fix: add customizable final_snapshot_identifier

to be able to have multiple db apply/destroy lifecycles in the same
account

Author: kaiehrhardt

docs/terraform.md

@@ -71,6 +71,7 @@
 | <a name="input_engine"></a> [engine](#input\_engine) | The name of the database engine to be used for this DB cluster. Defaults to `docdb`. Valid values: `docdb` | `string` | `"docdb"` | no |
 | <a name="input_engine_version"></a> [engine\_version](#input\_engine\_version) | The version number of the database engine to use | `string` | `"3.6.0"` | no |
 | <a name="input_environment"></a> [environment](#input\_environment) | ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT' | `string` | `null` | no |
+| <a name="input_final_snapshot_identifier"></a> [final\_snapshot\_identifier](#input\_final\_snapshot\_identifier) | Name of the final DB snapshot, if skip_final_snapshot is false. | `string` | `""` | no |
 | <a name="input_external_security_group_id_list"></a> [external\_security\_group\_id\_list](#input\_external\_security\_group\_id\_list) | List of external security group IDs to attach to the Document DB | `list(string)` | `[]` | no |
 | <a name="input_id_length_limit"></a> [id\_length\_limit](#input\_id\_length\_limit) | Limit `id` to this many characters (minimum 6).<br>Set to `0` for unlimited length.<br>Set to `null` for keep the existing setting, which defaults to `0`.<br>Does not affect `id_full`. | `number` | `null` | no |
 | <a name="input_instance_class"></a> [instance\_class](#input\_instance\_class) | The instance class to use. For more details, see https://docs.aws.amazon.com/documentdb/latest/developerguide/db-instance-classes.html#db-instance-class-specs | `string` | `"db.r4.large"` | no |

main.tf

@@ -64,7 +64,7 @@ resource "aws_docdb_cluster" "default" {
   backup_retention_period         = var.retention_period
   preferred_backup_window         = var.preferred_backup_window
   preferred_maintenance_window    = var.preferred_maintenance_window
-  final_snapshot_identifier       = lower(module.this.id)
+  final_snapshot_identifier       = var.final_snapshot_identifier != "" ? var.final_snapshot_identifier : lower(module.this.id)
   skip_final_snapshot             = var.skip_final_snapshot
   deletion_protection             = var.deletion_protection
   apply_immediately               = var.apply_immediately

variables.tf

@@ -81,6 +81,12 @@ variable "snapshot_identifier" {
   description = "Specifies whether or not to create this cluster from a snapshot. You can use either the name or ARN when specifying a DB cluster snapshot, or the ARN when specifying a DB snapshot"
 }
 
+variable "final_snapshot_identifier" {
+  type        = string
+  default     = ""
+  description = "Name of the final DB snapshot, if skip_final_snapshot is false."
+}
+
 variable "db_port" {
   type        = number
   default     = 27017