rbd: add Manager.GetVolumeGroupSnapshotByName

The Group Controller Server may need to fetch a VolumeGroupSnapshot that
was statically provisioned. In that case, only the name of the
VolumeGroupSnapshot is known and should be resolved to an object.

Signed-off-by: Niels de Vos <ndevos@ibm.com>

internal/rbd/manager.go

@@ -337,6 +337,68 @@ func (mgr *rbdManager) GetVolumeGroupSnapshotByID(
 	return vgs, nil
 }
 
+func (mgr *rbdManager) GetVolumeGroupSnapshotByName(
+	ctx context.Context,
+	name string,
+) (types.VolumeGroupSnapshot, error) {
+	pool, ok := mgr.parameters["pool"]
+	if !ok || pool == "" {
+		return nil, errors.New("required 'pool' option missing in volume group parameters")
+	}
+
+	// groupNamePrefix is an optional parameter, can be an empty string
+	prefix := mgr.parameters["groupNamePrefix"]
+
+	clusterID, err := util.GetClusterID(mgr.parameters)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get cluster-id: %w", err)
+	}
+
+	uuid, freeUUID, err := mgr.getGroupUUID(ctx, clusterID, pool, name, prefix)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get a UUID for volume group snapshot %q: %w", name, err)
+	}
+	defer func() {
+		// no error, no need to undo the reservation
+		if err == nil {
+			return
+		}
+
+		freeUUID()
+	}()
+
+	monitors, err := util.Mons(util.CsiConfigFile, clusterID)
+	if err != nil {
+		return nil, fmt.Errorf("failed to find MONs for cluster %q: %w", clusterID, err)
+	}
+
+	_ /*journalPoolID*/, poolID, err := util.GetPoolIDs(ctx, monitors, pool, pool, mgr.creds)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get the pool for volume group snapshot with uuid for %q: %w", uuid, err)
+	}
+
+	csiID, err := util.GenerateVolID(ctx, monitors, mgr.creds, poolID, pool, clusterID, uuid)
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate a unique CSI volume group with uuid %q: %w", uuid, err)
+	}
+
+	vgs, err := rbd_group.GetVolumeGroupSnapshot(ctx, csiID, mgr.csiID, mgr.creds, mgr)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get existing volume group snapshot with uuid %q: %w", uuid, err)
+	}
+
+	snapshots, err := vgs.ListSnapshots(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get snapshots for volume group snapshot %q: %w", vgs, err)
+	}
+
+	if len(snapshots) == 0 {
+		return nil, fmt.Errorf("volume group snapshot %q is incomplete, it has no snapshots", vgs)
+	}
+
+	return vgs, nil
+}
+
 func (mgr *rbdManager) CreateVolumeGroupSnapshot(
 	ctx context.Context,
 	vg types.VolumeGroup,

internal/rbd/types/manager.go

@@ -57,6 +57,10 @@ type Manager interface {
 	// CSI id/handle.
 	GetVolumeGroupSnapshotByID(ctx context.Context, id string) (VolumeGroupSnapshot, error)
 
+	// GetVolumeGroupSnapshotByName resolves the VolumeGroupSnapshot by the
+	// name (like the request-id).
+	GetVolumeGroupSnapshotByName(ctx context.Context, name string) (VolumeGroupSnapshot, error)
+
 	// CreateVolumeGroupSnapshot instructs the Manager to create a
 	// VolumeGroupSnapshot from the VolumeGroup. All snapshots in the
 	// returned VolumeGroupSnapshot have been taken while I/O on the