API gateway custom domain using AWS-CDK

 

Creating custom domains for RestApis is the best way to make sure your API or system can easily be used by 3rd parties.

This is a very useful way to identify the api-gateway URL. We also can create multiple api-gateway distributed across multiple environment.

Let's dive into the code.

Accessing api needs multiple components.

• Getting the hosted zone.
• Creating a new certificate based on the domain.
• Creating new rest api based on the domain and certificate.
• Creating a Record in route53.
• Creating a sample lambda and attaching to api gateway

import * as ec2 from 'aws-cdk-lib/aws-ec2';
import { Stack } from 'aws-cdk-lib';
import * as path from 'path';
import * as route53Targets from 'aws-cdk-lib/aws-route53-targets';
import * as lambdaNode from 'aws-cdk-lib/aws-lambda-nodejs';
import * as route53 from 'aws-cdk-lib/aws-route53';
import * as apigateway from 'aws-cdk-lib/aws-apigateway';
import * as acm from 'aws-cdk-lib/aws-certificatemanager';

export function CDKApiGateway(stack: Stack, envProps: props) {
  // VPC is already created.
 
  const vpc = ec2.Vpc.fromLookup(stack, 'VPC', {
    vpcName: `vpc`,
  });

  const hostedZone = route53.HostedZone.fromHostedZoneAttributes(stack, `route53-zone`, {
    zoneName: hostedZoneName!,
    hostedZoneId: hostedZoneId!,
  });

  const certificate = new acm.Certificate(stack, 'Certificate-api-test', {
    domainName: 'api.dev.**.***.com',
  });

  const api = new apigateway.RestApi(stack, 'example-custom-api-domain', {
    domainName: {
      domainName: 'api.dev.**.***.com',
      certificate,
    },
  });

  new route53.ARecord(stack, 'apiDNS-example-a-record', {
    zone: hostedZone,
    recordName: 'api.dev.**.***.com',
    target: route53.RecordTarget.fromAlias(new route53Targets.ApiGateway(api)),
  });

  const hello = new lambdaNode.NodejsFunction(stack, `lambda-hello`, {
    entry: path.join('functions/hello/src/hello.ts'),
    vpc,
    handler: 'handler',
    environment: {
      FUNCTION_NAME: 'hello',
    },
  });

  const top = api.root.addResource('api');

  const helloResource = top.addResource('hello', {
    defaultIntegration: new apigateway.LambdaIntegration(hello),
  });

  // Add method along with integration lambda with api gateway
  helloResource.addMethod('GET');
}

This is an example of how to create a custom api gateway.