How do I use Predefined variables in an Input transformer with CDK?

[luisMolina95]

My goal is for CDK to generate this template:

{
      "Arn": {
       "Fn::GetAtt": [
        "",
        "Arn"
       ]
      },
      "Id": "",
      "InputTransformer": {
       "InputPathsMap": { },
       "InputTemplate": "{\"ruleName\":<aws.events.rule-name>,\"originalEvent\":<aws.events.event.json>}"
      }
 }

I am trying this:

const Rule = new Rule(this, "ruleName", {
      eventBus,
      eventPattern: { },
      targets: [
        new LambdaFunction(lambda, {
          event: RuleTargetInput.fromObject({
            ruleName:EventField.fromPath("aws.events.rule-name"),
            originalEvent: EventField.fromPath("aws.events.rule-name"),
          }),
        }),
      ],
    });

But i am getting this instead:

{
      "Arn": {
       "Fn::GetAtt": [
        "",
        "Arn"
       ]
      },
      "Id": "",
      "InputTransformer": {
       "InputPathsMap": {
        "aws-events-rule-name": "aws.events.rule-name",
        "aws-events-event-json": "aws.events.event.json",
       },
       "InputTemplate": "{\"ruleName\":<aws-events-rule-name>,\"originalEvent\":<aws-events-event-json>}"
      }
}

Is it possible to use Predefined variables on CDK?

[luisMolina95]

This is my workaround, be aware that this does not work for aws.events.event.json and that if you remove EventField.fromPath("$") it becomes a contant instead of an input transform.

const inputTransformerEvent = RuleTargetInput.fromObject({
  ruleName: "<aws.events.rule-name>",
  originalEvent: EventField.fromPath("$"),
  });

{
      "Arn": {
       "Fn::GetAtt": [
        "",
        "Arn"
       ]
      },
      "Id": "",
      "InputTransformer": {
       "InputPathsMap": {
        "f1": "$"
       },
       "InputTemplate": "{\"ruleName\":\"<aws-events-rule-name>\",\"originalEvent\":<f1>}"
      }
}

[github-actions[bot]]

Hello! Reopening this discussion to make it searchable.