aws-apigatewayv2.CfnApiMapping: Says there is already a Construct with name when there is not

[aj-n]

Describe the bug

I am setting up domainName basePath and api mappings. The APIGateway Rest APIs are outputs of other stacks and they are imported into the current cdk app.
basePath mappings works flawlessly. However, when I try to use the apiMapping, it complains with There is already a Construct with name '${childName'} in ${typeName}

I am only adding it in one place. And the name I give it is definitlely unique.
I tried several methods that give the same error.

Expected Behavior

The ApiMapping and/or Stage constructs get initialized with no errors()

Current Behavior

Fatal error: There is already a Construct with name '${childName'} in ${typeName}

Reproduction Steps

import * as cdk from 'aws-cdk-lib';
import { EndpointType, ApiMapping, CfnApiMapping } from 'aws-cdk-lib/aws-apigatewayv2';
import { 
  aws_apigateway as apigateway,
  aws_certificatemanager as certificatemanager,
} from 'aws-cdk-lib';
import { Construct } from 'constructs';


export class MyStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);
 
      // Imports
      const myAPIID = cdk.Fn.importValue(`some-other-exported-api-id`);
      const myAPI = apigateway.RestApi.fromRestApiId(this, "myAPI", myAPIID);
      
      // Init of domain name
      const domainNameAsString = `......`;
      const CertificateARN = `.......`;
      const certificate = certificatemanager.Certificate.fromCertificateArn(this, "certificate", CertificateARN);
      const subdomain = `.....`;
      
      const domainName = new cdk.aws_apigateway.DomainName(this, `DomainName_${subdomain}`, {
        domainName: domainNameAsString,
        certificate,
        basePath: "/",
        endpointType: EndpointType.REGIONAL,
      });
      
      // Base paths work fine
      domainName.addBasePathMapping(myAPI, {
        basePath: `routeThatWorks`,
        stage: myAPI.deploymentStage,
      });
      
       
      //////// FAILURES In each of these methods
      
      ///////////
      // This fails because `myAPI.deploymentStage` resolves to `undefined`
      const basePath = `some/path`;
      domainName.addApiMapping(myAPI.deploymentStage, {
        basePath,
      });
      
      ///////////
      // I tried using the Cfn2 method:
      new CfnApiMapping(this, `ApiMapping_jumanji2`, {
         apiId: myAPI.restApiId,
         domainName: domainNameAsString,
         stage: `development`,
         apiMappingKey: `some/path`,
      });
      // ERROR:
      //     Error: There is already a Construct with name 'ApiMapping_jumanji2' in MyStack [MyStack]
      
      ///////////
      // I also tried to get the stage via reference to get around the first error but a similar thing occurs
      
      // So, I tried to get it via reference
      const stage = cdk.aws_apigateway.Stage.fromStageAttributes(this, "jumanji", {
        restApi: myAPI,
        stageName: `development`
      });
      domainName.addApiMapping(stage, {
        basePath,
      });
      // ERROR:
      //     Error: There is already a Construct with name 'jumanji' in MyStack [MyStack]
    }
}

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.137.0 (build bb90b4c)

Framework Version

No response

Node.js Version

v18.5.0

OS

OSX Sonoma 14.4.1

Language

TypeScript

Language Version

Typescript (5.4.5)

Other information

No response

[pahud]

The error occurres here:

aws-cdk/packages/aws-cdk-lib/aws-apigateway/lib/domain-name.ts

Line 244 in 5a918d1

const id = `Map:${options.basePath ?? 'none'}=>${Names.nodeUniqueId(targetStage.node)}`;

const basePath = `some/path`;
      domainName.addApiMapping(myAPI.deploymentStage, {
        basePath,
      });

This is because myAPI is actually a reference, cdk would have no idea about myAPI.deploymentStage because myAPI is not created by current cdk stack or app.

I think you will need to create the CfnApiMapping yourself.

This is my PoC:

export class MyDemoStack extends Stack {
  constructor(scope: Construct, id: string, props?: StackProps) {
    super(scope, id, props);
 
      // Imports
      const myAPIID = Fn.importValue(`some-other-exported-api-id`);
      const myAPI = agw.RestApi.fromRestApiId(this, "myAPI", myAPIID);

      
      // Init of domain name
      const domainNameAsString = 'foo.com';
      const CertificateARN = `.......`;
      const certificate = acm.Certificate.fromCertificateArn(this, "certificate", CertificateARN);
      const subdomain = `.....`;
      
      const domainName = new agw.DomainName(this, `DomainName_${subdomain}`, {
        domainName: domainNameAsString,
        certificate,
        basePath: "/",
        endpointType: agw.EndpointType.REGIONAL,
      });
      
      // Base paths work fine
      domainName.addBasePathMapping(myAPI, {
        basePath: `routeThatWorks`,
        stage: myAPI.deploymentStage,
      });
      
  
      new apigwv2.CfnApiMapping(this, `ApiMapping_jumanji2`, {
         apiId: myAPI.restApiId,
         domainName: domainNameAsString,
         stage: `development`,
         apiMappingKey: `some/path`,
      });
    }
}

And I can cdk synth or cdk diff without any error so I think it should work. Thoughts?

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[aj-n]

@pahud I tried this method as specified in my original submission

The error I got was Error: There is already a Construct with name 'ApiMapping_jumanji2' in MyStack [MyStack]

Even though this is the only time I am creating it

[pahud]

@pahud I tried this method as specified in my original submission

The error I got was Error: There is already a Construct with name 'ApiMapping_jumanji2' in MyStack [MyStack]

Even though this is the only time I am creating it

I guess you probably have some extra code generating the same construct id.

Can you just run my provided PoC above and see if you still have this error?

[aj-n]

Your PoC worked.

I was able to find the issue in my code. One of my deployment environments did in fact double-add it due to a configuration setting causing a loop.
Thank you for your help!

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