Don't allow deletion of in-progress backups

Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>

pkg/controller/backup_controller.go

@@ -66,6 +66,7 @@ type backupController struct {
 	clock            clock.Clock
 	logger           logrus.FieldLogger
 	pluginManager    plugin.Manager
+	backupTracker    BackupTracker
 }
 
 func NewBackupController(
@@ -77,6 +78,7 @@ func NewBackupController(
 	pvProviderExists bool,
 	logger logrus.FieldLogger,
 	pluginManager plugin.Manager,
+	backupTracker BackupTracker,
 ) Interface {
 	c := &backupController{
 		backupper:        backupper,
@@ -90,6 +92,7 @@ func NewBackupController(
 		clock:            &clock.RealClock{},
 		logger:           logger,
 		pluginManager:    pluginManager,
+		backupTracker:    backupTracker,
 	}
 
 	c.syncHandler = c.processBackup
@@ -261,6 +264,9 @@ func (controller *backupController) processBackup(key string) error {
 		return nil
 	}
 
+	controller.backupTracker.Add(backup.Namespace, backup.Name)
+	defer controller.backupTracker.Delete(backup.Namespace, backup.Name)
+
 	logContext.Debug("Running backup")
 	// execution & upload of backup
 	if err := controller.runBackup(backup, controller.bucket); err != nil {