vertx-kafka-consumer-producer project

This project illustrates how you can interact with Apache Kafka using vert.x

Tutorial used for vert.x Client

https://vertx.io/docs/vertx-kafka-client/java/

Steps

1. Download Kafka: https://kafka.apache.org/downloads
2. Start zookeeper ./bin/zookeeper-server-start.sh config/zookeeper.properties
3. Start kafka ./bin/kafka-server-start.sh config/server.properties
4. Create Topic ./bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic prices
5. Start the Application (quarkus:dev recommended since this is only a demo project)
6. Open the prices.html. The site should show changing prices.

Anatomy

In addition to the prices.html page, the application is composed by 4 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.
• KafkaConfiguration - used to configure and initialize Kafka

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

Running the application in dev mode

You can run your application in dev mode that enables live coding using:

./mvnw quarkus:dev

Packaging and running the application

The application can be packaged using ./mvnw package. It produces the vertx-kafka-consumer-producer-1.0-SNAPSHOT-runner.jar file in the /target directory. Be aware that it’s not an über-jar as the dependencies are copied into the target/lib directory.

The application is now runnable using java -jar target/vertx-kafka-consumer-producer-1.0-SNAPSHOT-runner.jar.

Creating a native executable

You can create a native executable using: ./mvnw package -Pnative.

Or, if you don't have GraalVM installed, you can run the native executable build in a container using: ./mvnw package -Pnative -Dquarkus.native.container-build=true.

You can then execute your native executable with: ./target/vertx-kafka-consumer-producer-1.0-SNAPSHOT-runner

If you want to learn more about building native executables, please consult https://quarkus.io/guides/building-native-image.

About Quarkus

This project uses Quarkus, the Supersonic Subatomic Java Framework.

If you want to learn more about Quarkus, please visit its website: https://quarkus.io/ .

Disclaimer

This is just a demo project. There are some errors left in this project. For example, when you close the prices.html you will not see the changing prices when opening it again. You have to restart the Quarkus-Application first before reopening.