feat: Update subnet group configuration and move from sub-module to root module

Author: bryantbiggs

README.md

@@ -2,6 +2,8 @@
 
 Terraform module which creates AWS ElastiCache resources.
 
+[![SWUbanner](https://raw.githubusercontent.com/vshymanskyy/StandWithUkraine/main/banner2-direct.svg)](https://github.com/vshymanskyy/StandWithUkraine/blob/main/docs/README.md)
+
 ## Usage
 
 See [`examples`](https://github.com/clowdhaus/terraform-aws-elasticache/tree/main/examples) directory for working examples to reference:
@@ -39,9 +41,7 @@ Examples codified under the [`examples`](https://github.com/clowdhaus/terraform-
 
 ## Modules
 
-| Name | Source | Version |
-|------|--------|---------|
-| <a name="module_subnet_group"></a> [subnet\_group](#module\_subnet\_group) | ./modules/subnet_group | n/a |
+No modules.
 
 ## Resources
 
@@ -50,6 +50,7 @@ Examples codified under the [`examples`](https://github.com/clowdhaus/terraform-
 | [aws_elasticache_cluster.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticache_cluster) | resource |
 | [aws_elasticache_parameter_group.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticache_parameter_group) | resource |
 | [aws_elasticache_replication_group.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticache_replication_group) | resource |
+| [aws_elasticache_subnet_group.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticache_subnet_group) | resource |
 
 ## Inputs
 
@@ -104,7 +105,7 @@ Examples codified under the [`examples`](https://github.com/clowdhaus/terraform-
 | <a name="input_snapshot_retention_limit"></a> [snapshot\_retention\_limit](#input\_snapshot\_retention\_limit) | (Redis only) Number of days for which ElastiCache will retain automatic cache cluster snapshots before deleting them | `number` | `null` | no |
 | <a name="input_snapshot_window"></a> [snapshot\_window](#input\_snapshot\_window) | (Redis only) Daily time range (in UTC) during which ElastiCache will begin taking a daily snapshot of your cache cluster. Example: `05:00-09:00` | `string` | `null` | no |
 | <a name="input_subnet_group_description"></a> [subnet\_group\_description](#input\_subnet\_group\_description) | Description for the Elasticache subnet group | `string` | `null` | no |
-| <a name="input_subnet_group_name"></a> [subnet\_group\_name](#input\_subnet\_group\_name) | Name of the subnet group to be used for the cache cluster. Changing this value will re-create the resource | `string` | `null` | no |
+| <a name="input_subnet_group_name"></a> [subnet\_group\_name](#input\_subnet\_group\_name) | The name of the subnet group. If `create_subnet_group` is `true`, this is the name assigned to the subnet group created. Otherwise, this is the name of an existing subnet group | `string` | `null` | no |
 | <a name="input_subnet_ids"></a> [subnet\_ids](#input\_subnet\_ids) | List of VPC Subnet IDs for the Elasticache subnet group | `list(string)` | `[]` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | A map of tags to add to all resources | `map(string)` | `{}` | no |
 | <a name="input_transit_encryption_enabled"></a> [transit\_encryption\_enabled](#input\_transit\_encryption\_enabled) | Enable encryption in-transit. Supported only with Memcached versions `1.6.12` and later, running in a VPC | `bool` | `null` | no |
@@ -128,7 +129,6 @@ Examples codified under the [`examples`](https://github.com/clowdhaus/terraform-
 | <a name="output_rep_group_member_clusters"></a> [rep\_group\_member\_clusters](#output\_rep\_group\_member\_clusters) | Identifiers of all the nodes that are part of this replication group |
 | <a name="output_rep_group_primary_endpoint_address"></a> [rep\_group\_primary\_endpoint\_address](#output\_rep\_group\_primary\_endpoint\_address) | Address of the endpoint for the primary node in the replication group, if the cluster mode is disabled |
 | <a name="output_rep_group_reader_endpoint_address"></a> [rep\_group\_reader\_endpoint\_address](#output\_rep\_group\_reader\_endpoint\_address) | Address of the endpoint for the reader node in the replication group, if the cluster mode is disabled |
-| <a name="output_subnet_group_ids"></a> [subnet\_group\_ids](#output\_subnet\_group\_ids) | The ElastiCache subnet group IDs |
 | <a name="output_subnet_group_name"></a> [subnet\_group\_name](#output\_subnet\_group\_name) | The ElastiCache subnet group name |
 <!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 

main.tf

@@ -39,7 +39,7 @@ resource "aws_elasticache_cluster" "this" {
   notification_topic_arn       = local.in_replication_group ? null : var.notification_topic_arn
   num_cache_nodes              = local.in_replication_group ? null : var.num_cache_nodes
   outpost_mode                 = var.outpost_mode
-  parameter_group_name         = local.in_replication_group ? null : var.parameter_group_name
+  parameter_group_name         = local.in_replication_group ? null : local.parameter_group_name
   port                         = local.in_replication_group ? null : coalesce(var.port, local.port)
   preferred_availability_zones = var.preferred_availability_zones
   preferred_outpost_arn        = var.preferred_outpost_arn
@@ -100,7 +100,7 @@ resource "aws_elasticache_replication_group" "this" {
   notification_topic_arn      = var.notification_topic_arn
   num_cache_clusters          = var.num_cache_clusters
   num_node_groups             = local.in_global_replication_group ? null : var.num_node_groups
-  parameter_group_name        = local.in_global_replication_group ? null : var.parameter_group_name
+  parameter_group_name        = local.in_global_replication_group ? null : local.parameter_group_name
   port                        = coalesce(var.port, local.port)
   preferred_cache_cluster_azs = var.preferred_cache_cluster_azs
   replicas_per_node_group     = var.replicas_per_node_group
@@ -122,6 +122,10 @@ resource "aws_elasticache_replication_group" "this" {
 # Parameter Group
 ################################################################################
 
+locals {
+  parameter_group_name = var.create && var.create_parameter_group ? aws_elasticache_parameter_group.this[0].id : var.parameter_group_name
+}
+
 resource "aws_elasticache_parameter_group" "this" {
   count = var.create && var.create_parameter_group ? 1 : 0
 
@@ -150,18 +154,12 @@ resource "aws_elasticache_parameter_group" "this" {
 # Subnet Group
 ################################################################################
 
-locals {
-  identifier           = local.in_replication_group ? var.replication_group_id : var.cluster_id
-  subnet_group_name    = var.create_subnet_group ? module.subnet_group.name : var.subnet_group_name
-  parameter_group_name = var.create_parameter_group ? module.parameter_group.id : var.parameter_group_name
-}
-
-module "subnet_group" {
-  source = "./modules/subnet_group"
+resource "aws_elasticache_subnet_group" "this" {
+  count = var.create && var.create_subnet_group ? 1 : 0
 
-  create      = var.create_subnet_group
-  identifier  = local.identifier
   name        = var.subnet_group_name
-  description = var.subnet_group_description
+  description = coalesce(var.subnet_group_description, "ElastiCache subnet group")
   subnet_ids  = var.subnet_ids
+
+  tags = var.tags
 }

modules/subnet_group/README.md

@@ -65,19 +65,6 @@ output "rep_group_reader_endpoint_address" {
   description = "Address of the endpoint for the reader node in the replication group, if the cluster mode is disabled"
   value       = try(aws_elasticache_replication_group.this[0].reader_endpoint_address, null)
 }
-################################################################################
-# Subnet Group
-################################################################################
-
-output "subnet_group_name" {
-  description = "The ElastiCache subnet group name"
-  value       = module.subnet_group.name
-}
-
-output "subnet_group_ids" {
-  description = "The ElastiCache subnet group IDs"
-  value       = module.subnet_group.ids
-}
 
 ################################################################################
 # Parameter Group
@@ -92,3 +79,12 @@ output "parameter_group_id" {
   description = "The ElastiCache parameter group name"
   value       = try(aws_elasticache_parameter_group.this[0].id, null)
 }
+
+################################################################################
+# Subnet Group
+################################################################################
+
+output "subnet_group_name" {
+  description = "The ElastiCache subnet group name"
+  value       = try(aws_elasticache_subnet_group.this[0].name, null)
+}

modules/subnet_group/main.tf

@@ -170,12 +170,6 @@ variable "snapshot_window" {
   default     = null
 }
 
-variable "subnet_group_name" {
-  description = "Name of the subnet group to be used for the cache cluster. Changing this value will re-create the resource"
-  type        = string
-  default     = null
-}
-
 variable "transit_encryption_enabled" {
   description = "Enable encryption in-transit. Supported only with Memcached versions `1.6.12` and later, running in a VPC"
   type        = bool
@@ -326,14 +320,20 @@ variable "create_subnet_group" {
   default     = false
 }
 
+variable "subnet_group_name" {
+  description = "The name of the subnet group. If `create_subnet_group` is `true`, this is the name assigned to the subnet group created. Otherwise, this is the name of an existing subnet group"
+  type        = string
+  default     = null
+}
+
 variable "subnet_group_description" {
   description = "Description for the Elasticache subnet group"
   type        = string
   default     = null
 }
 
 variable "subnet_ids" {
-  description = "List of VPC Subnet IDs for the Elasticache subnet group "
+  description = "List of VPC Subnet IDs for the Elasticache subnet group"
   type        = list(string)
   default     = []
 }