same session used for all virtual users?!

[Kasper Johansen]

Hi all, 

I have created this scenario (below code), which work fine with 1 user. But when I "rampUsers" to more then one user, all users get the same "Metadata.metadataMap" which is a `var metadataMap = Map( "..." -> "...", ...)` loaded from a scala `object`. What am I doing wrong? I did think that the `session` got set uniquely for each user? Thereby the `var metadataMap..` should be called each time a new user is started? 

```java

import io.gatling.core.Predef._

import io.gatling.core.structure.ScenarioBuilder

import io.gatling.http.protocol.HttpProtocolBuilder

import io.gatling.http.Predef._

import com.typesafe.config.{Config, ConfigFactory}

import scala.concurrent.duration._

class LoadSimulation extends Simulation {

  val config: Config = ConfigFactory.load()

  val httpConf: HttpProtocolBuilder = http.baseURL(config.getString("baseUrl"))

  val fileBufferFeeder: Seq[Array[Byte]] = LoadFile.iteratorOfFileByteArrays.toSeq

  val runNum: Int  = fileBufferFeeder.length - 1

  val scn: ScenarioBuilder = scenario("Load Test Simulation")

    .exec(session => session.set("START_MAP_METADATA", Metadata.metadataMap).set("CALL_ACTIVE", "True")).exec(session => {session.set("START_METADATA", JsonUtil.toJson(session("START_MAP_METADATA").as[Map[String, Any]]))})

    .foreach(fileBufferFeeder, "feedElement", "counter")

    {

      doIfOrElse(_("counter").as[Int] < runNum) {

          exec(

            http("Call wav upload ${counter}")

            .post(config.getString("baseUrl"))

            .bodyPart(ByteArrayBodyPart("file", _("feedElement").as[Array[Byte]]).fileName("file.wav").contentType("application/octet-stream")).asMultipartForm

            .bodyPart(StringBodyPart("call", _("START_METADATA").as[String]).fileName("call.json").contentType("application/json")).asMultipartForm

            .queryParam("callactive", _("CALL_ACTIVE").as[String])

            .header("Content-Type", "multipart/form-data")

            .check(status.is(204))

    ).pause(1 second)} {

      exec(session => session.set("STOP_METADATA", JsonUtil.toJson(session("START_MAP_METADATA").as[Map[String, Any]].updated("stop", System.currentTimeMillis()))).set("CALL_ACTIVE", "False"))

        .exec(

          http("Call wav upload ${counter}")

            .post(config.getString("baseUrl"))

            .bodyPart(ByteArrayBodyPart("file", _("feedElement").as[Array[Byte]]).fileName("file.wav").contentType("application/octet-stream")).asMultipartForm

            .bodyPart(StringBodyPart("call", _("STOP_METADATA").as[String]).fileName("call.json").contentType("application/json")).asMultipartForm

            .queryParam("callactive", _("CALL_ACTIVE").as[String])

            .header("Content-Type", "multipart/form-data")

            .check(status.is(204))

        ).pause(1 second)}

    }

  /* Here we ramp up the users */

  setUp(

    scn.inject(rampUsers(10).over(30 second))

  ).protocols(httpConf)

}

```

Thanks for your help. 

[Kasper Johansen]

Ok all sessions are unique.. I guess it was just me not thinking right.. The 

metadataMap = Map( "..." -> "...", ...)` loaded from a scala `object`. 

was acting like a val event though it was set as var. 

But I have now changed it to 
```scala 

def metadataMap(): Map[String, Any]= {

+    Map( ...

```

And now everything works like a charm.. Thanks gatling for such a great tool.