How to dynamically create samples

[frgirard]

The documentation URL

https://jmeter.apache.org/usermanual/component_reference.html#JSR223_Sampler

Feedback

I need a JSR223 groovy script to be able to dynamically create samples. This script receives kafka records which have headers including processing times. I'd like to be able to create samples using these timestamp info.
In my script, I create sampleresults :

def sr = new org.apache.jmeter.samplers.SampleResult(t_in, t_out - t_in)

But there's no way I know to add this sampleresult to JMeter results (.jtl, listeners...).
How could I do that ?
Thanks a lot !

[FSchumacher]

Have you thought about adding those samples as sub results into your given SampleResult?

https://jmeter.apache.org/api/org/apache/jmeter/samplers/SampleResult.html#addSubResult(org.apache.jmeter.samplers.SampleResult)

[frgirard]

Yes I did, but there are 3 issues with this method :

• I cannot setIgnore() the groovy script generating the subresults, hence the jtl file is "polluted" with these samples
• The subresults are not considered by some listeners like summary report
• subresults have different names (-0, -1, -2 ... is appended to the sampler label) while I'm trying to aggregate them

[FSchumacher]

First point might be annoying, but it is critical? Report could ignore those sample, could not it?
For the second point. Do you think those listeners should be enhanced to support subsamples?

Another way of implementing creation of samples would be by setting an array like object in the sampler and using a while/loop controller afterwards to iterate over the values of the array, using those values to fill in samplers.

[frgirard]

First point is quite critical because I won't be able to postprocess the jtl file (blazemeter)

About the alternate way, do you suggest I use a loop controler then alter each sample created with the values I want ? I'm not sure I can alter the sample start time for instance.

[FSchumacher]

In Groovy space, you can do quite a lot. I would try it out. But it should be possible to use SampleResult#setStartTime(long) on the current sample.

[frgirard]

Ok it seems to work, but I had to put the loop in a teardown threadgroup.
I'm using SampleResult.setStartTime() and SampleResult.setEndTime().

However, it rises an exception on every loop :

2022-11-17 12:02:39,362 ERROR o.a.j.s.SampleResult: sampleEnd called twice java.lang.Throwable: Invalid call sequence at org.apache.jmeter.samplers.SampleResult.sampleEnd(SampleResult.java:1147) ~[ApacheJMeter_core.jar:5.5] at org.apache.jmeter.protocol.java.sampler.JSR223Sampler.sample(JSR223Sampler.java:82) ~[ApacheJMeter_java.jar:5.5] at org.apache.jmeter.threads.JMeterThread.doSampling(JMeterThread.java:651) ~[ApacheJMeter_core.jar:?] at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:570) ~[ApacheJMeter_core.jar:?] at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:501) ~[ApacheJMeter_core.jar:?] at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:268) ~[ApacheJMeter_core.jar:?] at java.lang.Thread.run(Thread.java:750) ~[?:1.8.0_345]
Any idea on how I could fix that ?

[FSchumacher]

Yes, the exception comes from JSR223Sampler calling SampleResult#sampleEnd() without checking, if the sampler has set a timestamp (not equal to 0) first. Should probably fixed.

[frgirard]

Thanks a lot for your help, @FSchumacher !

[PavanMudigondaTR]

@frgirard Could you please provide a sample on how you were able to do this "How to dynamically create samples
"?

I opened a new issue but no one responsed #6273