terraform-module-scaffolder

Terraform Module Scaffolder

This skill helps create well-structured Terraform modules following best practices and conventions.

When to Use

Use this skill when:

• Creating a new Terraform module from scratch
• Setting up standardized module structure
• Need templates for common AWS/Azure/GCP resources
• Want to ensure module follows Terraform conventions

Module Structure

Generate modules with this standard structure:

module-name/
├── main.tf           # Primary resource definitions
├── variables.tf      # Input variables
├── outputs.tf        # Output values
├── versions.tf       # Provider and Terraform version constraints
├── README.md         # Module documentation
└── examples/         # Usage examples (optional)
    └── basic/
        └── main.tf

Instructions

1. Gather Requirements

Ask the user:

• What is the module name?
• What cloud provider (AWS, Azure, GCP, multi-cloud)?
• What resources should the module create?
• Any specific requirements or constraints?

2. Create Core Files

main.tf - Include:

• Resource definitions with clear naming
• Local values for computed attributes
• Data sources if needed

variables.tf - Include:

• Required variables first, then optional
• Clear descriptions for each variable
• Sensible defaults where appropriate
• Type constraints (string, number, bool, list, map, object)
• Validation rules for critical inputs

outputs.tf - Include:

• Resource IDs and ARNs
• Connection information (endpoints, URLs)
• Computed attributes that other modules might need
• Clear descriptions for each output

versions.tf - Include:

• Terraform version constraint (use ~> for minor version)
• Provider version constraints
• Required providers block

README.md - Include:

• Module description and purpose
• Usage example
• Requirements section
• Inputs table (can be auto-generated later)
• Outputs table (can be auto-generated later)

3. Apply Best Practices

• Use consistent naming: resource_type-purpose (e.g., s3-logs, vpc-main)
• Add tags to all taggable resources with variables for custom tags
• Use terraform fmt formatting
• Include lifecycle blocks where appropriate
• Add depends_on only when implicit dependencies don't work
• Use count or for_each for conditional resources

4. Add Example Usage

Create examples/basic/main.tf showing minimal working example:

module "example" {
  source = "../.."
  
  # Required variables
  name = "example"
  
  # Optional variables with common values
  tags = {
    Environment = "dev"
    ManagedBy   = "terraform"
  }
}

Validation Checklist

Before completing, verify:

• All files use consistent formatting (terraform fmt)
• Variables have descriptions and appropriate types
• Outputs have descriptions
• Version constraints are specified
• README includes usage example
• Module follows naming conventions
• Tags are configurable via variables