OpenFeign: A Declarative REST Client

OpenFeign is an open-source project initially developed by Netflix and now maintained by the open-source community. It simplifies the process of writing web services by providing a declarative approach to REST API consumption using the FeignClient interface.

Features

• Declarative REST Client: Write cleaner and more maintainable code by declaring interfaces.
• Integration Friendly: Ideal for consuming third-party APIs and microservice endpoints.
• Dynamic Implementation: Automatically creates dynamic implementations for declared FeignClient interfaces.

Dependencies

To use OpenFeign in your project, add the following dependency to your pom.xml file:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

Project Overview

This project demonstrates the use of OpenFeign in a microservice architecture with the following components:

Microservices

1. Employee Service
   • Manages employee-related data and operations.
2. Address Service
   • Handles address-related information for employees.

Getting Started

Prerequisites

• Java Development Kit (JDK 8 or above)
• Maven
• Spring Boot

Steps to Run the Project

1. Clone this repository.
2. Navigate to each service directory and build the project using:

   mvn clean install

3. Run each service using:

   mvn spring-boot:run

4. Test the endpoints using tools like Postman or cURL.

How OpenFeign Works

1. Declare a @FeignClient interface with the desired REST API endpoints.
2. OpenFeign dynamically generates the implementation at runtime.
3. Use the client as a Spring Bean in your services to make API calls effortlessly.

Example FeignClient Declaration

@FeignClient(name = "address-service", url = "http://localhost:8081")
public interface AddressClient {
    @GetMapping("/addresses/{id}")
    Address getAddressById(@PathVariable("id") Long id);
}

Benefits

• Reduces boilerplate code for REST API calls.
• Simplifies integration between microservices.

License

This project is licensed under the MIT License. See the LICENSE file for details.

---

Developed with ❤️ for simplifying microservice communication.