Pass session expression language variable in ELFileBody - gatling

Question

I encounter an issue using Gatling EL in ELFileBody.
I have the following exec :
exec(myFunction("${myEmail}", otherParameters))
and the function :
def myFunction((email: String) = {
exec((s: Session) => s.set("email", email))
.exec(http("MyFunction")
.put("/myUrl")
.headers(Headers.basic_headers_json)
.body(ElFileBody("LinkToMyJsonFile"))
.asJson
.check(status.is(200)))
}
my myEmail is set in session. Yet, when the exec runs myFunction, the variable is replaced in the json by "${myEmail}" instead of beeing evaluated.
Have you an idea how I can resolve it be able to pass myEmail session variable in the exec through myFunction?
Thanks a lot in advance
JF

Answer 1

your function takes a string and you are then putting that string into a session variable - so when you pass in "${myEmail}" gatling is putting that string literal into the session var. So when gatling does the substitution in the ELFile body it's using exactly what you've specified.
I'm assuming you already have the email you want in the ${myEmail} session var - why not just edit the file to use ${myEmail} in place of "${email}"?
a more idiomatic approach would be to pass in an Expression[String], validate it and set the result into the ${email} var
def myFunction((email: Expression[String]) = {
exec((s: Session) => email.apply(s) match {
case Success(address) => s.set("email", address)
case Failure(error) => {
println(s"There was an error: $error")
s
}
}
...
This will retrieve the value of ${myEmail} if there is one or just the string literal if that's the case, and put it in the ${email} var. The error would be thrown if you provided a session var for which there was no value