How to run JSR223 PreProcessor only once

Question

I have a test plan in jMeter that requires some parameters that needs to be calculated before running the test. In order to calculate these parameters, I created a JSR223 PreProcessor directly under test plan as seen below.

My problem is PreProcessor seems to run before every request which is not what I want. I need to calculate these parameters only once and use them in testing.

Is there a way to run the JSR223 PreProcessor only once, or should I use another method?

Thanks in advance.

Edit:

As @ubik-load-pack suggested, I tried "setUp Thread Group" as following but variables created in the code was not available under "Thread Group". They were also present neither in the logs (logging is used in the code) nor in the View Results Tree (via Debug PostProcessor)

I also tried "Once Only Controller" which also didn't work, same as above.

For more information here is content of my JSR223 PreProcessor. (Not the whole code, there will be more variables here so using date functions is not a solution for me by the way.)

Answer 1

By design a PreProcessor runs before any Sampler runs.

So if you want to run something only once per user, you can do the following:

• Use a Once Only Controller and put in it a JSR223 Sampler that will contain your code.

If you want to do it once for all users, then use a setupThreadGroup that will contain your JSR223 Sampler and configure it with 1 thread. It will run once before the regular Thread Groups are started.

EDIT after you updated your question:

• As I wrote, you cannot use the setupThreadGroup approach if you want to reuse variables in Thread Groups so stick to OnceOnlyController approach for your request

• With the Once Only Controller it is not working because you misread my answer, I am suggesting to use a JSR223 Sampler not PreProcessor as a preprocessor will run only if there is a sampler that runs.