Performance Testing with Gatling, Maven and Scala

This post shows how to set up a Gatling simulation test using Maven and Scala on IntelliJ IDE.

If you don’t already have Scala plugin for IntelliJ IDE, you can install it from the plugins section under preference:

Once the Scala plugin is installed, then you need to create a Maven project and choose a Scala archetype

If the desired archetype is not listed, you can click the “Add archetype” button and add the following details

<groupId>net.alchim31.maven</groupId>
<artifactId>scala-archetype-simple</artifactId>
<version>1.6</version>

Next, add the following section to the pom file which indicates which version of libraries we will be using

<properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <encoding>UTF-8</encoding>
    <scala.version>2.11.7</scala.version>
    <scala.compat.version>2.11</scala.compat.version>
</properties>

Then, add the required Scala and Gatling dependencies in the pom file

<dependencies>
    <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-library</artifactId>
      <version>${scala.version}</version>
    </dependency>
    <dependency>
      <groupId>io.gatling.highcharts</groupId>
      <artifactId>gatling-charts-highcharts</artifactId>
      <version>${gatling.version}</version>
      <scope>test</scope>
    </dependency>
 </dependencies>

And finally, add the build section in the pom file

<build>
    <sourceDirectory>src/main/scala</sourceDirectory>
    <testSourceDirectory>src/test/scala</testSourceDirectory>
    <plugins>
      <!-- Gatling Maven plugin that runs the load-simulation. -->
      <plugin>
        <groupId>io.gatling</groupId>
        <artifactId>gatling-maven-plugin</artifactId>
        <version>${gatling-plugin.version}</version>
        <configuration>
          <simulationClass>com.example.perf.simulations.HttpSimulation</simulationClass>
        </configuration>
      </plugin>
    </plugins>
  </build>

Once all the sections in the pom file have been updated, we are now ready to create a Gatling simulation class in Scala.

• In src/test/scala, create a package named com.example.gatling.simulations.
• In this package, create a Scala class named HttpSimulation with the following implementation.

package com.example.gatling.simulations

import io.gatling.core.Predef._
import io.gatling.http.Predef._
import io.gatling.http.config.HttpProtocolBuilder.toHttpProtocol
import io.gatling.http.request.builder.HttpRequestBuilder.toActionBuilder

/**
  * Example Gatling load test that sends two HTTP requests to the same URL.
  */
class HttpSimulation extends Simulation {

    val theHttpProtocolBuilder = http
        .baseURL("https://computer-database.gatling.io")

    val theScenarioBuilder = scenario("Scenario1")
        .exec(
            http("myRequest1").get("/")
        )

    setUp(
        theScenarioBuilder.inject(atOnceUsers(1))
    ).protocols(theHttpProtocolBuilder)
}

To execute your test, just run

mvn gatling:execute