Terraplate

Terraplate gives you DRY Terraform templates and modules (!) and an anti bike shedding tool by providing a 'convention over configuration' approach to laying out multiple infrastructures over many environments.

Terraplate does not actually run Terraform (or Terragrunt) to create or destroy infrastructure. It's job is to generate the Terraform code that you run.

Terraplate has an ansible role for each and every Terraform resource. The roles are generic and simply template out the relevant terraform code. The real time savings comes from combining these generic roles into a collection of customized related resources which we call 'components'. There are several component, for e.g. bastion host, s3 web app, ec2 instance with elb, etc

All of these 'components' could be written in Terraform code, but then we start the copy/paste repetive code cycle. Using Terraplate Components allows the Terraform code to remain DRY while making it easy to combine TF resources in many disparate combinations.

The playbooks in this repository are intended to demonstrate how Terraplate and Terraplate Components work. As components are usually customized per project, we maintain components in a separate repostitory here: Terraplate Components.

We think this approach is useful and removes the tedious copy/paste and enabling powerful composition of resources quickly and easily.

Dependencies

• Terraform ;-)
• Terragrunt to define variable values in tfvars files
• Ansible to define roles and playbooks to generate your terraform code (minimum version 2.2.0)

Using

The Terraplate role itself does not generate any specific Terraform module or template. Your roles do that. The Terraplate role provides tasks that will generate the Terraform artificats based on the values in your role. Your role needs to define the following:

• vars/main.yml
• files/main.tf
• tasks/main.yml

See the Terraplate Roles for examples

In order to generate the Terraform code that your role defines you run an ansible playbook. Your playbook needs to:

• set the fact 'package' to a value
• include a role at the top 'terraplate/setup'

After that setup work is done your playbook should include the roles that you have defined. See the Terraplate Playbooks for examples

Concepts

Component

This is an envrionment agnostic definition that:

• wraps the Terraform module defined by your role in a file named 'role'.tf
• includes a remote-state.tf and a provider.tf
• reads playbook defined variables in a hash under the nomenclature package_component_namspace_component_name

Instance

This is an environment specific definition that:

• includes a tfvars file with the values to feed to the component
• reads playbook defined variables in a hash under the nomenclature package_instance_namspace_instance_name

Variables

The naming convention for variables allows your roles to define default values for every value that is fed to your Terraform module but also allows your playbooks to easily override any of those values