terraform-module

Scaffold a Terraform module

Creates a module with the canonical five-file layout. Apply the terraform-style skill's conventions while filling in real content, and finish with the terraform-validate workflow.

1. Name the module and pick providers

• Directory: kebab-case, named for what the module manages (modules/ecr-registry, not modules/registry-stuff). One cohesive concern per module.
• Decide which providers the module needs and their major-version constraints before writing resources — they go in terraform.tf on day one.

2. Create the five canonical files

Copy the skeletons from this skill's templates/ directory into the new module directory and replace the placeholder content:

File	Template shows
terraform.tf	required_version + required_providers with major-version pins
main.tf	a primary resource named main, plus naming-convention reminders
variables.tf	a required flat variable, an object variable with optional() defaults
outputs.tf	flat primary-attribute outputs and one grouped object output
README.md	title, purpose paragraph, Usage example, Inputs/Outputs tables

Every variable and output keeps a description — the linter enforces this.

3. Apply the house style

While implementing, follow the terraform-style skill. The rules that most often shape a new module's interface:

• set(string) for unordered unique inputs; primary resource named main;
• name_prefix (trailing -) for account-unique named resources;
• boolean-gated resources via for_each = toset(var.x ? ["true"] : []);
• outputs named for the attribute, cohesive facets grouped into one object;
• optional strings default to null, never "".

Split cohesive resource families into domain files (iam-node.tf, signing.tf) once main.tf grows past a screenful — the five canonical files are the floor, not the ceiling.

4. Document and validate

• Fill in the README's Usage example with a realistic call (module "x" { source = "../..." }) showing only the inputs a typical caller sets.
• Run the terraform-validate workflow (fmt → init/validate → tflint) on the new module before committing.