exec Chainbuilder and Expression function difference

Gatling (Open-Source)
1

I have a scenario with three basic exec steps:

  • Add some stuff to the session
  • Post some data
  • get some data for verification

Running code similar to this:

1 val simpleScenario = scenario("DEA Promotions Extended") 2 .feed(ssv(getFilename()).circular) 3 .exec{session => 4 session.set("x", "y") 5 } 6 .exec(CreatePromotion.postForStage(this.stage)) // produces: "Write DEA Promotion permission" 7 .exec{ 8 http("Lookup detailed DEA Promotion permission") 9 .get(...) 10 .headers(...) 11 .check(status.is(200)) 12 13 }

I’ve got my two operations neatly shown in the overview while the scenario runs:

2

https://gatling.io/docs/current/general/scenario/#exec

Warning

Gatling DSL components are immutable ActionBuilder(s) that have to be chained altogether and are only built once on startup. The results is a workflow chain of Action(s). These builders don’t do anything by themselves, they don’t trigger any side effect, they are just definitions. As a result, creating such DSL components at runtime in functions is completely meaningless. If you want conditional paths in your execution flow, use the proper DSL components (doIf, randomSwitch, etc)

3

Hi Stéphane,

I’ve read this paragraph many times, but still don’t understand how this relates to the issue i’m facing at the moment.

The ability to pass-through the session is mentioned above the passage you refering to:

https://gatling.io/docs/2.3/general/scenario/#exec

So what am i doing wrong here?

salut,

Matthias

4

7 .exec{ session =>
8 http(“Lookup detailed DEA Promotion permission”)

You’re exactly doing what is described as not working. You can’t create http request inside session functions.

5

Thanks for clarifying this!

I was mislead by the fact that the http call was actually running …

It might be a good idea to mention this in the exec documentation example as something which won’t work.

So how am i supposed to get a reference to the session in an followup step?

6

I was mislead by the fact that the http call was actually running ...

The builder gets instanciated, but no HTTP request is actually sent.

It might be a good idea to mention this in the exec documentation example
as something which won't work.

It's already mentioned in this very same page:

exec { session =>

  if (someSessionBasedCondition(session)) {
    // just create a builder that is immediately discarded, hence
doesn't do anything
    // you should be using a doIf here
    http("Get Homepage").get("http://github.com/gatling/gatling"\)
  }
  session}