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Lab 1: Your first Vert.x Project

Vert.x Logo.svg

In this lab, you will develop a HelloWorld vertical to create your first Vert.x application. You will run the application locally.

Later labs will introduce you to OpenShift and containerized microservices.

Requirements

  • Knowledge of Java language

  • Developer environment with a modern web browser, Git, Maven, a text editor or IDE,

Conventions

  • Commands that you execute in the Linux shell are preceeded by a $ character. Do not include this when you are typing or copying/pasting the commands.

  • Hostnames, usernames and passwords, and OpenShift resource names will be different for each participant. Take care to substitute the correct values for your environment when doing the exercises.

  • Screenshots may differ slightly from actual product.

1. Clone the Repository

To get started, use git to copy the necessary lab files to your local environment:

$ cd $HOME
$ git clone https://github.com/rhoar-enablement/vert.x

This will create a copy of the lab materials in the vert.x subdirectory.

$ cd $HOME/vert.x
$ ls
lab1 lab2 ...

Each lab is self-contained within each of the subdirectories.

Note
 You can choose any directory to house your lab code, these instructions use $HOME as an example.

2. Open lab1 using the IDE

Each lab in this course is housed in separate directories.

  • Use your favorite IDE and open the project files for lab1. The files

Once loaded, you should see the lab files and be able to navigate amongst the files. The components of this first project are laid out in different subdirectories according to Maven best practices:

  • pom.xml - The Maven project file

  • src/main/java - The source code to the project

  • src/main/resources - The static resource files referenced in the code

3. Examine the Maven POM file

  • In your IDE, open the file: pom.xml

The Maven POM file pom.xml defines the structure of the project and how to build and run it. The major components of the POM file include:

<project>

Identifiers and descriptions of the project

<properties>

Maven directives and project values (such as versions) referenced later in the POM file

<dependencies>

Defines the needed components for the app.

<build>

Directives for building the project.

4. Add Code for the Verticle

  • In your IDE, open the file: src/main/java/io/vertx/sample/MyFirstVerticle.java

  • Add the following code to this file (copy/paste):

package io.vertx.sample;

import io.vertx.core.AbstractVerticle;

public class MyFirstVerticle extends AbstractVerticle {

    @Override
    public void start() {

      // Handle each incoming HTTP request

    vertx.createHttpServer()
    .requestHandler(req -> {
            req.response().end(
              "Hello: Time on the server is "
              + java.time.LocalDateTime.now());
    })
    .listen(8080);

    }

}

5. Run your App

  • To run this application, type the following:

$ mvn compile vertx:run

  • The Maven build process will display a message once the server is up and running.

[INFO] --- vertx-maven-plugin:1.0.5:run (default-cli) @ my-first-vertx-app ---
[INFO] Launching Vert.x Application
[INFO] Vert.x application redeploy enabled
[INFO] Observing path:/Users/chaddarby/_foobar2/vert.x/lab1/src/main
[INFO] Aug 2, 2017 5:30:10 PM io.vertx.core.impl.launcher.commands.Watcher
[INFO] INFO: Watched paths: [/Users/chaddarby/_foobar2/vert.x/lab1/target/classes]
[INFO] Aug 2, 2017 5:30:10 PM io.vertx.core.impl.launcher.commands.Watcher
[INFO] INFO: Starting the vert.x application in redeploy mode
[INFO] Starting vert.x application...
[INFO] eaa8cf6f-9524-4fe7-8b75-ee92816879a7-redeploy
[INFO] Aug 2, 2017 5:30:11 PM io.vertx.core.impl.launcher.commands.VertxIsolatedDeployer
[INFO] INFO: Succeeded in deploying verticle

6. Test your App

You will see a hello message in the browser.

Note
 Any changes that you make to the Java source code are automatically reloaded.

  • Make a change to the service to give a different response message. For example include your name in the response. You will see the following console logs

[INFO] Aug 2, 2017 5:16:53 PM io.vertx.core.impl.launcher.commands.Watcher
[INFO] INFO: Redeployment done in 75 ms.
[INFO] Aug 2, 2017 5:16:54 PM io.vertx.core.impl.launcher.commands.VertxIsolatedDeployer
[INFO] INFO: Succeeded in deploying verticle

  • In your browser, reload the page. Verify the updated response.

  • Stop the service, by pressing CTRL-C in the terminal window

7. Building and running the Uberjar

  • You can also run your Vert.x application as an Uberjar:

$ mvn clean package

You’ll see several lines of output, and see that your project will auto-detect the necessary components needed to run the app later.

% ls target/*.jar
target/my-first-vertx-app-1.0.0-SNAPSHOT-swarm.jar

This file contains our project along with the necessary runtime to execute it.

  • Let’s run the project using plain Java:

$ java -jar target/my-first-vertx-app-1.0-SNAPSHOT.jar

If successful, you should see:

Aug 2, 2017 5:35:08 PM io.vertx.core.impl.launcher.commands.VertxIsolatedDeployer INFO: Succeeded in deploying verticle

This is your indication that the project is now running and ready to accept requests.

8. Test the Application

You should see your application output.

Congratulations!

9. Stop the service

  • To stop the service, simply press CTRL-C in the terminal window where the service is executing.

Caution
 Be careful to not leave services running that you are no longer using in this course, as port conflicts may arise later on.