Table of contents
What is gRPC:
gRPC is a modern, high-performance, and lightweight open source framework for building scalable, distributed systems. It is a highly efficient and low-latency framework, designed to work over a variety of transport layers, such as TCP, HTTP/2, or even unencrypted UDP.
gRPC supports multiple programming languages, such as C++, Java, Python, Go, and Ruby, so it can be used to build a wide range of applications and services.
To know more about gRPC and REST API comparison here is my blog link:
What is Spring Boot:
Spring Boot is a popular open source framework for building web applications and microservices using the Spring framework. Some key features and benefits of Spring Boot: Auto-configuration, Embedded Servers, Standalone application, Ease of integration with other OSS projects like spring cloud, Spring data, Apache camel, Kafka etc.
Here is an example of a gRPC service implemented using Spring Boot:
Step 1: Start by adding the gRPC and Spring Boot dependencies to your build file:
dependencies {
implementation 'io.grpc:grpc-netty-shaded:1.32.1'
implementation 'io.grpc:grpc-protobuf:1.32.1'
implementation 'io.grpc:grpc-stub:1.32.1'
implementation 'org.springframework.boot:spring-boot-starter-grpc'
}
Step 2: define your gRPC service contract using Protocol Buffers. For example, let’s say you have a service named employeeService with a single method named info() that takes a EmployeeRequest message and returns a EmployeeResponse message. Your .proto file might look like below
syntax = "proto3";
service EmployeeService {
rpc greet (EmployeeRequest) returns (EmployeeResponse);
}
message EmployeeRequest {
string name = 1;
}
message EmployeeResponse {
string message = 1;
}
Step 3: After this, use the protoc compiler to generate the gRPC service and message classes for your service. This could be jar file which can be used as dependency in service and client project
Step 4: Create the implementation of service, this will contain the actual logic to handle the incoming requests.
@GRpcService
public class EmployeeServiceImpl extends EmployeeServiceGrpc.EmployeeServiceImplBase {
@Override
public void info(EmployeeRequest request, StreamObserver responseObserver) {
String employeeId = request.getid();
//Logic to fetch employee details from DB or other service
EmployeeDetails empDetails = Service.getDetails(employeeId);
String message = "Hello, " + empDetails.getName();
EmployeeResponse response = EmployeeResponse.newBuilder().setMessage(message)
.setEmployeeDetails(empDetails).build();
responseObserver.onNext(response);
responseObserver.onCompleted();
}
}
Step 5: Finally, in your Spring Boot application, add the @EnableGRpcServer annotation to enable the gRPC server.
@SpringBootApplication
@EnableGRpcServer
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Step 6: Run your spring boot application, and it will start the gRPC server on port 6565 by default.
PS: This is just a basic example of how to implement a gRPC service using Spring Boot, there are many other considerations and configurations that may be necessary depending on the specific requirements of your application.
References: