ERROR when returning hasura variables - Auth Webhook - AWS Lambda

[costas90]

I am trying to return the hasura variables in a nodejs 12 AWS Lambda but I get the error:

GraphQL error: Invalid response from authorization hook: Error in $.hasuraVariables: parsing Text failed, expected String, but encountered Object

My code:

let hasuraVariables = {
    "X-Hasura-Role": "user", 
    "X-Hasura-User-Id": user.id, 
};

if (user.publisher && user.publisher.id) {
    Object.assign(hasuraVariables, {
        "X-Hasura-Publisher-Id": user.publisher.id.toString()
    }) 
}

const body = JSON.stringify({
    hasuraVariables
});
console.log("body", body)

return {
    "statusCode": "200",
    "body": body
}

If I log the body its:

{"hasuraVariables":{"X-Hasura-Role":"user","X-Hasura-User-Id":"d61ea04f-421b-48a8-92a2-de6d00491425","X-Hasura-Publisher-Id":"110"}}

If I return the variables without stringify first:

return {
    "statusCode": "200",
    "body": hasuraVariables
}

I get the error:

GraphQL error: Invalid response from authorization hook: Error in $: Failed reading: satisfy. Expecting object key at ''X-Hasura-Role':'user','X-Hasura-User-Id':'d61ea04f-421b-48a8-92a2-de6d00491425','X-Hasura-Pub'

What is the correct way to return the variables?