cognito: Remove custom resource from UserPoolDomain to get `CloudFrontDistribution` attribute

Describe the feature

Currently we use an AwsCutstomResource to get cloudFrontDomainName attribute for a UserPoolDomain resource.

https://github.com/aws/aws-cdk/blob/4b9643f28edc2c530809931ccd7a17a811891af2/packages/aws-cdk-lib/aws-cognito/lib/user-pool-domain.ts#L129-L136

But actually CFn exposes the attribute natively. We can remove the unnecessary custom resource usage.

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-cognito-userpooldomain.html#aws-resource-cognito-userpooldomain-return-values

Use Case

To get a CloudFront domain for a user pool domain without using a custom resource. c.f. https://docs.aws.amazon.com/cognito/latest/developerguide/cognito-user-pools-add-custom-domain.html

Proposed Solution

We can just replace it with a getAtt call.

  public get cloudFrontDomainName(): string {
    return resource.getAtt('CloudFrontDistribution').toString(),
  }

Other Information

No response

Acknowledgements

[ ] I may be able to implement this feature request
[ ] This feature might incur a breaking change

CDK version used

2.155.0

Environment details (OS name and version, etc.)

macOS

Yes, it makes sense to remove usage of custom resource given that CloudFrontDistribution could be obtained from Fn::GetAtt. We would also need to store resource reference in a private field.

The following code works:

import * as cdk from 'aws-cdk-lib';
import * as cognito from 'aws-cdk-lib/aws-cognito';

export class CdktestStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const userPool = cognito.UserPool.fromUserPoolId(this, 'userpool', 'us-east-2_G27QXonjy');

    const resource = new cognito.CfnUserPoolDomain(this, 'Resource', {
      userPoolId: userPool.userPoolId,
      domain: 'myexampledomain'
    });

    const cloudFrontDistribution = resource.getAtt('CloudFrontDistribution');
    new cdk.CfnOutput(this, 'CloudFrontDistribution', { value: cloudFrontDistribution.toString()});
  }
}

produces the below output during cdk deploy:

✨  Synthesis time: 4.44s

CdktestStack:  start: Building 3d7f64ff11c6c4f29991c464279067ff6118a2f56e5e24e568922a6fc616da65:139480602983-us-east-2
CdktestStack:  success: Built 3d7f64ff11c6c4f29991c464279067ff6118a2f56e5e24e568922a6fc616da65:139480602983-us-east-2
CdktestStack:  start: Publishing 3d7f64ff11c6c4f29991c464279067ff6118a2f56e5e24e568922a6fc616da65:139480602983-us-east-2
CdktestStack:  success: Published 3d7f64ff11c6c4f29991c464279067ff6118a2f56e5e24e568922a6fc616da65:139480602983-us-east-2
CdktestStack: deploying... [1/1]
CdktestStack: creating CloudFormation changeset...

 ✅  CdktestStack

✨  Deployment time: 18.79s

Outputs:
CdktestStack.CloudFrontDistribution = d1lcia0inyjsq.cloudfront.net
Stack ARN:
arn:aws:cloudformation:us-east-2:139480602983:stack/CdktestStack/ad8fa120-6f9b-11ef-8dd4-02a04ad84bdd

✨  Total time: 23.24s

aws / aws-cdk