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

This example Akka source code file (MetricsSelectorSpec.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

actor, address, akka, capacitymetricsselector, cluster, map, matchers, mixmetricsselector, nodemetrics, none, route, router, routing, set, systemloadaveragemetricsselector, wordspec

The MetricsSelectorSpec.scala Akka example source code

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

package akka.cluster.routing

import org.scalatest.WordSpec
import org.scalatest.Matchers

import akka.actor.Address
import akka.cluster.Metric
import akka.cluster.NodeMetrics
import akka.cluster.StandardMetrics._

@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
class MetricsSelectorSpec extends WordSpec with Matchers {

  val abstractSelector = new CapacityMetricsSelector {
    override def capacity(nodeMetrics: Set[NodeMetrics]): Map[Address, Double] = Map.empty
  }

  val a1 = Address("akka.tcp", "sys", "a1", 2551)
  val b1 = Address("akka.tcp", "sys", "b1", 2551)
  val c1 = Address("akka.tcp", "sys", "c1", 2551)
  val d1 = Address("akka.tcp", "sys", "d1", 2551)

  val decayFactor = Some(0.18)

  val nodeMetricsA = NodeMetrics(a1, System.currentTimeMillis, Set(
    Metric.create(HeapMemoryUsed, 128, decayFactor),
    Metric.create(HeapMemoryCommitted, 256, decayFactor),
    Metric.create(HeapMemoryMax, 512, None),
    Metric.create(CpuCombined, 0.1, decayFactor),
    Metric.create(SystemLoadAverage, 0.5, None),
    Metric.create(Processors, 8, None)).flatten)

  val nodeMetricsB = NodeMetrics(b1, System.currentTimeMillis, Set(
    Metric.create(HeapMemoryUsed, 256, decayFactor),
    Metric.create(HeapMemoryCommitted, 512, decayFactor),
    Metric.create(HeapMemoryMax, 1024, None),
    Metric.create(CpuCombined, 0.5, decayFactor),
    Metric.create(SystemLoadAverage, 1.0, None),
    Metric.create(Processors, 16, None)).flatten)

  val nodeMetricsC = NodeMetrics(c1, System.currentTimeMillis, Set(
    Metric.create(HeapMemoryUsed, 1024, decayFactor),
    Metric.create(HeapMemoryCommitted, 1024, decayFactor),
    Metric.create(HeapMemoryMax, 1024, None),
    Metric.create(CpuCombined, 1.0, decayFactor),
    Metric.create(SystemLoadAverage, 16.0, None),
    Metric.create(Processors, 16, None)).flatten)

  val nodeMetricsD = NodeMetrics(d1, System.currentTimeMillis, Set(
    Metric.create(HeapMemoryUsed, 511, decayFactor),
    Metric.create(HeapMemoryCommitted, 512, decayFactor),
    Metric.create(HeapMemoryMax, 512, None),
    Metric.create(Processors, 2, decayFactor)).flatten)

  val nodeMetrics = Set(nodeMetricsA, nodeMetricsB, nodeMetricsC, nodeMetricsD)

  "CapacityMetricsSelector" must {

    "calculate weights from capacity" in {
      val capacity = Map(a1 -> 0.6, b1 -> 0.3, c1 -> 0.1)
      val weights = abstractSelector.weights(capacity)
      weights should be(Map(c1 -> 1, b1 -> 3, a1 -> 6))
    }

    "handle low and zero capacity" in {
      val capacity = Map(a1 -> 0.0, b1 -> 1.0, c1 -> 0.005, d1 -> 0.004)
      val weights = abstractSelector.weights(capacity)
      weights should be(Map(a1 -> 0, b1 -> 100, c1 -> 1, d1 -> 0))
    }

  }

  "HeapMetricsSelector" must {
    "calculate capacity of heap metrics" in {
      val capacity = HeapMetricsSelector.capacity(nodeMetrics)
      capacity(a1) should be(0.75 +- 0.0001)
      capacity(b1) should be(0.75 +- 0.0001)
      capacity(c1) should be(0.0 +- 0.0001)
      capacity(d1) should be(0.001953125 +- 0.0001)
    }
  }

  "CpuMetricsSelector" must {
    "calculate capacity of cpuCombined metrics" in {
      val capacity = CpuMetricsSelector.capacity(nodeMetrics)
      capacity(a1) should be(0.9 +- 0.0001)
      capacity(b1) should be(0.5 +- 0.0001)
      capacity(c1) should be(0.0 +- 0.0001)
      capacity.contains(d1) should be(false)
    }
  }

  "SystemLoadAverageMetricsSelector" must {
    "calculate capacity of systemLoadAverage metrics" in {
      val capacity = SystemLoadAverageMetricsSelector.capacity(nodeMetrics)
      capacity(a1) should be(0.9375 +- 0.0001)
      capacity(b1) should be(0.9375 +- 0.0001)
      capacity(c1) should be(0.0 +- 0.0001)
      capacity.contains(d1) should be(false)
    }
  }

  "MixMetricsSelector" must {
    "aggregate capacity of all metrics" in {
      val capacity = MixMetricsSelector.capacity(nodeMetrics)
      capacity(a1) should be((0.75 + 0.9 + 0.9375) / 3 +- 0.0001)
      capacity(b1) should be((0.75 + 0.5 + 0.9375) / 3 +- 0.0001)
      capacity(c1) should be((0.0 + 0.0 + 0.0) / 3 +- 0.0001)
      capacity(d1) should be((0.001953125) / 1 +- 0.0001)
    }
  }

}