golang grpc demo

1、安装 gRPC 和 Protobuf

protobuf 安装链接：https://liqiang.io/post/install-protobuf-in-centos-f0a9b926

protoc-gen-go 二进制构建

git clone https://github.com/golang/protobuf.git
cd protobuf
go build protoc-gen-go/main.go -o /bin/protoc-gen-go

2、定义.proto 文件

mkdir helloworld
cd helloworld

#cat hello.proto
syntax = "proto3";

package helloworld;

option go_package = "./helloworld";

// 定义服务
service Greeter {
	// 定义方法
	rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// 定义请求参数
message HelloRequest {
	string name = 1;
}

// 定义响应参数
message HelloReply {
	string message = 1;
}

3、生成 golang 代码

cd ..
protoc -I helloworld/ helloworld/hello.proto --go_out=plugins=grpc:helloworld

4、实现服务器

cd helloworld

#cat server.go
package main

import (
	"context"
	"log"
	"net"

	"google.golang.org/grpc"

	pb "helloworld/helloworld" // 导入生成的代码
)

const (
	port = ":50051"
)

// 定义服务
type server struct {
	pb.UnimplementedGreeterServer
}

// 实现 SayHello 方法
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() {
	// 监听端口
	lis, err := net.Listen("tcp", port)
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}

	// 创建 grpc 服务
	s := grpc.NewServer()

	// 注册服务
	pb.RegisterGreeterServer(s, &server{})
	log.Printf("server listening at %v", lis.Addr())

	// 启动服务
	if err := s.Serve(lis); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

5、实现客户端

#cat client.go
package main

import (
	"context"
	"log"
	"os"
	"time"

	"google.golang.org/grpc"

	pb "helloworld/helloworld" // 导入生成的代码
)

const (
	address = "localhost:50051"
	defaultName = "world"
)

func main() {
	// 建立连接
	conn, err := grpc.Dial(address, grpc.WithInsecure(), grpc.WithBlock())
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()

	// 创建客户端
	c := pb.NewGreeterClient(conn)

	// 设置超时
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()

	// 构建请求
	name := defaultName
	if len(os.Args) > 1 {
		name = os.Args[1]
	}

	r, err := c.SayHello(ctx, &pb.HelloRequest{Name: name})
	if err != nil {
		log.Fatalf("could not greet: %v", err)
	}

	log.Printf("Greeting: %s", r.GetMessage())
}

6、运行示例

go mod init
go mod tidy
go mod vendor

# server
#go run server.go
2023/05/24 19:00:21 server listening at [::]:50051
2023/05/24 19:00:24 Received: world

# client
#go run client.go
2023/05/24 19:00:24 Greeting: Hello world