Project Structure

Here’s an example project structure.

├── app
│   ├── modules
│   │   └── example
│   │       └── test
│   └── stacks
│       └── demo
│           └── tfvars
├── config
│   ├── app.rb
│   ├── args
│   │   └── terraform.rb
│   ├── env
│   │   ├── dev.rb
│   │   └── prod.rb
│   ├── hooks
│   │   ├── terraform.rb
│   │   └── terraspace.rb
│   └── terraform
│       ├──
│       └──
├── seed
│   └── tfvars
│       └── modules
│           └── example
├── spec
└── Terrafile

Here’s an description of the folders and files:

Name Description
app/modules Reusable modules or library code. Use terraspace new module to generate a module.
app/modules/example/test Which each module, you can have an optional test folder where you would put tests specific to the module: Module-level tests
app/stack Business specific modules. Use terraspace new stack to generate a stack. It is often useful to start here and then abstract generic logic to the app/modules folder.
app/stack/demo/tfvars Within each stack folder, you can have a tfvars folder and define different variables. You can use tfvars layering to use the same code to create different environments.
config/app.rb Terraspace project-level settings. Configure things like the logger and test framework.
config/args Terraspace supports customizing the args passed to the terraform commands. See Config Args Docs.
config/env Where you put environment-specific overrides of the config/app.rb settings.
config/hooks Terraspace supports a variety of hooks. They can be used to customize and finely control the Terraform lifecycle process. See Config Hooks Docs.
config/terraform Common code that gets built with the deployed stack. It can be dynamically controlled to keep your code DRY.
seed/tfvars Where you configure tfvars files for modules. Note, you can also configure tfvars files with a subfolder directly in the module, but it is not encouraged since modules should be reusable library code.
spec Where you put Project-level tests.
Terrafile The Terrafile is where you define additional terraform modules to be loaded by terraform bundle.

Modules vs Stacks

Both modules and stacks are terraform modules. The difference is organizational and how they are meant to be used.

  • Modules are reusable pieces of code. Generally, it contains non-business specific logic.
  • Stacks are meant to be used to group together modules. Generally, this is where business-specific logic goes.

For example, the app1 stack could be designed to use the instance module. Another, app2 stack could use the instance and rds modules.