Referencing REST API resource from CDK in amplify custom resource - aws-api-gateway

Question

I need to customize the method handler for a REST API endpoint and point it to SQS instead of a Lambda function. I'm stalling out trying to get a full reference to the RestApi object...
The RestApi object I get back from RestApi.fromRestApiId is incomplete; I can't do this:
const restApi = apigateway.RestApi.fromRestApiId(this, 'RestApi', dependencies.api.rest.ApiId);
const queueResource = restApi.root.resourceForPath('/webhooks');
...without getting this error:
Error: root is not configured when imported using fromRestApiId(). Use fromRestApiAttributes() API instead.
I can't use RestApi.fromRestApiAttributes as that requires the rootResourceId -- which I can't seem to find a reference to. The documentation for RestApi.fromRestApiAttributes shows this, but I don't have props:
const api = RestApi.fromRestApiAttributes(this, 'RestApi', {
restApiId: props.restApiId,
rootResourceId: props.rootResourceId,
});
Does anyone know how to access the rootResourceId?

Answer 1

The root resource (/) id is a alphanumeric string like 4cfzeywftb, which can be found in the console breadcrumbs:
APIs > API (076t2zozc0) > Resources> / (4cfzeywftb)
or by calling get-resources:
aws apigateway get-resources --rest-api-id 076t2zozc0
{
"items": [
{
"id": "4cfzeywftb",
"path": "/",
"resourceMethods": {
"ANY": {}
}
},
{
"id": "36g7tq",
"parentId": "4cfzeywftb",
"pathPart": "{proxy+}",
"path": "/{proxy+}",
"resourceMethods": {
"ANY": {}
}
}
]
}