Demonstration of using AWS CDK

index.ts

/*
I was curious as to whether it was possible to make resources
created using CDK constructs work with raw CloudFormation
resources and vice versa.

This aws-cdk app demonstrates a VPC and an ELB that belongs to it
in different, dependant stacks, leveraging CFN outputs / imports,
and leveraging CDK's method of passing information from one
stack to another.
*/

import cdk = require("@aws-cdk/cdk");
import ec2 = require("@aws-cdk/aws-ec2");
import elb = require("@aws-cdk/aws-elasticloadbalancing");

interface ElbProps {
  vpc: ec2.VpcNetworkRefProps;
}

// A VPC made using CDK constructs
class VpcDemoStack extends cdk.Stack {
  public readonly vpcRef: ec2.VpcNetworkRefProps;

  constructor(parent: cdk.App, id: string, props?: cdk.StackProps) {
    super(parent, id, props);
    const vpc = new ec2.VpcNetwork(this, "DemoVPC");

    this.vpcRef = vpc.export();
  }
}

// A VPC made using Cloudformation primitives - much simpler than
// what the CDK construct would produce, but enough for a demonstration.
class VpcCFNDemoStack extends cdk.Stack {
  public readonly vpcRef: ec2.VpcNetworkRefProps;

  constructor(parent: cdk.App, id: string, props?: cdk.StackProps) {
    super(parent, id, props);
    const vpc = new ec2.cloudformation.VPCResource(this, "DemoCFNVPC", {
      cidrBlock: "10.0.0.0/16"
    });
    const publicSubnet = new ec2.cloudformation.SubnetResource(
      this,
      "DemoCFNSubnet1",
      {
        cidrBlock: "10.0.54.0/24",
        availabilityZone: "us-east-1a",
        vpcId: vpc.ref
      }
    );

    const privateSubnet = new ec2.cloudformation.SubnetResource(
      this,
      "DemoCFNSubnet2",
      {
        cidrBlock: "10.0.55.0/24",
        availabilityZone: "us-east-1a",
        vpcId: vpc.ref
      }
    );

    // This is the exact same data type as what our CDK-based
    // VPC is exporting - we're just populating it manually!
    const vpcProps = {
      vpcId: vpc.ref,
      availabilityZones: ["us-east-1a"],
      publicSubnetIds: [publicSubnet.ref],
      privateSubnetIds: [privateSubnet.ref]
    };
    this.vpcRef = ec2.VpcNetworkRef.import(
      this,
      "ExternalVPC",
      vpcProps
    ).export();
  }
}

// A Load Balancer made using a CDK construct
class ElbDemoStack extends cdk.Stack {
  constructor(parent: cdk.App, id: string, props: ElbProps) {
    super(parent, id);

    const vpc = ec2.VpcNetworkRef.import(this, "ExternalVPC", props.vpc);

    new ec2.ClassicLoadBalancer(this, "DemoELB", {
      vpc,
      listeners: [{ externalPort: 80 }]
    });
  }
}

// A Load Balancer made using Cloudformation primitives
class ElbCFNDemoStack extends cdk.Stack {
  constructor(parent: cdk.App, id: string, props: ElbProps) {
    super(parent, id);

    const vpc = ec2.VpcNetworkRef.import(this, "ExternalVPC", props.vpc);

    new elb.cloudformation.LoadBalancerResource(this, "DemoELBCFN", {
      subnets: vpc.privateSubnets.map(s => s.subnetId),
      scheme: "internal",
      listeners: [
        {
          loadBalancerPort: "80",
          protocol: "HTTP",
          instancePort: "80",
          instanceProtocol: "HTTP"
        }
      ]
    });
  }
}

class MyApp extends cdk.App {
  constructor(argv: string[]) {
    super(argv);

    const cdkVpcStack = new VpcDemoStack(this, "vpc-demo");

    const cloudformationVpcStack = new VpcCFNDemoStack(this, "vpc-cfn-demo");

    /* 
    Demonstrate creating a VPC using a CDK construct and then using it
    with a CFK construct load balancer and a CloudFormation primitive
    load balancer
    */
    new ElbDemoStack(this, "cdk-vpc-to-cdk-elb-demo", {
      vpc: cdkVpcStack.vpcRef
    });
    new ElbCFNDemoStack(this, "cdk-vpc-to-cfn-elb-demo", {
      vpc: cdkVpcStack.vpcRef
    });

    /*
    Demonstrate creating a VPC using Cloudformation primitives and then
    using it with a CDK construct and a Cloudformation primitive respectively
    */
    new ElbDemoStack(this, "cfn-vpc-to-cdk-elb-demo", {
      vpc: cloudformationVpcStack.vpcRef
    });
    new ElbCFNDemoStack(this, "cfn-vpc-to-cfn-elb-demo", {
      vpc: cloudformationVpcStack.vpcRef
    });
  }
}

process.stdout.write(new MyApp(process.argv).run());