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Deploying to Heroku

In this guide you will learn how to deploy a Quarkus based web application as a web-dyno to Heroku.

This guide covers:

  • Update Quarkus HTTP Port

  • Install the Heroku CLI

  • Deploy the application to Heroku

  • Deploy the application as Docker image to Heroku

  • Deploy the native application as Docker image to Heroku

Prerequisites

To complete this guide, you need:

Introduction

Heroku is a platform as a service (PaaS) that enables developers to build, run, and operate applications entirely in the cloud. It supports several languages like Java, Ruby, Node.js, Scala, Clojure, Python, PHP, and Go. In addition, it offers a container registry that can be used to deploy prebuilt container images.

Heroku can be used in different ways to run a Quarkus application:

  • As a plain Java program running in a container defined by Heroku’s environment

  • As a containerized Java program running in a container defined by the Quarkus build process

  • As a containerized native program running in a container defined by the Quarkus build process

All three approaches need to be aware of the port that Heroku assigns to it to handle traffic. Luckily, there’s a dynamic configuration property for it.

The guide assumes that you have the Heroku CLI installed.

Common project setup

This guide will take as input an application developed in the Getting Started guide.

Make sure you have the getting-started application at hand, or clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive. The solution is located in the getting-started directory.

Heroku can react on changes in your repository, run CI and redeploy your application when your code changes. Therefore, we start with a valid repository already.

Also, make sure your Heroku CLI is working:

heroku --version
heroku login

Prepare the Quarkus HTTP Port

Heroku picks a random port and assigns it to the container that is eventually running your Quarkus application. That port is available as an environment variable under $PORT. The easiest way to make Quarkus in all deployment scenarios aware of it is using the following configuration:

quarkus.http.port=${PORT:8080}

This reads as: "Listen on $PORT if this is a defined variable, otherwise listen on 8080 as usual." Run the following to add this to your application.properties:

echo "quarkus.http.port=\${PORT:8080}" >> src/main/resources/application.properties
git commit -am "Configure the HTTP Port."

Deploy the repository and build on Heroku

The first variant uses the Quarkus Maven build to create the quarkus-app application structure containing the runnable "fast-jar" as well as all libraries needed inside Heroku’s build infrastructure and then deploying that result, the other one uses a local build process to create an optimized container.

Two additional files are needed in your application’s root directory:

  • system.properties to configure the Java version

  • Procfile to configure how Heroku starts your application

Quarkus needs JDK 11, so we specify that first:

echo "java.runtime.version=11" >> system.properties
git add system.properties
git commit -am "Configure the Java version for Heroku."

We will deploy a web application so we need to configure the type web in the Heroku Procfile like this:

echo "web: java \$JAVA_OPTS -jar target/quarkus-app/quarkus-run.jar" >> Procfile
git add Procfile
git commit -am "Add a Procfile."

Your application should already be runnable via heroku local web.

Let’s create an application in your account and deploy that repository to it:

heroku create
git push heroku master
heroku open

The application will have a generated name and the terminal should output that. heroku open opens your default browser to access your new application.

To access the REST endpoint via curl, run:

APP_NAME=`heroku info | grep  "=== .*" |sed "s/=== //"`
curl $APP_NAME.herokuapp.com/hello

Of course, you can use the Heroku CLI to connect this repo to your GitHub account, too, but this is out of scope for this guide.

Deploy as container

The advantage of pushing a whole container is that we are in complete control over its content and maybe even choose to deploy a container with a native executable running on GraalVM.

First, login to Heroku’s container registry:

heroku container:login

We need to add an extension to our project to build container images via the Quarkus Maven plugin:

mvn quarkus:add-extension -Dextensions="container-image-docker"
git add pom.xml
git commit -am "Add container-image-docker extension."

The image we are going to build needs to be named accordingly to work with Heroku’s registry and deployment. We get the generated name via heroku info and pass it on to the (local) build:

APP_NAME=`heroku info | grep  "=== .*" |sed "s/=== //"`
mvn clean package\
  -Dquarkus.container-image.build=true\
  -Dquarkus.container-image.group=registry.heroku.com/$APP_NAME\
  -Dquarkus.container-image.name=web\
  -Dquarkus.container-image.tag=latest

With Docker installed, you can now push the image and release it:

docker push registry.heroku.com/$APP_NAME/web
heroku container:release web --app $APP_NAME

You can and should check the logs to see if your application is now indeed running from the container:

heroku logs --app $APP_NAME --tail

The initial push is rather big, as all layers of the image need to be transferred. The following pushes will be smaller.

The biggest advantage we take when deploying our app as a container is to deploy a container with the natively compiled application. Why? Because Heroku will stop or sleep the application when there’s no incoming traffic. A native application will wake up much faster from its sleep.

The process is pretty much the same. We opt in to compiling a native image inside a local container, so that we don’t have to deal with installing GraalVM locally:

APP_NAME=`heroku info | grep  "=== .*" |sed "s/=== //"`
mvn clean package\
  -Dquarkus.container-image.build=true\
  -Dquarkus.container-image.group=registry.heroku.com/$APP_NAME\
  -Dquarkus.container-image.name=web\
  -Dquarkus.container-image.tag=latest\
  -Pnative\
  -Dquarkus.native.container-build=true

After that, push and release again:

docker push registry.heroku.com/$APP_NAME/web
heroku container:release web --app $APP_NAME