Make default security group optional (#9)

Author: s2504s

main.tf

@@ -38,6 +38,7 @@ resource "aws_iam_role" "default" {
 }
 
 resource "aws_security_group" "default" {
+  count       = "${var.create_default_security_group}"
   name        = "${module.label.id}"
   vpc_id      = "${var.vpc_id}"
   description = "Instance default security group (only egress access is allowed)"
@@ -88,7 +89,7 @@ resource "aws_instance" "default" {
   user_data = "${data.template_file.user_data.rendered}"
 
   vpc_security_group_ids = [
-    "${compact(concat(list(aws_security_group.default.id), var.security_groups))}",
+    "${compact(concat(list(var.create_default_security_group ? join("", aws_security_group.default.*.id) : ""), var.security_groups))}",
   ]
 
   iam_instance_profile        = "${aws_iam_instance_profile.default.name}"

outputs.tf

@@ -22,8 +22,8 @@ output "ssh_key_pair" {
   value = "${var.ssh_key_pair}"
 }
 
-output "security_group_id" {
-  value = "${aws_security_group.default.id}"
+output "security_group_ids" {
+  value = "${compact(concat(list(var.create_default_security_group ? join("", aws_security_group.default.*.id) : ""), var.security_groups))}"
 }
 
 output "role" {

variables.tf

@@ -36,6 +36,7 @@ variable "vpc_id" {}
 
 variable "security_groups" {
   type = "list"
+  default = []
 }
 
 variable "subnets" {
@@ -103,3 +104,8 @@ variable "metric_threshold" {
 variable "default_alarm_action" {
   default = "action/actions/AWS_EC2.InstanceId.Reboot/1.0"
 }
+
+variable "create_default_security_group" {
+  description = "Create default Security Group with Egress traffic allowed only"
+  default = true
+}