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

# À vous de créer :
# 1. Un VPC personnalisé avec auto_create_subnetworks = false
# 2. Trois sous-réseaux (frontend, backend, database)
# 3. Règles de firewall :
#    - HTTP/HTTPS vers frontend
#    - SSH vers toutes les instances
#    - Port 8000 de frontend vers backend
#    - Port 3306 de backend vers database

# VPC
resource "google_compute_network" "vpc_terraform" {
  name                    = "vpc_terraform"
  auto_create_subnetworks = false
}

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

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

# Sous-réseau
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_tags = ["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"]
}