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Tutorial 3: Multiple Environments with tfvars

Use one infrastructure project for dev and prod by adding variables, tfvars files, and Nx target configurations so you can run plan/apply per environment.

What You'll Do​

  • Add variables and tfvars/dev.tfvars, tfvars/prod.tfvars to terraform-infra
  • Add a configurations block to project.json so --configuration=dev and --configuration=prod pick the right var file
  • Run plan and apply per environment

Prerequisites​

Step 1: Add Variables​

Edit packages/terraform-infra/variables.tf (add or merge):

variable "environment" {
  description = "Environment name"
  type        = string
}

variable "instance_count" {
  description = "Number of instances"
  type        = number
  default     = 1
}

Use them in packages/terraform-infra/main.tf, for example:

resource "local_file" "config" {
  content  = "env=${var.environment} count=${var.instance_count}\n"
  filename = "${path.module}/config-${var.environment}.txt"
}

output "environment" {
  value = var.environment
}

Step 2: Add tfvars Files​

Create the directory and files:

mkdir -p packages/terraform-infra/tfvars

packages/terraform-infra/tfvars/dev.tfvars:

environment    = "dev"
instance_count = 1

packages/terraform-infra/tfvars/prod.tfvars:

environment    = "prod"
instance_count = 3

Step 3: Add Target Configurations in project.json​

So that terraform-plan and terraform-destroy use the correct var file per environment, add configurations to the inferred targets. Edit packages/terraform-infra/project.json and add (or merge into) the targets section:

"targets": {
  "terraform-init": {
    "metadata": { "backendProject": "terraform-setup" }
  },
"terraform-plan": {
      "options": {
        "args": ["-var-file=tfvars/dev.tfvars"]
      },
      "configurations": {
        "prod": {
          "args": ["-var-file=tfvars/prod.tfvars"]
        }
      }
    },
    "terraform-destroy": {
      "options": {
        "args": ["-var-file=tfvars/dev.tfvars"]
      },
      "configurations": {
        "prod": {
          "args": ["-var-file=tfvars/prod.tfvars"]
        }
      }
    }
}

The args array overrides the default command arguments. Paths in -var-file are relative to the project root (where the command runs). Nx merges these with the plugin-inferred targets. If your file already has terraform-init with metadata.backendProject, add only the terraform-plan and terraform-destroy blocks. The Configuration guide has more on using args and configurations.

Step 4: Run Per Environment​

Dev (default):

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

Prod:

nx run terraform-infra:terraform-plan --configuration=prod
nx run terraform-infra:terraform-apply --configuration=prod

terraform-apply uses the plan from the same configuration, so run plan with the same --configuration before apply.

Verify:

cat packages/terraform-infra/config-dev.txt
cat packages/terraform-infra/config-prod.txt

Summary​

You used one project with tfvars and target configurations to run plan/apply for dev and prod. For more patterns, see the Configuration guide and Examples.