AWS API Gateway, default base mappings with CDK - amazon-web-services

Question

I'm setting up an environment with AWS CDK but I'm having trouble with API Gateway and base mappings for custom domains.
I got an API that should have two stages: "internal" and "external".
Whenever I create a new RestApi and either specify domainName as a prop to the construcor, or use the addDomainName method afterwards. This will always create a default Base Mapping, which I do not want. I want to add my own mappings like this:
apiGateway.domainName.addBasePathMapping(apiGateway, { basePath: 'internal', stage: internalStage });
apiGateway.domainName.addBasePathMapping(apiGateway, { basePath: 'external', stage: externalStage });
The problem if I do the above is that the default mapping have already been created and since it will be created with an empty basePath, I can't add any other mappings to the same API.
I've checked the source code and there does not seem to be a way to pass mappings when you add a domain, they are always created automatically.
Is there a way to change the default mappings, or to get pass this problem in another way?
Example that would be nice:
apiGateway.domainName.basePathMappings[0] = { ... }
My code right now:
const apiGateway = new apigw.RestApi(this, 'RestApi', {
deploy: false,
domainName: {
domainName: 'sub.example.com',
certificate,
endpointType: apigw.EndpointType.REGIONAL,
securityPolicy: apigw.SecurityPolicy.TLS_1_2,
},
});
const deployment = new apigw.Deployment(this, 'Deployment', { api: apiGateway });
const internalStage = new apigw.Stage(this, 'InternalStage', {
stageName: 'internal',
deployment,
});
apiGateway.domainName.addBasePathMapping(apiGateway, { basePath: 'internal', stage: internalStage });
const externalStage = new apigw.Stage(this, 'ExternalStage', {
stageName: 'external',
deployment,
});
apiGateway.domainName.addBasePathMapping(apiGateway, { basePath: 'external', stage: externalStage });
The generated syntax when i run Synth, will show 3 different AWS::ApiGateway::BasePathMapping.
One for internal, one for external (with basePath set correctly) and one is the default created one with no basePath (which I want gone).

Answer 1

The moment we add a domainName either by passing to RestApi or by calling .addDomainName , cdk is adding a base path mapping /.
I was able to work around by using cfn resources for DomainName and Base path mapping.
const cfnInternalDomain = new apigw.CfnDomainName(this, "internal-domain", {
domainName: internalDomainName,
regionalCertificateArn: myCert.certificateArn,
endpointConfiguration: { types: [apigw.EndpointType.REGIONAL] },
});
const intBasePath = new apigw.CfnBasePathMapping(
this,
"internal-base-path",
{
basePath: "intPath",
domainName: cfnInternalDomain.ref,
restApiId: myRestApi.restApiId,
stage: internalStage.stageName,
}
);
This is full code.
const myRestApi = new apigw.RestApi(this, "rest-api", {
deploy: false,
});
myRestApi.root.addMethod("ANY", new apigw.MockIntegration());
const deployment = new apigw.Deployment(this, "api-deployment", {
api: myRestApi,
retainDeployments: false,
});
const internalStage = new apigw.Stage(this, "internal-stage", {
stageName: "internal",
deployment,
});
const internalDomainName = "internal.mytest.domain.com";
const cfnInternalDomain = new apigw.CfnDomainName(this, "internal-domain", {
domainName: internalDomainName,
regionalCertificateArn: myCert.certificateArn,
endpointConfiguration: { types: [apigw.EndpointType.REGIONAL] },
});
const intBasePath = new apigw.CfnBasePathMapping(
this,
"internal-base-path",
{
basePath: "intPath",
domainName: cfnInternalDomain.ref,
restApiId: myRestApi.restApiId,
stage: internalStage.stageName,
}
);