Bed Service (Event sourcing example)

Pre-requisites

• JDK 1.8
• Kafka (Latest version)

Steps:

• Start zookeeper and kafka broker by executing the following commands from kafka directory (in two separate terminals)

  bin/zookeeper-server-start.sh config/zookeeper.properties

  bin/kafka-server-start.sh config/server.properties

• Build the application by running ./gradlew clean build from inside the cloned repository

• Run the application by running java -jar build/libs/Bedservice-0.0.1-SNAPSHOT.jar

• Navigate to the URL localhost:8080/beds and verify that it returns an empty collection

• Add a bed by running the following at a terminal window (you can also use postman)

  curl -X POST -H "Content-Type: application/json" --data '{"id":"1234","location":"first floor general ward"}' "http://localhost:8080/create

• Navigate to the URL localhost:8080/beds and verify that it returns the bed that you just created with status Available

• Add a few more beds

• Book a bed by going to the kafka directory and executing

  bin/kafka-console-producer.sh \
  --broker-list localhost:9092 \
  --topic bedRequestTopic \
  --property "parse.key=true" \
  --property "key.separator=:"

  and then entering 1234:{"aggregateId": "1234", "occupantId":"XYZ", "type":"bookBed"} at the prompt

• Navigate to the URL localhost:8080/beds and verify that the status of the corresponding bed has changed to Booked.

• Verify that attempting to book the same bed again logs an error in the application console.

• In case you want to see the events getting published to the kafka topic, execute the following command from the kafka directory

  bin/kafka-console-consumer.sh --topic bedEvents --bootstrap-server localhost:9092 --property print.key=true --from-beginning