backend: Add Delete() to restic.Backend interface

internal/backend/local/local.go

@@ -275,7 +275,7 @@ func (b *Local) List(ctx context.Context, t restic.FileType) <-chan string {
 }
 
 // Delete removes the repository and all files.
-func (b *Local) Delete() error {
+func (b *Local) Delete(ctx context.Context) error {
 	debug.Log("Delete()")
 	return fs.RemoveAll(b.Path)
 }

internal/backend/rest/rest.go

@@ -349,3 +349,34 @@ func (b *restBackend) Close() error {
 	// same function.
 	return nil
 }
+
+// Remove keys for a specified backend type.
+func (b *restBackend) removeKeys(ctx context.Context, t restic.FileType) error {
+	for key := range b.List(ctx, restic.DataFile) {
+		err := b.Remove(ctx, restic.Handle{Type: restic.DataFile, Name: key})
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// Delete removes all data in the backend.
+func (b *restBackend) Delete(ctx context.Context) error {
+	alltypes := []restic.FileType{
+		restic.DataFile,
+		restic.KeyFile,
+		restic.LockFile,
+		restic.SnapshotFile,
+		restic.IndexFile}
+
+	for _, t := range alltypes {
+		err := b.removeKeys(ctx, t)
+		if err != nil {
+			return nil
+		}
+	}
+
+	return b.Remove(ctx, restic.Handle{Type: restic.ConfigFile})
+}

internal/backend/sftp/sftp.go

@@ -499,3 +499,8 @@ func (r *SFTP) Close() error {
 	<-r.result
 	return nil
 }
+
+// Delete removes all data in the backend.
+func (r *SFTP) Delete(context.Context) error {
+	return r.c.RemoveDirectory(r.p)
+}

internal/restic/backend.go

@@ -40,6 +40,9 @@ type Backend interface {
 	// IsNotExist returns true if the error was caused by a non-existing file
 	// in the backend.
 	IsNotExist(err error) bool
+
+	// Delete removes all data in the backend.
+	Delete(ctx context.Context) error
 }
 
 // FileInfo is returned by Stat() and contains information about a file in the