ZIO learning - an authentication service / published by https://github.com/dacr/code-examples-manager #b7a7176e-6d20-4035-8c1d-08c9be42083f/dc52c7ab80a5835375a7e49f9b0dcb133b9058e7

zio-learning-14-service-2.sc

// summary : ZIO learning - an authentication service
// keywords : scala, zio, learning, service, authentication, environment, pure-functional, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : b7a7176e-6d20-4035-8c1d-08c9be42083f
// created-on : 2021-05-01T21:42:05+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.4.2"
//> using dep "dev.zio::zio:2.0.13"
//> using dep "fr.janalyse::zio-worksheet:2.0.13.0"
// ---------------------
import zio.*, zio.worksheet.*

case class AuthToken(token: String)

trait Authenticator:
  def authenticate: Task[AuthToken]

case class AuthenticatorLive() extends Authenticator:
  override def authenticate: Task[AuthToken] =
    for
      username <- System.env("APP_USERNAME")
      password <- System.env("APP_PASSWORD")
      token     = s"secured-auth-token-for-$username"
    yield AuthToken(token)

object Authenticator:
  val live = ZLayer.succeed(AuthenticatorLive())

  def authenticate: RIO[Authenticator, AuthToken] = ZIO.serviceWithZIO(_.authenticate)

// -------------------------------------------------------------

val app: ZIO[Authenticator, Throwable, Unit] =
  for
    _     <- Console.printLine("started")
    token <- Authenticator.authenticate
    _     <- Console.printLine(s"got token $token")
  yield ()

// -------------------------------------------------------------

app.provideLayer(Authenticator.live).unsafeRun