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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