Insufficient details on error debugging Gatling script

Gatling (Open-Source)
1

Gatling crashes on error with no details about it.

The log level is set to warn in the logback config. It appeared the error was caused when the referred session parameters were not found in the simulation. I wish I saw more details about parameters in the log to narrow the search field.

Instead, I just got the following:

2021-11-08 10:44:46,726 main 10:44:46.726 [main] [ERROR] i.g.a.Gatling$ - Run crashed
java.lang.ClassNotFoundException: OMS_to_SAP
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at io.gatling.app.Selection$Selector.$anonfun$singleSimulationFromConfig$2(Selection.scala:71)
at scala.util.Try$.apply(Try.scala:210)
at io.gatling.app.Selection$Selector.findUserDefinedSimulationInClassloader$1(Selection.scala:71)
… 15 common frames omitted
Wrapped by: java.lang.IllegalArgumentException: User defined Simulation class OMS_to_SAP could not be loaded
at io.gatling.app.Selection$Selector.findUserDefinedSimulationInClassloader$1(Selection.scala:80)
at io.gatling.app.Selection$Selector.$anonfun$singleSimulationFromConfig$4(Selection.scala:85)
at scala.Option.orElse(Option.scala:477)
at io.gatling.app.Selection$Selector.$anonfun$singleSimulationFromConfig$3(Selection.scala:85)
at scala.Option.flatMap(Option.scala:283)
at io.gatling.app.Selection$Selector.singleSimulationFromConfig(Selection.scala:83)
at io.gatling.app.Selection$Selector.$anonfun$selection$1(Selection.scala:52)
at scala.Option.getOrElse(Option.scala:201)
at io.gatling.app.Selection$Selector.selection(Selection.scala:44)
at io.gatling.app.Selection$.apply(Selection.scala:36)
at io.gatling.app.Runner.run0(Runner.scala:61)
at io.gatling.app.Runner.run(Runner.scala:49)
at io.gatling.app.Gatling$.start(Gatling.scala:83)
at io.gatling.app.Gatling$.fromArgs(Gatling.scala:45)
at io.gatling.app.Gatling$.main(Gatling.scala:37)
at io.gatling.app.Gatling.main(Gatling.scala)

2

java.lang.ClassNotFoundException: OMS_to_SAP

This is pretty explicit: you don’t have any Simulation class named OMS_to_SAP.

3

Actually, it is not true. There is such a class. The root cause was that a parameter was renamed and was not found then.