(NLB): NetworkLoadBalancer.fromLookup returning dummy NLBs

[vneekhra]

Describe the bug

I am trying to fetch the NLB using its tags and using below method to fetch it.

`const nlb = this.getNLBByTag(tagNLB, props);

this.link = new VpcLink(this, app-${props.stage}-vpclink, {
targets: [nlb],
});

private getNLBByTag(tag: string, props: APPDomainVPCStackProps): INetworkLoadBalancer{
const nlbOptions: NetworkLoadBalancerLookupOptions = {
loadBalancerTags: {
component: "apigw",
application: "app",
env: "dev"
},
};
return NetworkLoadBalancer.fromLookup(this, app-${props.stage}-nlb, nlbOptions);
}`

Now this NetworkLoadBalancer.fromLookup method seems returning three results as below

1. arn:aws:elasticloadbalancing:us-west-2:123456789012:loadbalancer/network/my-load-balancer/50dc6c495c0c9188
2. arn:aws:elasticloadbalancing:us-east-2::loadbalancer/net/b72e485999b754299ae2067c2c1b3747/3eb24f395333b0d4
3. arn:aws:elasticloadbalancing:us-east-2::loadbalancer/net/b72e485999b754299ae2067c2c1b3747/3eb24f395333b0d4

Not sure why it is returning "my-load-balancer" nlb, even though it is not there in any of the AWS account and region.
Then for 2nd arn, it is showing dummy AZs: availabilityZones: [ 'dummy1a', 'dummy1b' ]
for 3rd arn: it is correct and that is what I am expecting. But ideally fromLookup method should only return one arn.

also in cdk.context.json file, I can only see one actual NLB, not any other dummy NLBs.
I am not checking-in this file cdk.context.json in git.

Expected Behavior

It should return only one arn which is mentioned in point #3 in describe section

Current Behavior

this NetworkLoadBalancer.fromLookup method returning three results as below

1. arn:aws:elasticloadbalancing:us-west-2:123456789012:loadbalancer/network/my-load-balancer/50dc6c495c0c9188
2. arn:aws:elasticloadbalancing:us-east-2::loadbalancer/net/b72e485999b754299ae2067c2c1b3747/3eb24f395333b0d4
3. arn:aws:elasticloadbalancing:us-east-2::loadbalancer/net/b72e485999b754299ae2067c2c1b3747/3eb24f395333b0d4

Reproduction Steps

npm install
cdk synth "" -c stage=$ENV
cdk deploy "" -c stage=$ENV --require-approval never

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.86.0

Framework Version

No response

Node.js Version

18

OS

Linux

Language

Typescript

Language Version

No response

Other information

Should we check-in cdk.context.json file in git?
Since I am running the cdk code using pipeline, that's why I have not committed cdk.context.json file, but I can see that the file is getting created and which has only one NLB and other vpc and subnet info.

[peterwoodworth]

Should we check-in cdk.context.json file in git?

Yes

See also best practices "Commit cdk.context.json"

[github-actions]

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[vneekhra]

@peterwoodworth did you check the issue I mentioned in the bug section? why the method NetworkLoadBalancer.fromLookup is returning 3 results? and what could be the possible work around?

[peterwoodworth]

I don't know what you mean by "returning three results". I took it to mean that one of those three results can occur any time you run this, in which case this would be easily solved by committing the cdk.context.json as you state that is functioning correctly, and our documentation I linked states you might get inconsistent behavior in a pipeline environment. If you're seeing three results at once, I'm not really sure how or what that means.