mig.tf

variable "project" {
  type = "string"
}

variable "name" {
  type = "string"
}

variable "network" {
  type = "string"
}

variable "subnet" {
  type = "string"
}

variable "env" {
  type    = "string"
  default = ""
}

variable "zone" {
  type    = "string"
  default = "europe-west1-b"
}

variable "service_port" {
  type        = "string"
  description = "Port the service is listening on."
  default     = "80"
}

variable "service_port_name" {
  type        = "string"
  description = "Name of the port the service is listening on."
  default     = "http"
}

variable "size" {
  type        = "string"
  description = "Target size of the managed instance group."
  default     = 3
}

variable "type" {
  type    = "string"
  default = "n1-standard-1"
}

variable "disk_size" {
  type = "string"

  // in GB
  default = "50"
}

variable "disk_type" {
  type = "string"

  // default to mechanical disk
  default = "pd-standard"
}

variable "disk_image" {
  type = "string"

  // make use of debian stretch
  default = "debian-9"
}

variable "can_ip_forward" {
  type    = "string"
  default = false
}

// simulate a "depends_on" since we can't use it atm for module-to-module dependencies
variable "depends_id" {
  type    = "list"
  default = [""]
}

locals {
  full_name = "${var.env == "" ? "${var.name}" : "${var.name}-${var.env}"}"
}

resource "google_compute_instance" "private_instance" {
  count        = "${var.size}"
  name         = "instance-${random_id.suffix.dec}-${count.index + 1}"
  machine_type = "${var.type}"
  zone         = "${var.zone}"
  project      = "${var.project}"

  tags = ["private-instance"]

  boot_disk {
    initialize_params {
      size  = "${var.disk_size}"
      type  = "${var.disk_type}"
      image = "${var.disk_image}"
    }
  }

  network_interface {
    subnetwork = "${var.subnet}"
  }

  can_ip_forward = "${var.can_ip_forward}"

  lifecycle {
    create_before_destroy = true
  }
}

resource "google_compute_instance_group" "default" {
  project     = "${var.project}"
  zone        = "${var.zone}"
  name        = "ig-${local.full_name}"
  description = "manages ${var.size} instances in the \"${var.zone}\" zone"

  instances = ["${google_compute_instance.private_instance.*.self_link}"]

  named_port {
    name = "${var.service_port_name}"
    port = "${var.service_port}"
  }
}

output name {
  description = "Pass through of input `name`."
  value       = "${var.name}"
}

output self_link {
  description = "Link to the `instance_group` property of the instance group manager resource."
  value       = "${google_compute_instance_group.default.self_link}"
}

output service_port {
  description = "Pass through of input `service_port`."
  value       = "${var.service_port}"
}

output service_port_name {
  description = "Pass through of input `service_port_name`."
  value       = "${var.service_port_name}"
}

output instance_ips {
  value       = "${google_compute_instance.private_instance.*.network_interface.0.address}"
}