From ca5be4378b8ca0a0a93617570bc70981b8fbb2ff Mon Sep 17 00:00:00 2001
From: dcowan-vestmark <dcowan@vestmark.com>
Date: Mon, 14 May 2018 09:43:41 -0500
Subject: [PATCH] Adding configurable maximum subnet variable and more
 descriptive tagging (#29)

* Updating to use supplied availablity zones for cidr calculation

* Updating to use supplied availablity zones for cidr calculation

* Revert "Updating to use supplied availablity zones for cidr calculation"

This reverts commit ad782e89c5597ed8bfe8fb4e0e2df0de9754a1e8.

* Adding abilityt to control az count

* Adding ability to control az count

* Adding ability to control az count

* Adding ability to control az count

* Adding ability to control az count

* Adding ability to control az count

* Adding ability to control az count

* Adding tags to nat resources

* Updating naming of subnets

* Formatting fixes

* Formatting fixes

* Cleanup from pull request review

* Cleanup from pull request review

* Adding attributes to label and description to max_subnets variable

* Adding attributes to label and description to max_subnets variable

* Adding attributes to label and description to max_subnets variable
---
 nat.tf       | 11 +++++++++++
 private.tf   | 15 ++++++++++-----
 public.tf    | 15 ++++++++++-----
 variables.tf |  5 +++++
 4 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/nat.tf b/nat.tf
index fa7e12c3..ae4fabe1 100644
--- a/nat.tf
+++ b/nat.tf
@@ -1,3 +1,12 @@
+module "nat_label" {
+  source    = "git::https://github.com/cloudposse/terraform-null-label.git?ref=tags/0.3.3"
+  namespace = "${var.namespace}"
+  stage     = "${var.stage}"
+  name      = "${var.name}"
+  delimiter = "${var.delimiter}"
+  tags      = "${var.tags}"
+}
+
 locals {
   nat_gateways_count = "${var.nat_gateway_enabled == "true" ? length(var.availability_zones) : 0}"
 }
@@ -5,6 +14,7 @@ locals {
 resource "aws_eip" "default" {
   count = "${local.nat_gateways_count}"
   vpc   = true
+  tags  = "${module.private_label.tags}"
 
   lifecycle {
     create_before_destroy = true
@@ -15,6 +25,7 @@ resource "aws_nat_gateway" "default" {
   count         = "${local.nat_gateways_count}"
   allocation_id = "${element(aws_eip.default.*.id, count.index)}"
   subnet_id     = "${element(aws_subnet.public.*.id, count.index)}"
+  tags          = "${module.nat_label.tags}"
 
   lifecycle {
     create_before_destroy = true
diff --git a/private.tf b/private.tf
index 9cfe9bc7..12c95e93 100644
--- a/private.tf
+++ b/private.tf
@@ -9,17 +9,22 @@ module "private_label" {
 }
 
 module "private_subnet_label" {
-  source    = "git::https://github.com/cloudposse/terraform-null-label.git?ref=tags/0.3.3"
-  namespace = "${var.namespace}"
-  stage     = "${var.stage}"
-  name      = "private"
+  source     = "git::https://github.com/cloudposse/terraform-null-label.git?ref=tags/0.3.3"
+  namespace  = "${var.namespace}"
+  stage      = "${var.stage}"
+  name       = "subnet"
+  attributes = ["private"]
+}
+
+locals {
+  private_subnet_count = "${var.max_subnet_count == 0 ? length(data.aws_availability_zones.available.names) : var.max_subnet_count}"
 }
 
 resource "aws_subnet" "private" {
   count             = "${length(var.availability_zones)}"
   vpc_id            = "${data.aws_vpc.default.id}"
   availability_zone = "${element(var.availability_zones, count.index)}"
-  cidr_block        = "${cidrsubnet(signum(length(var.cidr_block)) == 1 ? var.cidr_block : data.aws_vpc.default.cidr_block, ceil(log(length(data.aws_availability_zones.available.names) * 2, 2)), count.index)}"
+  cidr_block        = "${cidrsubnet(signum(length(var.cidr_block)) == 1 ? var.cidr_block : data.aws_vpc.default.cidr_block, ceil(log(local.private_subnet_count * 2, 2)), count.index)}"
 
   tags = {
     "Name"      = "${module.private_subnet_label.id}${var.delimiter}${replace(element(var.availability_zones, count.index),"-",var.delimiter)}"
diff --git a/public.tf b/public.tf
index 9949f7d2..20ca5bca 100644
--- a/public.tf
+++ b/public.tf
@@ -1,8 +1,9 @@
 module "public_subnet_label" {
-  source    = "git::https://github.com/cloudposse/terraform-null-label.git?ref=tags/0.3.3"
-  namespace = "${var.namespace}"
-  stage     = "${var.stage}"
-  name      = "public"
+  source     = "git::https://github.com/cloudposse/terraform-null-label.git?ref=tags/0.3.3"
+  namespace  = "${var.namespace}"
+  stage      = "${var.stage}"
+  name       = "${var.name}"
+  attributes = ["public"]
 }
 
 module "public_label" {
@@ -15,11 +16,15 @@ module "public_label" {
   tags       = "${var.tags}"
 }
 
+locals {
+  public_subnet_count = "${var.max_subnet_count == 0 ? length(data.aws_availability_zones.available.names) : var.max_subnet_count}"
+}
+
 resource "aws_subnet" "public" {
   count             = "${length(var.availability_zones)}"
   vpc_id            = "${data.aws_vpc.default.id}"
   availability_zone = "${element(var.availability_zones, count.index)}"
-  cidr_block        = "${cidrsubnet(signum(length(var.cidr_block)) == 1 ? var.cidr_block : data.aws_vpc.default.cidr_block, ceil(log(length(data.aws_availability_zones.available.names) * 2, 2)), length(data.aws_availability_zones.available.names) + count.index)}"
+  cidr_block        = "${cidrsubnet(signum(length(var.cidr_block)) == 1 ? var.cidr_block : data.aws_vpc.default.cidr_block, ceil(log(local.public_subnet_count * 2, 2)), local.public_subnet_count + count.index)}"
 
   tags = {
     "Name"      = "${module.public_subnet_label.id}${var.delimiter}${replace(element(var.availability_zones, count.index),"-",var.delimiter)}"
diff --git a/variables.tf b/variables.tf
index d5af49a1..23bdcbc8 100644
--- a/variables.tf
+++ b/variables.tf
@@ -36,6 +36,11 @@ variable "region" {
   description = "AWS Region (e.g. `us-east-1`)"
 }
 
+variable "max_subnet_count" {
+  default     = 0
+  description = "Sets the maximum amount of subnets to deploy.  0 will deploy a subnet for every availablility zone within the region"
+}
+
 variable "vpc_id" {
   type        = "string"
   description = "VPC ID where subnets will be created (e.g. `vpc-aceb2723`)"