Update tf_subnets with cidr_block input (#9)

cloudposse · Aug 21, 2017 · a52f912 · a52f912
1 parent 9c41cf1
commit a52f912
Show file tree

Hide file tree

Showing 6 changed files with 44 additions and 16 deletions.
diff --git a/README.md b/README.md
@@ -29,19 +29,21 @@ module "subnets" {
   region                     = "${var.region}"
   vpc_id                     = "${var.vpc_id}"
   igw_id                     = "${var.igw_id}"
+  cidr_block                 = "${var.cidr_block}"
   vpc_default_route_table_id = "${var.vpc_default_route_table_id}"
 }
 ```
 
 ## Variables
 
-|  Name                        |  Default       |  Description                                              | Required |
-|:----------------------------:|:--------------:|:--------------------------------------------------------:|:--------:|
-| namespace                    | ``             | Namespace (e.g. `cp` or `cloudposse`)                    | Yes      |
-| stage                        | ``             | Stage (e.g. `prod`, `dev`, `staging`)                     | Yes      |
-| name                         | ``             | Name  (e.g. `bastion` or `db`)                           | Yes      |
-| region                       | ``             | AWS Region where module should operate (e.g. `us-east-1`)| Yes      |
-| vpc_id                       | ``             | The VPC ID where subnets will be created (e.g. `vpc-aceb2723`)         | Yes      |
-| igw_id                       | ``             | The Internet Gateway ID public route table will point to (e.g. `igw-9c26a123`) | Yes       |
-| vpc_default_route_table_id   | ``             | The scheduling expression. (e.g. cron(0 20 * * ? *) or rate(5 minutes) | No       |
-| availability_zones           | []             | The scheduling expression. (e.g. cron(0 20 * * ? *) or rate(5 minutes) | Yes       |
+|  Name                        |  Default       |  Description                                                                                                                         | Required |
+|:----------------------------:|:--------------:|:------------------------------------------------------------------------------------------------------------------------------------:|:--------:|
+| namespace                    | ``             | Namespace (e.g. `cp` or `cloudposse`)                                                                                                | Yes      |
+| stage                        | ``             | Stage (e.g. `prod`, `dev`, `staging`)                                                                                                | Yes      |
+| name                         | ``             | Name  (e.g. `bastion` or `db`)                                                                                                       | Yes      |
+| region                       | ``             | AWS Region where module should operate (e.g. `us-east-1`)                                                                            | Yes      |
+| vpc_id                       | ``             | The VPC ID where subnets will be created (e.g. `vpc-aceb2723`)                                                                       | Yes      |
+| igw_id                       | ``             | The Internet Gateway ID public route table will point to (e.g. `igw-9c26a123`)                                                       | Yes      |
+| cidr_block                   | ``             | The base CIDR block which will be divided into subnet CIDR blocks (e.g. `10.0.0.0/16`)                                               | Yes      |
+| vpc_default_route_table_id   | ``             | The default route table for public subnets. Provides access to the Internet. If not set here, will be created. (e.g. `rtb-f4f0ce12`) | No       |
+| availability_zones           | []             | The list of Availability Zones where subnets will be created (e.g. `["us-eas-1a", "us-eas-1b"]`)                                     | Yes      |
diff --git a/main.tf b/main.tf
@@ -10,3 +10,5 @@ provider "aws" {
 data "aws_vpc" "default" {
   id = "${var.vpc_id}"
 }
+
+data "aws_availability_zones" "available" {}
diff --git a/outputs.tf b/outputs.tf
@@ -5,3 +5,7 @@ output "public_subnet_ids" {
 output "private_subnet_ids" {
   value = ["${aws_subnet.private.*.id}"]
 }
+
+output "test" {
+  value = "${data.aws_availability_zones.available.count}"
+}
diff --git a/private.tf b/private.tf
@@ -10,8 +10,16 @@ resource "aws_subnet" "private" {
 
   vpc_id            = "${data.aws_vpc.default.id}"
   availability_zone = "${element(var.availability_zones, count.index)}"
-  cidr_block        = "${cidrsubnet(data.aws_vpc.default.cidr_block, length(var.availability_zones), length(var.availability_zones)  + count.index)}"
-  tags              = "${module.private_label.tags}"
+
+  cidr_block = "${
+    cidrsubnet(
+    signum(length(var.cidr_block)) == 1 ?
+    var.cidr_block : data.aws_vpc.default.cidr_block,
+    ceil(log(length(data.aws_availability_zones.available.names) * 2, 2)),
+    count.index)
+  }"
+
+  tags = "${module.private_label.tags}"
 }
 
 resource "aws_route_table" "private" {

diff --git a/public.tf b/public.tf
@@ -10,7 +10,14 @@ resource "aws_subnet" "public" {
 
   vpc_id            = "${data.aws_vpc.default.id}"
   availability_zone = "${element(var.availability_zones, count.index)}"
-  cidr_block        = "${cidrsubnet(data.aws_vpc.default.cidr_block, length(var.availability_zones), count.index)}"
+
+  cidr_block = "${
+    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)
+  }"
 
   tags = "${module.public_label.tags}"
 }
@@ -23,17 +30,18 @@ resource "aws_route_table" "public" {
     cidr_block = "0.0.0.0/0"
     gateway_id = "${var.igw_id}"
   }
+
   tags = "${module.public_label.tags}"
 }
 
 resource "aws_route_table_association" "public" {
-  count = "${signum(length(var.vpc_default_route_table_id)) == 1 ? 0 : length(var.availability_zones)}"
+  count          = "${signum(length(var.vpc_default_route_table_id)) == 1 ? 0 : length(var.availability_zones)}"
   subnet_id      = "${element(aws_subnet.public.*.id, count.index)}"
   route_table_id = "${aws_route_table.public.id}"
 }
 
 resource "aws_route_table_association" "public_default" {
-  count = "${signum(length(var.vpc_default_route_table_id)) == 1 ? length(var.availability_zones) : 0}"
+  count          = "${signum(length(var.vpc_default_route_table_id)) == 1 ? length(var.availability_zones) : 0}"
   subnet_id      = "${element(aws_subnet.public.*.id, count.index)}"
   route_table_id = "${var.vpc_default_route_table_id}"
-}
+}
diff --git a/variables.tf b/variables.tf
@@ -18,6 +18,10 @@ variable "vpc_id" {
   default = ""
 }
 
+variable "cidr_block" {
+  default = ""
+}
+
 variable "availability_zones" {
   type = "list"
 }