feat: Add intra subnet VPN route propagation (#421)

Author: DrFaust92

README.md

@@ -457,6 +457,7 @@ It is possible to integrate this VPC module with [terraform-aws-transit-gateway
 | private\_subnet\_suffix | Suffix to append to private subnets name | `string` | `"private"` | no |
 | private\_subnet\_tags | Additional tags for the private subnets | `map(string)` | `{}` | no |
 | private\_subnets | A list of private subnets inside the VPC | `list(string)` | `[]` | no |
+| propagate\_intra\_route\_tables\_vgw | Should be true if you want route table propagation | `bool` | `false` | no |
 | propagate\_private\_route\_tables\_vgw | Should be true if you want route table propagation | `bool` | `false` | no |
 | propagate\_public\_route\_tables\_vgw | Should be true if you want route table propagation | `bool` | `false` | no |
 | public\_acl\_tags | Additional tags for the public subnets network ACL | `map(string)` | `{}` | no |

main.tf

@@ -1066,6 +1066,19 @@ resource "aws_vpn_gateway_route_propagation" "private" {
   )
 }
 
+resource "aws_vpn_gateway_route_propagation" "intra" {
+  count = var.create_vpc && var.propagate_intra_route_tables_vgw && (var.enable_vpn_gateway || var.vpn_gateway_id != "") ? length(var.intra_subnets) : 0
+
+  route_table_id = element(aws_route_table.intra.*.id, count.index)
+  vpn_gateway_id = element(
+    concat(
+      aws_vpn_gateway.this.*.id,
+      aws_vpn_gateway_attachment.this.*.vpn_gateway_id,
+    ),
+    count.index,
+  )
+}
+
 ###########
 # Defaults
 ###########

variables.tf

@@ -1333,6 +1333,12 @@ variable "vpn_gateway_az" {
   default     = null
 }
 
+variable "propagate_intra_route_tables_vgw" {
+  description = "Should be true if you want route table propagation"
+  type        = bool
+  default     = false
+}
+
 variable "propagate_private_route_tables_vgw" {
   description = "Should be true if you want route table propagation"
   type        = bool