postman pre-request script integrating with local server that links temp credentials through

script.js

const profile = pm.collectionVariables.get("aws_profile")
if (!profile) {
    console.log('No aws_profile variable set, using aws_profile: default')
    pm.collectionVariables.set("aws_profile", "default");
}

const a = pm.collectionVariables.get("aws_access_key")
const b = pm.collectionVariables.get("aws_secret_key")
if (!a && !b) {
    console.log('Using nn-auth served aws_access_key and aws_secret_key at collection level')
    pm.sendRequest({
        url: `https://localhost:9898/aws/${profile}`,
        method: "POST",
        }, function (_, response) {
            if (response.status == "OK") {
                const body = response.json()
                pm.collectionVariables.set("aws_access_key", body.accessKey)
                pm.collectionVariables.set("aws_secret_key", body.secretKey)
                if (body.sessionToken) {
                    pm.collectionVariables.set("aws_session_token", body.sessionToken)
                }
                console.log(`Using aws credentials from '${profile}'`)
                return
            } else {
                throw new Error(response.text() || "Error fetching AWS credentials, did you run: nn-auth --no-proxy serve-postman?")
            }
        }
    )
}
else {
    console.log('Using in Postman collection defined aws_access_key_id and aws_secret_access_key')
}