简单rpc应用

这里来介绍一个简单的rpc应用

首先我们安装需要的包

go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.26
go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.1

创建消息文件实现代码如下

syntax = "proto3";  //声明语法为proto3语法，不声明的话默认的是proto2的语法

option go_package="./;pb";

package pb; //包名

//Greeter 微服务
service Greeter {
    //sends a greeting
    rpc SayHello(HelloRequest) returns (HelloReply) {}

}

//HelloRequest 请求数据格式
message HelloRequest {
    string name=1;   //这里1并不是说name的值为1，这里的1是一个唯一的编号
}

//HelloReply 响应数据格式
message HelloReply {
    string message=1;  //这里的1也不是值。是一个唯一的编号
}

然后需要编译生成相应文件

//前面路径./pb表示输出路径，后面的路径./pb/hello.proto表示当前需要编译的文件所在位置
protoc --go_out=./pb ./pb/hello.proto  
//前面路径./pb表示输出路径，后面的路径./pb/hello.proto表示当前需要编译的文件所在位置
protoc --go-grpc_out=./pb ./pb/hello.proto

生成的hello.pb.go代码如下

// Code generated by protoc-gen-go. DO NOT EDIT.
// versions:
// 	protoc-gen-go v1.26.0
// 	protoc        v4.25.0
// source: pb/hello.proto

package pb

import (
	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
	reflect "reflect"
	sync "sync"
)

const (
	// Verify that this generated code is sufficiently up-to-date.
	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
	// Verify that runtime/protoimpl is sufficiently up-to-date.
	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
)

// HelloRequest 请求数据格式
type HelloRequest struct {
	state         protoimpl.MessageState
	sizeCache     protoimpl.SizeCache
	unknownFields protoimpl.UnknownFields

	Name string `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
}

func (x *HelloRequest) Reset() {
	*x = HelloRequest{}
	if protoimpl.UnsafeEnabled {
		mi := &file_pb_hello_proto_msgTypes[0]
		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
		ms.StoreMessageInfo(mi)
	}
}

func (x *HelloRequest) String() string {
	return protoimpl.X.MessageStringOf(x)
}

func (*HelloRequest) ProtoMessage() {}

func (x *HelloRequest) ProtoReflect() protoreflect.Message {
	mi := &file_pb_hello_proto_msgTypes[0]
	if protoimpl.UnsafeEnabled && x != nil {
		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
		if ms.LoadMessageInfo() == nil {
			ms.StoreMessageInfo(mi)
		}
		return ms
	}
	return mi.MessageOf(x)
}

// Deprecated: Use HelloRequest.ProtoReflect.Descriptor instead.
func (*HelloRequest) Descriptor() ([]byte, []int) {
	return file_pb_hello_proto_rawDescGZIP(), []int{0}
}

func (x *HelloRequest) GetName() string {
	if x != nil {
		return x.Name
	}
	return ""
}

// HelloReply 响应数据格式
type HelloReply struct {
	state         protoimpl.MessageState
	sizeCache     protoimpl.SizeCache
	unknownFields protoimpl.UnknownFields

	Message string `protobuf:"bytes,1,opt,name=message,proto3" json:"message,omitempty"`
}

func (x *HelloReply) Reset() {
	*x = HelloReply{}
	if protoimpl.UnsafeEnabled {
		mi := &file_pb_hello_proto_msgTypes[1]
		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
		ms.StoreMessageInfo(mi)
	}
}

func (x *HelloReply) String() string {
	return protoimpl.X.MessageStringOf(x)
}

func (*HelloReply) ProtoMessage() {}

func (x *HelloReply) ProtoReflect() protoreflect.Message {
	mi := &file_pb_hello_proto_msgTypes[1]
	if protoimpl.UnsafeEnabled && x != nil {
		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
		if ms.LoadMessageInfo() == nil {
			ms.StoreMessageInfo(mi)
		}
		return ms
	}
	return mi.MessageOf(x)
}

// Deprecated: Use HelloReply.ProtoReflect.Descriptor instead.
func (*HelloReply) Descriptor() ([]byte, []int) {
	return file_pb_hello_proto_rawDescGZIP(), []int{1}
}

func (x *HelloReply) GetMessage() string {
	if x != nil {
		return x.Message
	}
	return ""
}

var File_pb_hello_proto protoreflect.FileDescriptor

var file_pb_hello_proto_rawDesc = []byte{
	0x0a, 0x0e, 0x70, 0x62, 0x2f, 0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f,
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	0x65, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x07, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65,
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}

var (
	file_pb_hello_proto_rawDescOnce sync.Once
	file_pb_hello_proto_rawDescData = file_pb_hello_proto_rawDesc
)

func file_pb_hello_proto_rawDescGZIP() []byte {
	file_pb_hello_proto_rawDescOnce.Do(func() {
		file_pb_hello_proto_rawDescData = protoimpl.X.CompressGZIP(file_pb_hello_proto_rawDescData)
	})
	return file_pb_hello_proto_rawDescData
}

var file_pb_hello_proto_msgTypes = make([]protoimpl.MessageInfo, 2)
var file_pb_hello_proto_goTypes = []interface{}{
	(*HelloRequest)(nil), // 0: pb.HelloRequest
	(*HelloReply)(nil),   // 1: pb.HelloReply
}
var file_pb_hello_proto_depIdxs = []int32{
	0, // 0: pb.Greeter.SayHello:input_type -> pb.HelloRequest
	1, // 1: pb.Greeter.SayHello:output_type -> pb.HelloReply
	1, // [1:2] is the sub-list for method output_type
	0, // [0:1] is the sub-list for method input_type
	0, // [0:0] is the sub-list for extension type_name
	0, // [0:0] is the sub-list for extension extendee
	0, // [0:0] is the sub-list for field type_name
}

func init() { file_pb_hello_proto_init() }
func file_pb_hello_proto_init() {
	if File_pb_hello_proto != nil {
		return
	}
	if !protoimpl.UnsafeEnabled {
		file_pb_hello_proto_msgTypes[0].Exporter = func(v interface{}, i int) interface{} {
			switch v := v.(*HelloRequest); i {
			case 0:
				return &v.state
			case 1:
				return &v.sizeCache
			case 2:
				return &v.unknownFields
			default:
				return nil
			}
		}
		file_pb_hello_proto_msgTypes[1].Exporter = func(v interface{}, i int) interface{} {
			switch v := v.(*HelloReply); i {
			case 0:
				return &v.state
			case 1:
				return &v.sizeCache
			case 2:
				return &v.unknownFields
			default:
				return nil
			}
		}
	}
	type x struct{}
	out := protoimpl.TypeBuilder{
		File: protoimpl.DescBuilder{
			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
			RawDescriptor: file_pb_hello_proto_rawDesc,
			NumEnums:      0,
			NumMessages:   2,
			NumExtensions: 0,
			NumServices:   1,
		},
		GoTypes:           file_pb_hello_proto_goTypes,
		DependencyIndexes: file_pb_hello_proto_depIdxs,
		MessageInfos:      file_pb_hello_proto_msgTypes,
	}.Build()
	File_pb_hello_proto = out.File
	file_pb_hello_proto_rawDesc = nil
	file_pb_hello_proto_goTypes = nil
	file_pb_hello_proto_depIdxs = nil
}

生成的hello_prpc.pb.go代码如下

// Code generated by protoc-gen-go-grpc. DO NOT EDIT.

package pb

import (
	context "context"
	grpc "google.golang.org/grpc"
	codes "google.golang.org/grpc/codes"
	status "google.golang.org/grpc/status"
)

// This is a compile-time assertion to ensure that this generated file
// is compatible with the grpc package it is being compiled against.
// Requires gRPC-Go v1.32.0 or later.
const _ = grpc.SupportPackageIsVersion7

// GreeterClient is the client API for Greeter service.
//
// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://pkg.go.dev/google.golang.org/grpc/?tab=doc#ClientConn.NewStream.
type GreeterClient interface {
	// sends a greeting
	SayHello(ctx context.Context, in *HelloRequest, opts ...grpc.CallOption) (*HelloReply, error)
}

type greeterClient struct {
	cc grpc.ClientConnInterface
}

func NewGreeterClient(cc grpc.ClientConnInterface) GreeterClient {
	return &greeterClient{cc}
}

func (c *greeterClient) SayHello(ctx context.Context, in *HelloRequest, opts ...grpc.CallOption) (*HelloReply, error) {
	out := new(HelloReply)
	err := c.cc.Invoke(ctx, "/pb.Greeter/SayHello", in, out, opts...)
	if err != nil {
		return nil, err
	}
	return out, nil
}

// GreeterServer is the server API for Greeter service.
// All implementations must embed UnimplementedGreeterServer
// for forward compatibility
type GreeterServer interface {
	// sends a greeting
	SayHello(context.Context, *HelloRequest) (*HelloReply, error)
	mustEmbedUnimplementedGreeterServer()
}

// UnimplementedGreeterServer must be embedded to have forward compatible implementations.
type UnimplementedGreeterServer struct {
}

func (UnimplementedGreeterServer) SayHello(context.Context, *HelloRequest) (*HelloReply, error) {
	return nil, status.Errorf(codes.Unimplemented, "method SayHello not implemented")
}
func (UnimplementedGreeterServer) mustEmbedUnimplementedGreeterServer() {}

// UnsafeGreeterServer may be embedded to opt out of forward compatibility for this service.
// Use of this interface is not recommended, as added methods to GreeterServer will
// result in compilation errors.
type UnsafeGreeterServer interface {
	mustEmbedUnimplementedGreeterServer()
}

func RegisterGreeterServer(s grpc.ServiceRegistrar, srv GreeterServer) {
	s.RegisterService(&Greeter_ServiceDesc, srv)
}

func _Greeter_SayHello_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
	in := new(HelloRequest)
	if err := dec(in); err != nil {
		return nil, err
	}
	if interceptor == nil {
		return srv.(GreeterServer).SayHello(ctx, in)
	}
	info := &grpc.UnaryServerInfo{
		Server:     srv,
		FullMethod: "/pb.Greeter/SayHello",
	}
	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
		return srv.(GreeterServer).SayHello(ctx, req.(*HelloRequest))
	}
	return interceptor(ctx, in, info, handler)
}

// Greeter_ServiceDesc is the grpc.ServiceDesc for Greeter service.
// It's only intended for direct use with grpc.RegisterService,
// and not to be introspected or modified (even as a copy)
var Greeter_ServiceDesc = grpc.ServiceDesc{
	ServiceName: "pb.Greeter",
	HandlerType: (*GreeterServer)(nil),
	Methods: []grpc.MethodDesc{
		{
			MethodName: "SayHello",
			Handler:    _Greeter_SayHello_Handler,
		},
	},
	Streams:  []grpc.StreamDesc{},
	Metadata: "pb/hello.proto",
}

服务端程序main.go实现代码如下

package main

import (
	"context"
	"fmt"
	"log"
	"net"

	pb "pro02/pb" //起别名

	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
)

const (
	port = ":50051" //定义一个端口常量
)

type server struct {
	pb.UnimplementedGreeterServer
} //服务对象

// SayHello 实现服务的接口 在proto中定义的所有服务都是接口
// server实现了GreeterClient接口的SayHello方法，所以可以把server直接当成这个接口使用
func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
	return &pb.HelloReply{Message: "Hello " + in.Name}, nil
}

func main() {
	lis, err := net.Listen("tcp", port) //监听
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}
	s := grpc.NewServer() //起一个服务

	//server实现了GreeterClient接口的SayHello方法，所以可以把server直接当成这个接口使用
	pb.RegisterGreeterServer(s, &server{})
	// 注册反射服务 这个服务是CLI使用的 跟服务本身没有关系
	reflection.Register(s)
	fmt.Println("开始启动服务")
	if err := s.Serve(lis); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

客户端程序main.go实现代码如下

package main

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

	pb "pro02/pb"

	"google.golang.org/grpc"
)

const (
	address     = "localhost:50051" //ip地址端口号
	defaultName = "world"           //默认值，如果没有给定这个值，那么默认就是这个值
)

func main() {
	//建立连接
	conn, err := grpc.Dial(address, grpc.WithInsecure())
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()
	c := pb.NewGreeterClient(conn)  //新建一个客户端

	// Contact the server and print out its response.
	name := defaultName   //首先给一个默认值
	if len(os.Args) > 1 { //判断Hello后面是否有值，有就将值改为这个后面的值
		name = os.Args[1]
	}
	// 1秒的上下文
	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)
	}

	//输出结果
	log.Printf("Greeting: %s", r.Message)
}

项目左侧包结构如下

?

详细操作步骤：

(1)首先初始化项目，会生成一个go.mod文件，这个是go的包管理工具

//pro02表示当前项目名称
go mod init pro02

(2)然后新建pb包，然后在pb包下面新建hello.proto文件，然后实现消息文件hello.proto

(3)编译消息文件hello.proto.

//前面路径./pb表示输出路径，后面路径./pb/hello.proto表示当前需要编译的文件所在位置
protoc --go_out=./pb ./pb/hello.proto  
//前面路径./pb表示输出路径，后面路径./pb/hello.proto表示当前需要编译的文件所在位置
protoc --go-grpc_out=./pb ./pb/hello.proto

编译成功之后会在输出路径下生成一个hello.pb.go文件和一个hello_grpc.pb.go文件，如下图所示

(4)进入server包，运行server包下面的main.go文件

cd server
go run main.go

由于我在server的main.go程序中写了一个打印"开始启动服务"，所以我们可以在终端看到“开始启动服务”，如果看到了说明服务启动成功，否则说明启动失败，如下图所示就表示成功了。

?

(5)上面启动了一个终端，这里需要打开一个新的终端，进入client包，在客户端程序中进行测试，

测试：

cd client
go run .\main.go 你好呀

?上述的go run .\main.go 命令后面输入你好呀那就会在控制台上面打印Hello 你好呀，也就是说在这个命令后面输入什么就会打印什么内容，如果后面没有带任何内容，就会输出我们程序中给定的默认值Hello world。当然我们可以通过改动程序代码实现我们其他需要打印出来的内容。

如果程序执行结果如下图所示，表示程序代码实现是正确的，并且操作过程也是正确的。

到这里就实现了一个简单的rpc应用了。?