gRPC服务器如何调用REST端点

Question

我目前刚接触gRPC技术并且正在阅读它。

我目前的理解是gRPC只是另一种协议，就像REST是一样。现在假设我启动了一个我希望客户端使用的gRPC服务器，但是在那个gRPC服务器中，我希望能够从外部消费者RESTful Apis获取信息，（例如https://developer.riotgames.com/api-methods/）是还有可能吗？

Answer 1

是的，有可能。您可以使用自己的gRPC服务代码调用其他API和服务。

让您的客户打电话给您的gRPC服务。然后，您的服务对外部API进行REST调用（可能使用客户端请求中的参数到您的gRPC服务）并对其进行处理。将结果返回给您的客户，但是您的gRPC服务会响应。

Answer 2

由于grcp-gateway go-grpc-tutorial

，您需要使用phuongdo生成上可用的代理完整代码

1. 安装代码：

   $sudo apt install libprotobuf-dev
   
   go get google.golang.org/grpc
   
   go get -u github.com/golang/protobuf/{proto,protoc-gen-go}
   
   go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway
   

2. 定义服务，pb / service.proto：

   syntax = "proto3";
   
   option go_package = "echo";
   
   package echo;
   
   import "google/api/annotations.proto";
   
     //Message represents a simple message sent to the Echo service.
   
    message Message {
   
    string id = 1;
   
   string msg = 2;
   }
   
   
    //Echo service responds to incoming echo requests.
   
   service EchoService {
   
     //Echo method receives a simple message and returns it.
   
      //The message posted as the id parameter will also be returned.
   
   rpc Echo(Message) returns (Message) {
   
   option (google.api.http) = {
   
       post: "/v1/example/echo/{id}/{msg}"
   };
   }
   }
   

3. 为服务器和clinet生成存根

   $ protoc -I/usr/local/include -I. \
   -I$GOPATH/src \
   -I$GOPATH/src/github.com/grpc-ecosystem/grpc-
    gateway/third_party/googleapis \
    --go_out=google/api/annotations.proto=github.com/grpc-ecosystem/grpc-
    gateway/third_party/googleapis/google/api,plugins=grpc:. \
    pb/service.proto
   

{li>

和reverse proxy的{​​{1}}

REST API

4. 服务器/ server.go：

   $ protoc -I/usr/local/include -I. \
   -I$GOPATH/src \
   -I$GOPATH/src/github.com/grpc-ecosystem/grpc-
    gateway/third_party/googleapis \
   --grpc-gateway_out=logtostderr=true:. \
   pb/service.proto
   

5. 写rest api，server / server-rproxy.go：

   package main
   
   import (
   "flag"
   
   "github.com/golang/glog"
   pb "github.com/go-grpc-tutorial/pb"
   "golang.org/x/net/context"
   "google.golang.org/grpc"
   "net"
   )
   
   // Implements of EchoServiceServer
   
   type echoServer struct{}
   
   func newEchoServer() pb.EchoServiceServer {
   return new(echoServer)
   }
   
   func (s *echoServer) Echo(ctx context.Context, msg *pb.Message) 
    (*pb.Message, error) {
   glog.Info(msg)
   return msg, nil
   }
   
   func Run() error {
   listen, err := net.Listen("tcp", ":50051")
   if err != nil {
       return err
   }
   server := grpc.NewServer()
   pb.RegisterEchoServiceServer(server, newEchoServer())
   server.Serve(listen)
   return nil
   }
   
   func main() {
   flag.Parse()
   defer glog.Flush()
   
   if err := Run(); err != nil {
       glog.Fatal(err)
   }
   }
   

6. 构建客户端服务器/ client.go：

   package main
   
    import (
   "flag"
   "net/http"
   "github.com/grpc-ecosystem/grpc-gateway/runtime"
   "github.com/golang/glog"
   pb "github.com/go-grpc-tutorial/pb"
   "golang.org/x/net/context"
   "google.golang.org/grpc"
    )
   
    var (
   echoEndpoint = flag.String("echo_endpoint", "localhost:50051", 
   "endpoint of EchoService")
    )
   
   func RunEndPoint(address string, opts ...runtime.ServeMuxOption) 
    error {
   ctx := context.Background()
   ctx, cancel := context.WithCancel(ctx)
   defer cancel()
   
   mux := runtime.NewServeMux(opts...)
   dialOpts := []grpc.DialOption{grpc.WithInsecure()}
   err := pb.RegisterEchoServiceHandlerFromEndpoint(ctx, mux, *echoEndpoint, dialOpts)
   if err != nil {
       return err
   }
   
   http.ListenAndServe(address, mux)
   return nil
    }
   
   func main() {
   flag.Parse()
   defer glog.Flush()
   
   if err := RunEndPoint(":8080"); err != nil {
       glog.Fatal(err)
   }
    }
   

7. 最后运行服务器，客户端，休息和呼叫休息：

    package main
   
   import (
   "log"
   "os"
   
   "golang.org/x/net/context"
   "google.golang.org/grpc"
   pb "github.com/go-grpc-tutorial/pb"
   )
   
    const (
   address = "localhost:50051"
    defaultName = "PhuongDV"
   )
   
   func main() {
   // Set up a connection to the server.
   conn, err := grpc.Dial(address, grpc.WithInsecure())
   if err != nil {
       log.Fatalf("did not connect: %v", err)
   }
   defer conn.Close()
   c := pb.NewEchoServiceClient(conn)
   
   // Contact the server and print out its response.
   name := defaultName
   if len(os.Args) > 1 {
       name = os.Args[1]
   }
   r, err := c.Echo(context.Background(), &pb.Message{Id: "1", Msg: name})
   if err != nil {
       log.Fatalf("could not greet: %v", err)
   }
   log.Printf("Greeting: %s", r.Msg)
   }
   

   1：https://github.com/phuongdo/go-grpc-tutorial   2：https://i.stack.imgur.com/C4s7s.png