fix(ec2): private DNS for custom endpoints has incorrect default

[flemjame-at-amazon]

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

Currently if I create an InterfaceVpcEndpoint to a non-AWS service, I must set the privateDnsEnabled field to be false, like so:

InterfaceVpcEndpoint vpce = new InterfaceVpcEndpoint(construct, "VPCe", InterfaceVpcEndpointProps.builder()
            // Private DNS is only supported by AWS services
            .privateDnsEnabled(Boolean.FALSE)
            .vpc(vpc)
            .service(providerService)
            .build());

This is because the default is "true", which works for AWS services but not for custom hosted services. This change exposes a privateDnsDefault for different IInterfaceVpcEndpointService implementations, and VpcEndpoint will use that as the default if privateDnsEnabled is not specified. This way, I could create a service like so, without having to specify private DNS settings:

    // Here I create a VPC endpoint to a custom hosted service
    IInterfaceVpcEndpointService providerService = new InterfaceVpcEndpointService(serviceName, servicePort);

    InterfaceVpcEndpoint vpce = new InterfaceVpcEndpoint(construct, "VPCe", InterfaceVpcEndpointProps.builder()
            .vpc(vpc)
            .service(providerService)
            .build());

This should break no existing functionality:

• Users overriding privateDnsEnabled
  • Will continue to have their setting applied
• Users not overriding privateDnsEnabled
  • If they are using InterfaceVpcEndpointAwsService, then the default associated with InterfaceVpcEndpointAwsService will be applied, which is true, which matches the current behavior
  • Users cannot use an InterfaceVpcEndpoint without overriding privateDnsEnabled, because only AWS services support private DNS

Commit Message

fix(ec2): private DNS for custom endpoints has incorrect default

Currently if I create an InterfaceVpcEndpoint to a non-AWS service, I must set the privateDnsEnabled field to be "false". This is because the default is "true", which works for AWS services but not for custom hosted services. This change exposes a privateDnsDefault for different IInterfaceVpcEndpointService implementations, and VpcEndpoint will use that as the default if privateDnsEnabled is not specified. This way, I could create a service without having to specify private DNS settings.

[aws-cdk-automation]

AWS CodeBuild CI Report

• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository

[aws-cdk-automation]

AWS CodeBuild CI Report

• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository

[aws-cdk-automation]

AWS CodeBuild CI Report

• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository

[rix0rrr]

Why is this optional?

[flemjame-at-amazon]

I made this optional for backwards compatibility -- any existing CDK code specifying a service like:

  const interfaceVpcEndpoint = new ec2.InterfaceVpcEndpoint(stack, 'InterfaceEndpoint', {
    vpc,
    service: {
      name: 'com.amazonaws.us-west-2.workspaces',
      port: 80
    }
  });

Will get compilation errors if I don't make the field optional:

Property 'privateDnsDefault' is missing in type '{ name: string; port: number; }' 
but required in type 'IInterfaceVpcEndpointService'.

[rix0rrr]

I see. That's not how you're supposed to supply that value though, but I get it.

Pull request has been modified.

[aws-cdk-automation]

AWS CodeBuild CI Report

• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository

[aws-cdk-automation]

AWS CodeBuild CI Report

• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository

[mergify]

Thank you for contributing! Your pull request is now being automatically merged.

[jogold]

@rix0rrr there's a package-lock.json committed here...

[rix0rrr]

Ahh doh.

[aws-cdk-automation]

AWS CodeBuild CI Report

• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository

[aws-cdk-automation]

AWS CodeBuild CI Report

• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository

[mergify]

Thank you for contributing! Your pull request is now being automatically merged.