Using during in a foreach loop

Gatling (Open-Source)
1

Hi,

I’m trying to use Gatling (V2.2.2) to compare the perfs of multiple map servers at different zoom levels with different number of users. So basically, my scenario looks like that:

val scn = scenario("User").group(_ => PerfConfig.nbUsers.toString) {
  foreach(PerfConfig.baseUrls, "base_url") {
    group(session => PerfConfig.baseUrlMap(session("base_url").as[String])) {
      foreach(steps.reverse, "level") {
        exec(session => {
          println("Starting level " + session("level").as[String])
          session
        })
          .during(30 seconds) {
            exec(session => PerfConfig.addRandomTileInfo(session)).exec(fetchTile)
          }
          .exec(session => {
            println("Done level " + session("level").as[String])
            session
          })
      }
    }
  }
}

The full code can be found there:
https://github.com/pvalsecc/ms_perfs/tree/master/perfs/com/camptocamp

My problem is that after the first iteration of “during” is done, I have multiple un-wanted behaviors:

  • “Done level 7” is printed a lot of times (one for each fetchTile execution, I guess). I don’t see why this is like that since it is done after the “during” loop. I’ve tried to put the “during” inside an exec by itself, but it didn’t help.
  • Gatling freezes and doesn’t do anymore query. It just prints the summary report every 5 seconds with no new query in it.

It’s not possible to chain a “during” with other stuff to do after?

Thanks for your help.

2

Hi,

Could you please provide a runnable reproducer, please?
This similar sample works fine for me.

3

Stéphane,

I’ve tried your reproducer and it works fine with gatling 2.2.1 (with the denvazh/gatling:2.2.1 docker image). With 2.2.2 (with the denvazh/gatling:2.2.2 docker image) it goes mad and outputs that:
gatling_1 | attr1=1 attr2=1
gatling_1 | Loop Done
gatling_1 | Loop Done

… (tons of them)
gatling_1 | 12:24:24.756 [ERROR] a.a.ActorSystemImpl - Uncaught error from thread [GatlingSystem-akka.actor.default-dispatcher-4] shutting down JVM since ‘akka.jvm-exit-on-fatal-error’ is enabled
gatling_1 | java.lang.StackOverflowError: null
gatling_1 | at sun.nio.cs.UTF_8.updatePositions(UTF_8.java:77)
gatling_1 | at sun.nio.cs.UTF_8.access$200(UTF_8.java:57)
gatling_1 | at sun.nio.cs.UTF_8$Encoder.encodeArrayLoop(UTF_8.java:636)
gatling_1 | at sun.nio.cs.UTF_8$Encoder.encodeLoop(UTF_8.java:691)
gatling_1 | at java.nio.charset.CharsetEncoder.encode(CharsetEncoder.java:579)
gatling_1 | at sun.nio.cs.StreamEncoder.implWrite(StreamEncoder.java:271)
gatling_1 | at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:125)
gatling_1 | at java.io.OutputStreamWriter.write(OutputStreamWriter.java:207)
gatling_1 | at java.io.BufferedWriter.flushBuffer(BufferedWriter.java:129)
gatling_1 | at java.io.PrintStream.write(PrintStream.java:526)
gatling_1 | at java.io.PrintStream.print(PrintStream.java:669)
gatling_1 | at java.io.PrintStream.println(PrintStream.java:823)
gatling_1 | at scala.Console$.println(Console.scala:148)
gatling_1 | at scala.Predef$.println(Predef.scala:315)
gatling_1 | at com.camptocamp.ComplexLoopSimulation$$anonfun$2.apply(ComplexLoopSimulation.scala:26)
gatling_1 | at com.camptocamp.ComplexLoopSimulation$$anonfun$2.apply(ComplexLoopSimulation.scala:25)
gatling_1 | at io.gatling.core.action.SessionHook.execute(SessionHook.scala:38)
gatling_1 | at io.gatling.core.action.BlockExit.exitBlock(BlockExit.scala:37)
gatling_1 | at io.gatling.core.action.BlockExit$.noBlockExitTriggered(BlockExit.scala:122)
gatling_1 | at io.gatling.core.action.Loop.execute(Loop.scala:52)
gatling_1 | at io.gatling.core.action.Action$class.$bang(Action.scala:35)
gatling_1 | at io.gatling.core.action.Loop.$bang(Loop.scala:36)
gatling_1 | at io.gatling.core.action.SessionHook.io$gatling$core$action$SessionHook$$$anonfun$1(SessionHook.scala:38)
gatling_1 | at io.gatling.core.action.SessionHook$lambda$$execute$1.apply(SessionHook.scala:38)
gatling_1 | at io.gatling.core.action.SessionHook$lambda$$execute$1.apply(SessionHook.scala:38)
gatling_1 | at io.gatling.commons.validation.Success.map(Validation.scala:32)
gatling_1 | at io.gatling.core.action.SessionHook.execute(SessionHook.scala:38)
gatling_1 | at io.gatling.core.action.BlockExit.exitBlock(BlockExit.scala:37)
gatling_1 | at io.gatling.core.action.BlockExit$.noBlockExitTriggered(BlockExit.scala:122)

… (smells like an infinite recusion)

With 2.2.1, my stuff works fine. So, looks like a bug within the 2.2.2 image.

Thanks for your help.

4

You’re running into https://github.com/gatling/gatling/issues/3060, which is already fixed.
Use the snapshot for now.