ObtainImpersonatorToken.scala

private def obtainImpersonatorToken(): Future[String] = {
  import io.circe.generic.auto._
  sttp
    .post(uri"${config.authServerUrl}/realms/${config.realm}/protocol/openid-connect/token")
    .body(
      "grant_type" -> "password",
      "username" -> config.impersonatorUsername,
      "password" -> config.impersonatorPassword,
      "client_id" -> config.clientId
    )
    .response(asJson[TokenResponse])
    .send()
    .flatMap {
      _.body match {
        case Left(error) => Future.failed(new RuntimeException(error))
        case Right(Left(circeError)) => Future.failed(circeError)
        case Right(Right(tokenResponse)) => Future.successful(tokenResponse.access_token)
      }
    }
}