Quarkus - Google Cloud Functions (Serverless) with RESTEasy, Undertow, or Vert.x Web

The quarkus-google-cloud-functions-http extension allows you to write microservices with RESTEasy (JAX-RS), Undertow (Servlet), Vert.x Web, or Funqy HTTP, and make these microservices deployable to the Google Cloud Functions runtime.

One Google Cloud Functions deployment can represent any number of JAX-RS, Servlet, Vert.x Web, or Funqy HTTP endpoints.

As the Google Cloud Function Java engine is a new Beta feature of Google Cloud, this extension is flagged as experimental.

This technology is considered experimental.

In experimental mode, early feedback is requested to mature the idea. There is no guarantee of stability nor long term presence in the platform until the solution matures. Feedback is welcome on our mailing list or as issues in our GitHub issue tracker.

For a full list of possible extension statuses, check our FAQ entry.


To complete this guide, you need:


This guide walks you through generating a sample project followed by creating three HTTP endpoints written with JAX-RS APIs, Servlet APIs, Vert.x Web, or Funqy HTTP APIs. Once built, you will be able to deploy the project to Google Cloud.

If you don’t want to follow all these steps, you can go right to the completed example.

Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive.

The solution is located in the google-cloud-functions-http-quickstart directory.

Creating the Maven Deployment Project

Create an application with the quarkus-google-cloud-functions-http extension. You can use the following Maven command to create it:

mvn io.quarkus:quarkus-maven-plugin:1.13.7.Final:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=google-cloud-functions-http \
    -DclassName="org.acme.quickstart.GreetingResource" \
    -Dpath="/hello" \

Login to Google Cloud

Login to Google Cloud is necessary for deploying the application and it can be done as follows:

gcloud auth login

At the time of this writing, Cloud Functions are still in beta so make sure to install the beta command group.

gcloud components install beta

Creating the endpoints

For this example project, we will create four endpoints, one for RESTEasy (JAX-RS), one for Undertow (Servlet), one for Vert.x Web (reactive routes) and one for Funqy HTTP.

If you don’t need endpoints of each type, you can remove the corresponding extensions from your pom.xml.

The JAX-RS endpoint

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

public class GreetingResource {

    public String hello() {
        return "hello";

The Servlet endpoint

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "ServletGreeting", urlPatterns = "/servlet/hello")
public class GreetingServlet extends HttpServlet {
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.addHeader("Content-Type", "text/plain");

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String name = req.getReader().readLine();
        resp.addHeader("Content-Type", "text/plain");
        resp.getWriter().write("hello " + name);

The Vert.x Web endpoint

import static io.vertx.core.http.HttpMethod.GET;

import io.quarkus.vertx.web.Route;
import io.vertx.ext.web.RoutingContext;

public class GreetingRoutes {
    @Route(path = "/vertx/hello", methods = GET)
    void hello(RoutingContext context) {
        context.response().headers().set("Content-Type", "text/plain");

The Funqy HTTP endpoint

import io.quarkus.funqy.Funq;

public class GreetingFunqy {
    public String funqy() {
        return "Make it funqy";

Build and Deploy to Google Cloud

Quarkus forces a packaging of type uber-jar for your function as Google Cloud Function deployment requires a single JAR.

Package your application using the standard mvn clean package command. The result of the previous command is a single JAR file inside the target/deployment directory that contains the classes and the dependencies of the project.

Then you will be able to use gcloud to deploy your function to Google Cloud.

gcloud beta functions deploy quarkus-example-http \
  --entry-point=io.quarkus.gcp.functions.http.QuarkusHttpFunction \
  --runtime=java11 --trigger-http --source=target/deployment

The entry point must always be set to io.quarkus.gcp.functions.http.QuarkusHttpFunction as this is the class that integrates Cloud Functions with Quarkus.

The first time you launch this command, you can have the following error message:

ERROR: (gcloud.beta.functions.deploy) OperationError: code=7, message=Build Failed: Cloud Build has not been used in project <project_name> before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/cloudbuild.googleapis.com/overview?project=<my-project> then retry.

This means that Cloud Build is not activated yet. To overcome this error, open the URL shown in the error, follow the instructions and then wait a few minutes before retrying the command.

This command will give you as output a httpsTrigger.url that points to your function.

You can then call your endpoints via:

  • For JAX-RS: {httpsTrigger.url}/hello

  • For servlet: {httpsTrigger.url}/servlet/hello

  • For Vert.x Web: {httpsTrigger.url}/vertx/hello

  • For Funqy: {httpsTrigger.url}/funqy

Testing locally

The easiest way to locally test your function is using the Cloud Function invoker JAR.

You can download it via Maven using the following command:

mvn dependency:copy \
  -Dartifact='com.google.cloud.functions.invoker:java-function-invoker:1.0.0-beta1' \

Before using the invoker, you first need to build your function via mvn package.

Then you can use it to launch your function locally.

java -jar java-function-invoker-1.0.0-beta1.jar \
  --classpath target/deployment/google-cloud-functions-http-1.0.0-SNAPSHOT-runner.jar \
  --target io.quarkus.gcp.functions.http.QuarkusHttpFunction
The --classpath parameter needs to be set to the previously packaged JAR that contains your function class and all Quarkus related classes.

Your endpoints will be available on http://localhost:8080.

What’s next?

You can use our Google Cloud Functions Funqy binding to use Funqy, a provider agnostic function as a service framework, that allow to deploy HTTP function or Background function to Google Cloud.