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

This example Akka source code file (MetricValuesSpec.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, akka, cluster, cpu, heapmemory, metricscollectorfactory, metricvalue, metricvaluesspec, nodemetrics, seq, test, testing, testkit, utilities

The MetricValuesSpec.scala Akka example source code

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

package akka.cluster

import scala.util.Try
import akka.actor.Address
import akka.testkit.AkkaSpec
import akka.cluster.StandardMetrics._

@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
class MetricValuesSpec extends AkkaSpec(MetricsEnabledSpec.config) with MetricsCollectorFactory {

  val collector = createMetricsCollector

  val node1 = NodeMetrics(Address("akka.tcp", "sys", "a", 2554), 1, collector.sample.metrics)
  val node2 = NodeMetrics(Address("akka.tcp", "sys", "a", 2555), 1, collector.sample.metrics)

  val nodes: Seq[NodeMetrics] = {
    (1 to 100).foldLeft(List(node1, node2)) { (nodes, _) ⇒
      nodes map { n ⇒
        n.copy(metrics = collector.sample.metrics.flatMap(latest ⇒ n.metrics.collect {
          case streaming if latest sameAs streaming ⇒ streaming :+ latest
        }))
      }
    }
  }

  "NodeMetrics.MetricValues" must {
    "extract expected metrics for load balancing" in {
      val stream1 = node2.metric(HeapMemoryCommitted).get.value.longValue
      val stream2 = node1.metric(HeapMemoryUsed).get.value.longValue
      stream1 should be >= (stream2)
    }

    "extract expected MetricValue types for load balancing" in {
      nodes foreach { node ⇒
        node match {
          case HeapMemory(address, _, used, committed, _) ⇒
            used should be > (0L)
            committed should be >= (used)
            // Documentation java.lang.management.MemoryUsage says that committed <= max,
            // but in practice that is not always true (we have seen it happen). Therefore
            // we don't check the heap max value in this test.
            // extract is the java api
            StandardMetrics.extractHeapMemory(node) should not be (null)
        }

        node match {
          case Cpu(address, _, systemLoadAverageOption, cpuCombinedOption, processors) ⇒
            processors should be > (0)
            if (systemLoadAverageOption.isDefined)
              systemLoadAverageOption.get should be >= (0.0)
            if (cpuCombinedOption.isDefined) {
              cpuCombinedOption.get should be <= (1.0)
              cpuCombinedOption.get should be >= (0.0)
            }
            // extract is the java api
            StandardMetrics.extractCpu(node) should not be (null)
        }
      }
    }
  }

}