How to concatenate constant string with jsonpath : <p>I have AWS step machine and one of the step is used to notify failure using SNS service. I want to select some metadata from <code>input</code> json into outgoing message. So i am trying to concatenate constant string with jsonpath like below</p>

<pre><code>"Notify Failure": {
      "Type": "Task",
      "Resource": "arn:aws:states:::sns:publish",
      "Parameters": {
        "Message.$": "A job submitted through Step Functions failed for document id $.document_id",
        "Subject":"Job failed",
        "TopicArn": "arn:aws:sns:us-west-2:xxxxxxx:xxxxxxxx"
      },
      "End": true
    }
</code></pre>

<p>where <code>document_id</code> is one of the property in input json</p>

<p>However when i try save state machine defination i get error</p>

<blockquote>
  <p>There is a problem with your ASL definition, please review it and try
  again The value for the field 'Message.$' must be a valid JSONPath</p>
</blockquote>
