date	2025-07-16 16:50:18 -0400
draft	true
params	author Robin Hutty
title	Modules for OpenTofu/Terraform

• These modules are only intended to be "child" modules; they are only intended to be called by other OpenTofu/Terraform modules.
• Modules that are intended to be root/parent modules, modules which can be called by Terragrunt or OpenTofu/Terraform directly live are also available.
• The directory hierarchy for these modules is organized according to GitLab’s convention which uses module-system/module-name, e.g. aws/aws-ec2. Each module SHOULD be pinned using SemVer2.0, although you MAY skip that for modules that are still in initial development and are not yet used anywhere.

Use an existing module

From OpenTofu/Terraform directly

module "<your identifier for the module>" {

# source = "..."
# version = "~> 0.1.0"

# Then pass variables
# foo = "bar"
}

From Terragrunt

terraform {

# source = "..."
# version = "~> 0.1.0"

}

inputs = {

# Then pass variables
# foo = "bar"

}

Developing

How to develop an existing module

TODO: pre-commit, conventional commits, style guidelines, testing, etc.

How to develop a new module

Use boilerplate to generate scaffolding for new modules so that creating/updating our body of terraform module code is familiar/conventional (for low cognitive load), easy to write, easy to test, and less error-prone. See the author's announcement for more details. In some ways, it is much like other TF scaffolding tools like tfscaffold or perhaps even more tool like the more general cookiecutter. See my article on [Tips for TF][4] for code for a new TF module.

In the "sibling" level repository, templates, is a boilerplate template which can scaffold a new tf module, providing various conveniences to help jumpstart a new highly conventional tf module.

The basic command, which should be run from the root of this repository once you have cloned the above repo, is:

boilerplate --template-url ../templates/boilerplate/tf_module \
  --output-folder ./modules/<module-system>/<new-module-name> \
  --non-interactive --var ModuleName=<new-module-name>

How to develop the boilerplate template for tf-modules

Want to contribute to improving the template for tf modules?

See the templates/boilerplate README

Metadata

1. Canonical Source: https://github.com/robinhutty/tf-modules
2. Unless otherwise noted on a per-module basis, these TF modules are licensed as License: BSD-3-Clause