Apache Kafka is an open source distributed data streaming platform that can process, publish, store, and subscribe to streams of data in real time developed by LinkedIn and Apache. It can handle data streams from many sources and deliver them to many consumers.

This is a Java Spring Boot application that demonstrates how to use Apache Kafka to produce and consume dummy location data. Many tech giants like Uber, Zomato etc. use Apache Kafka as a datahub for continuous location update of the cabs or delivery partner(in the case of food delivery companies) ans then pass it on to the end user.

1. Prerequisites:

   • Java 11 or higher
   • Apache Kafka (installation instructions: Apache Kafka Quickstart)

2. Useful commands:

   • To Start the Zookeeper and Kafka server using following commands

     bin\windows\zookeeper-server-start.bat config\zookeeper.properties
     bin\windows\kafka-server-start.bat config\server.properties

   • To create Kafka topic named location-update-topic:

   bin\windows\kafka-topics.bat --create --topic location-update-topic --bootstrap-server localhost:9092

   • To start the Producer on this topic:

     bin\windows\kafka-console-producer.bat --topic location-update-topic --bootstrap-server localhost:9092

   • To start the Consumer on this topic:

     bin\windows\kafka-console-consumer.bat --topic location-update-topic --from-beginning --bootstrap-server localhost:9092

   • Or you can directly run the Spring Boot application to register the producer and consumer for the same topic.

3. Producing and Consuming Data:

   • The producer endpoint (/update) generates and sends 200,000 sample location data entries to the Kafka topic location-data-topic.
   • The consumer consumes messages from the location-data-topic topic and logs them to the console.
   • You can simultaneously view this from console as well.

• src/main/java/com/deliveryboy/service/: Contains the service class for producing location data.
• src/main/java/com/deliveryboy/controller/: Contains the controller class for exposing the REST Endpoint.
• src/main/java/com/deliveryboy/config/: Contains the Kafka configuration class.
• src/main/resources/: Contains application properties and Kafka configuration. Similarly for Consumer ther are similar files

Kafka configurations can be modified in src/main/resources/application.properties.

• Access the producer endpoint at http://localhost:8080/location/update and hit POST request to start producing data.
• Check the console logs to see the consumed data.