Gatling Template Based Requests

IdentitySimulation.scala

package qeperf

import io.gatling.core.Predef._
import io.gatling.http.Predef._

class IdentitySimulation extends Simulation {

  val httpConf = http
    .baseURL("http://identity.openstack.com")
    .acceptHeader("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
    .acceptLanguageHeader("en-US,en;q=0.5")
    .acceptEncodingHeader("gzip, deflate")
    .userAgentHeader("Mozilla/5.0 (Windows NT 5.1; rv:31.0) Gecko/20100101 Firefox/31.0")

  val scn = scenario("Auth")
    .exec(
      session =>
        session
          .set("identityURL", "")
          .set("userID", 1)
          .set("username", "carl")
          .set("password", "qwerty"))
    .exec(
      Tokens.authenticate(
        session => Tokens.buildAuthRequest(session)))

  setUp(
    scn.inject(atOnceUsers(1))
  ).protocols(httpConf)
}

Tokens.scala

package qeperf

import io.gatling.core.Predef._
import io.gatling.http.Predef._

import io.gatling.core.session.Expression

object Tokens {

  object AuthenticateBody {
    case class Params(userID: Int,
                      username: String,
                      password: Option[String],
                      apiKey: Option[String])

    private[this] def passwordTemplate(pass: String) = s""""password": "$pass""""
    private[this] def apiKeyTemplate(apiKey: String) = s""""apiKey": "$apiKey""""

    def passwordOrKey(params: Params): String =
      params.password match {
        case Some(password) => passwordTemplate(password)
        case None => params.apiKey match {
          case Some(apiKey) => apiKeyTemplate(apiKey)
          case None => ""
        }
      }

    def template(params: Params): String =
      s"""{
         |  "auth": {
         |    "passwordCredentials": {
         |      "username": "${params.username}",
         |      ${passwordOrKey(params)}
         |   }
         |}""".stripMargin
  }

  val buildAuthRequest: Expression[AuthenticateBody.Params] = (session: Session) =>
    AuthenticateBody.Params(
      session("userID").as[Int],
      session("username").as[String],
      password = session("password").asOption[String],
      apiKey = session("apiKey").asOption[String]
    )

  def authenticate(params: Expression[AuthenticateBody.Params]) =
    http("POST /tokens")
      .post("${identityURL}/tokens")
      .body(StringBody(session => AuthenticateBody.template(params(session).get)))

}