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))
总结
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