Terraform

BigConfig main idea is that it is better to write Clojure to generate JSON instead of HCL.

clojure

(ns core
  (:require
   [big-config.utils :refer [deep-merge sort-nested-map]]
   [big-tofu.core :refer [add-suffix construct]]
   [big-tofu.create :as create]
   [cheshire.core :as json]))

(let [{:keys [aws-account-id
              region] :as data} {:aws-account-id "111111111111"
                                 :region "eu-west-1"
                                 :module "example"}
      queues (->> (for [n (range 2)]
                    (create/sqs (add-suffix :alpha/big-sqs (str "-" n))))
                  flatten
                  (map construct))
      kms (->> (create/kms :alpha/big-kms)
               (map construct))
      bucket (format "tf-state-%s-%s" aws-account-id region)
      provider (create/provider (assoc data :bucket bucket))
      m (->> [provider]
             (into kms)
             (into queues)
             (apply deep-merge)
             sort-nested-map)]
  (json/generate-string m {:pretty true}))

HCL

data "aws_caller_identity" "current" {}

data "aws_iam_policy_document" {
  alpha_big_kms_data_policy = {
    statement = {
      actions = ["kms:*"]
      effect = Allow
      principals = {
        identifiers = ["arn:aws:iam::${data.aws_caller_identity.current.account_id}:root"]
        type = AWS
      }
      resources = ["*"]
    }
  }
}

provider "aws" {
  region = eu-west-1
}

resource "aws_kms_key" "alpha_big_kms" {}

resource "aws_kms_key_policy" "alpha_big_kms_resource_policy" {
  key_id = resource.aws_kms_key.alpha_big_kms.id
  policy = data.aws_iam_policy_document.alpha_big_kms_data_policy.json
}

resource "aws_sqs_queue" "alpha_big_sqs_0" {
  name = alpha_big_sqs_0
}

resource "aws_sqs_queue" "alpha_big_sqs_1" {
  name = alpha_big_sqs_1
}

terraform {
  backend "s3" {
    bucket = tf-state-111111111111-eu-west-1
    encrypt = true
    key = example.tfstate
    region = eu-west-1
  }

  required_providers "aws" {
    source = hashicorp / aws
    version = "~> 5.0"
  }
  required_version = ">= 1.8.0"
}

JSON

{
  "data" : {
    "aws_caller_identity" : {
      "current" : { }
    },
    "aws_iam_policy_document" : {
      "alpha_big_kms_data_policy" : [ {
        "statement" : [ {
          "actions" : [ "kms:*" ],
          "effect" : "Allow",
          "principals" : [ {
            "identifiers" : [ "arn:aws:iam::${data.aws_caller_identity.current.account_id}:root" ],
            "type" : "AWS"
          } ],
          "resources" : [ "*" ]
        } ]
      } ]
    }
  },
  "provider" : {
    "aws" : {
      "region" : "eu-west-1"
    }
  },
  "resource" : {
    "aws_kms_key" : {
      "alpha_big_kms" : { }
    },
    "aws_kms_key_policy" : {
      "alpha_big_kms_resource_policy" : {
        "key_id" : "${resource.aws_kms_key.alpha_big_kms.id}",
        "policy" : "${data.aws_iam_policy_document.alpha_big_kms_data_policy.json}"
      }
    },
    "aws_sqs_queue" : {
      "alpha_big_sqs_0" : {
        "name" : "alpha_big_sqs_0"
      },
      "alpha_big_sqs_1" : {
        "name" : "alpha_big_sqs_1"
      }
    }
  },
  "terraform" : {
    "backend" : {
      "s3" : {
        "bucket" : "tf-state-111111111111-eu-west-1",
        "encrypt" : true,
        "key" : "example.tfstate",
        "region" : "eu-west-1"
      }
    },
    "required_providers" : {
      "aws" : {
        "source" : "hashicorp/aws",
        "version" : "~> 5.0"
      }
    },
    "required_version" : ">= 1.8.0"
  }
}

Requirements

BigConfig requires Clojure and Babashka. You should also configure dirvenv for your shell.

brew

brew install clojure/tools/clojure
brew install borkdude/brew/babashka
brew install direnv

devbox

devbox global add clojure
devbox global add babashka
devbox global add direnv

Getting started

1. Create the Terraform project

   # Add big-config as tool to Clojure
   clojure -Ttools install-latest :lib io.github.amiorin/big-config :as big-config
   
   # Invoke the terraform template
   clojure -Tbig-config terraform

2. Configure git

   git init
   git add
   git commit
   git push

3. Shows the Babashka tasks

   bb tasks

4. Show the BigConfig DSL manual.

   bb show-help

Conclusion

Terraform supports both HCL and JSON files. Instead of learning a new language (HCL) you can use Clojure to generate the JSON files.

Terraform library Clojure functions to help you to generate Terraform JSON files.