Gatling use session.set and feed simultaneously

Question

If I use .get("/***/quotes-${endPoint}/quotes?source=rtbp&userid=test&symbol=${pTypeSymbol}${authM}${pEqSymbol}") then ${pEqSymbol} work but ${pTypeSymbol} will be ${pEqSymbol} it's incorrect example of get it should be in code below

val getApiKeyScenario = scenario("getApiKey")
    .feed(getApiKeyData)
    .feed(pEqSymbolFeed)
    .feed(pOptionSymbol)
    .feed(pOtherSymbol)
    .exec(session => session
      .set("endPoint", "v1")
      .set("pTypeSymbol", "${pEqSymbol}")
      .set("authM", "&apikey=***********"))
    .exec(http("getApiKeyRequest")
      .get("/******/quotes-${endPoint}/quotes?source=rtbp&userid=test&symbol=${pTypeSymbol}${authM}")
      .check(status.is(200))
      .check(checkIf(doLogResponse) {
        bodyString.saveAs("pResponse")
      })
    )
    .doIf(doLogResponse) {
      logResponse()
    }

If I try .set("pTypeSymbol", pEqSymbolFeed.readRecords.head("pEqSymbol")) will be loop If I try .set("pTypeSymbol", s"${pEqSymbol.isDefined}") not found: value pEqSymbol If I try s"${pEqSymbol}" not found: value pEqSymbol

I logs now is GET *******/quotes-v1/quotes?source=rtbp&userid=test&symbol=${pEqSymbol}&apikey=****** But should be GET *******/quotes-v1/quotes?source=rtbp&userid=test&symbol="Here my value from feed"&apikey=******

Answer 1

Please read the official documentation:

This Expression Language only works on String values being passed to Gatling DSL methods. Such Strings are parsed only once, when the Gatling simulation is being instantiated.

For example queryParam("latitude", session => "${latitude}") wouldn’t work because the parameter is not a String, but a function that returns a String.

In your example, you don't need to copy pEqSymbol into pTypeSymbol, you can directly write:

.exec(session => session
      .set("endPoint", "v1")
      .set("authM", "&apikey=***********"))
    .exec(http("getApiKeyRequest")
      .get("/******/quotes-${endPoint}/quotes?source=rtbp&userid=test&symbol=${pEqSymbol}${authM}")
      )
    )

But if you insist on copying, you have to use the Session API:

.set("pTypeSymbol", session("pEqSymbol").as[String])