title: How can I turn a simple iterative loop into a feeder in Gatling?
body: <p>In order to populate a system with data en masse before running performance scripts, our ideal use-case would be to do so with Gatling. Data need not be different, beyond having a unique Primary ID. </p>
  
  <pre><code>object Object {
  
   val create = repeat(4, "n")
   {
   exec(http("Create Object") 
   .post("/our/api/objects")
   .body(ELFileBody("CreateObject_0001_request.txt"))
   .check(status.is(201)))
   }
  }
  
  val createObjects = scenario("ModularSimulation").exec(CreateObjects.create);
  
  setUp(
   createObjects.inject(atOnceUsers(1))
  ).protocols(httpProtocol)
  </code></pre>
  
  <p>The above example can create any number of objects by changing the value of the <code>repeat</code>, however at large scales (e.g. 100,000 objects) it becomes impractical to do this linearly. So what I would like to do is have a shared pool of objects to be created by, say, 100 users. </p>
  
  <p>This is - of course - the use case for a feeder. Rather than generate a static <code>.csv file</code> or use <code>Redis</code> it seems simplest to use a simple iterative loop (e.g. <code>0</code> to <code>100000</code>). </p>
  
  <p>I know (from <a href="http://gatling.io/docs/2.1.4/session/feeder.html" rel="nofollow noreferrer">documentation</a> and other <a href="https://stackoverflow.com/questions/35348845/simple-feeder-in-gatling-without-using-a-csv-file">questions</a>) that Feeder is a type alias for <code>Iterator[Map[String, T]]</code> so I presume this should be very straightforward - but I can't seem to find a <em>simple</em> example of this most basic case. </p>
  
  <p>Any help would be much appreciated. </p>