What would be the best way to define a gatling a user flow using ChainBuilder?

Question

I am new to Scala and Gatling and I am trying to figure out what would be the best way to define a user story and pass it a ChainBuilder to Gatling Scenario.

When I say user Story In my case I mean a flow that will consist of Login, many different calls and then a loop over another list of calls for the whole duration of the test.

I have created the following function to create a scenario:

 def createScenario(name: String, feed: FeederBuilder, chains: ChainBuilder*): ScenarioBuilder = {
    scenario(name).feed(feed).forever() {
      exec(chains).pause(Config.pauseBetweenRequests)
    }
  }

And here is how I execute this function:

val scenario = createScenario(Config.testName, feeder.random,
  setSessionParams(PARAM1, Config.param1),
  setSessionParams(PARAM2, Config.param2),
  login, 
  executeSomeCall1, 
  executeSomeCall2, 
  executeSomeCall3, 
  executeSomeCall4, 
  executeSomeCall5, 
  executeSomeCall6, 
  executeSomeCall7, 
  executeSomeCall8, 
  executeSomeCall9,   
  )

Here is an example of what executeSomeCall function looks like:

  def executeSomeCall = {
    exec(http("ET Call Home")
      .post("/et/call/home")
      .body(ElFileBody("/redFingerBody.json")).asJson
      .check(status is 200))
  }

My first question:

Is that the correct way to define a chain of rest calls and feed it to the scenario? I am asking that because what I see when I define a flow like that is that for some reason not all the my REST calls are actually executed. Weirdly enough, if I change the order of the calls it does work and all functions are called. (So I am definitely doing something wrong)

My second question:

How can I define an infinite loop within this flow? (Infinite for as long as the test is running)

So for example, I'd like the above flow to start and when it reaches executeSomeCall8, it will then loop executeSomeCall8 and executeSomeCall9 for the whole duration of the test.

Answer 1

I don't see why your calls would not be executed, however the way you're constructing your scenario is not that flexible. You can make use of chaining without requiring a createScenario() method.

That leads to your second question, when you have the scenario chained like:

val scn = scenario("something")
...
.exec(someCall7)
.forever(){
exec(sommeCall8)
.exec(someCall9)
}
...

where someCallN in my case look like:

val someCall = http("request name")
.get("/some/uri")
...

Note: foerever() is just an example, you can use other loop statements that suits your needs. I hope it helps.