Multi-region serverless application with AWS CDK

MultiRegionServerlessCDK.ts

import {
  RestApi,
  CfnAuthorizer,
  DomainName,
  EndpointType,
  CfnBasePathMapping
} from "@aws-cdk/aws-apigateway";
import { Certificate, ValidationMethod } from "@aws-cdk/aws-certificatemanager";
import { Construct } from "@aws-cdk/core";
import {
  CfnHealthCheck,
} from "@aws-cdk/aws-route53";
import { LayerVersion } from "@aws-cdk/aws-lambda";

export class RootResources extends Construct {
  api: RestApi;
  layer: LayerVersion;
  authorizer: CfnAuthorizer;

  constructor(
    parent: Construct,
    name: string,
    props: {
      userPoolArn: string;
      region: string;
    }
  ) {
    super(parent, name);

    // API
    this.api = new RestApi(this, "RegionalApi", {
      endpointTypes: [EndpointType.REGIONAL]
    });

    const certificate = new Certificate(this, "ApiCertificate", {
      domainName: "api.multi.com",
      validationMethod: ValidationMethod.DNS
    });

    const domain = new DomainName(this, "APIDomain", {
      domainName: "api.multi.com",
      certificate,
      endpointType: EndpointType.REGIONAL
    });

    new CfnBasePathMapping(this, "Resource", {
      basePath: "(none)",
      domainName: domain.domainName,
      restApiId: this.api.restApiId,
      stage: this.api.deploymentStage.stageName
    });

    new CfnHealthCheck(this, "ApiHealthCheck", {
      healthCheckConfig: {
        port: 443,
        type: "HTTPS",
        resourcePath: "/prod/health/check",
        fullyQualifiedDomainName: `${this.api.restApiId}.execute-api.${props.region}.amazonaws.com`,
        requestInterval: 30,
        failureThreshold: 2
      }
    });
  }
}