Gatling Tool at Riviera Scala Clojure

This evening, at Riviera Scala Clojure, we received Stéphane Landelle and Romain Sertelon, Gatling Tools developers.

It's been quite some times I look for stress test tool that is intended for developers, instead of testers. You know, soemething like Caliper, but for stress tests.For a simple reason, I would like to profile my application and identify the problem on the load before even going to QA testing. Profiling can be done using a tool like Yourkit. But for load test, I haven't found anything convincing.

Of course, I used JMeter in the past. But I really want to have something that can be coded, but stays simple. JMeter, well...., it's  not that.

So, Gatling caught my attention. It has already caught my attention since Stéphane mentioned it in Paris Scala User Group mailing list back in December. So, here they are,  presenting the product in front of Riviera Scala Clojure group.

Performance, DSL, and Reporting
One thing that makes Gatling different is its performance. The performance of Gatling is claimed to be superior than JMeter. This is because Gatling uses Akka and AsyncHttp that allow optimization of concurrent execution of scenarios. The argument really makes sense to me, and I would really love to see it in real. Check their wiki to see the performance benchmark compared to JMeter: https://github.com/excilys/gatling/wiki/Benchmarks

The second important point in Gatling is DSL. The DSL is intended to allow programmatic scenario to be expressed easily. DSL in Gatling,  is nothing more than a fluent API, so, no need to worry, it's Scala. Check here to see the examples of the API.

You may notice that the API is quite simple -- maybe too simple? I found the DSL too imperative, but maybe this is a pragmatic choice by Gatling developer. I would have preferred the DSL to be a little bit more functional with use of pattern matching, partial function, and function composition, and other functional programming concepts instead of sequencing, the use of doIf, and loop.

The reporting is actually an interesting part of Gatling. Unfortunately, we were not lucky enough to have a full blown presentation on it, only an after presentation discussion.

Conclusion 
Gatling is an interesting tool to see if you"re interested in having a lightweight load test tool  like me. Its performance benchmark is quite promising. I have had a look at the codes, played with it, and it looks quite promising. The wiki page contains quite extensive information. But, I give you a puzzle: please find me in the wiki a scala file that shows the scenario example. Go ahead, if you can find it in 30 minutes, you're better than I am :-)