fix: add retain_backups_on_delete to mssql submodule (#764)

Author: nika-pr

modules/mssql/README.md

@@ -74,6 +74,7 @@ module "mssql" {
 | project\_id | The project ID to manage the Cloud SQL resources | `string` | n/a | yes |
 | random\_instance\_name | Sets random suffix at the end of the Cloud SQL resource name | `bool` | `false` | no |
 | region | The region of the Cloud SQL resources | `string` | `"us-central1"` | no |
+| retain\_backups\_on\_delete | When this parameter is set to true, Cloud SQL retains backups of the instance even after the instance is deleted. The ON\_DEMAND backup will be retained until customer deletes the backup or the project. The AUTOMATED backup will be retained based on the backups retention setting. | `bool` | `false` | no |
 | root\_password | MSSERVER password for the root user. If not set, a random one will be generated and available in the root\_password output variable. | `string` | `""` | no |
 | secondary\_zone | The preferred zone for the read replica instance, it should be something like: `us-central1-a`, `us-east1-c`. | `string` | `null` | no |
 | sql\_server\_audit\_config | SQL server audit config settings. | `map(string)` | `{}` | no |

modules/mssql/main.tf

@@ -63,6 +63,7 @@ resource "google_sql_database_instance" "default" {
     deletion_protection_enabled = var.deletion_protection_enabled
     connector_enforcement       = local.connector_enforcement
     enable_dataplex_integration = var.enable_dataplex_integration
+    retain_backups_on_delete    = var.retain_backups_on_delete
 
     dynamic "backup_configuration" {
       for_each = !local.is_secondary_instance && var.backup_configuration.enabled ? [var.backup_configuration] : []

modules/mssql/variables.tf

@@ -241,6 +241,12 @@ variable "backup_configuration" {
   }
 }
 
+variable "retain_backups_on_delete" {
+  description = "When this parameter is set to true, Cloud SQL retains backups of the instance even after the instance is deleted. The ON_DEMAND backup will be retained until customer deletes the backup or the project. The AUTOMATED backup will be retained based on the backups retention setting."
+  type        = bool
+  default     = false
+}
+
 variable "db_name" {
   description = "The name of the default database to create"
   type        = string