Allow storage update operation to unavailable db instance (#200)

Issue [#2214](aws-controllers-k8s/community#2214)

Description of changes:
With this change we allow the controller to make a storage update 
call when the DB instance is unavailable due to a `storage-full` status.

This case is not easy to test, since the minimum storage to allocate is 20GiB.
Options for testing:
* Create an existing DB instance that is already unavailable due to `storage-full`
  status and update storage (this would then require us to fill up the remaining space)

more ideas are welcome...


By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

apis/v1alpha1/ack-generate-metadata.yaml

@@ -1,5 +1,5 @@
 ack_generate_info:
-  build_date: "2024-10-10T04:05:06Z"
+  build_date: "2024-11-25T18:12:36Z"
   build_hash: 36c2d234498c2bc4f60773ab8df632af4067f43b
   go_version: go1.23.2
   version: v0.39.1

pkg/resource/db_instance/hooks.go

@@ -581,3 +581,12 @@ func setDeleteDBInstanceInput(
 	input.DeleteAutomatedBackups = params.DeleteAutomatedBackup
 	return nil
 }
+
+// needStorageUpdate
+func needStorageUpdate(
+	r *resource,
+	delta *ackcompare.Delta,
+) bool {
+	return strings.Contains(*r.ko.Status.DBInstanceStatus, "storage-full") &&
+		delta.DifferentAt("Spec.AllocatedStorage")
+}

templates/hooks/db_instance/sdk_update_pre_build_request.go.tpl

@@ -14,7 +14,7 @@
 		ackcondition.SetSynced(desired, corev1.ConditionTrue, nil, nil)
 		return desired, nil
 	}
-	if !instanceAvailable(latest) {
+	if !instanceAvailable(latest) && !needStorageUpdate(latest, delta) {
 		msg := "DB instance cannot be modifed while in '" + *latest.ko.Status.DBInstanceStatus + "' status"
 		ackcondition.SetSynced(desired, corev1.ConditionFalse, &msg, nil)
 		return desired, requeueWaitUntilCanModify(latest)