Go Grpc Gateway兼容HTTP协议文档自动生成网关

go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway
go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger
go get -u github.com/golang/protobuf/protoc-gen-go

cd $GOPATH/src/
mkdir -p grpc-gateway-demo/gateway
cd grpc-gateway-demo/gateway
vim gateway.proto
syntax = "proto3";
package gateway;
# 新增以下引入
import "google/api/annotations.proto";
message StringMessage {
    string value = 1;
}
# 修改方法增加http定义
# service Gateway {
#   rpc SayHello Echo(StringMessage) returns (StringMessage) {}
# }
service Gateway {
   rpc Echo(StringMessage) returns (StringMessage) {
       option (google.api.http) = {
           post: "/v1/example/echo"
           body: "*"
       };
   }
}

cd ..
vim grpc_service.go
package main
import (
    "log"
    "net"
    pb "grpc-gateway-demo/gateway"
    "google.golang.org/grpc"
    "golang.org/x/net/context"
)
const (
    PORT = ":9192"
)
type server struct {}
func (s *server) Echo(ctx context.Context, in *pb.StringMessage) (*pb.StringMessage, error) {
    log.Println("request: ", in.Value)
    return &pb.StringMessage{Value: "Hello " + in.Value}, nil
}
func main() {
    lis, err := net.Listen("tcp", PORT)
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    }
    s := grpc.NewServer()
    pb.RegisterGatewayServer(s, &server{})
    log.Println("rpc服务已经开启")
    s.Serve(lis)
}

go build grpc_service.go
./grpc_service

vim grpc_gateway.go
package main
import (
    "flag"
    "net/http"
    "log"
    "github.com/golang/glog"
    "golang.org/x/net/context"
    "github.com/grpc-ecosystem/grpc-gateway/runtime"
    "google.golang.org/grpc"
    gw "grpc-gateway-demo/gateway"
)
var (
    echoEndpoint = flag.String("echo_endpoint", "localhost:9192", "endpoint of Gateway")
)
func run() error {
    ctx := context.Background()
    ctx, cancel := context.WithCancel(ctx)
    defer cancel()
    mux := runtime.NewServeMux()
    opts := []grpc.DialOption{grpc.WithInsecure()}
    err := gw.RegisterGatewayHandlerFromEndpoint(ctx, mux, *echoEndpoint, opts)
    if err != nil {
        return err
    }
    log.Println("服务开启")
    return http.ListenAndServe(":8080", mux)
}
func main() {
    flag.Parse()
    defer glog.Flush()
    if err := run(); err != nil {
        glog.Fatal(err)
    }
}

go build grpc_gateway.go
./grpc_gateway

curl -X POST -k http://localhost:8080/v1/example/echo -d '{"value":" world"}'
{"value":"Hello  world"}

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