ZIO learning - using cached with renew automatically the underlying effect ? / published by https://github.com/dacr/code-examples-manager #17b65c6e-4664-41a0-b01b-f71a98889e64/5659e9e4c6820a4557ce906e5f7fbc6e31eae576

zio-learning-30-cached-4-renew-effect.sc

// summary : ZIO learning - using cached with renew automatically the underlying effect ?
// keywords : scala, cached, ttl, zio, @testable
// publish : gist
// authors : David Crosson
// license : Apache License Version 2.0 (https://www.apache.org/licenses/LICENSE-2.0.txt)
// id : 17b65c6e-4664-41a0-b01b-f71a98889e64
// created-on : 2022-01-26T18:19:59+01:00
// 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"
// ---------------------

import zio.*

object Encapsulated extends ZIOAppDefault {

  case class AuthToken(token: String) {
    override def toString: String = token
  }

  object AuthToken {
    def apply(): ZIO[Any, Option[Throwable], AuthToken] = {
      ZIO
        .attempt(AuthToken(java.util.UUID.randomUUID().toString))
        .timeout(3.seconds)
        .retry(Schedule.exponential(50.millis, 2).jittered && Schedule.recurs(4))
        .some
    }
  }

  val run = for {
    ref                  <- AuthToken().flatMap(Ref.make)
    getTokenAndRenew      = AuthToken().flatMap(newToken => ref.modify(n => (n, newToken)))
    cachedInvalidator    <- getTokenAndRenew.cachedInvalidate(2.seconds)
    (cached, invalidator) = cachedInvalidator
    a1                   <- cached
    a2                   <- cached
    _                    <- invalidator // Enough to invalidate !
    a3                   <- cached
    a4                   <- cached
    _                    <- Clock.sleep(2100.millis)
    a5                   <- cached
    a6                   <- cached
    _                    <- Console.printLine(List(a1, a2, a3, a4, a5, a6).mkString("\n"))
  } yield ()

}

Encapsulated.main(Array.empty)