Unique VU index per scenario or data parameterization in multiple scenarios

Grafana k6 OSS Support
1

Hey, I have a question which as far as I see, was already asked long time ago here: Shared state or unique sequential vu index per scenario

But it looks like there’s still no answer) Or maybe I just couldn’t find it.
I need to use data parameterization per scenario. Using VU indexes works fine if working with 1 scenario. But when it comes to several scenarios - I couldn’t find the answer how to do this.

Let’s say I have 4 scenarios. Each scenario uses 25 users. So in the setup() I create arrays of users and share them. It’s not a problem to access the needed array itself. The question is - how do I make each VU working with only 1 user from the shared array? Especially assuming those VU indexes are random and scenario 1 might get VU index 90 etc. So I can’t use VU index to access the array. Some VU index per scenario would work but it looks like there’s no any.

Or maybe there is a way to read some file per scenario and use only 1 line per virtual user inside that scenario? It’s possible in jMeter but I can’t figure out how to do this in K6.

Please help

3

Hi @eugene_tst,
Welcome back to the community forum :tada:

did you try to use exec.scenario.iterationInTest index as explained in the Data Parameterization guide?

If it is not enough, can you clarify better your case, please?

1 Like
5

Hi, @codebien , the scenario.iterationInTest is not what I needed because it’s not connected to the VU itself. I ended up using 2 instances of k6 for what I need…

The case is the following:
First of all, I’m using more than 1 scenario (let’s say, 2 scenarios).
I register users during the setup and put them to arrays so each array is made for it’s own scenario (scenario a1 users might have some own properties).
What I need is being able to work with exact array for exact scenario (array a1 is used in scenario a1 only). As VUs indexes are allocated randomly, I can’t rely on the VU index and use it as an array index. Of course, I could use iteration indexes in some simple cases but in my specific situation this would lead to re-login each user which is absolutely not what I wanted. Having some kind of scenario VU indexes would help me because I need to use each VU with the same app user during the whole run.

Also, being able to modify the shared objects would help here so I could use 1 shared array and set needed properties during the test runtime but it’s not possible, I can only read the shared data from setup and not modify it…