pekko/akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala

package akka.actor.routing

import org.scalatest.WordSpec
import org.scalatest.matchers.MustMatchers

import akka.testing._
import akka.testing.Testing.{sleepFor, testMillis}
import akka.util.duration._

import akka.actor.Actor
import akka.actor.Actor._
import akka.routing._

import java.util.concurrent.atomic.AtomicInteger


class RoutingSpec extends WordSpec with MustMatchers {
  import Routing._

  "Routing" must {

    "dispatch" in {
      val Test1 = "test1"
      val Test2 = "test2"
      val Test3 = "test3"

      val t1 = actorOf(new Actor {
        def receive = {
          case Test1 => self.reply(3)
          case Test2 => self.reply(7)
        }
      }).start()

      val t2 = actorOf( new Actor() {
        def receive = {
          case Test3 => self.reply(11)
        }
      }).start()

      val d = dispatcherActor {
        case Test1 | Test2 => t1
        case Test3 => t2
      }.start()

      val result = for {
        a <- (d !! (Test1, testMillis(5 seconds))).as[Int]
        b <- (d !! (Test2, testMillis(5 seconds))).as[Int]
        c <- (d !! (Test3, testMillis(5 seconds))).as[Int]
      } yield a + b + c

      result.isDefined must be (true)
      result.get must be (21)

      for(a <- List(t1, t2, d)) a.stop()
    }

    "have messages logged" in {
      val msgs = new java.util.concurrent.ConcurrentSkipListSet[Any]
      val latch = TestLatch(2)

      val actor = actorOf(new Actor {
        def receive = { case _ => }
      }).start()

      val logger = loggerActor(actor, x => { msgs.add(x); latch.countDown() }).start()

      val foo: Any = "foo"
      val bar: Any = "bar"

      logger ! foo
      logger ! bar

      latch.await

      msgs must ( have size (2) and contain (foo) and contain (bar) )

      actor.stop()
      logger.stop()
    }

    "dispatch to smallest mailbox" in {
      val t1Count = new AtomicInteger(0)
      val t2Count = new AtomicInteger(0)
      val latch = TestLatch(500)

      val t1 = actorOf(new Actor {
        def receive = {
          case x =>
            sleepFor(50 millis) // slow actor
            t1Count.incrementAndGet
            latch.countDown()
        }
      }).start()

      val t2 = actorOf(new Actor {
        def receive = {
          case x =>
            t2Count.incrementAndGet
            latch.countDown()
        }
      }).start()

      val d = loadBalancerActor(new SmallestMailboxFirstIterator(t1 :: t2 :: Nil))

      for (i <- 1 to 500) d ! i

      latch.await(10 seconds)

      // because t1 is much slower and thus has a bigger mailbox all the time
      t1Count.get must be < (t2Count.get)

      for(a <- List(t1, t2, d)) a.stop()
    }


    "listen" in {
      val fooLatch = TestLatch(2)
      val barLatch = TestLatch(2)
      val barCount = new AtomicInteger(0)

      val broadcast = actorOf(new Actor with Listeners {
        def receive = listenerManagement orElse {
          case "foo" => gossip("bar")
        }
      }).start()

      def newListener = actorOf(new Actor {
        def receive = {
          case "bar" =>
            barCount.incrementAndGet
            barLatch.countDown()
          case "foo" =>
            fooLatch.countDown()
        }
      }).start()

      val a1 = newListener
      val a2 = newListener
      val a3 = newListener

      broadcast ! Listen(a1)
      broadcast ! Listen(a2)
      broadcast ! Listen(a3)

      broadcast ! Deafen(a3)

      broadcast ! WithListeners(_ ! "foo")
      broadcast ! "foo"

      barLatch.await
      barCount.get must be (2)

      fooLatch.await

      for(a <- List(broadcast, a1 ,a2 ,a3)) a.stop()
    }

    "be defined at" in {
      import akka.actor.ActorRef

      val Yes = "yes"
      val No  = "no"

      def testActor() = actorOf( new Actor() {
        def receive = {
          case Yes => "yes"
        }
      }).start()

      val t1 = testActor()
      val t2 = testActor()
      val t3 = testActor()
      val t4 = testActor()

      val d1 = loadBalancerActor(new SmallestMailboxFirstIterator(t1 :: t2 :: Nil))
      val d2 = loadBalancerActor(new CyclicIterator[ActorRef](t3 :: t4 :: Nil))

      t1.isDefinedAt(Yes) must be (true)
      t1.isDefinedAt(No)  must be (false)
      t2.isDefinedAt(Yes) must be (true)
      t2.isDefinedAt(No)  must be (false)
      d1.isDefinedAt(Yes) must be (true)
      d1.isDefinedAt(No)  must be (false)
      d2.isDefinedAt(Yes) must be (true)
      d2.isDefinedAt(No)  must be (false)

      for(a <- List(t1, t2, d1, d2)) a.stop()
    }
  }

  "Actor Pool" must {

    "have expected capacity" in {
      val latch = TestLatch(2)
      val count = new AtomicInteger(0)

      val pool = actorOf(
        new Actor with DefaultActorPool
                  with FixedCapacityStrategy
                  with SmallestMailboxSelector
        {
          def factory = actorOf(new Actor {
            def receive = {
              case _ =>
                count.incrementAndGet
                latch.countDown()
                self reply_? "success"
            }
          }).start()

          def limit = 2
          def selectionCount = 1
          def partialFill = true
          def instance = factory
          def receive = _route
        }).start()

      val successes = TestLatch(2)
      val successCounter = Some(actorOf(new Actor {
        def receive = {
          case "success" => successes.countDown()
        }
      }).start())

      implicit val replyTo = successCounter
      pool ! "a"
      pool ! "b"

      latch.await
      successes.await

      count.get must be (2)

      (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size must be (2)

      pool.stop()
    }


    "pass ticket #705" in {
      val pool = actorOf(
        new Actor with DefaultActorPool
                  with BoundedCapacityStrategy
                  with MailboxPressureCapacitor
                  with SmallestMailboxSelector
                  with BasicFilter
        {
          def lowerBound = 2
          def upperBound = 20
          def rampupRate = 0.1
          def backoffRate = 0.1
          def backoffThreshold = 0.5
          def partialFill = true
          def selectionCount = 1
          def instance = factory
          def receive = _route
          def pressureThreshold = 1
          def factory = actorOf(new Actor {
            def receive = {
              case req: String => {
                sleepFor(10 millis)
                self.reply_?("Response")
              }
            }
          })
        }).start()

      try {
        (for (count <- 1 to 500) yield pool.!!![String]("Test", 20000)) foreach {
          _.await.resultOrException.get must be ("Response")
        }
      } finally {
        pool.stop()
      }
    }

    "grow as needed under pressure" in {
      // make sure the pool starts at the expected lower limit and grows to the upper as needed
      // as influenced by the backlog of blocking pooled actors

      var latch = TestLatch(3)
      val count = new AtomicInteger(0)

      val pool = actorOf(
        new Actor with DefaultActorPool
                  with BoundedCapacityStrategy
                  with ActiveFuturesPressureCapacitor
                  with SmallestMailboxSelector
                  with BasicNoBackoffFilter
        {
          def factory = actorOf(new Actor {
            def receive = {
              case n: Int =>
                sleepFor(n millis)
                count.incrementAndGet
                latch.countDown()
            }
          })

          def lowerBound = 2
          def upperBound = 4
          def rampupRate = 0.1
          def partialFill = true
          def selectionCount = 1
          def instance = factory
          def receive = _route
        }).start()

      // first message should create the minimum number of delgates

      pool ! 1

      (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size must be (2)

      var loops = 0
      def loop(t: Int) = {
        latch = TestLatch(loops)
        count.set(0)
        for (m <- 0 until loops) {
          pool !!! t
          sleepFor(50 millis)
        }
      }

      // 2 more should go thru without triggering more

      loops = 2

      loop(500)
      latch.await
      count.get must be (loops)

      (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size must be (2)

      // a whole bunch should max it out

      loops = 10
      loop(500)
      latch.await
      count.get must be (loops)

      (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size must be (4)

      pool.stop()
    }

    "grow as needed under mailbox pressure" in {
      // make sure the pool starts at the expected lower limit and grows to the upper as needed
      // as influenced by the backlog of messages in the delegate mailboxes

      var latch = TestLatch(3)
      val count = new AtomicInteger(0)

      val pool = actorOf(
        new Actor with DefaultActorPool
                  with BoundedCapacityStrategy
                  with MailboxPressureCapacitor
                  with SmallestMailboxSelector
                  with BasicNoBackoffFilter
        {
          def factory = actorOf(new Actor {
            def receive = {
              case n: Int =>
                sleepFor(n millis)
                count.incrementAndGet
                latch.countDown()
            }
          })

          def lowerBound = 2
          def upperBound = 4
          def pressureThreshold = 3
          def rampupRate = 0.1
          def partialFill = true
          def selectionCount = 1
          def instance = factory
          def receive = _route
        }).start()

      var loops = 0
      def loop(t: Int) = {
        latch = TestLatch(loops)
        count.set(0)
        for (m <- 0 until loops) {
          pool ! t
        }
      }

      // send a few messages and observe pool at its lower bound
      loops = 3
      loop(500)
      latch.await
      count.get must be (loops)

      (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size must be (2)

      // send a bunch over the theshold and observe an increment
      loops = 15
      loop(500)

      latch.await(10 seconds)
      count.get must be (loops)

      (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size must be >= (3)

      pool.stop()
    }

    "round robin" in {
      val latch1 = TestLatch(2)
      val delegates = new java.util.concurrent.ConcurrentHashMap[String, String]

      val pool1 = actorOf(
        new Actor with DefaultActorPool
                  with FixedCapacityStrategy
                  with RoundRobinSelector
                  with BasicNoBackoffFilter
        {
          def factory = actorOf(new Actor {
            def receive = {
              case _ =>
                delegates put(self.uuid.toString, "")
                latch1.countDown()
            }
          })

          def limit = 1
          def selectionCount = 1
          def rampupRate = 0.1
          def partialFill = true
          def instance = factory
          def receive = _route
        }).start()

      pool1 ! "a"
      pool1 ! "b"

      latch1.await
      delegates.size must be (1)

      pool1.stop()

      val latch2 = TestLatch(2)
      delegates.clear()

      val pool2 = actorOf(
        new Actor with DefaultActorPool
                  with FixedCapacityStrategy
                  with RoundRobinSelector
                  with BasicNoBackoffFilter
        {
          def factory = actorOf(new Actor {
            def receive = {
              case _ =>
                delegates put(self.uuid.toString, "")
                latch2.countDown()
            }
          })

          def limit = 2
          def selectionCount = 1
          def rampupRate = 0.1
          def partialFill = false
          def instance = factory
          def receive = _route
        }).start()

      pool2 ! "a"
      pool2 ! "b"

      latch2.await
      delegates.size must be (2)

      pool2.stop()
    }

    "backoff" in {
      val latch = TestLatch(10)

      val pool = actorOf(
        new Actor with DefaultActorPool
                  with BoundedCapacityStrategy
                  with MailboxPressureCapacitor
                  with SmallestMailboxSelector
                  with Filter
                  with RunningMeanBackoff
                  with BasicRampup
        {
          def factory = actorOf(new Actor {
            def receive = {
              case n: Int =>
                sleepFor(n millis)
                latch.countDown()
            }
          })

          def lowerBound = 1
          def upperBound = 5
          def pressureThreshold = 1
          def partialFill = true
          def selectionCount = 1
          def rampupRate = 0.1
          def backoffRate = 0.50
          def backoffThreshold = 0.50
          def instance = factory
          def receive = _route
        }).start()

      // put some pressure on the pool

      for (m <- 0 to 10) pool ! 250

      sleepFor(5 millis)

      val z = (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size

      z must be >= (2)

      // let it cool down

      for (m <- 0 to 3) {
        pool ! 1
        sleepFor(500 millis)
      }

      (pool !! ActorPool.Stat).asInstanceOf[Option[ActorPool.Stats]].get.size must be <= (z)

      pool.stop()
    }
  }
}