kafka-quickstart

Quarkus Kafka Quickstart

This project illustrates how Quarkus applications can interact with Apache Kafka using MicroProfile Reactive Messaging.

Start the application

The application is composed of two applications communicating through Kafka. Interactions with Kafka is managed by MicroProfile Reactive Messaging.

They can be started in dev mode using:

mvn -f producer quarkus:dev

and in another terminal:

mvn -f processor quarkus:dev

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

Then, open your browser at http://localhost:8080/quotes.html. You can send quote requests and observe received quotes.

Anatomy

The application is composed of the following components:

Producer

The producer application receive requests from the user (via HTTP) and sends quote requests to the Kafka broker. Two main components compose the application:

• QuoteProducer generates uniquely identified quote requests and sends them to the Kafka topic quote-requests. It also consumes the Kafka topic quotes and relays received messages to the browser using Server-Sent Events.
• quotes.html sends quote requests to the previous endpoint and updates quotes with received prices.

Processor

The processor application receives quote requests from Kafka, processes them, and writes results into the quotes Kafka topic. The application has one main class:

• QuoteProcessor consumes quote request ids from the quote-requests Kafka topic and responds back to the quotes topic with a Quote object containing a random price.

The connection to Kafka is configured in the src/main/resources/application.properties file.

Running the application in Docker

To run the application in Docker, first make sure that both services are built:

mvn package

Then launch Docker Compose:

docker-compose up

This will create a single-node Kafka cluster and launch both applications.

Running in native

You can compile the application into a native binary using:

mvn package -Dnative

As you are running in prod mode, you need a Kafka cluster.

If you have Docker installed, you can simply run:

export QUARKUS_MODE=native
docker-compose up --build

Alternatively, you can follow the instructions from the Apache Kafka web site.

Then run both applications respectively with:

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

and in another terminal:

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