AWS API Gateway Mapping Template JSON - json

Question

I've got a API stage that's NOT using "Lambda Proxy integration" which has a Lambda function passing an error.
In the mapping template I have this:
$input.path("$.errorMessage")
Which results in the output of this:
{
"headers": {
"apiVersion": "20190218.1",
"isTesting": true
},
"body": {
"statusCode": 503,
"status": "Service Unavailable",
"title": "One or more of our data providers are currently offline for scheduled maintenance"
}
}
The header values are mapped to template headers and pull through correctly, however I need the body to transform to this:
{
"statusCode": 503,
"status": "Service Unavailable",
"title": "One or more of our data providers are currently offline for scheduled maintenance"
}
Whatever I have tried, body always returns as a blank string, an empty body, or an invalid JSON.
This is the closest I've got but it returns an invalid JSON:
$util.parseJson($input.path("$.errorMessage")).body
Result (comes back with no quotes):
{statusCode=503, status=Service Unavailable, title=One or more of our data providers are currently offline for scheduled maintenance}
Is it possible to do what I'm after? I can't find a reverse for $util.parseJson (i.e, stringify).
Thanks!

Answer 1

I think the original poster has probably moved on in the past 11 months, but in case anyone else stumbles across this question, $input.json('$.errorMessage.body') should work.