Create your first Java-based simulation

    Learn how to get started with Gatling and create a Gatling simulation.

    Gatling is a highly flexible load-testing platform. You can write load tests in Java, Kotlin, and Scala or use our no-code feature with Gatling Enterprise. In this guide, we cover a “Hello world”-style example of how to:

    Setup

    This section guides you through installation and setting up your developer environment. Gatling has a lot of optionalities, including:

    • build tools,
    • CI/CD integrations,
    • Java, Kotlin, and Scala SDKs

    This guide uses the Java SDK with the Maven wrapper. Gatling recommends that developers use the Java SDK unless they are already experienced with Scala or Kotlin. Java is widely taught in CS courses, requires less CPU for compiling, and is easier to configure in Maven and Gradle. You can adapt the steps to your development environment using reference documentation links provided throughout the guide.

    Sign up for Gatling Enterprise Cloud

    Gatling Enterprise Cloud is a fully managed SaaS solution for load testing. Sign up for a trial account to run your first test on Gatling Enterprise Cloud. The Gatling website has a full list of Enterprise features.

    Install Gatling

    This guide uses the Gatling Java SDK with Maven, which is accessed by downloading and extracting the following zipfile:

    Download Gatling

    Simulation construction

    This guide introduces the basic Gatling HTTP features. Gatling provides a cloud-hosted web application https://computer-database.gatling.io for running sample simulations. You’ll learn how to construct simulations using the Java SDK. Code examples for the Kotlin and Scala SDKs are available throughout the Documentation.

    Learn the simulation components

    A Gatling simulation consists of the following:

    • importing Gatling classes,
    • configuring the protocol (commonly HTTP),
    • describing a scenario,
    • setting up the injection profile (virtual user profile).

    The following procedure teaches you to develop the simulation from each constituent component. If you want to skip ahead and copy the final simulation, jump to Test execution. Learn more about simulations in the Documentation.

    Setup the file

    Once you have downloaded and extracted the Gatling zip file, open the project in your integrated development environment (IDE). Gatling recommends the IntelliJ community edition.

    1. Navigate to and open src/test/java/computerdatabase/ComputerDatabaseSimulation.java.
    2. Modify the simulation by deleting everything below line 7 import io.gatling.javaapi.http.*;.
    3. The simulation should now look like the following:
    package computerdatabase;

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

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

    Extend the Simulation class

    You must extend Gatling’s Simulation class to write a script. To extend the Simulation class, after the import statements, add:

    public class ComputerDatabaseSimulation extends Simulation {

}

    Define the protocol class

    Inside the ComputerDatabaseSimulation class, add an HTTP protocol class. Learn about all of the HttpProtocolBuilder options in the Documentation. For this example, the baseUrl property is hardcoded as the Gatling computer database test site, and the acceptHeader and contentTypeHeaderproperties are set toapplication/json`.

    public class ComputerDatabaseSimulation extends Simulation {

  // Add the HttpProtocolBuilder:
  HttpProtocolBuilder httpProtocol =
    http.baseUrl("https://computer-database.gatling.io")
      // set the "accept" header to a value suited for the expected response
      .acceptHeader("text/html");
}

    Write the scenario

    The next step is to describe the user journey. For a web application, this usually consists of a user arriving at the application and then a series of interactions with the application. The following scenario mocks a user arriving on the home page of the Gatling sample application.

    public class ComputerDatabaseSimulation extends Simulation {

  HttpProtocolBuilder httpProtocol =
    http.baseUrl("https://computer-database.gatling.io")
        // set the "accept" header to a value suited for the expected response
        .acceptHeader("text/html");

  // Add the ScenarioBuilder:
  ScenarioBuilder myScenario = scenario("My Scenario")
    .exec(http("Request 1").get("/computers/"));
}

    See the Documentation for the available scenario components.

    Define the injection profile

    The final component of a Gatling simulation is the injection profile. The injection profile is contained in the setUp block. The following example adds 2 users per second for 60 seconds. See the Documentation for all of the injection profile options.

    public class ComputerDatabaseSimulation extends Simulation {

  HttpProtocolBuilder httpProtocol =
    http.baseUrl("https://computer-database.gatling.io")
        // set the "accept" header to a value suited for the expected response
        .acceptHeader("text/html");

  ScenarioBuilder myScenario = scenario("My Scenario")
    .exec(
      http("Request 1").get("/computers/")
    );

  // Add the setUp block:
  {
    setUp(
      myScenario.injectOpen(constantUsersPerSec(2).during(60))
    ).protocols(httpProtocol);
  }
}

    Congrats! You have written your first Gatling simulation. The next step is to learn how to run the simulation locally and on Gatling Enterprise Cloud.

    Test execution

    Now, you should have a completed simulation that looks like the following:

    package computerdatabase;

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

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

public class ComputerDatabaseSimulation extends Simulation {

  HttpProtocolBuilder httpProtocol =
    http.baseUrl("https://computer-database.gatling.io")
      .acceptHeader("application/json")
      .contentTypeHeader("application/json");

  ScenarioBuilder myFirstScenario = scenario("My First Scenario")
    .exec(http("Request 1")
      .get("/computers/"));

  {
    setUp(
      myFirstScenario.injectOpen(constantUsersPerSec(2).during(60))
    ).protocols(httpProtocol);
  }
}

    Run the Simulation on Gatling Enterprise Cloud

    Gatling Enterprise Cloud is a feature-rich SaaS platform that is designed for teams and organizations to get the most out of load testing. With the trial account, you created in the Prerequisites section, you can upload and run your test with advanced configuration, reporting, and collaboration features.

    From Gatling 3.11 packaging and running simulations on Gatling Enterprise Cloud is simplified by using configuration as code. In this tutorial, we only use the default configuration to demonstrate deploying your project. You can learn more about customizing your configuration with our configuration-as-code guide.

    To deploy and run your simulation on Gatling Enterprise Cloud, use the following procedure:

    1. Generate an API token with the Configure permission in your Gatling Enterprise Cloud account.

    2. Add the API token to your current terminal session by replacing <your-API-token> with the API token generated in step 1 and running the following command:

          
      export GATLING_ENTERPRISE_API_TOKEN=<your-API-token>

      set GATLING_ENTERPRISE_API_TOKEN=<your-API-token>

    3. Run the following command in your terminal to deploy and start your simulation:

          
      ./mvnw gatling:enterpriseStart

      mvnw.cmd gatling:enterpriseStart

    Watch the Simulation deploy automatically and generate real-time reports.

    Run the Simulation locally for debugging Optional

    The open-source version of Gatling allows you to run simulations locally, generating load from your computer. Running a new or modified simulation locally is often useful to ensure it works before launching it on Gatling Enterprise Cloud. Using the Java SDK, you can launch your test with the following command in the project root directory:

        
    ./mvnw gatling:test

    mvnw.cmd gatling:test

    Select 1 Run the Simulation locally to start the test.

    When the test has finished, there is an HTML link in the terminal that you can use to access the static report.

    Keep learning

    You have successfully run your first test! To keep learning, we recommend the following resources:

    Edit this page on GitHub

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