Redshift public subnets (#222)

* add public subnet for redshift to enable access for kinesis

* fix redshift subnet group name

* fix redshift public association

* add public redshift to documentation

* fix doc typo

* update code after review

Author: bmihaescu

README.md

@@ -165,6 +165,14 @@ Sometimes it is handy to have public access to RDS instances (it is not recommen
   enable_dns_support   = true
 ```
 
+## Public access to Redshift cluster
+
+Sometimes it is handy to have public access to Redshift clusters (for example if you need to access it by Kinesis - VPC endpoint for Kinesis is not yet supported by Redshift) by specifying these arguments:
+
+```hcl
+  enable_public_redshift = true  # <= Default it will be placed into private subnet route table
+```
+
 ## Terraform version
 
 Terraform version 0.10.3 or newer is required for this module to work.
@@ -271,6 +279,7 @@ Terraform version 0.10.3 or newer is required for this module to work.
 | redshift\_subnet\_suffix | Suffix to append to redshift subnets name | string | `"redshift"` | no |
 | redshift\_subnet\_tags | Additional tags for the redshift subnets | map | `{}` | no |
 | redshift\_subnets | A list of redshift subnets | list | `[]` | no |
+| enable\_public\_redshift | Should be true if you want Redshift cluster to be placed into public subnet route table | string | `"false"` | no |
 | reuse\_nat\_ips | Should be true if you don't want EIPs to be created for your NAT Gateways and will instead pass them in via the 'external_nat_ip_ids' variable | string | `"false"` | no |
 | secondary\_cidr\_blocks | List of secondary CIDR blocks to associate with the VPC to extend the IP Address pool | list | `[]` | no |
 | single\_nat\_gateway | Should be true if you want to provision a single shared NAT Gateway across all of your private networks | string | `"false"` | no |

main.tf

@@ -569,12 +569,19 @@ resource "aws_route_table_association" "database" {
 }
 
 resource "aws_route_table_association" "redshift" {
-  count = "${var.create_vpc && length(var.redshift_subnets) > 0 ? length(var.redshift_subnets) : 0}"
+  count = "${var.enable_public_redshift == false && var.create_vpc && length(var.redshift_subnets) > 0 ? length(var.redshift_subnets) : 0}"
 
   subnet_id      = "${element(aws_subnet.redshift.*.id, count.index)}"
   route_table_id = "${element(coalescelist(aws_route_table.redshift.*.id, aws_route_table.private.*.id), (var.single_nat_gateway || var.create_redshift_subnet_route_table ? 0 : count.index))}"
 }
 
+resource "aws_route_table_association" "redshift_public" {
+  count = "${var.enable_public_redshift && var.create_vpc && length(var.redshift_subnets) > 0 ? length(var.redshift_subnets) : 0}"
+
+  subnet_id      = "${element(aws_subnet.redshift.*.id, count.index)}"
+  route_table_id = "${element(coalescelist(aws_route_table.redshift.*.id, aws_route_table.public.*.id), (var.single_nat_gateway || var.create_redshift_subnet_route_table ? 0 : count.index))}"
+}
+
 resource "aws_route_table_association" "elasticache" {
   count = "${var.create_vpc && length(var.elasticache_subnets) > 0 ? length(var.elasticache_subnets) : 0}"
 

variables.tf

@@ -102,6 +102,11 @@ variable "create_redshift_subnet_route_table" {
   default     = false
 }
 
+variable "enable_public_redshift" {
+  description = "Controls if redshift should have public routing table"
+  default     = false
+}
+
 variable "create_elasticache_subnet_route_table" {
   description = "Controls if separate route table for elasticache should be created"
   default     = false