Gateway

Herts gRPC Gateway

Herts supports a gateway for gRPC.
Http Client -> Http Server -> gRPC Server.

Install requirements

Gateway supports to connect gRPC with unary server only.

build.gradle

def grpcVersion = 'x.x.x'
dependencies {
    implementation 'org.hertsstack:herts-gateway:1.0.0'
    implementation 'org.hertsstack:herts-http:1.1.0'
    implementation 'org.hertsstack:herts-http-client:1.1.0'
    implementation 'org.hertsstack:herts-metrics:1.1.0'

    implementation "io.grpc:grpc-protobuf:${grpcVersion}"
    implementation "io.grpc:grpc-services:${grpcVersion}"
    implementation "io.grpc:grpc-stub:${grpcVersion}"
}

Quick start

gRPC Server

gRPC server interface definition.


@HertsRpcService(value = HertsType.Unary)
public interface UserService extends HertsService {

  Map<String, String> getUser(String id);
}

Implementation class of interface.

public class UserServiceImpl extends HertsServiceUnary<UserService> implements UserService {

  public UserServiceImpl() {
  }

  public Map<String, String> getUser(String id) {
    return Collections.singletonMap("name", "Foo");
  }
}

Start gRPC unary server.

public class Main {

  public static void main(String[] args) {
    HertsMetricsSetting metrics = HertsMetricsSetting.builder()
        .isRpsEnabled(true)
        .isLatencyEnabled(true)
        .build();

    UserService userService = new UserServiceImpl();

    HertsRpcServerEngine engine = HertsRpcServerEngineBuilder.builder()
        .registerHertsRpcService(userService)
        .enableMetrics(metrics)
        .build();

    engine.start();
  }
}

Gateway Server

Start a gateway by UserService interface.
Gateway is automated a binding interface.

public class Main {

  public static void main(String[] args) {
    HertsGatewayEngine engine = HertsGatewayBuilder.builder()
        .gatewayPort(9876)
        .rpcHost("localhost")
        .rpcPort(9999)
        .registerHertsRpcService(UserService.class, null)
        .build();

    engine.start();
  }
}

Gateway Client

You can call Gateway server by HertsHttpClient package.
You should call gatewayApi(true) on builder

public class Main {
  public static void main(String[] args) {
    
    HertsHttpClient client = HertsHttpClient
        .builder("localhost")
        .registerHertsService(UserService.class)
        .secure(false)
        .gatewayApi(true) 
        .port(9876)
        .build();

    UserService service = client.createHertsService(UserService.class);
    var res = service.getUser("id");
    System.out.println(res);
  }
}