Switch backup finalizer to DeleteBackupRequest

We ran into a lot of problems using a finalizer on the backup to allow
the Ark server to clean up all associated backup data when deleting a
backup.

Users also found it less than desirable that deleting the heptio-ark
namespace resulted in all the backup data being deleted.

This removes the finalizer and replaces it with an explicit
DeleteBackupRequest that is created as a means of requesting the
deletion of a backup and all its associated data. This is what `ark
backup delete` does.

If you use kubectl to delete a backup or to delete the heptio-ark
namespace, this no longer deletes associated backups. Additionally, as
long as the heptio-ark namespace still exists, the Ark server's
BackupSyncController will continually sync backups into the heptio-ark
namespace from object storage.

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

pkg/backup/delete_helpers.go

@@ -0,0 +1,47 @@
+/*
+Copyright 2018 the Heptio Ark contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package backup
+
+import (
+	"fmt"
+
+	"github.com/heptio/ark/pkg/apis/ark/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// NewDeleteBackupRequest creates a DeleteBackupRequest for the backup identified by name.
+func NewDeleteBackupRequest(name string) *v1.DeleteBackupRequest {
+	return &v1.DeleteBackupRequest{
+		ObjectMeta: metav1.ObjectMeta{
+			GenerateName: name + "-",
+			Labels: map[string]string{
+				v1.BackupNameLabel: name,
+			},
+		},
+		Spec: v1.DeleteBackupRequestSpec{
+			BackupName: name,
+		},
+	}
+}
+
+// NewDeleteBackupRequestListOptions creates a ListOptions with a label selector configured to
+// find DeleteBackupRequests for the backup identified by name.
+func NewDeleteBackupRequestListOptions(name string) metav1.ListOptions {
+	return metav1.ListOptions{
+		LabelSelector: fmt.Sprintf("%s=%s", v1.BackupNameLabel, name),
+	}
+}