Golang中四种gRPC模式

文章目录

1. Unary RPC
2. Server-side streaming RPC
3. Client-side streaming RPC
4. Bidirectional streaming RPC
4. ALTS
- 4.1 ALTS的介绍
- 4.2 gRPC客户端使用ALTS传输安全协议
- 4.3 Server Authorization

本博客需要你有一点基本的gRPC的常识，如果你完全是新手建议访问官网全面了解。

1. Unary RPC

proto文件如下

syntax = "proto3";
option go_package=".;service";

message HelloRequest {
  // Name of the person to greet
  string name = 1;
}

message HelloResponse {
  // Greeting message
  string greeting = 1;
}

service HelloService {
  // RPC method to say hello
  rpc SayHello (HelloRequest) returns (HelloResponse){}
}

使用命令(注意命令路径和自己的对应):

protoc -I . --go-grpc_out=require_unimplemented_servers=false:. --go_out=.  *.proto

对应目录上有xx.pb.go和xx_grpc.pb.go
然后对应目录实现服务端接口

package main

import (
	"context"
	"fmt"
	"google.golang.org/grpc"
	"net"
	"test_grpc/service"
)

type HelloService struct {
}

func (hs *HelloService) SayHello(ctx context.Context, req *service.HelloRequest) (*service.HelloResponse, error) {
	resp := &service.HelloResponse{
		Greeting: fmt.Sprintf("hello %s --from Golang Server", req.Name),
	}
	return resp, nil
}

func main() {
	// listen on 127.0.0.1:50051
	listen, err := net.Listen("tcp", "127.0.0.1:50051")
	if err != nil {
		fmt.Println("Error happened when listen on 127.0.0.1:50051:", err)
		return
	}

	// grpc server
	s := grpc.NewServer()

	// register HelloService in grpc server
	service.RegisterHelloServiceServer(s, &HelloService{})

	// start rpc server
	fmt.Println("Golang rpc server is waiting messages......")
	if err = s.Serve(listen); err != nil {
		fmt.Println("Error happened when start rpc server:", err)
		return
	}
}

客户端接口如下：

package main

import (
	"context"
	"fmt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"test_grpc/service"
	"time"
)

func main() {
	// connect to server
	conn, err := grpc.Dial("127.0.0.1:50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		fmt.Println("Connect to rpc server err:", err)
		return
	}
	defer conn.Close()

	// init service client
	c := service.NewHelloServiceClient(conn)

	// init context with timeout
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()

	// send message
	req := &service.HelloRequest{Name: "Golang"}
	r, err := c.SayHello(ctx, req)
	if err != nil {
		fmt.Println("Send message err:", err)
		return
	}
	fmt.Println("Client:", r.Greeting)
}

实际上为了更好得感受gRPC这种跨语言调用的感觉，可以尝试使用python编写client端代码，直接复制proto文件，在python中使用以下命令生成对应的proto文件（注意命令和自己的对应）：

python -m grpc_tools.protoc -I . --python_out=. --pyi_out=. --grpc_python_out=. *.proto

使用python实现的客户端代码如下：

# client template
# grpc server address
channel = grpc.insecure_channel("127.0.0.1:50051")
stub = hello_pb2_grpc.HelloServiceStub(channel)

# send request
response = stub.SayHello(hello_pb2.HelloRequest(name="Python"))

print(response.greeting)
# hello Python --from Golang Server

2. Server-side streaming RPC

重新给出这个的proto文件，服务端将以流式数据的形式发送给客户端数据

syntax = "proto3";
option go_package=".;service";

message HelloRequest {
  // Name of the person to greet
  string name = 1;
}

message HelloResponse {
  // Greeting message
  string greeting = 1;
}

service HelloService {
  // RPC method to say hello
  rpc SayHello (HelloRequest) returns (stream HelloResponse){}
}

同理，生成对应的proto文件后，在对应的文件先生成server端的代码：

package main

import (
	"fmt"
	"google.golang.org/grpc"
	"net"
	"test_grpc/service"
)

type HelloService struct {
}

func (hs *HelloService) SayHello(req *service.HelloRequest, stream service.HelloService_SayHelloServer) error {
	resp := &service.HelloResponse{
		Greeting: fmt.Sprintf("hello %s --from Golang Server", req.Name),
	}
	// 连续发送5次
	for i := 0; i < 5; i++ {
		if err := stream.Send(resp); err != nil {
			return err
		}
	}
	return nil
}

func main() {
	// listen on 127.0.0.1:50051
	listen, err := net.Listen("tcp", "127.0.0.1:50051")
	if err != nil {
		fmt.Println("Error happened when listen on 127.0.0.1:50051:", err)
		return
	}

	// grpc server
	s := grpc.NewServer()

	// register HelloService in grpc server
	service.RegisterHelloServiceServer(s, &HelloService{})

	// start rpc server
	fmt.Println("Golang rpc server is waiting messages......")
	if err = s.Serve(listen); err != nil {
		fmt.Println("Error happened when start rpc server:", err)
		return
	}
}

同理给出客户端的代码：

package main

import (
	"context"
	"fmt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"io"
	"log"
	"test_grpc/service"
	"time"
)

func main() {
	// connect to server
	conn, err := grpc.Dial("127.0.0.1:50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		fmt.Println("Connect to rpc server err:", err)
		return
	}
	defer conn.Close()

	// init service client
	c := service.NewHelloServiceClient(conn)

	// init context with timeout
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()

	// send message
	req := &service.HelloRequest{Name: "Golang"}
	stream, err := c.SayHello(ctx, req)
	if err != nil {
		fmt.Println("Send message err:", err)
		return
	}

	// 加载消息
	for {
		resp, err := stream.Recv()
		// 读到结束标志
		if err == io.EOF {
			log.Fatalf("end.....")
			break
		}

		if err != nil {
			log.Fatalf("failed to receive response: %v", err)
		}

		log.Printf("Greeting: %s", resp.Greeting)
	}
}

3. Client-side streaming RPC

对应的proto文件如下

syntax = "proto3";
option go_package=".;service";

message HelloRequest {
  // Name of the person to greet
  string name = 1;
}

message HelloResponse {
  // Greeting message
  string greeting = 1;
}

service HelloService {
  // RPC method to say hello
  rpc SayHello (stream HelloRequest) returns (HelloResponse){}
}

同理使用protoc命令生成对应的proto文件，后先编写client端的代码，如下：

package main

import (
	"context"
	"fmt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"log"
	"test_grpc/service"
	"time"
)

func main() {
	// connect to server
	conn, err := grpc.Dial("127.0.0.1:50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		fmt.Println("Connect to rpc server err:", err)
		return
	}
	defer conn.Close()

	// init service client
	c := service.NewHelloServiceClient(conn)

	// init context with timeout
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()

	// create stream

	stream, err := c.SayHello(ctx)
	if err != nil {
		log.Fatalf("could not greet: %v", err)
	}

	names := []string{"World", "Gophers", "Anthropic"}

	for _, name := range names {
		// request body
		req := &service.HelloRequest{Name: name}
		if err := stream.Send(req); err != nil {
			log.Fatalf("faild to send request: %v", err)
		}
	}

	resp, err := stream.CloseAndRecv()
	if err != nil {
		log.Fatalf("%v.CloseAndRecv() got error %v, want %v", stream, err, nil)
	}
	log.Printf("Greeting: %s", resp.Greeting)
}

对应得完成服务端的代码：

package main

import (
	"fmt"
	"google.golang.org/grpc"
	"io"
	"net"
	"strings"
	"test_grpc/service"
)

type HelloService struct {
}

func (hs *HelloService) SayHello(stream service.HelloService_SayHelloServer) error {
	var strs []string
	for {
		msg, err := stream.Recv()
		if err == io.EOF {
			break
		}
		if err != nil {
			return err
		}

		strs = append(strs, msg.Name)
	}

	resp := &service.HelloResponse{Greeting: strings.Join(strs, " ")}

	err := stream.SendAndClose(resp)
	if err != nil {
		return err
	}
	return nil
}

func main() {
	// listen on 127.0.0.1:50051
	listen, err := net.Listen("tcp", "127.0.0.1:50051")
	if err != nil {
		fmt.Println("Error happened when listen on 127.0.0.1:50051:", err)
		return
	}

	// grpc server
	s := grpc.NewServer()

	// register HelloService in grpc server
	service.RegisterHelloServiceServer(s, &HelloService{})

	// start rpc server
	fmt.Println("Golang rpc server is waiting messages......")
	if err = s.Serve(listen); err != nil {
		fmt.Println("Error happened when start rpc server:", err)
		return
	}
}

4. Bidirectional streaming RPC

新的proto文件被如下给出：

syntax = "proto3";
option go_package=".;service";

message HelloRequest {
  // Name of the person to greet
  string name = 1;
}

message HelloResponse {
  // Greeting message
  string greeting = 1;
}

service HelloService {
  // RPC method to say hello
  rpc SayHello (stream HelloRequest) returns (stream HelloResponse){}
}

和上文中的操作一致，同时给出server端的代码：

package main

import (
	"fmt"
	"google.golang.org/grpc"
	"io"
	"log"
	"net"
	"test_grpc/service"
)

type HelloService struct {
}

func (hs *HelloService) SayHello(stream service.HelloService_SayHelloServer) error {
	for {
		msg, err := stream.Recv()
		if err == io.EOF {
			break
		}
		if err != nil {
			return err
		}

		name := msg.Name
		resp := &service.HelloResponse{Greeting: name}

		if err = stream.Send(resp); err != nil {
			log.Fatalf("Failed to send a resp:%s", err)
		}
	}

	return nil
}

func main() {
	// listen on 127.0.0.1:50051
	listen, err := net.Listen("tcp", "127.0.0.1:50051")
	if err != nil {
		fmt.Println("Error happened when listen on 127.0.0.1:50051:", err)
		return
	}

	// grpc server
	s := grpc.NewServer()

	// register HelloService in grpc server
	service.RegisterHelloServiceServer(s, &HelloService{})

	// start rpc server
	fmt.Println("Golang rpc server is waiting messages......")
	if err = s.Serve(listen); err != nil {
		fmt.Println("Error happened when start rpc server:", err)
		return
	}
}

同时给出下面的client端的代码：

package main

import (
	"context"
	"fmt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"io"
	"log"
	"test_grpc/service"
	"time"
)

func main() {
	// connect to server
	conn, err := grpc.Dial("127.0.0.1:50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		fmt.Println("Connect to rpc server err:", err)
		return
	}
	defer conn.Close()

	// init service client
	c := service.NewHelloServiceClient(conn)

	// init context with timeout
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()

	// create stream
	stream, err := c.SayHello(ctx)
	if err != nil {
		log.Fatalf("could not greet: %v", err)
	}

	names := []string{"World", "Gophers", "Anthropic"}

	waitc := make(chan struct{})
	go func() {
		for {
			resp, err := stream.Recv()
			if err == io.EOF {
				close(waitc)
				return
			}
			if err != nil {
				log.Fatalf("%v.CloseAndRecv() got error %v, want %v", stream, err, nil)
			}
			log.Printf("Greeting: %s", resp.Greeting)
		}
	}()

	go func() {
		for _, name := range names {
			// request body
			req := &service.HelloRequest{Name: name}
			if err := stream.Send(req); err != nil {
				log.Fatalf("faild to send request: %v", err)
			}

			// send delay
			time.Sleep(1)
		}
		// 发送结束的消息
		if err := stream.CloseSend(); err != nil {
			log.Fatalf("failed to close stream: %v", err)
		}
	}()

	<-waitc
}

一定要注意关闭发送或者避免针对一个已经关闭stream进行发送消息，读取消息是被允许的，这里有一点类似chan

4. ALTS

4.1 ALTS的介绍

应用层传输安全（ALTS）是谷歌开发的一种相互验证和传输加密系统。它用于确保谷歌基础设施内 RPC 通信的安全。ALTS 类似于相互 TLS，但经过设计和优化，可满足 Google 生产环境的需要。ALTS在gRPC中有以下的特征：

使用ALTS作为传输协议创建gRPC的服务端和客户端；
ALSTS是一个端到端的保护，具有隐私性和完成性；
应用可以访问对等信息比如对等服务账户；
支持客户端和服务端的认知；
最小的代码更改就能使用ALTS；

值得注意的是ALTS被全部发挥作用如果应用程序运行在CE或者GKE中

4.2 gRPC客户端使用ALTS传输安全协议

gRPC客户端使用ALTS认证去连接服务端，正如下面代码中所描述的：

import (
  "google.golang.org/grpc"
  "google.golang.org/grpc/credentials/alts"
)

altsTC := alts.NewClientCreds(alts.DefaultClientOptions())
// connect to server
conn, err := grpc.Dial("127.0.0.1:50051", grpc.WithTransportCredentials(altsTC))

gRPC服务端能够使用ALTS认证来运行客户端连接到它，正如下面的描述：

import (
  "google.golang.org/grpc"
  "google.golang.org/grpc/credentials/alts"
)

altsTC := alts.NewServerCreds(alts.DefaultServerOptions())
server := grpc.NewServer(grpc.Creds(altsTC))

4.3 Server Authorization

gRPC 内置了使用 ALTS 的服务器授权支持。使用 ALTS 的 gRPC 客户端可以在建立连接前设置预期的服务器服务账户。然后，在握手结束时，服务器授权会保证服务器身份与客户端指定的服务账户之一相匹配。否则，连接将失败。

import (
  "google.golang.org/grpc"
  "google.golang.org/grpc/credentials/alts"
)

clientOpts := alts.DefaultClientOptions()
clientOpts.TargetServiceAccounts = []string{expectedServerSA}
altsTC := alts.NewClientCreds(clientOpts)
conn, err := grpc.Dial(serverAddr, grpc.WithTransportCredentials(altsTC))