Golang에서 gRPC 사용하기 (Client / Server)

 

해당 포스팅에선 protobuf 작성 및 해당 protobuf 컴파일하여 Client / Server Stub 생성 후 사용하는 예제까지 

진행 하려고 합니다. 

실습 환경

OS : MacOS
go version : go version go1.19 darwin/arm64
protoc --version : libprotoc 3.21.5

 

1.  gRPC 설치하기

go get -u google.golang.org/gpc
go get -u google.golang.org/grpc/cmd/protoc-gen-go-grpc
go install google.golang.org/grpc/cmd/protoc-gen-go-grpc

 

2. protobuf 작성

	syntax = "proto3";
	option go_package = ".;student";
	service StudentInfo {
	rpc addStudent(Student) returns (StudentNum);
	rpc getStudent(StudentNum) returns (Student);
	}
	message Student {
	string num = 1;
	string name = 2;
	string birth = 3;
	}
	message StudentNum {
	string num = 1;
	}

view raw studentInfo.proto hosted with ❤ by GitHub

 

3. protobuf 컴파일 및 스텁 생성

protoc -I protobuf/ protobuf/studentInfo.proto --go_out=./pb/student --go-grpc_out=./pb/student

 

4. Client 코드 작성

	package main
	import (
	"context"
	"google.golang.org/grpc"
	pb "grpcTest/pb/student"
	"log"
	"time"
	)
	const (
	address = "localhost:8081"
	)
	func main() {
	//Make connection
	conn, err := grpc.Dial(address, grpc.WithInsecure())
	if err != nil {
	log.Fatalf("connect err: %v", err)
	}
	defer conn.Close()
	//Make StudentInfo Client
	c := pb.NewStudentInfoClient(conn)
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	//Student Info
	studentInfo := &pb.Student{
	Name: "Heejin Kim",
	Birth: "1993-11-09",
	}
	//Add StudentInfo
	r, err := c.AddStudent(ctx, studentInfo)
	if err != nil {
	log.Fatalf("Fail AddStudent: %v", err)
	}
	log.Printf("Add Student num: %v ", r.Num)
	//Get Student Info
	student, err := c.GetStudent(ctx, &pb.StudentNum{Num: r.Num})
	if err != nil {
	log.Fatalf("Could not get product: %v", err)
	}
	log.Printf("Get Student %v", student.String())
	}

view raw main.go hosted with ❤ by GitHub

5. Server 코드 작성

	package main
	import (
	"context"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	pb "grpcTest/pb/student"
	"log"
	"net"
	"strconv"
	)
	const (
	port = ":8081"
	)
	type server struct {
	studentMap map[string]*pb.Student
	pb.UnimplementedStudentInfoServer
	}
	func (s *server) AddStudent(ctx context.Context, in *pb.Student) (*pb.StudentNum, error) {
	if s.studentMap == nil {
	s.studentMap = make(map[string]*pb.Student)
	}
	in.Num = strconv.Itoa(len(s.studentMap) + 1)
	s.studentMap[in.Num] = in
	log.Printf("Student %v : %v - Added.", in.Num, in.Name)
	return &pb.StudentNum{Num: in.Num}, status.New(codes.OK, "").Err()
	}
	func (s *server) GetStudent(ctx context.Context, in *pb.StudentNum) (*pb.Student, error) {
	student, exists := s.studentMap[in.Num]
	if exists && student != nil {
	log.Printf("Student %v : %v - Retrieved.", student.Num, student.Name)
	return student, status.New(codes.OK, "").Err()
	}
	return nil, status.Errorf(codes.NotFound, "Not Found Student.", in.Num)
	}
	func main() {
	lis, err := net.Listen("tcp", port)
	if err != nil {
	log.Fatalf("failed to listen: %v", err)
	}
	s := grpc.NewServer()
	pb.RegisterStudentInfoServer(s, &server{})
	if err := s.Serve(lis); err != nil {
	log.Fatalf("failed to serve: %v", err)
	}
	}

view raw main.go hosted with ❤ by GitHub

 

6. 실행 예제

Client

Server