[Gatling2] adding random int as query param

[Uladzimir Kazimirchyk]

Hi!

I need to avoid server request caching so i decided to add a random int as query param to urls.

I'm trying to add additional parameter via .queryParam("param", "value") and use 

ThreadLocalRandom.current.nextInt(1000) as a random number generator. The problem is --

when I add .toString and pass this value to .queryParam I get an error:

type mismatch;

 found   : () => String

 required: io.gatling.core.session.Session => io.gatling.core.validation.Validation[String]

13:25:58.444 [ERROR] i.g.a.ZincCompiler$ -     .queryParam("testParam", ThreadLocalRandom.current.nextInt(1000).toString)

What am I doing wrong..?

Thanks.

[Stéphane Landelle]

Hi,

This indeed fails to compile with 2M3a but compiles fine with master, not sure why...

Anyway, this won't work as you expect because you're passing a value, not a function, ie it will be only evaluated once, when the scenario is built, not every time a request is built and sent.

long form: .queryParam("testParam", (session: Session) =>ThreadLocalRandom.current.nextInt(1000).toString)

can omit session type as the compiler can infer it: .queryParam("testParam", session =>ThreadLocalRandom.current.nextInt(1000).toString)

session is not used here anyway: .queryParam("testParam", _ =>ThreadLocalRandom.current.nextInt(1000).toString)

Cheers,

Stéphane

2013/11/5 Uladzimir Kazimirchyk <kazim...@gmail.com>

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[Uladzimir Kazimirchyk]

Stéphane,

so I need something like this:

val httpProtocol = http.baseURL("http://some.url.com")

  def getRand(i: Int) : String = ThreadLocalRandom.current.nextInt(i).toString

  val scn = scenario("Load test")

    .feed(csv("test_data.csv").random)

    .exec(http("srvc_call").get("${url}")

    .queryParam("testParam", getRand(1000))

    .check(status.is(200))

  )

Right?

[Stéphane Landelle]

Nope, getRand(1000) will still be evaluated once.

_ => getRand(1000)

2013/11/5 Uladzimir Kazimirchyk <kazim...@gmail.com>

[Uladzimir Kazimirchyk]

and now I get ClassNotFoundException

java.lang.reflect.InvocationTargetException

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:606)

at scala_maven_executions.MainHelper.runMain(MainHelper.java:164)

at scala_maven_executions.MainWithArgsInFile.main(MainWithArgsInFile.java:26)

Caused by: java.lang.ClassNotFoundException: performance.img_srvc.Img_perftest.scala

at scala.tools.nsc.interpreter.AbstractFileClassLoader.findClass(AbstractFileClassLoader.scala:69)

at java.lang.ClassLoader.loadClass(ClassLoader.java:424)

at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

at io.gatling.app.SimulationClassLoader$$anonfun$simulationClasses$1.apply(SimulationClassLoader.scala:56)

at io.gatling.app.SimulationClassLoader$$anonfun$simulationClasses$1.apply(SimulationClassLoader.scala:55)

at scala.Option.map(Option.scala:145)

at io.gatling.app.SimulationClassLoader.simulationClasses(SimulationClassLoader.scala:55)

at io.gatling.app.Gatling.start(Gatling.scala:174)

at io.gatling.app.Gatling$.fromMap(Gatling.scala:59)

at io.gatling.app.Gatling$.runGatling(Gatling.scala:80)

at io.gatling.app.Gatling$.main(Gatling.scala:54)

at io.gatling.app.Gatling.main(Gatling.scala)

That drives me crazy :)

What could be the reason?

[Stéphane Landelle]

o_O

Is performance.img_srvc the expected package name and Img_perftest the expected Simulation class name?

Is performance/img_srvc a valid folder hierarchy?

2013/11/5 Uladzimir Kazimirchyk <kazim...@gmail.com>

[Uladzimir Kazimirchyk]

Yes. I guess if it was wrong then I should get the same error earlier(instead of Type Mismatch one).

But when I corrected the error with types in .queryParam - I got this one. That's strange...

[Stéphane Landelle]

At this point, I can't help you find out what's wrong with getting my hands on your files.

Can you share?

2013/11/5 Uladzimir Kazimirchyk <kazim...@gmail.com>

[Uladzimir Kazimirchyk]

My bad, sorry. I added .scala extension to class name when running by maven.
So it was looking for scala class :)

[Stéphane Landelle]

Ahhhhhhh :)

2013/11/5 Uladzimir Kazimirchyk <kazim...@gmail.com>