event.json

{
  "RequestType": "Create",
  "ServiceToken": "arn:aws:lambda:us-east-1:571593187444:function:phil-heroku-keys",
  "ResponseURL": "https://cloudformation-custom-resource-response-useast1.s3.amazonaws.com/arn%3Aaws%3Acloudformation%3Aus-east-1%3A571593187444%3Astack/phil-custom-resource-2/58647de0-256b-11e9-9c2c-0a5c603a1bba%7CAMIInfo%7C116c469e-ad82-4835-93f0-ee75bec7b581?AWSAccessKeyId=AKIAJRWMYHFMH4DEFKD&Expires=1548955063&Signature=zoot%2BHkTGTrUt5XtEimyVet6Q%3D",
  "StackId": "arn:aws:cloudformation:us-east-1:571593187444:stack/phil-custom-resource-2/58647de0-256b-11e9-9c2c-0a5c603a1bba",
  "RequestId": "116c469e-ad82-4835-93f0-ee75bec7b581",
  "LogicalResourceId": "HerokuKeys",
  "ResourceType": "Custom::HerokuKeys",
  "ResourceProperties": {
    "ServiceToken": "arn:aws:lambda:us-east-1:571593187444:function:phil-heroku-keys",
    "AppName": "your-heroku-app",
    "Key": "AKIA12234",
    "Secret": "adk32+393212"
  }
}