GetUserId.scala

private def getUserId(username: String, token: String): Future[String] = {
  import io.circe.generic.auto._
  sttp
    .get(uri"${config.authServerUrl}/admin/realms/${config.realm}/users?username=$username")
    .auth.bearer(token)
    .response(asJson[List[UserResponse]])
    .send()
    .flatMap {
      _.body match {
        case Left(error) => Future.failed(new RuntimeException(error))
        case Right(Left(circeError)) => Future.failed(circeError)
        case Right(Right(user :: Nil)) => Future.successful(user.id)
        case _ => Future.failed(new RuntimeException(s"Couldn't find a single user with username $username"))
      }
    }
}