Coffeeshop Demo with Quarkus

This directory contains a set of demo around reactive in Quarkus with Kafka. It demonstrates the elasticity and resilience of the system.

Build

mvn clean package

Prerequisites

Install Kafka locally for the Kafka tools e.g.

brew install kafka

Run Kafka with:

docker-compose up

In case of previous run, you can clean the state with

docker-compose down
docker-compose rm

Then, create the orders topic with ./create-topics.sh

Run the demo

You need to run:

• the coffee shop service
• the HTTP barista
• the Kafka barista

Im 3 terminals:

cd coffeeshop-service
mvn compile quarkus:dev

cd barista-http
java -Dbarista.name=tom -jar target/barista-http-1.0-SNAPSHOT-runner.jar

cd barista-kafka
mvn compile quarkus:dev

Execute with HTTP

The first part of the demo shows HTTP interactions:

• Barista code: me.escoffier.quarkus.coffeeshop.BaristaResource
• CoffeeShop code: me.escoffier.quarkus.coffeeshop.CoffeeShopResource.http
• Generated client: me.escoffier.quarkus.coffeeshop.http.BaristaService

Order coffees with:

while [ true ]
do
http POST :8080/http product=latte name=clement
http POST :8080/http product=expresso name=neo
http POST :8080/http product=mocha name=flore
done

Stop the HTTP Barista, you can't order coffee anymore.

Execute with Kafka

• Barista code: me.escoffier.quarkus.coffeeshop.KafkaBarista: Read from orders, write to queue

• Bridge in the CoffeeShop: me.escoffier.quarkus.coffeeshop.messaging.CoffeeShopResource#messaging just enqueue the orders in a single thread (one counter)

• Get prepared beverages on me.escoffier.quarkus.coffeeshop.dashboard.BoardResource and send to SSE

• Open browser to http://localhost:8080/

• Order coffee with:

http POST :8080/messaging product=latte name=clement
http POST :8080/messaging product=expresso name=neo
http POST :8080/messaging product=mocha name=flore

Baristas do breaks

1. Stop the Kafka barista
2. Continue to enqueue order

http POST :8080/messaging product=frappuccino name=clement
http POST :8080/messaging product=chai name=neo
http POST :8080/messaging product=hot-chocolate name=flore

1. On the dashboard, the orders are in the "IN QUEUE" state
2. Restart the barista
3. They are processed

2 baristas are better

1. Start a second barista with:

java -Dquarkus.http.port=9095 -Dbarista.name=tom -jar target/barista-kafka-1.0-SNAPSHOT-runner.jar

1. Order more coffee

http POST :8080/messaging product=frappuccino name=clement
http POST :8080/messaging product=chai name=neo
http POST :8080/messaging product=hot-chocolate name=flore
http POST :8080/messaging product=latte name=clement
http POST :8080/messaging product=expresso name=neo
http POST :8080/messaging product=mocha name=flore

The dashboard shows that the load is dispatched among the baristas.