Registering Pebble Extensions with Java

Gatling (Open-Source)
1

I am attempting to register pebble extensions, but I dont think I am able to in Java.

Here is a portion of Engine.java

public class Engine {

   public static void main(String[] args) {
      GatlingPropertiesBuilder props = new GatlingPropertiesBuilder()
 
   List<Extension> extensions = List.of(
        new CustomExtensions()
   );
   
   PebbleExtensions.register(extensions);

   Gatling.fromMap(props.build());
   }
}

Here is a custom extensions class

public class CustomExtensions extends AbstractExtension {

   public CustomExtensions(){
   }

   @Override
    public Map<String, Filter> getFilters(){
	   Map<String, Filter> filters = new HashMap<>();
	   filters.put("OrNull", new OrNull());
	   return filters;
    }
}

We just converted the project from Scala to Java, I really hope we dont need to go back. I do believe we need Pebble templates for Gatling to be efficient for us, and extensions would go a long way in helping use Pebble templates effectively.

2

You’re not registering Pebble extensions the correct way.

You’re not supposed to use PebbleExtensions directly, it’s a Gatling internal. Its visibility is private[gatling].

Instead, you’re supposed to use registerPebbleExtensions directly in your Simulation, as described in the documentation.

3

I looked for that method but was unable to find it initially. That launched me down a rabbit hole. Your response made me dig again and I was able to find it at

import static io.gatling.javaapi.core.CoreDsl.registerPebbleExtensions;

Thank you

4

As (poorly?) explained in the documentation for your first scenario, there are several required imports.

For java:

import io.gatling.javaapi.core.*;
import io.gatling.javaapi.http.*;

import static io.gatling.javaapi.core.CoreDsl.*;
import static io.gatling.javaapi.http.HttpDsl.*;

(Yes, even with the empty line, the four imports are mandatory in all your java file that use Gatling DSL)

Cheers

5

Ah theres the disconnect. Since I am registering the Custom Extensions in the Engine class, I didnt even think of adding those imports.

6

Really, you’re not supposed to do it in Engine but in your Simulations.
And your not supposed to use the Engine class for anything than launching manually from your IDE.

7

I can understand the logic of registering extensions in simulations, as that allows various combinations of extensions to be available as needed.

Engine just seemed a convenient place to make it available to all simulations.