Added conditional project designation feature for relevant modules.

modules/network/main.tf

@@ -1,13 +1,17 @@
+data "google_client_config" "default" {}
+
 # VPC
 resource "google_compute_network" "network" {
   name                    = var.name
   auto_create_subnetworks = false
+  project                 = var.project_id != null ? var.project_id : data.google_client_config.default.project
 }
 
 # Subnets
 resource "google_compute_subnetwork" "subnet" {
   count         = length(var.subnets)
   name          = var.subnets[count.index].name
+  project       = var.project_id != null ? var.project_id : data.google_client_config.default.project
   ip_cidr_range = var.subnets[count.index].cidr
   region        = var.subnets[count.index].region != null ? var.subnets[count.index].region : var.subnets[0].region
   network       = google_compute_network.network.id
@@ -18,6 +22,7 @@ resource "google_compute_router" "cr" {
   count   = var.nat ? 1 : 0
   name    = "${var.name}-router"
   network = var.name
+  project = var.project_id != null ? var.project_id : data.google_client_config.default.project
 
   depends_on = [google_compute_network.network]
 }
@@ -25,6 +30,7 @@ resource "google_compute_router" "cr" {
 resource "google_compute_router_nat" "nat" {
   count                              = var.nat ? 1 : 0
   name                               = "${var.name}-nat"
+  project                            = var.project_id != null ? var.project_id : data.google_client_config.default.project
   router                             = google_compute_router.cr[0].name
   nat_ip_allocate_option             = "AUTO_ONLY"
   source_subnetwork_ip_ranges_to_nat = "ALL_SUBNETWORKS_ALL_IP_RANGES"

modules/network/variables.tf

@@ -3,6 +3,13 @@ variable "name" {
   type        = string
 }
 
+variable "project_id" {
+  description = "The GCP project ID. If not provided, the default project will be used."
+  type        = string
+  nullable    = true
+  default     = null
+}
+
 # A Cloud NAT will be created in the same region as the first subnet.
 variable "subnets" {
   description = "A list of subnets with names and CIDRs."