From 697ce226d2fbd4e90065574ce2cf2b0f7216ae68 Mon Sep 17 00:00:00 2001
From: xpk <xpk@headdesk.me>
Date: Thu, 7 Dec 2023 18:02:39 +0800
Subject: [PATCH] UPD: module now supports more than 2 AZs. Still defaults to 2
 for compatibility

---
 modules/networking/vpc-subnet-manual/main.tf  | 33 ++++++++++---------
 .../networking/vpc-subnet-manual/variables.tf |  6 ++++
 2 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/modules/networking/vpc-subnet-manual/main.tf b/modules/networking/vpc-subnet-manual/main.tf
index 1e7566e..5e08c13 100644
--- a/modules/networking/vpc-subnet-manual/main.tf
+++ b/modules/networking/vpc-subnet-manual/main.tf
@@ -1,9 +1,3 @@
-data "aws_caller_identity" "this" {}
-
-data "aws_availability_zones" "available-az" {
-  state = "available"
-}
-
 data "aws_default_tags" "this" {
   lifecycle {
     postcondition {
@@ -13,29 +7,36 @@ data "aws_default_tags" "this" {
   }
 }
 
+data "aws_caller_identity" "this" {}
+
+data "aws_availability_zones" "available-az" {
+  state = "available"
+}
+
+
 locals {
-  no-az    = 2 # hard-coding to 2AZ
-  vpc-cidr = var.vpc-cidr
+  vpc-cidr         = var.vpc-cidr
+  enabled-az-names = slice(data.aws_availability_zones.available-az.names, 0, var.num_azs)
 }
 
 resource "aws_subnet" "private-subnets" {
   count             = length(var.private-subnet-cidrs)
   vpc_id            = aws_vpc.vpc.id
-  availability_zone = element(data.aws_availability_zones.available-az.names, count.index % 2)
+  availability_zone = element(local.enabled-az-names, count.index)
   cidr_block        = var.private-subnet-cidrs[count.index]
-  tags = merge(data.aws_default_tags.this.tags, {
-    Name = "${var.resource-prefix}-private-${split("-", element(data.aws_availability_zones.available-az.names, count.index))[2]}-${count.index + 1}"
-  })
+  tags =  {
+    Name = "${var.resource-prefix}-private-${split("-", element(local.enabled-az-names, count.index))[2]}-${count.index + 1}"
+  }
 }
 
 resource "aws_subnet" "public-subnets" {
   count             = length(var.public-subnet-cidrs)
   vpc_id            = aws_vpc.vpc.id
-  availability_zone = element(data.aws_availability_zones.available-az.names, count.index % 2)
+  availability_zone = element(local.enabled-az-names, count.index)
   cidr_block        = var.public-subnet-cidrs[count.index]
-  tags = merge(data.aws_default_tags.this.tags, {
-    Name = "${var.resource-prefix}-public-${split("-", element(data.aws_availability_zones.available-az.names, count.index))[2]}-${count.index + 1}"
-  })
+  tags = {
+    Name = "${var.resource-prefix}-public-${split("-", element(local.enabled-az-names, count.index))[2]}-${count.index + 1}"
+  }
 }
 
 resource "aws_vpc" "vpc" {
diff --git a/modules/networking/vpc-subnet-manual/variables.tf b/modules/networking/vpc-subnet-manual/variables.tf
index c2f6b74..d9a3ceb 100644
--- a/modules/networking/vpc-subnet-manual/variables.tf
+++ b/modules/networking/vpc-subnet-manual/variables.tf
@@ -34,4 +34,10 @@ variable "secondary_cidr_blocks" {
   type        = list(string)
   description = "Additional cidr blocks"
   default     = []
+}
+
+variable num_azs {
+  description = "By default, use 2 AZs for redundancy"
+  type = number
+  default = 2
 }
\ No newline at end of file