CustomeResource error resource.getAtt('Response')

[entest-hai]

Describe the bug

I follow this example to create a custom resource. However, there is error due to these lines

    // custom resource
    const resource = new CustomResource(this, "Resource", {
      serviceToken: provider.serviceToken,
      properties: props,
    });

    // 
    this.response = resource.getAtt('Response').toString(); 

Got error

Received response status [FAILED] from custom resource. Message returned: See the details in CloudWatch Log Stream: 2022/05/08/[$LATEST]293aa907cb9443eba850d678af331cbe (RequestId: 1a5830d9-8e5e-46d9-873e-51e6f7fe9147)

Expected Behavior

Should be no error

Current Behavior

Create Failed

Reproduction Steps

custom-resource-handler.py

def main(event, context):
    import logging as log
    import cfnresponse
    log.getLogger().setLevel(log.INFO)

    # This needs to change if there are to be multiple resources in the same stack
    physical_id = 'TheOnlyCustomResource'

    try:
        log.info('Input event: %s', event)

        # Check if this is a Create and we're failing Creates
        if event['RequestType'] == 'Create' and event['ResourceProperties'].get('FailCreate', False):
            raise RuntimeError('Create failure requested')

        # Do the thing
        message = event['ResourceProperties']['Message']
        attributes = {
            'Response': 'You said "%s"' % message
        }

        cfnresponse.send(event, context, cfnresponse.SUCCESS, attributes, physical_id)
    except Exception as e:
        log.exception(e)
        # cfnresponse's error message is always "see CloudWatch"
        cfnresponse.send(event, context, cfnresponse.FAILED, {}, physical_id)

custom-resource-stack.ts

import {
  aws_lambda,
  CfnOutput,
  CustomResource,
  custom_resources,
  Duration,
  Stack,
  StackProps,
} from "aws-cdk-lib";
import { Construct } from "constructs";
import * as path from "path";
import * as fs from "fs";

export interface CustomResourceStackProps {
  message: string; 
}

export class CustomResourceStack extends Construct {

  public readonly response: string; 

  constructor(scope: Construct, id: string, props: CustomResourceStackProps) {
    super(scope, id);

    // lambda
    const fn = new aws_lambda.SingletonFunction(this, "Singleton", {
      uuid: "f7d4f730-4ee1-11e8-9c2d-fa7ae01bbebc",
      code: new aws_lambda.InlineCode(
        fs.readFileSync(path.join(__dirname, "custom-resource-handler.py"), {
          encoding: "utf-8",
        })
      ),
      handler: "index.main",
      timeout: Duration.seconds(300),
      runtime: aws_lambda.Runtime.PYTHON_3_7,
    });

    // provider
    const provider = new custom_resources.Provider(this, "Provider", {
      onEventHandler: fn,
    });

    // custom resource
    const resource = new CustomResource(this, "Resource", {
      serviceToken: provider.serviceToken,
      properties: props,
    });

    // get attribute 
    this.response = resource.getAtt('Response').toString(); 


  }
}

index.ts

#!/usr/bin/env node
import 'source-map-support/register';
import * as cdk from 'aws-cdk-lib';
import { CustomResourceStack } from '../lib/custom-resource-stack';
import { CfnOutput } from 'aws-cdk-lib';

const app = new cdk.App();

class MyStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const resource = new CustomResourceStack(
      this,
      'CustomResourceDemoStack',
      {
        message: 'Create a custom resource'
      }
    )

    // publish the custom resource output 
    new CfnOutput(
      this, 
      'ResponseMessage',
      {
        description: 'the message that came back from the Custom Resource',
        value: resource.response
      }
    )

  }
}

new MyStack(app, 'CustomResrouceStackDemo');

package.json

{
  "name": "custom-resource",
  "version": "0.1.0",
  "bin": {
    "custom-resource": "bin/custom-resource.js"
  },
  "scripts": {
    "build": "tsc",
    "watch": "tsc -w",
    "test": "jest",
    "cdk": "cdk"
  },
  "devDependencies": {
    "@types/jest": "^27.4.1",
    "@types/node": "10.17.27",
    "jest": "^27.5.1",
    "ts-jest": "^27.1.4",
    "aws-cdk": "2.23.0",
    "ts-node": "^10.7.0",
    "typescript": "~3.9.7"
  },
  "dependencies": {
    "aws-cdk-lib": "2.23.0",
    "constructs": "^10.0.0",
    "source-map-support": "^0.5.21"
  }
}

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.23

Framework Version

No response

Node.js Version

v16.15.0

OS

Amazon Linux 2

Language

Typescript

Language Version

3.9.7

[peterwoodworth]

You're right, I'm able to reproduce this. Thanks for letting us know, we'll get it fixed up soon!

[balx]

Instead of using cfnresponse, return { 'Data': attributes } should fix the issue.

def main(event, context):
    import logging as log
    log.getLogger().setLevel(log.INFO)

    # This needs to change if there are to be multiple resources in the same stack
    physical_id = 'TheOnlyCustomResource'

    try:
        log.info('Input event: %s', event)

        # Check if this is a Create and we're failing Creates
        if event['RequestType'] == 'Create' and event['ResourceProperties'].get('FailCreate', False):
            raise RuntimeError('Create failure requested')

        # Do the thing
        message = event['ResourceProperties']['Message']
        attributes = {
            'Response': 'You said "%s"' % message
        }

        return { 'Data': attributes }
    except Exception as e:
        log.exception(e)
        return { 'Data': {} }

[github-actions]

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