readme.md

Terraform Puppet Hiera

Here's how to do Puppet-like data hierarchy in pure Terraform. No need for extra tooling like Terragrunt / Terraform Cloud / Pulumi etc. if you're just loading envs, common, region and app data...

Input

terraform plan -var="env=test" -var="deployment=apps/api" -var="region=us-west-1"

Output

Changes to Outputs:
  + data = {
      + bar     = "buzz"
      + environ = "test"
      + foo     = "bar"
    }

data:common.yaml

foo: bar

data:deployments:apps:api.yaml

bar: buzz

data:environments:test.yaml

environ: test

main.tf

module "vars" {
    source = "./modules/variables"
    environment = "test"
    deployment = "apps/api"
}

output "data" {
    value = module.vars.data
}

modules:variables:main.tf

// Provides Puppet Hiera-like functionality
// Loads YAML files and merges them into a single map

variable "environment" {
    type = string
}

variable "deployment" {
    type = string
}

output "data" {
    value = merge(
        yamldecode(file("./data/common.yaml")),
        yamldecode(file("./data/environments/${var.environment}.yaml")),
        yamldecode(file("./data/deployments/${var.deployment}.yaml"))
    )
}