Jmeter select a random value from previous thread group variables

Question

In my test plan, I have a setup thread group. I save the result of that setup thread group as a variable and use it in my following thread group. I was able to achieve this with the JSON extractor.

What I want to do is run the setup thread group multiple times so it can produce a pool of that variable. And in the following thread group, I randomly pick one from the pool to use. How can I achieve that?

I also have a teardown thread group, that needs to read from the pool of variable and tear down one by one.

Answer 1

1. Add JSR223 PostProcessor after the JSON Extractor in the setUp Thread Group

2. Put the following code into "Script" area:

    props.put('id_' + vars.get('__jm__setUp Thread Group__idx'), vars.get('id'))

   this will create the following JMeter Properties:

    id_0=value from 1st iteration id_1=value from 2nd iteration etc.

3. Then in main or tearDown Thread Group you will be able to get the random value using __P() and __Random() functions combination like:

    ${__P(id_${__Random(0,4,)},)}

Demo:

More information:

• JMeter Functions and Variables
• Top 8 JMeter Java Classes You Should Be Using with Groovy