From 43735d1295c70d36997de5610c4fd76790ed8ddb Mon Sep 17 00:00:00 2001
From: Michele Cantelli <emmekappa@gmail.com>
Date: Sat, 19 May 2018 18:05:05 +0200
Subject: [PATCH] Adding indexes support (#4)

* Adding indexes support

* Updating README

* Fixing scalable_dimension for indexes autoscaling
---
 README.md    |  2 ++
 main.tf      | 18 ++++++++++++++++++
 variables.tf |  6 ++++++
 3 files changed, 26 insertions(+)

diff --git a/README.md b/README.md
index 068dd80..b99f28e 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,7 @@ module "dynamodb_autoscaler" {
   stage                        = "dev"
   name                         = "cluster"
   dynamodb_table_name          = "cp-dev-cluster-terraform-state-lock"
+  dynamodb_indexes             = [ "first-index", "second-index" ]
   dynamodb_table_arn           = "arn:aws:dynamodb:us-east-1:123456789012:table/cp-dev-cluster-terraform-state-lock"
   autoscale_write_target       = 10
   autoscale_read_target        = 10
@@ -33,6 +34,7 @@ module "dynamodb_autoscaler" {
 | `stage`                          | ``           | Stage (_e.g._ `prod`, `dev`, `staging`)                                         | Yes      |
 | `name`                           | ``           | Name  (_e.g._ `app` or `cluster`)                                               | Yes      |
 | `dynamodb_table_name`            | ``           | DynamoDB table name                                                             | Yes      |
+| `dynamodb_indexes`               | `[]`         | List of DynamoDB indexes                                                        | No       |
 | `dynamodb_table_arn`             | ``           | DynamoDB table ARN                                                              | Yes      |
 | `attributes`                     | `[]`         | Additional attributes (_e.g._ `policy` or `role`)                               | No       |
 | `tags`                           | `{}`         | Additional tags  (_e.g._ `map("BusinessUnit","XYZ")`                            | No       |
diff --git a/main.tf b/main.tf
index d8f5306..7703c2c 100644
--- a/main.tf
+++ b/main.tf
@@ -86,6 +86,15 @@ resource "aws_appautoscaling_target" "read_target" {
   service_namespace  = "dynamodb"
 }
 
+resource "aws_appautoscaling_target" "read_target_index" {
+  count              = "${length(var.dynamodb_indexes)}"
+  max_capacity       = "${var.autoscale_max_read_capacity}"
+  min_capacity       = "${var.autoscale_min_read_capacity}"
+  resource_id        = "table/${var.dynamodb_table_name}/index/${element(var.dynamodb_indexes, count.index)}"
+  scalable_dimension = "dynamodb:index:ReadCapacityUnits"
+  service_namespace  = "dynamodb"
+}
+
 resource "aws_appautoscaling_policy" "read_policy" {
   count              = "${var.enabled == "true" ? 1 : 0}"
   name               = "DynamoDBReadCapacityUtilization:${aws_appautoscaling_target.read_target.resource_id}"
@@ -112,6 +121,15 @@ resource "aws_appautoscaling_target" "write_target" {
   service_namespace  = "dynamodb"
 }
 
+resource "aws_appautoscaling_target" "write_target_index" {
+  count              = "${length(var.dynamodb_indexes)}"
+  max_capacity       = "${var.autoscale_max_write_capacity}"
+  min_capacity       = "${var.autoscale_min_write_capacity}"
+  resource_id        = "table/${var.dynamodb_table_name}/index/${element(var.dynamodb_indexes, count.index)}"
+  scalable_dimension = "dynamodb:index:WriteCapacityUnits"
+  service_namespace  = "dynamodb"
+}
+
 resource "aws_appautoscaling_policy" "write_policy" {
   count              = "${var.enabled == "true" ? 1 : 0}"
   name               = "DynamoDBWriteCapacityUtilization:${aws_appautoscaling_target.write_target.resource_id}"
diff --git a/variables.tf b/variables.tf
index 8ed96f3..47350d5 100644
--- a/variables.tf
+++ b/variables.tf
@@ -41,6 +41,12 @@ variable "dynamodb_table_arn" {
   description = "DynamoDB table ARN"
 }
 
+variable "dynamodb_indexes" {
+  type        = "list"
+  description = "List of DynamoDB indexes"
+  default     = []
+}
+
 variable "autoscale_write_target" {
   default     = 10
   description = "The target value for DynamoDB write autoscaling"