How to search Java documentation - onCase along with percent

Gatling (Open-Source)
1

Gatling version 3.14.3:
Gatling flavor: java kotlin scala javascript typescript
Gatling build tool: [X ] maven gradle sbt bundle npm

I found an out-of-date example of Gatling Java code as follows (intended to log out 10% of the time)

public static ChainBuilder logout =
randomSwitch().on(
Choice.withWeight(10, exec(
http(“Logout”).post(“/logout”)

Choice.withWeight no longer is valid. Searching the Gatling documentation, I viewed the 3.11 release notes, which said " Drop deprecated Choice#withKey and Choice#withWeight, use onCase and percent instead"

However, I must be doing something incorrectly when searching the Java DSL. I could not find any Gatling documentation showing how to properly use onCase along with percent.

I ended up finding a working example on a different web site that used randomSwitch.

Not sure if this is the proper way to implement percent or if there is a cleaner way to create a ChainBuilder instance using onCase(percent(10.0).then(exec …

I would appreciate learning the right way to search and view the entire Java DSL to find examples. Can you share any tips / techniques on how to leverage the documentation?

Search for “randomSwitch” → returns link to scenario randomSwitch and includes example of using percent. :grinning_face:

Search for “percent” → nothing found in the DSL Java documentation. :upside_down_face:

Search for “onCase” → nothing found in the DSL Java documentation. :upside_down_face:

Is this the cleanest way to implement the logic when there we only have one request we want apply percent to:

public static ChainBuilder logout =
randomSwitch().on(
percent(10.0).then(exec(
http(“Logout”).post(“/logout”)

Thanks!

2

Code samples are not indexed. doSwitch and randomSwitch are a bit of a special case where all other languages than Scala need an extra method as they don’t have nice native support for couples.
I’m not sure how we can improve things. cc @Shaun

Is this the cleanest way to implement the logic when there we only have one request we want apply percent to:

Yes

1 Like
3

Thanks!

One documentation idea might be to offer paid Enterprise users to access a customized AI search that has a robust set of code examples to augment the search :grinning_face:

Just for amusement, I tried Microsoft Copilot and it wildly missed the mark at first.

“generate a Java Chainbuilder for Gatling that runs a request 25% of the time”

First response was one that would work but is over-engineered:

ChainBuilder conditionalRequest = exec(session -> {
    Random rand = new Random();
    // Generate a value between 0 and 99. If less than 25, execute the request.
    if (rand.nextInt(100) < 25) {
        return session.set("shouldRun", true);
    } else {
        return session.set("shouldRun", false);
    }
}).doIf("#{shouldRun}", 
    exec(http("25% Request")
        .get("/your-endpoint-here"))
);

Second answer after additional prompt was close but not quite right:

ChainBuilder conditionalRequest = 
    percent(25).exec(
        http("25% Request")
            .get("/your-endpoint-here")
    );

After one more prompt it reverted to using Choice.withWeight which of course is no longer supported. Then with a final prompt it finally got things right.

I also posted an update on https://stackoverflow.com/questions/74059322/how-to-perform-random-switch-in-gatling-java/79712654#79712654

ChainBuilder conditionalRequest = 
    randomSwitch().on(
        // 25% chance to run request
        percent(25).exec(
            http("25% Chance")
                .get("/your-endpoint-here")
        ),
        // 75% or any other percentage, or can remove entirely if no other no action
        percent(75).exec(
            http("75% Chance")
                .get("/your-other-endpoint-here")
        ),
        // yet another percentage
        percent(33).exec(
            http("33% Chance")
                .get("/your-additional-endpoint-here")
        )
    );
4

Hi @LeslieM, I help maintain the documentation at Gatling. Thanks for the feedback. I am working on some updates that should improve the search in cases like yours, but it might take a few days to notice a difference.

We will also investigate some AI-related enhancements after the summer.

Thanks for using Gatling and contributing to the community!

1 Like