Is it possible to change load during runtime?

Gatling (Open-Source)
1

Hi!

I suppose my question is not possible, but I’m asking just in case.
But I would like, just for fun, to change the load by reading users per seconds (constantUsersPerSec) from a file which I can edit the value in during runtime?

That means
1: I have a text-file with a value in for constant users per sec
2: I start a test and the value is read from the file
3: If I update the value in the file, the load will change accordingly runtime

We are going to have a hackaton, and my idea, just for fun is to connect some hardware (a potentiometer) to the computer to be able to change the load during runtime.
In addition create a website where we can update the same value.

Regards

2

Hi,

No, it’s not currently possible.
First, the injection function is computed upstream.
Then, Gatling doesn’t provide a way to interact at runtime.
However, that’s something we have in the FrontLine roadmap.

Cheers

3

Hi Stèphane,
I have a similar question.
I want to simulate a scenario where guest traffic goes up & down at each second/minute level. For the same reason I don’t want to use fixed number of users/tps as part of scenario.
A crude way is; I can have a file with no. of entries required each second & users finish the file & don’t loop in a second. Then for the next second they pick up next file & I am hoping pause function can give me that flexibility.
Any other suggestion would be appreciated.

Ayush

4

Since the number of users injected can’t be dynamically changed at runtime, you could probably do something along these lines:

  • Always inject the max number of users per second that you’ll need during your test- At the beginning of each user’s iteration, load whatever value you need from external source (file / redis / some external web server hosting etc, depending on your use case and taking scalability into account).
  • Evaluate that value loaded at runtime using a doIf() - programmatically calculate whether to run the iteration code (return true) or not (return false)
5

Thanks for the suggestion, I have been thinking along the same line. But only problem with including a doif() at a user level would be that I won’t have information regarding total load being injected or whether the file got completed or not.