gRPC( Remote Procedure Call by Google)

proto 文件定义服务以及消息类型:
syntax = "proto3";
...
package helloworld;

// The greeting service definition.
service Greeter {
// Sends a greeting // 提供|开放 sayHello 接口 // 接口逻辑写在服务中
rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
string name = 1;
}

// The response message containing the greetings
message HelloReply {
string message = 1;
}

开启服务器:
var PROTO_PATH = __dirname + '/../../protos/helloworld.proto';
var hello_proto = grpc.load(PROTO_PATH).helloworld;
/**
* Implements the SayHello RPC method.
*/
function sayHello(call, callback) {
callback(null, {message: 'Hello ' + call.request.name});
}

/**
* Starts an RPC server that receives requests for the Greeter service at the
* sample server port
*/
var server = new grpc.Server();
server.addProtoService(hello_proto.Greeter.service, {sayHello: sayHello}); // 这里定义了接口还要在proto文件中rpc提供
server.bind('0.0.0.0:50051', grpc.ServerCredentials.createInsecure());
server.start();

开启客户端:
...
var client = new hello_proto.Greeter('localhost:50051', grpc.credentials.createInsecure());
client.sayHello({name: 'world'}, function(err, response) {
console.log('Greeting:', response.message);
});