Spring Boot Load Balancer

This project demonstrates the implementation of a basic load balancer in Java Spring Boot. The load balancer supports two types of load balancing algorithms: Round Robin and IP Hash. This application is designed to be scalable, fault-tolerant, and robust.

Project Structure

The project is structured as follows:

src/
├── main/
│   ├── java/
│   │   └── com/
│   │       └── load/
│   │           └── balancer/
│   │               ├── BalancerApplication.java
│   │               ├── config/
│   │               │   ├── LoadBalancerConfig.java
│   │               ├── service/
│   │               │   ├── LoadBalancerService.java
│   │               │   ├── RoundRobinLoadBalancer.java
│   │               │   ├── IPHashLoadBalancer.java
│   └── resources/
│       └── application.yml
└── test/
    └── java/
        └── com/
            └── load/
                └── balancer/
                    └── BalancerApplicationTests.java

Code Explanation

1. BalancerApplication.java

This is the main entry point for the Spring Boot application.

• @SpringBootApplication: Marks the main class of the Spring Boot application, enabling auto-configuration and component scanning.
• SpringApplication.run(BalancerApplication.class, args);: Launches the Spring Boot application.

2. LoadBalancerConfig.java

This configuration class sets up the load balancing strategies.

• @Configuration: Indicates that the class can be used by the Spring IoC container as a source of bean definitions.
• @Bean: Marks methods that produce beans to be managed by Spring.

3. LoadBalancerService.java

This interface defines the contract for different load balancing strategies.

• getServer(List<String> servers): Method signature for selecting a server from a list.

4. RoundRobinLoadBalancer.java

Implements the Round Robin load balancing algorithm.

• Uses AtomicInteger to manage the current position in the server list.

5. IPHashLoadBalancer.java

Implements the IP Hash load balancing algorithm.

• Hashes the client's IP address to determine the server index.

6. application.yml

Contains the configuration for the Spring Boot application.

• server.port: Configures the server to run on port 8080.
• spring.cloud.loadbalancer.instances: Defines the backend instances for load balancing.

Running the Application

Steps to Run

1. Build the Project:

   ./gradlew clean build

2. Run the Application:

   ./gradlew bootRun