CDK for Terraform (cdktf) in TypeScript: Quick Start

In this post, I am going to explain how to build an EC2 instance with CDK for Terraform (TypeScript).

Link: Build AWS Infrastructure with TypeScript

what is CDK for Terraform (cdktf)?

It is a Cloud Development Kit (CDK) developed by HashiCorp and AWS.

Currently, the following languages are available as preview to run Terraform:

• TypeScript
• Python
• Java
• C#

version

To use cdktf in TypeScript, check the versions by:

% terraform -v
% node -v

expected:

• Terraform v0.12+
• Node.js v12.16+

install cdktf

On Mac, you can run:

% brew install cdktf
% cdktf --version
0.2.2

init

% mkdir typescript-aws
% cd typescript-aws
% cdktf init --template="typescript" --local

% tree -a
.
├── .gitignore
├── cdktf.json
├── help
├── main.ts
├── node_modules
│   ├── .bin
│  ...
│
├── package-lock.json
├── package.json
└── tsconfig.json

install dependencies

Initially, I was stuck with a provider error:

% cdktf get
ERROR: Please specify providers or modules in "cdktf.json" config file

Adding AWS as the provider solved the issue.

% vim cdktf.json

{
  "language": "typescript",
  "app": "npm run --silent compile && node main.js",
  "terraformProviders": ["aws@~> 2.0"],
  "terraformModules": [],
  "context": {
    "excludeStackIdFromLogicalIds": "true",
"allowSepCharsInLogicalIds": "true"
  }
}

% cdktf get
Generated typescript constructs in the output directory: .gen

sample code: create EC2

Replace the content of main.ts with the following:

import { Construct } from 'constructs'
import { App, TerraformStack, TerraformOutput } from 'cdktf'
import { AwsProvider, Instance } from './.gen/providers/aws'

class MyStack extends TerraformStack {
  constructor(scope: Construct, id: string) {
    super(scope, id)

    new AwsProvider(this, 'aws', {
      region: 'us-west-1',
    })

    const instance = new Instance(this, 'compute', {
      ami: 'ami-01456a894f71116f2',
      instanceType: 't2.micro',
      tags: {
        Name: 'TypeScript-Demo',
        fruit: 'blueberry',
        Address: '123 Main St',
      },
    })

    new TerraformOutput(this, 'public_ip', {
      value: instance.publicIp,
    })
  }
}

const app = new App()
new MyStack(app, 'typescript-aws')
app.synth()

TypeScript to Terraform

You can convert the code into Terraform format, then run terraform commands to check the plan and so on.

% cdktf synth
Generated Terraform code in the output directory: cdktf.out
% cd cdktf.out
% terraform plan

deploy & destroy

Also, you can use cdktf to deploy and destroy the resources directly.

% cdktf deploy

% cdktf destroy