delete.go

const myKindFinalizer = "grp.example.com/finalizer"

// DeletionReconciler controls the reconciliation of deleted resources
func (r *MykindReconciler) deletionReconciler(ctx context.Context, cr *grpv1alpha1.Mykind) (ctrl.Result, error) {
	// Finalizer logic here
	// More on finalizers: https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#finalizers
	if controllerutil.ContainsFinalizer(cr, myKindFinalizer) {
		// our finalizer is present, so lets handle any external dependency
		if err := r.doCleanup(cr); err != nil {
			// if fail to delete the external dependency here, return with error
			// so that it can be retried
      return r.manageDeleteFailure(ctx, cr, err)
		}

		// remove our finalizer from the list and update it.
		controllerutil.RemoveFinalizer(cr, myKindFinalizer)
		if err := r.Update(ctx, cr); err != nil {
			return r.manageDeleteFailure(ctx, cr, err)
		}
	}

	// Stop reconciliation as the item is being deleted
  return r.manageDeleteSuccess(ctx, cr)
}