Vert.x Application on Google App Engine Standard with Java 11

This sample shows how to deploy a Vert.x application to Google App Engine stadndard.

Setup

See Prerequisites.

Deploying

gcloud app deploy

See the application page

Navigate to https://<your-project-id>.appspot.com.

The application

The application is written to use Eclipse Vert.x to demonstrate the use of Vert.x Web as web server and Vert.x Web client.

Vert.x is a fully non-blocking toolkit and some parts of the application use callbacks.

The main class creates the Vert.x instance deploys the Server class:

Vertx vertx = Vertx.vertx();
vertx.deployVerticle(new Server());

The application

When the application starts

• it creates a Vert.x Web client for querying the Google metadata API for the project ID displayed in the response
• it creates a Vert.x Web router when it starts and initializes it to serve all the routes with the handleDefault method
• it starts an HTTP server on the port 8080

webClient = WebClient.create(vertx);

Router router = Router.router(vertx);

router.route().handler(this::handleDefault);

vertx.createHttpServer()
    .requestHandler(router)
    .listen(8080, ar -> startFuture.handle(ar.mapEmpty()));

HTTP requests are served by the handleDefault method. This method uses the WebClient to query the Google metadata API for the project ID and returns an Hello World string that contains the project ID name.