Terraform Environment Modules (using modules to ecapsulate configuration)

deploy.sh

# Looks like we are deploying one of our environments
cd terraform/environments/dev/us-east-1
# Initialise (sets up backend and downloads modules if any)
terraform init
# Let's see what's going to happen
terraform plan -out terraform.plan
# If you're happy, run the following
terraform apply terraform.plan

structure.md

<project root>
├── README.md                     # Where your docs should start
└── terraform                     # Terraform code lives here
    ├── environments              # When environment modules live, with out configuration
    │   └── prod                  # Prod environment
    │       └── us-east-1         # Environment region (a production environment can consist of many regions)
    │           └── main.tf       # Where your implementation of _entry-point is
    └── modules
        ├── _entry-point          # Your entry point module, "_main" also works
        │   ├── main.tf
        │   ├── outputs.tf        # Only needed if there is informaiton you want to expose
        │   └── variables.tf
        ├── frontend
        │   ├── main.tf
        │   ├── outputs.tf
        │   └── variables.tf
        ├── backend
        │   ├── main.tf
        │   ├── outputs.tf
        │   └── variables.tf
        └── database
            ├── main.tf
            ├── outputs.tf
            └── variables.tf

terraform-environments-test-us-east-1.tf

// main.tf
provider "aws" {
  region = "us-east-1"
}

module "this" {
  source = "../../modules/_entry-point"
  domain = "dev.example.com"
}
  
output "this" {
  value = module.this
}

terraform-modules-_entry-point.tf

// variables.tf

variable "domain" {
  type = string
}

// main.tf
// These are something youd implement

module "database" {
  source = "./database"
}

module "backend" {
  source            = "./backend"
  domain            = "backend.${var.domain}"
  database_url      = module.database.url
  database_username = module.database.username
  database_password = module.database.password
}

module "frontend" {
  source           = "./frontend"
  domain           = var.domain
  backend_endpoint = module.backend.endpoint
}

// outputs.tf
  
output "database" {
  value = module.database
}
  
output "backend" {
  value = module.backend
}
  
output "frontend" {
  value = module.frontend
}