APIGateway Type Error "addBasePathMapping is not a function"

[baer]

DomainName.fromDomainNameAttributes created an object that does not have the method addBasePathMapping. This appears to be because the fromDomainNameAttributes returns a stripped-down version of IDomainName, not the full-fledged one you would get from a DomainName created in the CDK stack.

This may be intentional, or a missing feature in the construct but the docs for BasePathMapping say that "In most cases, you will probably want to use DomainName.addBasePathMapping() to define mappings" so it's not something I was expecting. If the intention is that CDK functions *.from<AWS Service>Attributes like this one or the one defined in VPC read-only, that should be a bit more clear in the docs if possible.

Reproduction Steps

const { DomainName } = require(`@aws-cdk/aws-apigateway`);

const myDomain = DomainName.fromDomainNameAttributes(
  this,
  `myDomainResource`,
  { domainName: CERTIFICATE_URL }
);
myDomain.addBasePathMapping(excelProxyApi, {});

Error Log

/some/path/index.js:79
  myDomain.addBasePathMapping(excelProxyApi, {
                   ^
TypeError: excelProxyDomain.addBasePathMapping is not a function

Environment

• **CLI Version :2.0.9
• **Framework Version:1.36.1
• **OS :OSX
• **Language :JavaScript

Other

Some of the comments in this thread seem to be from other people who are confused by the same problem. #3103

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This is 🐛 Bug Report

[nija-at]

This API is not supported on imported DomainName. Instead you can use the constructor for BasePathMapping to achieve this.

The 'most cases' in the docs probably refers to when the domain is created is defined as part of the CDK app, and not imported.

[baer]

@nija-at The reason for using one of CDK's *.from<AWS Service>Attributes is because I do not have the option of building it from inside of CDK. There are a number of reasons for this, such as:

• An "infrastructure stack" created a service that an "application stack" is using
• The service was created before CDK was brought into the organization
• You've acquired a team/project/company who has preexisting services
• etc.

CloudFormation recently launched the ability to import existing resources into a CloudFormation stack, CDK does not support this at the time of writing and *.from<AWS Service>Attributes is the next-best option. I'm only suggesting that some clarity in communication might help folks.

[nija-at]

Thanks for the clarification @baer. I believe you are able to use the BasePathMapping constructor for all these use cases. Perhaps dropping that entire statement there would help.

[nija-at]

Are you able to submit a PR to us with some better phrasing here?

[baer]

You're correct that the BasePathMapping constructor will work for these cases. I created a PR to suggest addBasePathMapping only if they're not importing the Domain

#8017

[nija-at]

Resolving since we got the doc updates in - #8017.