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Tutorial 2: Add a Reusable Module

Add a reusable Terraform module (e.g. networking) and use it from your infrastructure project. Nx will detect the dependency and order runs correctly.

What You'll Do​

  • Create a reusable module with the generator (no backend = library-style module)
  • Reference it from terraform-infra
  • Run plan/apply and see the dependency in the graph

Prerequisites​

Step 1: Create the Module​

From the workspace root:

nx g nx-terraform:terraform-module networking

This creates packages/networking/ with no backend (reusable code only). See Project Types for module vs stateful.

Step 2: Add Inputs and Outputs​

Edit packages/networking/variables.tf:

variable "vpc_cidr" {
  description = "CIDR block for the VPC"
  type        = string
}

variable "subnet_count" {
  description = "Number of subnets"
  type        = number
  default     = 2
}

Edit packages/networking/outputs.tf:

output "vpc_id" {
  description = "VPC ID"
  value       = "vpc-${replace(var.vpc_cidr, ".", "-")}"
}

output "subnet_ids" {
  description = "Subnet IDs"
  value       = [for i in range(var.subnet_count) : "subnet-${i}"]
}

Edit packages/networking/main.tf to expose them (or leave minimal); the outputs above are enough for this tutorial.

Step 3: Use the Module in Infrastructure​

Edit packages/terraform-infra/main.tf and add a module block (adjust or replace existing content):

module "networking" {
  source = "../../networking"

  vpc_cidr     = "10.0.0.0/16"
  subnet_count = 3
}

resource "local_file" "example" {
  content  = "VPC: ${module.networking.vpc_id}"
  filename = "${path.module}/output.txt"
}

output "vpc_id" {
  value = module.networking.vpc_id
}

Ensure the local provider is in packages/terraform-infra/provider.tf if you use local_file (see Tutorial 1).

Step 4: Run and Verify​

nx run terraform-infra:terraform-init
nx run terraform-infra:terraform-plan
nx run terraform-infra:terraform-apply

Open the graph:

nx graph

You should see terraform-infra → networking. Dependencies are inferred from the module source and from terraform-init.metadata.backendProject. See Dependencies for details.

Summary​

You added a reusable module and consumed it from your infrastructure project. Next: Tutorial 3: Multiple environments with tfvars (one project, dev/prod via configurations).