feat: Add custom subnet names (#816)

Co-authored-by: Anton Babenko <anton@antonbabenko.com>

.pre-commit-config.yaml

 repos:
   - repo: https://github.com/antonbabenko/pre-commit-terraform
-    rev: v1.75.0
+    rev: v1.76.0
     hooks:
       - id: terraform_fmt
       - id: terraform_validate

examples/complete-vpc/main.tf

@@ -31,6 +31,13 @@ module "vpc" {
   redshift_subnets    = ["10.0.41.0/24", "10.0.42.0/24", "10.0.43.0/24"]
   intra_subnets       = ["10.0.51.0/24", "10.0.52.0/24", "10.0.53.0/24"]
 
+  private_subnet_names = ["Private Subnet One", "Private Subnet Two"]
+  # public_subnet_names omitted to show default name generation for all three subnets
+  database_subnet_names    = ["DB Subnet One"]
+  elasticache_subnet_names = ["Elasticache Subnet One", "Elasticache Subnet Two"]
+  redshift_subnet_names    = ["Redshift Subnet One", "Redshift Subnet Two", "Redshift Subnet Three"]
+  intra_subnet_names       = []
+
   create_database_subnet_group = false
 
   manage_default_network_acl = true

main.tf

@@ -370,9 +370,9 @@ resource "aws_subnet" "public" {
 
   tags = merge(
     {
-      "Name" = format(
-        "${var.name}-${var.public_subnet_suffix}-%s",
-        element(var.azs, count.index),
+      Name = try(
+        var.public_subnet_names[count.index],
+        format("${var.name}-${var.public_subnet_suffix}-%s", element(var.azs, count.index))
       )
     },
     var.tags,
@@ -397,9 +397,9 @@ resource "aws_subnet" "private" {
 
   tags = merge(
     {
-      "Name" = format(
-        "${var.name}-${var.private_subnet_suffix}-%s",
-        element(var.azs, count.index),
+      Name = try(
+        var.private_subnet_names[count.index],
+        format("${var.name}-${var.private_subnet_suffix}-%s", element(var.azs, count.index))
       )
     },
     var.tags,
@@ -425,9 +425,9 @@ resource "aws_subnet" "outpost" {
 
   tags = merge(
     {
-      "Name" = format(
-        "${var.name}-${var.outpost_subnet_suffix}-%s",
-        var.outpost_az,
+      Name = try(
+        var.outpost_subnet_names[count.index],
+        format("${var.name}-${var.outpost_subnet_suffix}-%s", var.outpost_az)
       )
     },
     var.tags,
@@ -452,9 +452,9 @@ resource "aws_subnet" "database" {
 
   tags = merge(
     {
-      "Name" = format(
-        "${var.name}-${var.database_subnet_suffix}-%s",
-        element(var.azs, count.index),
+      Name = try(
+        var.database_subnet_names[count.index],
+        format("${var.name}-${var.database_subnet_suffix}-%s", element(var.azs, count.index), )
       )
     },
     var.tags,
@@ -495,9 +495,9 @@ resource "aws_subnet" "redshift" {
 
   tags = merge(
     {
-      "Name" = format(
-        "${var.name}-${var.redshift_subnet_suffix}-%s",
-        element(var.azs, count.index),
+      Name = try(
+        var.redshift_subnet_names[count.index],
+        format("${var.name}-${var.redshift_subnet_suffix}-%s", element(var.azs, count.index))
       )
     },
     var.tags,
@@ -536,9 +536,9 @@ resource "aws_subnet" "elasticache" {
 
   tags = merge(
     {
-      "Name" = format(
-        "${var.name}-${var.elasticache_subnet_suffix}-%s",
-        element(var.azs, count.index),
+      Name = try(
+        var.elasticache_subnet_names[count.index],
+        format("${var.name}-${var.elasticache_subnet_suffix}-%s", element(var.azs, count.index))
       )
     },
     var.tags,
@@ -577,9 +577,9 @@ resource "aws_subnet" "intra" {
 
   tags = merge(
     {
-      "Name" = format(
-        "${var.name}-${var.intra_subnet_suffix}-%s",
-        element(var.azs, count.index),
+      Name = try(
+        var.intra_subnet_names[count.index],
+        format("${var.name}-${var.intra_subnet_suffix}-%s", element(var.azs, count.index))
       )
     },
     var.tags,

variables.tf

@@ -136,6 +136,48 @@ variable "private_subnet_suffix" {
   default     = "private"
 }
 
+variable "public_subnet_names" {
+  description = "Explicit values to use in the Name tag on public subnets. If empty, Name tags are generated."
+  type        = list(string)
+  default     = []
+}
+
+variable "private_subnet_names" {
+  description = "Explicit values to use in the Name tag on private subnets. If empty, Name tags are generated."
+  type        = list(string)
+  default     = []
+}
+
+variable "outpost_subnet_names" {
+  description = "Explicit values to use in the Name tag on outpost subnets. If empty, Name tags are generated."
+  type        = list(string)
+  default     = []
+}
+
+variable "intra_subnet_names" {
+  description = "Explicit values to use in the Name tag on intra subnets. If empty, Name tags are generated."
+  type        = list(string)
+  default     = []
+}
+
+variable "database_subnet_names" {
+  description = "Explicit values to use in the Name tag on database subnets. If empty, Name tags are generated."
+  type        = list(string)
+  default     = []
+}
+
+variable "redshift_subnet_names" {
+  description = "Explicit values to use in the Name tag on redshift subnets. If empty, Name tags are generated."
+  type        = list(string)
+  default     = []
+}
+
+variable "elasticache_subnet_names" {
+  description = "Explicit values to use in the Name tag on elasticache subnets. If empty, Name tags are generated."
+  type        = list(string)
+  default     = []
+}
+
 variable "outpost_subnet_suffix" {
   description = "Suffix to append to outpost subnets name"
   type        = string