JMeter: How do you run code that's not part of a sampler?

Question

I want to run code at the beginning that sets up variables, but as far as I can tell, the options for running code are:

1. Sampler: Appears in JMeter reports and screws up my numbers.
2. Pre-processor/Post-processor/Assertion: Must be attached to existing sampler.
3. Timer: This works sometimes, but it appears that if you have your timers higher in the tree than your samplers, they just get ignored.
4. Listener: Runs after your samplers (I want this code to run before everything else).

Is there a way to run code without modifying reports or attaching it to a sampler?

Answer 1

1. Add Test Action sampler to the place in the Test Plan where you want to run your code
2. Add JSR223 PreProcessor as a child of the Test Action sampler
3. Tick Cache compiled script if available box
4. Put your code into Script area

This is something you're looking for as

• Test Action sampler will not be reflected in the load report:

  Each sampler (except Test Action) generates one or more sample results.

• Currently Groovy is the best scripting option available in JMeter

  

Answer 2

See Execution order:

1. Configuration elements
2. Pre-Processors
3. Timers
4. Sampler ...

For example of Configuration element

The User Defined Variables Configuration element is different. It is processed at the start of a test, no matter where it is placed.

Inside it you can execute JMeter functions which include numerous options as to read from CSV, execute groovy or beanshell code...

Answer 3

You can add your action as a Sampler (no matter JSR223 or anything else) and then add a PostProcessor that will mark this Sampler's result as ignored. It can be done with JSR223 PostProcess with groovy script:

prev.setIgnore()

You can also control whether or not to ignore this sample based on the conditions.