CloudFormation Custom Resource responseKey

Question

I have got lambda backed Custom Stack in CloudFormation , So I need the fetch function output and put it to the AWS Console, how I can handle this problem?

My Stack is shown as below ;

     "CreateExistingVPC": {
  "Type": "Custom::CreateExistingVPC",
  "Properties": {
    "ServiceToken": { "Fn::If": ["LambdaAvailable",{ "Fn::GetAtt": [ "CustomLogic", "Outputs.LambdaAttachHostedZoneArn" ] }, { "Ref": "AWS::NoValue" } ] },
    "Region": { "Ref": "AWS::Region" },
    "HostedZoneId": { "Ref": "InternalHostedZone" },
    "VpcId": { "Fn::GetAtt": [ "VPC", "Outputs.VPC" ] }
  }
}
},

  "Outputs": {
  "Route53VPC": {
  "Description": "ExistingRoute53VPCStatus",
  "Value": { "Fn::GetAtt": [ "CreateExistingVPC", "{ ??????? }" ] }
}
}

In actually, I have found some answers but 'response key' not worked in my case , how I can find response key ??

AWS Cloudformation, Output value from Custom Resource

Answer 1

You need to use the variable you are using to return your response. e.g. (nodeJs)

module.exports.createPoolList = (event, context, callback) => {

  if (event.RequestType == 'Create') {
    let array = event.ResourceProperties.OpsPoolArnList.split(",");

    array.push(event.ResourceProperties.UserPool);

    let response = {
        'list': array.join(),
    };

    sendresponse(event, "SUCCESS", response, "");
  }

  if (event.RequestType == 'Delete') {
      sendresponse(event, "SUCCESS", null, "");
  }

  callback(null, "");
};

Here list is the variable which contains my output & returning in my response. The built payload looks like

let payload = {
    'StackId': event.StackId,
    'Status' : responsestatus,
    'Reason' : reason,
    'RequestId': event.RequestId,
    'LogicalResourceId': event.LogicalResourceId,
    'PhysicalResourceId': event.LogicalResourceId + 'qwerty',
    'Data': response
};

And I refer to this in my script as

!GetAtt <ResourceName>.list

Hope it helps.