Akka/Scala example source code file (DeadlineFailureDetectorSpec.scala)

This example Akka source code file (DeadlineFailureDetectorSpec.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

a, akka, akkaspec, clock, collection, concurrent, deadlinefailuredetector, deadlinefailuredetectorspec, finiteduration, list, long, seq, test, testing, time

The DeadlineFailureDetectorSpec.scala Akka example source code

/**
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 */

package akka.remote

import akka.testkit.AkkaSpec
import scala.collection.immutable.TreeMap
import scala.concurrent.duration._
import akka.remote.FailureDetector.Clock

@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
class DeadlineFailureDetectorSpec extends AkkaSpec {

  "A DeadlineFailureDetector" must {

    def fakeTimeGenerator(timeIntervals: Seq[Long]): Clock = new Clock {
      @volatile var times = timeIntervals.tail.foldLeft(List[Long](timeIntervals.head))((acc, c) ⇒ acc ::: List[Long](acc.last + c))
      override def apply(): Long = {
        val currentTime = times.head
        times = times.tail
        currentTime
      }
    }

    def createFailureDetector(
      acceptableLostDuration: FiniteDuration,
      clock: Clock = FailureDetector.defaultClock) =
      new DeadlineFailureDetector(acceptableLostDuration)(clock = clock)

    "mark node as monitored after a series of successful heartbeats" in {
      val timeInterval = List[Long](0, 1000, 100, 100)
      val fd = createFailureDetector(acceptableLostDuration = 5.seconds, clock = fakeTimeGenerator(timeInterval))
      fd.isMonitoring should be(false)

      fd.heartbeat()
      fd.heartbeat()
      fd.heartbeat()

      fd.isMonitoring should be(true)
      fd.isAvailable should be(true)
    }

    "mark node as dead if heartbeat are missed" in {
      val timeInterval = List[Long](0, 1000, 100, 100, 7000)
      val fd = createFailureDetector(acceptableLostDuration = 5.seconds, clock = fakeTimeGenerator(timeInterval))

      fd.heartbeat() //0
      fd.heartbeat() //1000
      fd.heartbeat() //1100

      fd.isAvailable should be(true) //1200
      fd.isAvailable should be(false) //8200
    }

    "mark node as available if it starts heartbeat again after being marked dead due to detection of failure" in {
      // 1000 regular intervals, 5 minute pause, and then a short pause again that should trigger unreachable again
      val regularIntervals = 0L +: Vector.fill(999)(1000L)
      val timeIntervals = regularIntervals :+ (5 * 60 * 1000L) :+ 100L :+ 900L :+ 100L :+ 7000L :+ 100L :+ 900L :+ 100L :+ 900L
      val fd = createFailureDetector(acceptableLostDuration = 7.seconds, clock = fakeTimeGenerator(timeIntervals))

      for (_ ← 0 until 1000) fd.heartbeat()
      fd.isAvailable should be(false) // after the long pause
      fd.heartbeat()
      fd.isAvailable should be(true)
      fd.heartbeat()
      fd.isAvailable should be(false) // after the 7 seconds pause
      fd.heartbeat()
      fd.isAvailable should be(true)
      fd.heartbeat()
      fd.isAvailable should be(true)
    }

    "accept some configured missing heartbeats" in {
      val timeInterval = List[Long](0, 1000, 1000, 1000, 4000, 1000, 1000)
      val fd = createFailureDetector(acceptableLostDuration = 5.seconds, clock = fakeTimeGenerator(timeInterval))

      fd.heartbeat()
      fd.heartbeat()
      fd.heartbeat()
      fd.heartbeat()
      fd.isAvailable should be(true)
      fd.heartbeat()
      fd.isAvailable should be(true)
    }

    "fail after configured acceptable missing heartbeats" in {
      val timeInterval = List[Long](0, 1000, 1000, 1000, 1000, 1000, 500, 500, 5000)
      val fd = createFailureDetector(acceptableLostDuration = 5.seconds, clock = fakeTimeGenerator(timeInterval))

      fd.heartbeat()
      fd.heartbeat()
      fd.heartbeat()
      fd.heartbeat()
      fd.heartbeat()
      fd.heartbeat()
      fd.isAvailable should be(true)
      fd.heartbeat()
      fd.isAvailable should be(false)
    }

  }

}