+ akka-cluster-metrics: new akka module

* new akka module split from akka-cluster * provide sigar provisioning * fix ewma usage * resolve #16121 * see #16354
2014-12-12 11:49:32 -06:00 · 2014-12-12 11:49:32 -06:00 · 7b9f77a073
commit 7b9f77a073
parent baca3644e2
121 changed files with 10462 additions and 215 deletions
--- a/akka-cluster-metrics/src/test/scala/akka/cluster/metrics/EWMASpec.scala
+++ b/akka-cluster-metrics/src/test/scala/akka/cluster/metrics/EWMASpec.scala
@ -0,0 +1,101 @@
+/**
+ * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.cluster.metrics
+
+import language.postfixOps
+import scala.concurrent.duration._
+import akka.testkit.{ LongRunningTest, AkkaSpec }
+import scala.concurrent.forkjoin.ThreadLocalRandom
+
+@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
+class EWMASpec extends AkkaSpec(MetricsConfig.defaultEnabled) with MetricsCollectorFactory {
+  import system.dispatcher
+
+  val collector = createMetricsCollector
+
+  "DataStream" must {
+
+    "calcualate same ewma for constant values" in {
+      val ds = EWMA(value = 100.0, alpha = 0.18) :+
+        100.0 :+ 100.0 :+ 100.0
+      ds.value should be(100.0 +- 0.001)
+    }
+
+    "calcualate correct ewma for normal decay" in {
+      val d0 = EWMA(value = 1000.0, alpha = 2.0 / (1 + 10))
+      d0.value should be(1000.0 +- 0.01)
+      val d1 = d0 :+ 10.0
+      d1.value should be(820.0 +- 0.01)
+      val d2 = d1 :+ 10.0
+      d2.value should be(672.73 +- 0.01)
+      val d3 = d2 :+ 10.0
+      d3.value should be(552.23 +- 0.01)
+      val d4 = d3 :+ 10.0
+      d4.value should be(453.64 +- 0.01)
+
+      val dn = (1 to 100).foldLeft(d0)((d, _) ⇒ d :+ 10.0)
+      dn.value should be(10.0 +- 0.1)
+    }
+
+    "calculate ewma for alpha 1.0, max bias towards latest value" in {
+      val d0 = EWMA(value = 100.0, alpha = 1.0)
+      d0.value should be(100.0 +- 0.01)
+      val d1 = d0 :+ 1.0
+      d1.value should be(1.0 +- 0.01)
+      val d2 = d1 :+ 57.0
+      d2.value should be(57.0 +- 0.01)
+      val d3 = d2 :+ 10.0
+      d3.value should be(10.0 +- 0.01)
+    }
+
+    "calculate alpha from half-life and collect interval" in {
+      // according to http://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
+      val expectedAlpha = 0.1
+      // alpha = 2.0 / (1 + N)
+      val n = 19
+      val halfLife = n.toDouble / 2.8854
+      val collectInterval = 1.second
+      val halfLifeDuration = (halfLife * 1000).millis
+      EWMA.alpha(halfLifeDuration, collectInterval) should be(expectedAlpha +- 0.001)
+    }
+
+    "calculate sane alpha from short half-life" in {
+      val alpha = EWMA.alpha(1.millis, 3.seconds)
+      alpha should be <= (1.0)
+      alpha should be >= (0.0)
+      alpha should be(1.0 +- 0.001)
+    }
+
+    "calculate sane alpha from long half-life" in {
+      val alpha = EWMA.alpha(1.day, 3.seconds)
+      alpha should be <= (1.0)
+      alpha should be >= (0.0)
+      alpha should be(0.0 +- 0.001)
+    }
+
+    "calculate the ewma for multiple, variable, data streams" taggedAs LongRunningTest in {
+      var streamingDataSet = Map.empty[String, Metric]
+      var usedMemory = Array.empty[Byte]
+      (1 to 50) foreach { _ ⇒
+        // wait a while between each message to give the metrics a chance to change
+        Thread.sleep(100)
+        usedMemory = usedMemory ++ Array.fill(1024)(ThreadLocalRandom.current.nextInt(127).toByte)
+        val changes = collector.sample.metrics.flatMap { latest ⇒
+          streamingDataSet.get(latest.name) match {
+            case None ⇒ Some(latest)
+            case Some(previous) ⇒
+              if (latest.isSmooth && latest.value != previous.value) {
+                val updated = previous :+ latest
+                updated.isSmooth should be(true)
+                updated.smoothValue should not be (previous.smoothValue)
+                Some(updated)
+              } else None
+          }
+        }
+        streamingDataSet ++= changes.map(m ⇒ m.name -> m)
+      }
+    }
+  }
+}