/add-gcp-module — Add New GCP Module Skill

Create a new GCP Terraform preset module following all project conventions.

Trigger

Use when asked to add a new GCP module, create a GCP preset, or scaffold a GCP Terraform module.

Workflow

1. Name the Module

GCP modules use snake_case directory names (e.g., api_gateway, cloud_run, cloud_sql).

gcp/<module_name>/

2. Create main.tf

Every main.tf must include:

terraform {
  required_version = ">= 1.0"

  required_providers {
    google = {
      source  = "hashicorp/google"
      version = ">= 5.0"
    }
  }
}

Key rules:

• •If using community modules, source from terraform-google-modules with version pin
• •Otherwise use direct google_* resources
• •If the module needs the random provider, add it with >= 3.5
• •Enable encryption, enforce least-privilege IAM by default

3. Create variables.tf

Required variables (every preset must declare these):

variable "project" {
  description = "GCP project ID"
  type        = string

  validation {
    condition     = can(regex("^[a-z][a-z0-9-]{4,28}[a-z0-9]$", var.project))
    error_message = "Project ID must be 6-30 characters, lowercase alphanumeric with hyphens."
  }
}

variable "region" {
  description = "GCP region"
  type        = string
}

variable "labels" {
  description = "Resource labels"
  type        = map(string)
  default     = {}
}

Validation patterns:

• •Null-safe validation: Always use ternary: var.x == null ? true : contains([...], var.x)
• •Use can(), regex(), trimspace(), contains() as appropriate
• •Variables without defaults become required root variables

4. Create outputs.tf

Declare outputs for cross-module wiring:

output "id" {
  description = "Resource ID"
  value       = google_<resource>.<name>.id
}

Common wiring outputs: id, name, self_link, network_id, ip_address.

5. Check Go Embedding

Verify patterns in zz_embed.go:

• •.tf files: already covered by gcp/*/*.tf
• •.tmpl files: NOT covered — if adding .tmpl files, add //go:embed gcp/*/*.tmpl to zz_embed.go

6. Format and Validate

terraform fmt gcp/<module_name>/
cd gcp/<module_name> && terraform init -backend=false -input=false && terraform validate

7. Verify Go Embed Compiles

go build ./...

Anti-Patterns

• •Using camelCase directory names (GCP uses snake_case)
• •Using tags instead of labels (GCP convention)
• •Using var.x == null || condition in validation
• •Forgetting project or region variables
• •Adding .tmpl files without updating zz_embed.go

Checklist

• • Directory: gcp/<snake_case_name>/
• • main.tf with required_providers (Google >= 5.0, Terraform >= 1.0)
• • variables.tf with project, region, labels variables
• • outputs.tf with wiring outputs
• • Null-safe validation (ternary pattern)
• • Security defaults (encryption, least-privilege IAM)
• • terraform fmt clean
• • terraform validate passes
• • go build ./... succeeds
• • zz_embed.go updated if .tmpl files added