Hello World

//  - proto/example.proto - 
syntax = "proto3";

option go_package = "proto;helloworld_proto";

package ua.made.helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  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; }

//  - main.go - 
// Package main implements a server for Greeter service.
package main

import (
	"context"
	"fmt"
	"log"
	"net"

	pb "github.com/butuzov/sandbox/grpc/helloworld/proto"
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
)

// server is used to implement helloworld.GreeterServer.
type server struct {
	pb.UnimplementedGreeterServer
}

// SayHello implements helloworld.GreeterServer
func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
	log.Printf("Received: %v", in.GetName())
	return &pb.HelloReply{Message: "Hello " + in.GetName()}, nil
}

func main() {
	listener, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}
	fmt.Println("listening on", listener.Addr().String())

	s := grpc.NewServer()
	pb.RegisterGreeterServer(s, &server{})

	reflection.Register(s)

	log.Fatalf("failed to serve: %v", s.Serve(listener))
}