如何在Golang中使用gRPC实现基础的服务端和客户端

$ go get -u google.golang.org/grpc
$ go get -u GitHub.com/golang/protobuf/protoc-gen-go

syntax = "proto3";

package greet;

service GreetService {
  rpc SayHello (HelloRequest) returns (HelloResponse) {}
}

message HelloRequest {
  string name = 1;
}

message HelloResponse {
  string message = 1;
}

$ protoc -I greet/ greet/greet.proto --go_out=plugins=grpc:greet

package main

import (
    "context"
    "log"
    "net"

    "google.golang.org/grpc"
    pb "path/to/greet"
)

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() {
    lis, err := net.Listen("tcp", ":50051")
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    }
    s := grpc.NewServer()
    pb.ReGISterGreetServiceServer(s, &server{})
    if err := s.Serve(lis); err != nil {
        log.Fatalf("failed to serve: %v", err)
    }
}

package main

import (
    "log"
    "os"
    "context"
    "google.golang.org/grpc"
    pb "path/to/greet"
)

func main() {
    address := "localhost:50051"
    if len(os.Args) > 1 {
        address = os.Args[1]
    }
    conn, err := grpc.Dial(address, grpc.WithInsecure())
    if err != nil {
        log.Fatalf("couldn't connect: %v", err)
    }
    defer conn.Close()

    c := pb.NewGreetServiceClient(conn)

    name := "world"
    if len(os.Args) > 2 {
        name = os.Args[2]
    }
    r, err := c.SayHello(context.Background(), &pb.HelloRequest{Name: name})
    if err != nil {
        log.Fatalf("error: %v", err)
    }
    log.Printf("Greeting: %s", r.Message)
}

$ go run greet_server.go

$ go run greet_client.go
Greeting: Hello world