanzenBug" Wanzenböck <moritz.wanzenboeck@linbit.com>

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Support to delete downloaded backups after restore operation (k8s only).
+
 ## [1.2.3] - 2023-08-31
 
 ### Changed

cmd/linstor-csi/linstor-csi.go

@@ -139,6 +139,7 @@ func main() {
 		driver.Expander(linstorClient),
 		driver.NodeInformer(linstorClient),
 		driver.TopologyPrefix(*propNs),
+		driver.ConfigureKubernetesIfAvailable(),
 	)
 	if err != nil {
 		log.Fatal(err)

pkg/client/linstor.go

@@ -910,7 +910,7 @@ func (s *Linstor) SnapDelete(ctx context.Context, snap *volume.Snapshot) error {
 }
 
 // VolFromSnap creates the volume using the data contained within the snapshot.
-func (s *Linstor) VolFromSnap(ctx context.Context, snap *volume.Snapshot, vol *volume.Info, params *volume.Parameters, topologies *csi.TopologyRequirement) error {
+func (s *Linstor) VolFromSnap(ctx context.Context, snap *volume.Snapshot, vol *volume.Info, params *volume.Parameters, snapParams *volume.SnapshotParameters, topologies *csi.TopologyRequirement) error {
 	logger := s.log.WithFields(logrus.Fields{
 		"volume":   fmt.Sprintf("%+v", vol),
 		"snapshot": fmt.Sprintf("%+v", snap),
@@ -987,6 +987,20 @@ func (s *Linstor) VolFromSnap(ctx context.Context, snap *volume.Snapshot, vol *v
 		return err
 	}
 
+	if snap.Remote != "" && snapParams != nil && snapParams.DeleteLocal {
+		logger.Info("deleting local copy of backup")
+
+		err := s.client.Resources.DeleteSnapshot(ctx, snap.SourceVolumeId, snap.SnapshotId)
+		if err != nil {
+			logger.WithError(err).Warn("deleting local copy of backup failed")
+		}
+
+		err = s.deleteResourceDefinitionAndGroupIfUnused(ctx, snap.GetSourceVolumeId())
+		if err != nil {
+			logger.WithError(err).Warn("deleting local RD of backup failed")
+		}
+	}
+
 	logger.Debug("success")
 	return nil
 }

pkg/client/mock.go

@@ -190,7 +190,7 @@ func (s *MockStorage) FindSnapsBySource(ctx context.Context, sourceVol *volume.I
 	return results[start:end], nil
 }
 
-func (s *MockStorage) VolFromSnap(ctx context.Context, snap *volume.Snapshot, vol *volume.Info, parameters *volume.Parameters, topologies *csi.TopologyRequirement) error {
+func (s *MockStorage) VolFromSnap(ctx context.Context, snap *volume.Snapshot, vol *volume.Info, parameters *volume.Parameters, snapParams *volume.SnapshotParameters, topologies *csi.TopologyRequirement) error {
 	s.createdVolumes = append(s.createdVolumes, vol)
 	return nil
 }

pkg/driver/driver.go

@@ -39,6 +39,11 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/dynamic"
+	"k8s.io/client-go/rest"
 
 	"github.com/piraeusdatastore/linstor-csi/pkg/client"
 	"github.com/piraeusdatastore/linstor-csi/pkg/linstor"
@@ -57,6 +62,7 @@ type Driver struct {
 	VolumeStatter volume.VolumeStatter
 	Expander      volume.Expander
 	NodeInformer  volume.NodeInformer
+	kubeClient    dynamic.Interface
 	srv           *grpc.Server
 	log           *logrus.Entry
 	version       string
@@ -236,6 +242,20 @@ func LogLevel(s string) func(*Driver) error {
 	}
 }
 
+func ConfigureKubernetesIfAvailable() func(*Driver) error {
+	return func(d *Driver) error {
+		cfg, err := rest.InClusterConfig()
+		if err != nil {
+			// Not running in kubernetes
+			return nil
+		}
+
+		d.kubeClient, err = dynamic.NewForConfig(cfg)
+
+		return err
+	}
+}
+
 // GetPluginInfo https://github.com/container-storage-interface/spec/blob/v1.6.0/spec.md#getplugininfo
 func (d Driver) GetPluginInfo(ctx context.Context, req *csi.GetPluginInfoRequest) (*csi.GetPluginInfoResponse, error) {
 	return &csi.GetPluginInfoResponse{
@@ -1259,7 +1279,14 @@ func (d Driver) createNewVolume(ctx context.Context, info *volume.Info, params *
 					"CreateVolume failed for %s: snapshot not found in storage backend", req.GetName())
 			}
 
-			if err := d.Snapshots.VolFromSnap(ctx, snap, info, params, req.GetAccessibilityRequirements()); err != nil {
+			snapParams, err := d.maybeGetSnapshotParameters(ctx, snap)
+			if err != nil {
+				logger.WithError(err).Warn("failed to fetch snapshot parameters, continuing without it")
+
+				snapParams = nil
+			}
+
+			if err := d.Snapshots.VolFromSnap(ctx, snap, info, params, snapParams, req.GetAccessibilityRequirements()); err != nil {
 				d.failpathDelete(ctx, info.ID)
 				return nil, status.Errorf(codes.Internal,
 					"CreateVolume failed for %s: %v", req.GetName(), err)
@@ -1301,7 +1328,7 @@ func (d Driver) createNewVolume(ctx context.Context, info *volume.Info, params *
 				}
 			}()
 
-			err = d.Snapshots.VolFromSnap(ctx, snap, info, params, req.GetAccessibilityRequirements())
+			err = d.Snapshots.VolFromSnap(ctx, snap, info, params, nil, req.GetAccessibilityRequirements())
 			if err != nil {
 				d.failpathDelete(ctx, info.ID)
 
@@ -1345,6 +1372,61 @@ func (d Driver) createNewVolume(ctx context.Context, info *volume.Info, params *
 	}, nil
 }
 
+func findMatchingSnapshotClassName(snap *volume.Snapshot, contents ...unstructured.Unstructured) string {
+	for i := range contents {
+		content := contents[i].Object
+		if driver, _, _ := unstructured.NestedString(content, "spec", "driver"); driver != linstor.DriverName {
+			continue
+		}
+
+		if handle, _, _ := unstructured.NestedString(content, "status", "snapshotHandle"); handle != snap.SnapshotId {
+			continue
+		}
+
+		if readyToUse, _, _ := unstructured.NestedBool(content, "status", "readyToUse"); !readyToUse {
+			continue
+		}
+
+		snapshotClass, _, _ := unstructured.NestedString(content, "spec", "volumeSnapshotClassName")
+
+		return snapshotClass
+	}
+
+	return ""
+}
+
+func (d Driver) maybeGetSnapshotParameters(ctx context.Context, snap *volume.Snapshot) (*volume.SnapshotParameters, error) {
+	if d.kubeClient == nil {
+		return nil, nil
+	}
+
+	gv := schema.GroupVersion{Group: "snapshot.storage.k8s.io", Version: "v1"}
+	contentGvr := gv.WithResource("volumesnapshotcontents")
+	classGvr := gv.WithResource("volumesnapshotclasses")
+
+	result, err := d.kubeClient.Resource(contentGvr).List(ctx, metav1.ListOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch list of snapshot contents")
+	}
+
+	snapshotClassName := findMatchingSnapshotClassName(snap, result.Items...)
+	if snapshotClassName == "" {
+		return nil, fmt.Errorf("failed to determine snapshot class name")
+	}
+
+	class, err := d.kubeClient.Resource(classGvr).Get(ctx, snapshotClassName, metav1.GetOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch snapshot class: %w", err)
+	}
+
+	rawParams, _, err := unstructured.NestedStringMap(class.Object, "parameters")
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse snapshot class: %w", err)
+	}
+
+	return volume.NewSnapshotParameters(rawParams, nil)
+}
+
 // maybeDeleteLocalSnapshot deletes the local portion of a snapshot according to their volume.SnapshotParameters.
 // It will not delete a snapshot that is not ready, does not have a remote target, or where local deletion is disabled.
 func (d Driver) maybeDeleteLocalSnapshot(ctx context.Context, snap *volume.Snapshot, params *volume.SnapshotParameters) error {

pkg/volume/volume.go

@@ -80,7 +80,7 @@ type SnapshotCreateDeleter interface {
 	// List Snapshots should return a sorted list of snapshots.
 	ListSnaps(ctx context.Context, start, limit int) ([]*Snapshot, error)
 	// VolFromSnap creates a new volume based on the provided snapshot.
-	VolFromSnap(ctx context.Context, snap *Snapshot, vol *Info, params *Parameters, topologies *csi.TopologyRequirement) error
+	VolFromSnap(ctx context.Context, snap *Snapshot, vol *Info, params *Parameters, snapParams *SnapshotParameters, topologies *csi.TopologyRequirement) error
 }
 
 // AttacherDettacher handles operations relating to volume accessiblity on nodes.