Scalable, event-driven coffee shop

How to use event sourcing in several services with an event-driven architecture, Apache Kafka and Java EE.

Run

1. Start Apache Kafka brokers, e.g. using Docker compose: wurstmeister/kafka-docker. Configure the KAFKA_ADVERTISED_HOST_NAME to your corresponding IP address.

2. Configure each of the kafka.properties files with bootstrap.servers=<your-IP>:9092.

3. Build and run the individual instances. On each of the orders/, beans/ and barista/ directories, execute build-run-local.sh. This builds the Gradle project, builds the Docker image and starts a new instance of the given service.

Usage

The following will demonstrate the usage of the HTTP endpoints and example responses.

1. In order to create coffee orders you have to add beans to the beans storage first:

$> curl http://localhost:8002/beans/resources/beans -i -XPOST \
  -H 'content-type: application/json' \
  -d '{"beanOrigin": "Colombia", "amount": 10}'

HTTP/1.1 204 No Content
X-Powered-By: Undertow/1
Server: WildFly/10
Date: Fri, 17 Nov 2017 20:49:26 GMT

1. Check the creation of the beans:

$> curl http://localhost:8002/beans/resources/beans

{"Colombia":10}

1. Create a new coffee order:

$> curl http://localhost:8001/orders/resources/orders/ -i -XPOST \
  -H 'Content-type: application/json' \
  -d '{"beanOrigin": "Colombia", "coffeeType": "Espresso"}'

HTTP/1.1 202 Accepted
Connection: keep-alive
X-Powered-By: Undertow/1
Server: WildFly/10
Location: http://localhost:8001/orders/resources/orders/c099c158-b748-4115-bed3-7b5dfff70771
Content-Length: 0
Date: Fri, 17 Nov 2017 20:51:16 GMT

1. Check the creation of the coffee order using your Location header, for example:

$> curl http://localhost:8001/orders/resources/orders/c099c158-b748-4115-bed3-7b5dfff70771

{"status":"started","type":"espresso","beanOrigin":"Colombia"}