but3-iac/tp-cloud/terraform/modules/network/main.tf

resource "google_compute_network" "vpc_terraform" {
  name                    = "vpc-terraform"
  auto_create_subnetworks = false
}


resource "google_compute_subnetwork" "subnet_frontend" {
  name          = "frontend"
  network       = google_compute_network.vpc_terraform.id
  ip_cidr_range = var.frontend_cidr
  region        = var.region
}

resource "google_compute_subnetwork" "subnet_backend" {
  name          = "backend"
  network       = google_compute_network.vpc_terraform.id
  ip_cidr_range = var.backend_cidr
  region        = var.region
}

resource "google_compute_subnetwork" "subnet_database" {
  name          = "database"
  network       = google_compute_network.vpc_terraform.id
  ip_cidr_range = var.database_cidr
  region        = var.region
}

resource "google_compute_firewall" "allow_user_frontend" {
  name    = "allow-user-frontend"
  network = google_compute_network.vpc_terraform.id

  allow {
    protocol = "tcp"
    ports    = ["80", "443"]
  }

  source_ranges = ["0.0.0.0/0"]
  target_tags   = ["frontend"]
}

resource "google_compute_firewall" "allow_frontend_backend" {
  name    = "allow-frontend-backend"
  network = google_compute_network.vpc_terraform.id

  allow {
    protocol = "tcp"
    ports    = ["8000"]
  }

  source_tags = ["frontend"]
  target_tags   = ["backend"]
}

resource "google_compute_firewall" "allow_ssh_all" {
  name    = "allow-ssh-all"
  network = google_compute_network.vpc_terraform.id

  allow {
    protocol = "tcp"
    ports    = ["22"]
  }

  source_ranges = ["0.0.0.0/0"]
  target_tags   = ["ssh"]
}

resource "google_compute_firewall" "allow_backend_database" {
  name    = "allow-backend-database"
  network = google_compute_network.vpc_terraform.id

  allow {
    protocol = "tcp"
    ports    = ["3306"]
  }

  source_tags = ["backend"]
  target_tags   = ["database"]
}