Example of RPC with golang

go-rpc-hello-world.go

package main

import (
	"errors"
	"log"
	"net"
	"net/rpc"
	"strconv"
	"sync"
	"time"
)

// Response - the response object
type Response struct {
	Message string
}

// Request - the RPC request object
type Request struct {
	Name string
}

// Handler - the struct to hold the handlers for the requests
type Handler struct {
	Name string
}

func (h *Handler) Execute(req Request, res *Response) (err error) {
	if req.Name == "" {
		err = errors.New("A name must be specified")
		return
	}

	res.Message = "Hello " + req.Name
	return
}

var (
	HandlerName = "Handler"
	port        = 8080
	addr        = "127.0.0.1:" + strconv.Itoa(port)
	request     = &Request{Name: "John"}
	response    = new(Response)
)

func main() {
	log.Println("Starting...")

	var wg sync.WaitGroup

	wg.Add(1)
	go func() {
		defer wg.Done()
		Server()

	}()
	time.Sleep(time.Second)
	wg.Add(1)
	go func() {
		defer wg.Done()
		Client()

	}()

	wg.Wait()
}

func Client() {
	log.Println("Starting Client")

	client, err := rpc.Dial("tcp", addr)
	if err != nil {
		log.Fatal(err)
	}
	defer client.Close()
	log.Println("Client Dial ", addr)

	// Call the specific method in handler name
	err = client.Call(HandlerName+".Execute", request, response)
	if err != nil {
		log.Fatal(err)
	}

	log.Println(response.Message)
}

func Server() {
	log.Println("Starting Server")
	server := rpc.NewServer()

	err := server.RegisterName(HandlerName, &Handler{})
	if err != nil {
		log.Fatal(err)
	}
	log.Println("Register Handler ")

	listener, err := net.Listen("tcp", addr)
	if err != nil {
		log.Fatal(err)
	}
	log.Println("Listen on port ", port)
	defer listener.Close()

	for {
		server.Accept(listener)
	}
}