Developing Reactive Streams with Quarkus and Red Hat OpenShift Streams for Apache Kafka

This project illustrates how you can interact with Red Hat OpenShift Streams for Apache Kafka using Quarkus Reactive application.

Creating a new Kafka instance on Red Hat OpenShift Streams

Go to cloud.redhat.com and log in with your Red Hat account. Create a new Kafka instance in Application Services menu then create a topic as well as service account. See more details about Getting started with Red Hat OpenShift Streams for Apache Kafka).

Update configurations

Replace the following configurations in application.properties with your service account and connection information of the Red Hat OpenShift Streams for Apache Kafka:

• KAFKA_BOOTSTRAP_SERVERS

• CLIENT_ID

• CLIENT_SECRET

Start the application

The application can be started using:

mvn quarkus:dev

NOTE: Quarkus Dev Services starts a Kafka broker for you automatically.

Then, open your browser to http://localhost:8080/prices.html, and you should see a fluctuating price.

Anatomy

In addition to the prices.html page, the application is composed by 3 components:

• PriceGenerator - a bean generating random price. They are sent to a Kafka topic

• PriceConverter - on the consuming side, the PriceConverter receives the Kafka message and convert the price. The result is sent to an in-memory stream of data

• PriceResource - the PriceResource retrieves the in-memory stream of data in which the converted prices are sent and send these prices to the browser using Server-Sent Events.

The interaction with Kafka is managed by MicroProfile Reactive Messaging. The configuration is located in the application configuration.

Running in native

You can compile the application into a native binary using:

mvn clean install -Pnative

Then run with:

./target/kafka-quickstart-1.0.0-SNAPSHOT-runner

Watch the demo