Wrapper Module Approach

The wrapper module pattern builds on top of existing community modules, enabling you to enforce organizational standards while reusing battle-tested code. This approach reduces maintenance overhead, maintains upstream compatibility, and ensures consistency across environments.

Why Use Wrapper Modules?

• Consistency
  Enforce company-wide naming conventions, tag policies, and resource configurations through standardized inputs.
• Scoped Customization
  Override only the settings you need, leaving the underlying community module intact for easier upstream upgrades.
• Maintainability
  Minimize drift from official releases by wrapping instead of forking—updating to new versions becomes straightforward.

Common Use Cases

Implementation Example

1. Create your wrapper module directory:
   modules/my-wrapper/

2. In modules/my-wrapper/main.tf, call the community module and map your inputs:

# modules/my-wrapper/main.tf
module "eks" {
  source       = "git::https://github.com/terraform-aws-modules/eks/aws"
  cluster_name = var.cluster_name       # mapped from wrapper input
  vpc_id       = var.vpc_id             # mapped from wrapper input
  tags = merge(
    var.organization_tags,              # enforced by your organization
    var.user_tags                       # additional user-provided tags
  )
  # ...other required community inputs
}

3. Declare only the variables your team needs in variables.tf:

# modules/my-wrapper/variables.tf
variable "cluster_name" {
  description = "Name of the EKS cluster"
  type        = string
}

variable "vpc_id" {
  description = "VPC ID for the EKS cluster"
  type        = string
}

variable "organization_tags" {
  description = "Tags enforced by the organization"
  type        = map(string)
  default     = { Project = "AcmeCorp" }
}

variable "user_tags" {
  description = "Additional tags from the user"
  type        = map(string)
  default     = {}
}

4. In your root Terraform or Terragrunt configuration, invoke modules/my-wrapper instead of the community module directly.

module "production_eks" {
  source = "../modules/my-wrapper"

  cluster_name       = "prod-cluster"
  vpc_id             = "vpc-0123456789abcdef0"
  organization_tags  = { Environment = "production", Team = "infra" }
  user_tags          = { Owner = "alice" }
}

Choosing Between Community, Custom, and Wrapper Modules

When to Use What

• Community Modules: Go-to for rapid prototyping or teams with minimal customization needs.
• Custom Modules: Best for specialized architectures requiring bespoke resource definitions.
• Wrapper Modules: Ideal for enforcing organizational governance on top of community best practices.

References

• Terraform Module Registry
• Terraform AWS EKS Module
• Terraform Best Practices