Pass instance IP around instead of ID

- Explanation: hashicorp/terraform#16559

terraform/apps/core.tf

@@ -3,7 +3,7 @@ module "core_app" {
   name = "core"
   docker_image = "rabblerouser/core"
   port = "${var.app_ports["core"]}"
-  aws_instance_id = "${var.aws_instance_id}"
+  aws_instance_ip = "${var.aws_instance_ip}"
   alb_listener_arn = "${var.alb_listener_arn}"
   alb_listener_rule_priority = "1"
   docker_credentials = "${var.docker_credentials}"
@@ -14,10 +14,17 @@ module "core_app" {
   env = ["SESSION_SECRET=${random_id.session_secret.hex}"]
 }
 
+data "aws_instance" "instance" {
+  filter {
+    name = "ip-address"
+    values = ["${var.aws_instance_ip}"]
+  }
+}
+
 resource "random_id" "session_secret" {
   keepers = {
     # Generate a new session secret when instance ID changes
-    ec2_instance_id = "${var.aws_instance_id}"
+    ec2_instance_id = "${data.aws_instance.instance.id}"
   }
   byte_length = 32
 }

terraform/apps/docker-node-app/data.tf

@@ -6,7 +6,10 @@ data "aws_vpc" "default_vpc" {
 }
 
 data "aws_instance" "instance" {
-  instance_id = "${var.aws_instance_id}"
+  filter {
+    name = "ip-address"
+    values = ["${var.aws_instance_ip}"]
+  }
 }
 
 data "aws_lb_listener" "alb_listener" {

terraform/apps/docker-node-app/docker.tf

@@ -1,6 +1,6 @@
 provider "docker" {
   version = "~> 0.1.0"
-  host = "tcp://${data.aws_instance.instance.public_ip}:2376"
+  host = "tcp://${var.aws_instance_ip}:2376"
   key_material = "${var.docker_credentials["key"]}"
   ca_material = "${var.docker_credentials["ca"]}"
   cert_material = "${var.docker_credentials["cert"]}"

terraform/apps/docker-node-app/event-forwarder/event-forwarder.tf

@@ -18,7 +18,7 @@ data "aws_s3_bucket_object" "event_forwarder_zip" {
 
 resource "random_id" "auth_token" {
   keepers = {
-    # Generate a new token when the lambda code updates or the EC2 instance changes
+    # Generate a new token when the lambda code updates
     lambda_zip_version = "${data.aws_s3_bucket_object.event_forwarder_zip.version_id}"
   }
 

terraform/apps/docker-node-app/networking.tf

@@ -35,5 +35,5 @@ resource "aws_lb_target_group" "alb_target_group" {
 
 resource "aws_lb_target_group_attachment" "alb_target_attachment" {
   target_group_arn = "${aws_lb_target_group.alb_target_group.arn}"
-  target_id = "${var.aws_instance_id}"
+  target_id = "${data.aws_instance.instance.id}"
 }

terraform/apps/docker-node-app/variables.tf

@@ -19,8 +19,8 @@ variable "env" {
   default = []
 }
 
-variable "aws_instance_id" {
-  description = "The ID of the EC2 instance where the app should be deployed"
+variable "aws_instance_ip" {
+  description = "The public IP address of the EC2 instance where this app should be deployed"
   type = "string"
 }
 

terraform/apps/group-mailer.tf

@@ -3,7 +3,7 @@ module "group_mailer_app" {
   name = "group-mailer"
   docker_image = "rabblerouser/group-mailer"
   port = "${var.app_ports["group_mailer"]}"
-  aws_instance_id = "${var.aws_instance_id}"
+  aws_instance_ip = "${var.aws_instance_ip}"
   alb_listener_arn = "${var.alb_listener_arn}"
   alb_listener_rule_priority = "3"
   docker_credentials = "${var.docker_credentials}"

terraform/apps/mailer.tf

@@ -3,7 +3,7 @@ module "mailer_app" {
   name = "mailer"
   docker_image = "rabblerouser/mailer"
   port = "${var.app_ports["mailer"]}"
-  aws_instance_id = "${var.aws_instance_id}"
+  aws_instance_ip = "${var.aws_instance_ip}"
   alb_listener_arn = "${var.alb_listener_arn}"
   alb_listener_rule_priority = "2"
   docker_credentials = "${var.docker_credentials}"

terraform/apps/variables.tf

@@ -13,8 +13,8 @@ variable "app_ports" {
   type = "map"
 }
 
-variable "aws_instance_id" {
-  description = "The ID of the EC2 instance where this app should be deployed"
+variable "aws_instance_ip" {
+  description = "The public IP address of the EC2 instance where this app should be deployed"
   type = "string"
 }
 

terraform/base/outputs.tf

@@ -2,8 +2,8 @@ output "host_ip" {
   value = "${aws_instance.web.public_ip}"
 }
 
-output "aws_instance_id" {
-  value = "${aws_instance.web.id}"
+output "aws_instance_ip" {
+  value = "${aws_instance.web.public_ip}"
 }
 
 output "alb_listener_arn" {

terraform/main.tf

@@ -55,7 +55,7 @@ module apps {
   route53_zone_id = "${local.route53_zone_id}"
 
   app_ports = "${local.app_ports}"
-  aws_instance_id = "${module.base.aws_instance_id}"
+  aws_instance_ip = "${module.base.aws_instance_ip}"
   alb_listener_arn = "${module.base.alb_listener_arn}"
   docker_credentials = "${module.base.docker_credentials}"
   stream_name = "${module.base.stream_name}"