reopen #192 (#213)

* implement create_before_destroy on instances

* add random provider to versions.tf

* run terraform fmt

* run `make readme` to pass ci action

* fix random_pet in case of enabled == true

* don't create resource in enabled == false

---------

Co-authored-by: Benjamin Smith <ben.smith.developer@gmail.com>

README.md

@@ -320,12 +320,14 @@ Available targets:
 | <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.0.0 |
 | <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 4.23.0 |
 | <a name="requirement_null"></a> [null](#requirement\_null) | >= 2.0 |
+| <a name="requirement_random"></a> [random](#requirement\_random) | >= 2.0 |
 
 ## Providers
 
 | Name | Version |
 |------|---------|
 | <a name="provider_aws"></a> [aws](#provider\_aws) | >= 4.23.0 |
+| <a name="provider_random"></a> [random](#provider\_random) | >= 2.0 |
 
 ## Modules
 
@@ -356,6 +358,7 @@ Available targets:
 | [aws_security_group_rule.ingress_cidr_blocks](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule) | resource |
 | [aws_security_group_rule.ingress_security_groups](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule) | resource |
 | [aws_security_group_rule.traffic_inside_security_group](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule) | resource |
+| [random_pet.instance](https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/pet) | resource |
 | [aws_iam_policy_document.enhanced_monitoring](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
 | [aws_partition.current](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/partition) | data source |
 

docs/terraform.md

@@ -6,12 +6,14 @@
 | <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.0.0 |
 | <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 4.23.0 |
 | <a name="requirement_null"></a> [null](#requirement\_null) | >= 2.0 |
+| <a name="requirement_random"></a> [random](#requirement\_random) | >= 2.0 |
 
 ## Providers
 
 | Name | Version |
 |------|---------|
 | <a name="provider_aws"></a> [aws](#provider\_aws) | >= 4.23.0 |
+| <a name="provider_random"></a> [random](#provider\_random) | >= 2.0 |
 
 ## Modules
 
@@ -42,6 +44,7 @@
 | [aws_security_group_rule.ingress_cidr_blocks](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule) | resource |
 | [aws_security_group_rule.ingress_security_groups](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule) | resource |
 | [aws_security_group_rule.traffic_inside_security_group](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule) | resource |
+| [random_pet.instance](https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/pet) | resource |
 | [aws_iam_policy_document.enhanced_monitoring](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
 | [aws_partition.current](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/partition) | data source |
 

main.tf

@@ -249,11 +249,20 @@ resource "aws_rds_cluster" "secondary" {
   }
 }
 
+resource "random_pet" "instance" {
+  count  = local.enabled ? 1 : 0
+  prefix = var.cluster_identifier == "" ? module.this.id : var.cluster_identifier
+  keepers = {
+    cluster_family = var.cluster_family
+    instance_class = var.serverlessv2_scaling_configuration != null ? "db.serverless" : var.instance_type
+  }
+}
+
 resource "aws_rds_cluster_instance" "default" {
   count                                 = local.cluster_instance_count
-  identifier                            = var.cluster_identifier == "" ? "${module.this.id}-${count.index + 1}" : "${var.cluster_identifier}-${count.index + 1}"
+  identifier                            = "${random_pet.instance[0].id}-${count.index + 1}"
   cluster_identifier                    = coalesce(join("", aws_rds_cluster.primary[*].id), join("", aws_rds_cluster.secondary[*].id))
-  instance_class                        = var.serverlessv2_scaling_configuration != null ? "db.serverless" : var.instance_type
+  instance_class                        = random_pet.instance[0].keepers.instance_class
   db_subnet_group_name                  = join("", aws_db_subnet_group.default[*].name)
   db_parameter_group_name               = join("", aws_db_parameter_group.default[*].name)
   publicly_accessible                   = var.publicly_accessible
@@ -291,7 +300,8 @@ resource "aws_rds_cluster_instance" "default" {
   ]
 
   lifecycle {
-    ignore_changes = [engine_version]
+    ignore_changes        = [engine_version]
+    create_before_destroy = true
   }
 }
 

versions.tf

@@ -10,5 +10,9 @@ terraform {
       source  = "hashicorp/null"
       version = ">= 2.0"
     }
+    random = {
+      source  = "hashicorp/random"
+      version = ">= 2.0"
+    }
   }
 }