elbv2: LoadBalancer.fromLookup()

[realharry]

In order to be able to create an Alias record on Route53 with an ALB target, one needs to use the ILoadBalancerV2 interface. However, currently all fields of ILoadBalancerV2 are required, which makes it difficult to use.

Reproduction Steps

1. Create a public hosted zone on Route53.
2. Try to add an ARecord targeting an existing application load balancer (e.g., with dns name something like abc.region.elb.amazonaws.com).
3. The ARecord constructor requires target field of type RecordTarget.
4. The RecordTarget constructor takes a field, aliasTarget, of type IAliasRecordTarget.
5. The constructor of LoadBalancerTarget, which implements IAliasRecordTarget, requires an argument of type, ILoadBalancerV2.
6. There is no easy way to construct an ``ILoadBalancerV2object withloadBalancerCanonicalHostedZoneId` or `loadBalancerDnsName`.

Error Log

N/A

Environment

• CLI Version - 1.30.0 (build 4f54ff7) :
• Framework Version: 1.30.0 ;
• OS Ubuntu 18:
• Language Typescript:

Other

This is needed, among other things, to support naked domains (zone apex record) pointing to the application load balancer.

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This is 🐛 Bug Report

[rix0rrr]

Hey! It looks like you're describing a solution rather than a problem.

Please describe your situation, what you're trying to achieve, and why you are having trouble achieving what you'd like to achieve. We then we will decide how to best solve the problem considering your use case and other use cases we'd like to enable.

This could be using the solution you suggested, but it could also be another solution altogether. For example, what if you didn't have to implement the interface at all, but we provided a class for you that did what you needed it to? Would you still care that its properties are required?

[rix0rrr]

In this particular case, by the way, these is no way around specifying the two pieces of information we need, because that's simply what route53 requires and there's no way to derive them.

The alias target needs the hosted zone ID and the hosted zone name, which you are expected to supply when calling ApplicationLoadBalancer.fromLoadBalancerAttributes().

I will interpret this as a request for a LoadBalancer.fromLookup().

[realharry]

Hi @rix0rrr good morning. thanks for the reply.

yes, the particular scenario/steps I'm describing may or may not be a bug. my goal is, "to create an Alias record on Route53 with an ALB target". (it seems) the api clearly provides a way to do this, e.g., using ILoadBalancerV2. but, at the end of the day, (at least for me) it was not possible. that was why I called it a bug.

it can be achieved in many different ways. but, in my view, the original api designer intended to use this particular apis for this particular purpose. that's why, I think, he/she introduced all these elaborate constructs like IAliasRecordTarget and LoadBalancerTarget, etc. (Obviously, I can only guess at this point.)

Again, I'm not insisting on a solution. The possible solution/steps I provided was based on my (limited) understanding of the api. I would probably consult with the original designer/implementer as to why he/she defined LoadBalancerTarget, etc. if nobody can really use it.

Thanks!

[gagan1510]

Any update on this? Facing the same issue.

[gagan1510]

@realharry were you able to do this using any work around? Would be of great help.

[gagan1510]

Any update on this?

[abramcav]

This does seem like a bug. If I look up a load balancer using any method, I should get a consistent load balancer object that I can use in any way a load balancer can be used. I'm sure there is much more to it under the hood, but from a user perspective, this is a bug.

[github-actions]

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