Create a custom resource with AWS Amplify and CDK - aws-amplify

Question

I'm trying to create a custom resource in AWS Amplify, using AWS CDK. And, I'm trying to use an existing lambda function as a provider event handler.
When I do amplify push the resource creation fails with no useful information. What am I doing wrong here? How can I troubleshoot this?
import * as cdk from '#aws-cdk/core';
import * as AmplifyHelpers from '#aws-amplify/cli-extensibility-helper';
import * as cr from "#aws-cdk/custom-resources";
import * as logs from "#aws-cdk/aws-logs";
import * as lambda from '#aws-cdk/aws-lambda';
import { AmplifyDependentResourcesAttributes } from "../../types/amplify-dependent-resources-ref"
export class cdkStack extends cdk.Stack {
constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps, amplifyResourceProps?: AmplifyHelpers.AmplifyResourceProps) {
super(scope, id, props);
/* Do not remove - Amplify CLI automatically injects the current deployment environment in this input parameter */
new cdk.CfnParameter(this, 'env', {
type: 'String',
description: 'Current Amplify CLI env name',
});
const dependencies: AmplifyDependentResourcesAttributes = AmplifyHelpers.addResourceDependency(this,
amplifyResourceProps.category,
amplifyResourceProps.resourceName,
[{
category: "function",
resourceName: "myFunction"
}]
);
const myFunctionArn = cdk.Fn.ref(dependencies.function.myFunction.Arn);
const importedLambda = lambda.Function.fromFunctionArn(this, "importedLambda", myFunctionArn);
const provider = new cr.Provider(this, "MyCustomResourceProvider", {
onEventHandler: importedLambda,
logRetention: logs.RetentionDays.ONE_DAY,
})
new cdk.CustomResource(this, "MyCustomResource", {
serviceToken: provider.serviceToken
})
}
}
Here's the error I get:
CREATE_FAILED custommyCustomResourceXXXX AWS::CloudFormation::Stack Parameters: [AssetParametersXXXX, .....] must have values.

Answer 1

I got a response from AWS support team. It looks like the AssetParameters error is caused by the fact that Amplify CLI currently doesn't support a high level construct of Custom Resource Provider inside the custom resource category in Amplify CLI. The resource should be created this way:
import * as cdk from '#aws-cdk/core';
import * as AmplifyHelpers from '#aws-amplify/cli-extensibility-helper';
import * as lambda from '#aws-cdk/aws-lambda';
import { AmplifyDependentResourcesAttributes } from "../../types/amplify-dependent-resources-ref"
export class cdkStack extends cdk.Stack {
constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps, amplifyResourceProps?: AmplifyHelpers.AmplifyResourceProps) {
super(scope, id, props);
/* Do not remove - Amplify CLI automatically injects the current deployment environment in this input parameter */
new cdk.CfnParameter(this, 'env', {
type: 'String',
description: 'Current Amplify CLI env name',
});
const dependencies: AmplifyDependentResourcesAttributes = AmplifyHelpers.addResourceDependency(this,
amplifyResourceProps.category,
amplifyResourceProps.resourceName,
[{
category: "function",
resourceName: "myFunction"
}]
);
const myFunctionArn = cdk.Fn.ref(dependencies.function.myFunction.Arn);
const importedLambda = lambda.Function.fromFunctionArn(this, "importedLambda", myFunctionArn);
new cdk.CustomResource(this, "MyCustomResource", {
serviceToken: importedLambda.functionArn
})
}
}