How to use 'counterName' of repeat() at variable?

Gatling (Open-Source)
1

Hi,

I tried to create an bunch of objects via service using the ‘counterName’ variable of a repeat function.
But neither the “id” is calculated correctly nor the “name” is resolved (e.g. “Test_0”).

reasons are:

  • my ID has to start at 1
  • the name should be printed in the logs (e.g. “create object ‘Test_0’”)
  1. I tried to access the session object but it seems not to be existing in repeat() but exec()
  2. But inside exec() I can’t define variables

And because I’m a very beginner to Scala I got no clue how to handle it.

.repeat(5, “object_index”) {
val id = Integer.getInteger("${object_index}") + 1;
val name = “Test_${object_index}”

exec(
http(“create object '” + name + “’”)
.post("/objects")
.basicAuth(userName, userPassword)
.body("{" +
““id”: + id +,” +
““name”: “” + name + “”,” +
“}”)
.check(status.is(200)))
}

Any help is welcome.

Regards Danny

2

Hi Danny,

You’re actually missing the point that all the DSL elements are builders, meaning that they are only evaluated once when the Simulation is built.

In your case, the "val id = … " block is only evaluated at build time.

You have multiple solutions:

  • Do everything inside the Simulation class just like you did

You have to add an extra step in order to compute your (loop index + 1)

repeat(5, “object_index”) {
exec(session => {
val id = session.getTypedAttributeInt + 1
session.setAttribute(“id”, id)
})
.exec(
http(“create object Test_${object_index}”)
.post("/objects")
.basicAuth(userName, userPassword)
.body("""{“id”: ${id}, “name:” Test_${object_index}}""")
.check(status.is(200)))
}

  • Use an external template for your JSON request body, as explained here:

https://github.com/excilys/gatling/wiki/HTTP#wiki-template-body

I personally would go with the second solution.

Hope that helps,

Stéphane

3

So the description of the http() can’t be changed during runtime because it is build once - understood.
I will try the SSP-Templates because my request bodies are getting bigger in near future.

Thanks a lot, Danny

4

It can be changed at runtime, but you have to understand what is evaluated at build time and what is evaluated at runtime.
Things evaluated at runtime are functions (usually Session => something) and EL (that are actually converted into functions).

In my above example, the request name “create object Test_${object_index}” is an EL that will be resolved every time a user sends this request.

Cheers,

Stéphane