feat: Add support for preserve_client_ip tg flag (#213)

Author: juho9000

examples/complete-nlb/main.tf

@@ -102,10 +102,11 @@ module "nlb" {
 
   target_groups = [
     {
-      name_prefix      = "tu1-"
-      backend_protocol = "TCP_UDP"
-      backend_port     = 81
-      target_type      = "instance"
+      name_prefix        = "tu1-"
+      backend_protocol   = "TCP_UDP"
+      backend_port       = 81
+      target_type        = "instance"
+      preserve_client_ip = true
       tags = {
         tcp_udp = true
       }

main.tf

@@ -70,6 +70,7 @@ resource "aws_lb_target_group" "main" {
   proxy_protocol_v2                  = lookup(var.target_groups[count.index], "proxy_protocol_v2", false)
   lambda_multi_value_headers_enabled = lookup(var.target_groups[count.index], "lambda_multi_value_headers_enabled", false)
   load_balancing_algorithm_type      = lookup(var.target_groups[count.index], "load_balancing_algorithm_type", null)
+  preserve_client_ip                 = lookup(var.target_groups[count.index], "preserve_client_ip", null)
 
   dynamic "health_check" {
     for_each = length(keys(lookup(var.target_groups[count.index], "health_check", {}))) == 0 ? [] : [lookup(var.target_groups[count.index], "health_check", {})]