gRPC Server Streaming

gRPC Server Streaming Server and Client.

Install requirements

build.gradle

def grpcVersion = 'x.x.x'
dependencies {
    implementation 'org.hertsstack:herts-core:1.1.0'
    implementation 'org.hertsstack:herts-rpc:1.1.0'
    implementation 'org.hertsstack:herts-rpc-client:1.1.0'
    
    implementation "io.grpc:grpc-protobuf:${grpcVersion}"
    implementation "io.grpc:grpc-services:${grpcVersion}"
    implementation "io.grpc:grpc-stub:${grpcVersion}"
}

Quick start

Shared implementation

You can define interface of gRPC endpoint.
This interface uses by server and client.
Required @HertsRpcService and extends HertsService

※ Server Steaming Interface supports void method only. Also, Required StreamObserver on method parameter

ServerStreamingService.java

import io.grpc.stub.StreamObserver;

@HertsRpcService(value = HertsType.ServerStreaming)
public interface ServerStreamingService extends HertsService {
    
    void foo(String id, final StreamObserver<Foo> responseObserver);

}

Implementation of Interface.
You should implement extends HertsServiceServerStreaming<T>. Generics is your interface.

UnaryServiceImpl.java


public class ServerStreamingServiceImpl extends HertsServiceServerStreaming<ServerStreamingService> implements ServerStreamingService {
    
    @Override
    public void foo(String id, final StreamObserver<Foo> responseObserver) {
        for (int i = 1; i <= 10; i++) {
            Foo foo = new Foo();
            foo.setName("name_" + id + "_" + i);
            responseObserver.onNext(foo);
        }
        responseObserver.onCompleted();
    }
    
}

Server implementation

Start gRPC ServerStreaming Server

public class Main {
  
    public static void main(String[] args) {

        // Inject other class if need it
        var service = new ServerStreamingServiceImpl();

        HertsRpcServerEngine engine = HertsRpcServerEngineBuilder.builder()
                .registerHertsRpcService(service)
                .build();

        engine.start();
    }
}

Run server. Default port is 9999

java -jar {Your Jar path}
2023-06-15 13:18:35.747 INFO org.hertstack.rpc.ReflectMethod printMethodName ServerStreamingService stats
2023-06-15 13:18:35.757 INFO org.hertstack.rpc.ReflectMethod printMethodName ServerStreamingService/foo
2023-06-15 13:18:35.946 INFO org.hertstack.rpc.HertsRpcServerEngineBuilder start Started Herts RPC server. gRPC type ServerStreaming Port 9999

Client implementation

Start gRPC Unary Client

public class Main {
  
    public static void main(String[] args) {

        HertsRpcClient client = HertsRpcClientBuilder
                .builder("localhost")
                .secure(false)
                .registerHertsRpcServiceInterface(ServerStreamingService.class)
                .connect();

        ServerStreamingService service = client.createHertsRpcService(ServerStreamingService.class);
        
        service.foo("ABC_id", new StreamObserver<Foo>() {
            @Override
            public void onNext(Foo res) {
                System.out.println(res.getName());
            }

            @Override
            public void onError(Throwable t) {
                t.printStackTrace();
            }

            @Override
            public void onCompleted() {
                System.out.println("Completed");
            }
        });
    }
}