RPC简介和grpc的使用

import "myproject/other_protos.proto";    // 导入其他 proto文件
syntax = "proto3"; // 指定proto版本
package hello;     // 指定默认包名
// 指定golang包名
option go_package = "hello";
message SearchRequest 
{
  required string query = 1;        // 必须赋值字段
  optional int32 page_number = 2 [default = 10];    // 可选字段
  repeated int32 result_per_page = 3; // 可重复字段 
}
message SearchResponse 
{
  message Result    // 嵌套定义
  {
    required string url = 1;
    optional string title = 2;
    repeated string snippets = 3;
  }
  repeated Result result = 1;
}
message SomeOtherMessage 
{
  optional SearchResponse.Result result = 1;  // 使用其他消息的定义
}
service List{       // 定义gRPC服务接口
  rpc getList(SearchRequest) returns (SearchResponse);
}

// 插件自动生成gRPC骨架和存根
protoc --go_out=plugins=grpc: ./ *.proto

syntax = "proto3";
package hello;
// 第一个分割参数，输出路径；第二个设置生成类的包路径
option go_package = "./proto/hello";
// 设置服务名称
service Greeter {
  // 设置方法
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}
// 请求信息用户名.
message HelloRequest {
  string name = 1;
}
// 响应信息
message HelloReply {
  string message = 1;
}

package main
import (
  "context"
  "flag"
  "fmt"
  "log"
  "net"
  "google.golang.org/grpc"
  pb "mygrpc/proto/hello"
)
var (
  port = flag.Int("port", 50051, "The server port")
)
type server struct {
  pb.UnimplementedGreeterServer
}
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() {
  flag.Parse()
  lis, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))
  if err != nil {
    log.Fatalf("failed to listen: %v", err)
  }
  // 开启rpc
  s := grpc.NewServer()
  // 注册服务
  pb.RegisterGreeterServer(s, &server{})
  log.Printf("server listening at %v", lis.Addr())
  if err := s.Serve(lis); err != nil {
    log.Fatalf("failed to serve: %v", err)
  }
}

package main
import (
  "context"
  "flag"
  "log"
  "time"
  "google.golang.org/grpc"
  "google.golang.org/grpc/credentials/insecure"
  pb "mygrpc/proto/hello" // 引入编译生成的包
)
const (
  defaultName = "world"
)
var (
  addr = flag.String("addr", "localhost:50051", "the address to connect to")
  name = flag.String("name", defaultName, "Name to greet")
)
func main() {
  flag.Parse()
  // 与服务建立连接.
  conn, err := grpc.Dial(*addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
  if err != nil {
    log.Fatalf("did not connect: %v", err)
  }
  defer conn.Close()
  // 创建指定服务的客户端
  c := pb.NewGreeterClient(conn)
  // 连接服务器并打印出其响应。
  ctx, cancel := context.WithTimeout(context.Background(), time.Second)
  defer cancel()
  // 调用指定方法
  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())
}