Go gRPC sample

client.go

// これは試してないけどこんなかんじぽい
package main

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

	"google.golang.org/grpc"
	pb "google.golang.org/grpc/examples/helloworld/helloworld"
)

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

func main() {
	// Set up a connection to the server.
	conn, err := grpc.Dial(address, grpc.WithInsecure(), grpc.WithBlock())
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()
	c := pb.NewGreeterClient(conn)

	// Contact the server and print out its response.
	name := defaultName
	if len(os.Args) > 1 {
		name = os.Args[1]
	}
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	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())
}

command.md

// helloworld以下のdirにサーバー用のメソッドを自動生成
$ protoc helloworld.proto --go_out=plugins=grpc:helloworld
// grpcurlでレスポンスチェック
$ grpcurl -plaintext localhost:8080 Greeter.SayHello

helloworld.proto

syntax = "proto3";

service Greeter {
	rpc SayHello (HelloRequest) returns (HelloReply) {}
	rpc SayHelloAgain (HelloRequest) returns (HelloReply){}
}


message HelloRequest {
  string name = 1;
}


message HelloReply {
  string message = 1;
}

server.go

package main

import (
	"context"
	"fmt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
	"grpc.sample/helloworld"
	"log"
	"net"
)

type server struct {
	helloworld.UnimplementedGreeterServer
}

const port = ":8080"

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

	s := grpc.NewServer()
	helloworld.RegisterGreeterServer(s, &server{})
	reflection.Register(s)
	fmt.Println("connect!")
	if err := s.Serve(lis); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

func (s *server) SayHello(ctx context.Context, in *helloworld.HelloRequest) (*helloworld.HelloReply, error) {
	return &helloworld.HelloReply{Message: "Hello" + in.GetName()}, nil
}