how can we use gatling-mqtt plugin in a maven project for load testing

Question

I have a java maven project and i want to be able to test the performance of our mqtt broker using gatling. I understand that gatling directly doesn't support mqtt protocol.

I came across gatling-mqtt plugin in github. I'm not sure how i can use this plugin in my maven project. I couldn't find an existing maven plugin or dependency for this.

I have added the following dependencies in pom.xml

<dependency>  
    <groupId>io.gatling.highcharts</groupId>  
    <artifactId>gatling-charts-highcharts</artifactId>  
    <version>2.2.5</version>  
</dependency>  
<dependency>  
    <groupId>io.gatling</groupId>  
    <artifactId>gatling-core</artifactId>  
    <version>2.2.4</version>  
</dependency>  
<dependency>  
    <groupId>org.fusesource.mqtt-client</groupId>  
    <artifactId>mqtt-client</artifactId>  
    <version>1.12</version>  
</dependency>

and the following plugins:

<plugin>  
    <groupId>net.alchim31.maven</groupId>  
    <artifactId>scala-maven-plugin</artifactId>  
    <version>3.2.2</version>  
</plugin>  
<plugin>  
    <groupId>io.gatling</groupId>  
    <artifactId>gatling-maven-plugin</artifactId>  
    <version>2.2.4</version>  
    <executions>  
        <execution>  
            <id>performanceTests</id>  
            <goals>  
                <goal>execute</goal>  
            </goals>  
            <configuration>  
                <simulationClass>simulation.Publish</simulationClass>  
            </configuration>  
        </execution>  
    </executions>  
</plugin>  

I'm trying to write a simulation very similar to this:

import io.gatling.core.Predef._
import org.fusesource.mqtt.client.QoS
import scala.concurrent.duration._

import com.github.mnogu.gatling.mqtt.Predef._

class MqttSimulation extends Simulation {
    val mqttConf = mqtt
    // MQTT broker
    .host("tcp://localhost:1883")

    val scn = scenario("MQTT Test")
    .exec(mqtt("request")
    // topic: "foo"
    // payload: "Hello"
    // QoS: AT_LEAST_ONCE
    // retain: false
    .publish("foo", "Hello", QoS.AT_LEAST_ONCE, retain = false))

    setUp(
    scn
    .inject(constantUsersPerSec(10) during(90 seconds)))
    .protocols(mqttConf)
}

But for writing such a scenario, I'm unable to use the mqtt object.
Error that i get is 'not found: value mqtt'

Answer 1

I created a jar of the gatling-mqtt project which I included in my project. I was then able to use the mqtt object.

You can create a jar by downloading sbt. In your console, from the project path run command '$sbt assembly'. This will create a jar for you.