Introduction

terranix-codegen generates Terranix NixOS modules from Terraform provider schemas.

What it does

Terranix lets you write Terraform configurations in Nix instead of HCL:

{
  resource.aws_instance.web = {
    ami = "ami-123456";
    instance_type = "t2.micro";
  };
}

This works, but every attribute is essentially untyped – Terranix accepts any attrset and passes it through to the Terraform JSON. You get no feedback from the NixOS module system about typos, wrong types, or missing required fields.

terranix-codegen fixes this by reading the Terraform provider schema (which defines every resource, every attribute, and every type) and generating NixOS module options declarations that match the exact structure Terranix already expects. You import the generated modules alongside your config and you get type checking, tab completion, and documentation for free – without changing how you write your Terranix code.

Usage

# Generate modules directly from provider specs (uses OpenTofu by default)
terranix-codegen generate -p aws -o ./providers
terranix-codegen generate -p hashicorp/aws:5.0.0 -p google -o ./providers

# Or from an existing schema JSON
tofu providers schema -json | terranix-codegen generate -o ./providers

# Inspect a provider schema
terranix-codegen show -p aws

# Dump schema as JSON
terranix-codegen schema -p aws --pretty

Pass -t terraform to use HashiCorp Terraform instead of OpenTofu.

Then import the generated modules in your Terranix config:

{
  imports = [ ./providers/registry.terraform.io/hashicorp/aws ];

  resource.aws_instance.web = {
    ami = "ami-123456";
    instance_type = "t2.micro";
  };
}

The generated modules only declare options – they don’t change the attrset structure or rename anything. Your existing Terranix configs work as before, but now with type checking.

Output structure

providers/
├── default.nix
└── registry.terraform.io/
    └── hashicorp/
        └── aws/
            ├── default.nix
            ├── provider.nix
            ├── resources/
            │   ├── default.nix
            │   ├── instance.nix
            │   └── ...
            └── data-sources/
                ├── default.nix
                ├── ami.nix
                └── ...

Each default.nix imports its siblings. You can import a whole provider or individual resource files.