浅尝 grpc

项目目录

demo_grpc/
├── client
│   └── main.go
├── go.mod
├── go.sum
├── protos
│   ├── helloworld.pb.go
│   └── helloworld.proto
└── server
    └── main.go

protos/helloworld.proto

syntax = "proto3";
package protos;
service HelloWorld {
  rpc SayHello (HelloRequest) returns (HelloResponse) {}
}
message HelloRequest {
  string name = 1;
}
message HelloResponse {
  string message = 1;
}

编译protobuf

protoc --go_out=plugins=grpc:. protos/helloworld.proto

server/main.go

package main

import (
	"context"
	pb "github/YngwieWang/prepare/demo_grpc/protos"
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
	"log"
	"net"
)

const grpcPort = ":50051"

type Server struct {}

func(s *Server) SayHello(ctx context.Context, in *pb.HelloRequest)(*pb.HelloResponse, error){
	return &pb.HelloResponse{Message: "Hello " + in.Name}, nil
}

func main() {
	listen, err := net.Listen("tcp", grpcPort)
	if err!=nil{
		log.Printf("failed to listen: %v", err)
		return
	}

	grpcServer := grpc.NewServer()
	pb.RegisterHelloWorldServer(grpcServer, &Server{})
	reflection.Register(grpcServer)
	grpcServer.Serve(listen)
}

client/main.go

package main

import (
	"context"
	pb "github/YngwieWang/prepare/demo_grpc/protos"
	"google.golang.org/grpc"
	"log"
	"os"
	"time"
)

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

func main() {
	conn, err := grpc.Dial(address, grpc.WithInsecure())
	if err != nil {
		log.Fatalf("failed to connect to server: %v", err)
	}
	defer conn.Close()
	c := pb.NewHelloWorldClient(conn)

	name := defaultName
	if len(os.Args) > 1{
		name = os.Args[1]
	}
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	res, err := c.SayHello(ctx, &pb.HelloRequest{Name: name})
	if err != nil {
		log.Fatalf("coule not greet: %v", err)
	}
	log.Println(res.Message)
}

proto 文件定义了 HelloWorld 服务的接口方法 SayHello 和两个数据结构，分别是请求和响应。编译后生成 RegisterHelloWorldServer 方法和 helloWorldClient 结构体及其生成函数。

server 文件中定义了 SayHello 方法的具体实现并将一个监听指定端口的 Server 结构体通过 RegisterHelloWorldServer 方法注册为 grpc server。

client 文件中连接服务器，调用生成函数生成一个 helloWorldClient 客户端结构体，然后调用客户端结构体的 SayHello 方法取得执行结果。