[SPARK-5559] Flaky test: o.a.s.streaming.flume.FlumeStreamSuite

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.1, 1.3.0
• Fix Version/s: 1.2.2, 1.3.1, 1.4.0
• Component/s: DStreams, Tests
• Labels: flaky-test
• Target Version/s: 1.4.0
• Assignee: Kousuke Saruta
• Reporter: Kousuke Saruta
• Created: 03/Feb/15 14:07
• Updated: 24/Mar/15 16:24
• Resolved: 24/Mar/15 16:23

Description

When we run FlumeStreamSuite on Jenkins, sometimes we get error like as follows.

sbt.ForkMain$ForkError: The code passed to eventually never returned normally. Attempted 52 times over 10.094849836 seconds. Last failure message: Error connecting to localhost/127.0.0.1:23456.
	at org.scalatest.concurrent.Eventually$class.tryTryAgain$1(Eventually.scala:420)
	at org.scalatest.concurrent.Eventually$class.eventually(Eventually.scala:438)
	at org.scalatest.concurrent.Eventually$.eventually(Eventually.scala:478)
	at org.scalatest.concurrent.Eventually$class.eventually(Eventually.scala:307)
	at org.scalatest.concurrent.Eventually$.eventually(Eventually.scala:478)
	at org.apache.spark.streaming.flume.FlumeStreamSuite.writeAndVerify(FlumeStreamSuite.scala:116)
	at org.apache.spark.streaming.flume.FlumeStreamSuite.org$apache$spark$streaming$flume$FlumeStreamSuite$$testFlumeStream(FlumeStreamSuite.scala:74)
	at org.apache.spark.streaming.flume.FlumeStreamSuite$$anonfun$3.apply$mcV$sp(FlumeStreamSuite.scala:66)
	at org.apache.spark.streaming.flume.FlumeStreamSuite$$anonfun$3.apply(FlumeStreamSuite.scala:66)
	at org.apache.spark.streaming.flume.FlumeStreamSuite$$anonfun$3.apply(FlumeStreamSuite.scala:66)
	at org.scalatest.Transformer$$anonfun$apply$1.apply$mcV$sp(Transformer.scala:22)
	at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85)
	at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
	at org.scalatest.Transformer.apply(Transformer.scala:22)
	at org.scalatest.Transformer.apply(Transformer.scala:20)
	at org.scalatest.FunSuiteLike$$anon$1.apply(FunSuiteLike.scala:166)
	at org.scalatest.Suite$class.withFixture(Suite.scala:1122)
	at org.scalatest.FunSuite.withFixture(FunSuite.scala:1555)
	at org.scalatest.FunSuiteLike$class.invokeWithFixture$1(FunSuiteLike.scala:163)
	at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:175)
	at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:175)
	at org.scalatest.SuperEngine.runTestImpl(Engine.scala:306)
	at org.scalatest.FunSuiteLike$class.runTest(FunSuiteLike.scala:175)

This error is caused by check-then-act logic when it find free-port .

  /** Find a free port */
  private def findFreePort(): Int = {
    Utils.startServiceOnPort(23456, (trialPort: Int) => {
      val socket = new ServerSocket(trialPort)
      socket.close()
      (null, trialPort)
    }, conf)._2
  }

Removing the check-then-act is not easy but we can reduce the chance of having the error by choosing random value for initial port instead of 23456.

Issue Links

• links to: [Github] Pull Request #4337 (sarutak)