User-Driver System with Spring Boot and Kafka

In modern applications, real-time data streaming is a critical feature for services like cab booking, food delivery, and more. In this blog, we’ll build a User Driver System using Spring Boot and Apache Kafka. This system will simulate real-time communication between drivers (producers) and users (consumers).

By the end, you’ll have a distributed system where:

• Drivers update their location in real-time.

• Users receive these updates instantly through Kafka.

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🔎 1. Introduction: What are we building and why?

The User Driver System consists of two microservices:

• Driver Service: Publishes cab location updates to a Kafka topic.

• User Service: Consumes location updates from the Kafka topic.

Key features:

• Real-Time Location Updates: Drivers send location updates (latitude, longitude) every second.

• Kafka Integration: Ensures reliable and scalable communication between services.

• Microservices Architecture: Two independent Spring Boot applications.

This project is ideal for:

• Learning Spring Boot Kafka integration.

• Building real-time systems with distributed microservices.

• Understanding producer-consumer communication in Kafka.

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📚 2. Architecture Overview

Components:

1. Kafka Broker: The central hub for message streaming.

2. Driver Service (Producer):

   • Sends location updates to the Kafka topic.

3. User Service (Consumer):

   • Listens to location updates from the Kafka topic.

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💻 3. Driver Service

The Driver Service simulates a driver sending periodic location updates to Kafka.

Kafka Configuration

The KafkaConfig class creates a Kafka topic named cab-location where location updates will be published.

@Configuration
public class KafkaConfig {

    @Bean
    public NewTopic topic() {
        return TopicBuilder.name(AppConstant.CAB_LOCATION).build();
    }
}

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Controller

The CabLocationController simulates location updates. It sends random coordinates to the Kafka topic every second.

@RestController
@RequestMapping("/location")
public class CabLocationController {

    @Autowired
    private CabLocationService cabLocationService;

    @PutMapping
    public ResponseEntity updateLocation() throws InterruptedException {
        int range = 100;
        while (range > 0) {
            cabLocationService.updateLocation(Math.random() + "," + Math.random());
            Thread.sleep(1000);
            range--;
        }
        return new ResponseEntity(Map.of("message", "location updated"), HttpStatus.OK);
    }
}

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Service

The CabLocationService sends location updates to the Kafka topic.

@Service
public class CabLocationService {

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;

    public void updateLocation(String location) {
        kafkaTemplate.send("cab-location", location);
    }
}

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Driver Service Dependencies

The pom.xml includes dependencies for Spring Boot Kafka and web modules.

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.kafka</groupId>
        <artifactId>spring-kafka</artifactId>
    </dependency>
</dependencies>

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📡 4. User Service

The User Service listens to location updates from the Kafka topic and prints them to the console.

Kafka Listener

The LocationService class consumes messages from the cab-location topic.

@Service
public class LocationService {

    @KafkaListener(topics = "cab-location", groupId = "user-group")
    public void cabLocation(String location) {
        System.out.println(location);
    }
}

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User Service Dependencies

The pom.xml includes dependencies for Kafka consumption.

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.kafka</groupId>
        <artifactId>spring-kafka</artifactId>
    </dependency>
</dependencies>

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🛠 5. How to Run the System

Prerequisites:

• Apache Kafka running locally.

• Java 21 installed.

Steps:

1. Start Kafka Broker:

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

2. Start Driver Service:

    cd cab-book-driver
    ./mvnw spring-boot:run
   

3. Start User Service:

    cd cab-book-user
    ./mvnw spring-boot:run
   

4. Update Locations: Send a PUT request to http://localhost:8080/location to start sending location updates.

5. View Updates: Check the User Service console for real-time location updates.

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🌟 6. GitHub Repository

The complete source code for this project is available on GitHub. Feel free to clone, fork, or contribute to the repository:

GitHub Link: User Driver with Kafka

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🌟 7. Conclusion

This project demonstrates how to use Apache Kafka with Spring Boot for real-time data streaming. You’ve learned:

• How to build producers and consumers with Kafka.

• How to integrate Kafka into Spring Boot applications.

• How to simulate real-time communication in a distributed system.

What’s Next?

• Add a database to store historical location data.

• Implement error handling for Kafka messages.

• Build a UI dashboard to display real-time locations on a map.

Happy coding! 🚕🚀