Gatling exec with session

Question

I need to make a request in Gatling, in which I'm able to access session items (without the expression language). I need to do this, because I want to inject data into a ByteArrayBody request from a csv feeder. To demonstrate my problem, I have a small example (without the actual need of the session).

The following scenario runs fine:

val scnBase: ScenarioBuilder = scenario("Test scneario").repeat(1){
  exec(http("Http Test test").get("http://google.de/"))
}

But that one doesn't (I get the exception There were no requests sent during the simulation, reports won't be generated):

val scnBase: ScenarioBuilder = scenario("Test scneario").repeat(1){
  exec(session => {
    http("Http Test test").get("http://google.de/")
    session
  })
}

I run my simulations in IntelliJ (which worked fine so far) and in the following (here minimized) simulation file:

package test.scala

import java.text.SimpleDateFormat
import java.util.Date

import io.gatling.core.Predef._
import io.gatling.core.body.ByteArrayBody
import io.gatling.core.structure.ScenarioBuilder
import io.gatling.http.Predef._
import io.gatling.http.protocol.HttpProtocolBuilder
import org.slf4j.LoggerFactory
import test.scala.TerminalTesterRequest.url
import test.scala.requests._
import test.scala.util.CharsetConverter

import scala.concurrent.duration._
import scala.language.postfixOps

class MySimulation extends Simulation {

  //base URL (actually this URL is different, but it's not important)
  val ecmsServerUri = "http://0.0.0.0"

  //base Protocol
  val httpProtocol: HttpProtocolBuilder = http
    .baseUrl(ecmsServerUri)
    .inferHtmlResources(BlackList(""".*\.js""", """.*\.css""", """.*\.gif""", """.*\.jpeg""", """.*\.jpg""", """.*\.ico""", """.*\.woff""", """.*\.(t|o)tf""", """.*\.png"""), WhiteList())
    .acceptHeader("*/*")
    .acceptEncodingHeader("gzip, deflate")
    .acceptLanguageHeader("en,en-US;q=0.7,de-DE;q=0.3")
    .userAgentHeader("Mozilla/4.0 (compatible; MSIE 6.0; MS Web Services Client Protocol 2.0.50727.8762)")

  val scnBase: ScenarioBuilder = scenario("Test scneario").repeat(1){
    exec(session => {
      http("Http Test test").get("http://google.de/")
      session
    })
  }

  setUp(
    scnBase.inject(constantUsersPerSec(1) during(1 seconds)).protocols(httpProtocol)
  ).maxDuration(5 minutes)
}

How can I run an exec request with the information of the session (or at least the data from the feeder)? I'm using Gatling 3.1.1

Answer 1

Build whatever you need in a function and put the result in the session, then refer that value in the actual request

val feeder = csv("foo.csv")

scenario("Test scenario")
  .feed(feeder)
  .exec(buildPostData)
  .exec(http("Http Test test")
    .post(createApiURL)  
    .body(ByteArrayBody("${postData}"))
    .check(status.is(200))
  )

def buildPostData: Expression[Session] = session => {
  val postData: Array[Byte] = 
    ... // getting values from csv record: session("csvHeader").as[String]
  session.set("postData", postData)
}