Master Terraform Docs: A Guide to Effective Documentation

Master Terraform Docs: A Guide to Effective Documentation

Want to improve your Terraform module documentation? This guide explains how to use terraform-docs to create clear and updated documentation automatically. It covers how to install the tool, set it up, and use it within your CI/CD pipelines as well.

Why Use Terraform-docs for Your Module Documentation?

• Terraform-docs helps you generate documentation for Terraform modules automatically, keeping it accurate and aligned with code changes.

• You can install terraform-docs on macOS, Windows, or Docker or set it up manually, making it accessible to everyone.

• With a YAML configuration file, you can customize your documentation by choosing what sections to include or hide, ensuring consistency across all the modules.

What is Terraform-docs and How Does It Help?

Terraform-docs is a tool that automatically generates documentation for your Terraform modules, saving you the time and effort of creating it on your own. It makes sure that your modules are clearly documented and easy to understand without any extra work from the Developer’s end.

By using terraform-docs, you can focus on building and deploying infrastructure while the tool handles your documentation part. It’s a simple way to keep your workflow organized and efficient.

Now, keeping your documentation up-to-date is an important task for all DevOps or Infrastructure engineers. As projects scale, clear and accurate documentation helps everyone in the team to stay aligned, minimizing errors and misconfigurations. Terraform-docs simplifies this process by keeping your documentation synced with code changes, making it a valuable tool for anyone working with Terraform.

How to Install Terraform-docs?

Installing terraform-docs is simple and works across different operating systems. Whether you use macOS, Windows, or Docker, there’s an option that fits your setup.

Here’s a quick guide to help you install Terraform-docs and start generating documentation for your Terraform modules with ease.

Homebrew Installation

If you're using macOS, you can easily install terraform-docs with Homebrew, a popular package manager. Just run the command brew install terraform-docs to set it up quickly and start automating your Terraform module documentation.

Windows Installation

Windows users can install terraform-docs using either Scoop or Chocolatey, two popular package managers.

• With Scoop, you can add the terraform-docs bucket from GitHub and install it quickly.

• With Chocolatey, just run choco install terraform-docs to set it up.

If you prefer manual installation, both Scoop and Chocolatey provide detailed instructions on their websites. These options make it easy to install terraform-docs on your Windows machine so you can focus on generating Terraform module documentation.

Docker Installation

Docker users can run terraform-docs in a container, which makes it a flexible choice for different environments. To use it, simply mount the directory containing your .tf files and run the Docker command:

docker run --rm --volume "$(pwd):/terraform-docs" -u $(id -u) quay.io/terraform-docs/terraform-docs:0.19.0 markdown /terraform-docs

Check the installation guide for detailed steps to integrate terraform-docs into your Docker workflows.

Pre-compiled Binary Installation

If you prefer pre-compiled binaries, you can download the latest stable version of terraform-docs from the GitHub Release page. Look for the binary under the ‘Assets’ section, download it, and move it to a directory included in your system’s PATH.

This method lets you set up terraform-docs quickly while ensuring you’re using the latest version.

Go Users Installation

Go users can install terraform-docs using the go install command. Run:

go install github.com/terraform-docs/terraform-docs@v0.19.0  

This installs the tool in the $(go env GOPATH)/bin directory.

If you see a “command not found” error, make sure the directory is included in your PATH. If needed, you can also try manual installation methods.

Configuration File Setup

Using terraform-docs helps keep your Terraform module documentation clear and consistent. The configuration is typically defined in a YAML file named .terraform-docs.yml, which is usually located in the module's root directory.

You can customize the documentation by:

• Showing or hiding sections using sections.show and sections.hide.

• Using Go templates to include details like inputs, outputs, and resources.

Once your configuration file is ready, generating documentation is easy. Run:

terraform-docs /module/path  

This creates markdown files with all the details about your Terraform modules. This setup ensures your documentation is always clear, complete, and easy for your team to follow.

What Formats Does Terraform-docs Support?

Terraform-docs supports multiple output formats, including Markdown and HTML. Markdown is the most commonly used format, as it clearly organizes inputs and outputs. You can customize Markdown tables by choosing which sections to show or hide, tailoring the documentation to your needs.

You can also include headers and footers from specific files to align the documentation with your project’s style. If the output.file option isn’t enabled, you can redirect the output to a file manually, giving you full control over how and where the documentation is saved.

Customizing Generated Documentation

With terraform-docs, you can easily customize your documentation by defining which sections to show or hide in the configuration file. This makes sure that the documentation focuses on the most relevant details.

By default, sections are displayed in a standard order, but you can add extra text or files using the include function in the content template. This flexibility lets you highlight specific inputs, outputs, or resources, making the documentation fit your project’s needs while keeping it clear and easy to follow.

You can use terraform-docs in CI/CD pipelines to automatically create and update documentation for Terraform modules. This ensures that README.md files stay current without needing manual updates, saving time and preventing errors from outdated information.

The configuration file for terraform-docs lets you control what details are included in the documentation. This file can be shared with your team or added to your CI system, so everyone follows the same process.

In Azure, for example, you can set up the pipeline to update documentation when changes are merged into the main branch. This setup involves creating a Personal Access Token (PAT), storing it securely in Azure Key Vault, and using it during the pipeline to push changes to the repository.

The pipeline can also clean up old README.md files before generating new ones, keeping everything accurate. A multi-stage pipeline helps organize the steps and works with both Windows and Linux environments.

Make sure the Azure DevOps service connection has the right permissions to commit and push changes from the pipeline. Once set up, terraform-docs runs automatically, keeping your documentation up-to-date with your code changes.

Troubleshooting Common Errors

Errors while using terraform-docs can be frustrating, but most issues can be fixed with a step-by-step approach. Start by reading the error message carefully—it often provides clues about what went wrong.

If you need more details, set the TF_LOG environment variable to DEBUG. This gives you detailed logs that can help identify the problem.

A common error is seeing ‘command not found’ after installing terraform-docs. This usually means the binary isn’t in your system’s PATH. To fix this, add the directory where terraform-docs is installed to your PATH.

Another issue can be version compatibility between Terraform and its providers. Always check that the versions you’re using work together to avoid unexpected errors.

If the problem persists, reaching out to the Terraform community can help. There are many users and experts who can offer advice and help you resolve the issue quickly.

Unlocking More with Terraform-docs Plugins

Terraform-docs provides advanced features using its configuration file, .terraform-docs.yml. This file allows you to customize how your documentation is generated, offering flexibility to match your project’s needs.

You can also use plugins with this configuration file to extend the functionality of terraform-docs. Plugins let you add custom features or modify how the documentation is generated.

To create a custom plugin, you need to:

1. Set up a repository with a specific naming convention.

2. Write a main.go file to define the plugin’s behavior and output.

3. Place the plugin in the correct directory so terraform-docs can use it.

These plugins can make your documentation process more efficient and tailored to your project requirements. By following the proper structure, you can unlock these advanced features and streamline your workflow.

Conclusion

Using terraform-docs can simplify how you manage documentation for your Terraform modules. It automates the process, keeping your documentation clear, consistent, and up-to-date as your code evolves.

In this guide, we covered key aspects of terraform-docs, including installation, configuration, output formats, and advanced features like plugins and CI/CD integration. By adding it to your workflow, you save time, reduce errors, and ensure your documentation stays aligned with your projects.

Make terraform-docs a part of your Terraform setup and let automation handle the documentation process so you can totally focus on building and managing your infrastructure.

Frequently Asked Questions

What is terraform-docs used for?

Terraform-docs automatically generates documentation for Terraform modules, making it clear and easy to use.

How do I install terraform-docs on macOS?

You can install terraform-docs on macOS using Homebrew. Run the command:

brew install terraform-docs  

Can terraform-docs be integrated into CI/CD pipelines?

Yes, you can use terraform-docs in CI/CD pipelines to automatically create and update README.md files. This keeps your documentation current and reduces manual work.

How do I customize the generated documentation?

Edit the .terraform-docs.yml file to choose which sections to show or hide and add any extra content you need. This lets you create documentation that fits your project’s needs.

What should I do if I encounter a 'command not found' error after installing terraform-docs?

This error means the installation directory isn’t in your system’s PATH. Add it to your PATH or reinstall the tool manually in a directory already included in your PATH.