advanced-go-programming-book/examples/ch4-04-grpc/basic/client/main.go

package main

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

	"google.golang.org/grpc"
)

type HelloServiceImpl struct{}

func (p *HelloServiceImpl) Hello(ctx context.Context, args *String) (*String, error) {
	reply := &String{Value: "hello:" + args.GetValue()}
	return reply, nil
}

func main() {
	go startGrpcServer()
	doClientWork()
}

func startGrpcServer() {
	grpcServer := grpc.NewServer()
	RegisterHelloServiceServer(grpcServer, &HelloServiceImpl{})

	lis, err := net.Listen("tcp", ":1234")
	if err != nil {
		log.Fatal(err)
	}

	grpcServer.Serve(lis)
}

func doClientWork() {
	conn, err := grpc.Dial("localhost:1234", grpc.WithInsecure())
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()

	client := NewHelloServiceClient(conn)
	reply, err := client.Hello(context.Background(), &String{Value: "hello"})
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(reply.GetValue())
}