前言

本文记录了grpc-gateway的简单使用。

定义proto

先来看看最常规的

syntax = "proto3";

package protos;

service Greeter {
rpc SayHello (HelloRequest) returns (HelloReply) {}
} message HelloRequest {
string name = 1;
} message HelloReply {
string message = 1;
}

然后加入gateway等相关的内容

syntax = "proto3";

package protos;

// 1 导入 gateway 相关的proto 以及 swagger 相关的 proto
import "google/api/annotations.proto";
import "protoc-gen-swagger/options/annotations.proto"; // 2 定义 swagger 相关的内容
option (grpc.gateway.protoc_gen_swagger.options.openapiv2_swagger) = {
info: {
title: "grpc gateway sample";
version: "1.0";
license: {
name: "MIT";
};
};
schemes: HTTP;
}; service Greeter {
rpc SayHello (HelloRequest) returns (HelloReply) {
// 3 标识接口路由
option (google.api.http) = {
post: "/hello_world"
body: "*"
};
}
} message HelloRequest {
string name = 1;
} message HelloReply {
string message = 1;
}

从proto生成文件

执行下面的三个命令。

protoc -I . --go_out=plugins=grpc:. hello.proto
protoc -I . --grpc-gateway_out=logtostderr=true:. hello.proto
protoc -I . --swagger_out=logtostderr=true:. hello.proto

gRPC+gRPC Gateway+swagger小记-LMLPHP

实现service和启动service

实现

package services

import (
"context"
pb "grpc-sample/protos"
"log"
) type server struct{} func NewServer() *server {
return &server{}
} func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
log.Println("request: ", in.Name)
return &pb.HelloReply{Message: "hello, " + in.Name}, nil
}

启动

package main

import (
"google.golang.org/grpc"
pb "grpc-sample/protos"
"grpc-sample/services"
"log"
"net"
) const (
PORT = ":9192"
) func main() {
lis, err := net.Listen("tcp", PORT) if err != nil {
log.Fatalf("failed to listen: %v", err)
} s := grpc.NewServer()
pb.RegisterGreeterServer(s, services.NewServer())
log.Println("rpc services started, listen on localhost:9192")
s.Serve(lis)
}

整合 swagger

先下载swagger ui的静态文件。

gRPC+gRPC Gateway+swagger小记-LMLPHP

把这些文件打包成go文件。

go-bindata --nocompress -pkg swagger -o gateway/swagger/datafile.go third_party/swagger-ui/...

gRPC+gRPC Gateway+swagger小记-LMLPHP

9M。。。

写 gateway

package main

import (
"github.com/elazarl/go-bindata-assetfs"
"log"
"net/http"
"path"
"strings" "github.com/golang/glog"
"github.com/grpc-ecosystem/grpc-gateway/runtime"
"golang.org/x/net/context"
"google.golang.org/grpc"
swagger "grpc-sample/gateway/swagger"
gw "grpc-sample/protos"
) func run() error {
ctx := context.Background()
ctx, cancel := context.WithCancel(ctx)
defer cancel() gwmux, err := newGateway(ctx)
if err != nil {
panic(err)
} mux := http.NewServeMux()
mux.Handle("/", gwmux)
mux.HandleFunc("/swagger/", serveSwaggerFile)
serveSwaggerUI(mux) log.Println("grpc-gateway listen on localhost:8080")
return http.ListenAndServe(":8080", mux)
} func newGateway(ctx context.Context) (http.Handler, error) {
opts := []grpc.DialOption{grpc.WithInsecure()} gwmux := runtime.NewServeMux()
if err := gw.RegisterGreeterHandlerFromEndpoint(ctx, gwmux, ":9192", opts); err != nil {
return nil, err
} return gwmux, nil
} func serveSwaggerFile(w http.ResponseWriter, r *http.Request) {
if !strings.HasSuffix(r.URL.Path, "swagger.json") {
log.Printf("Not Found: %s", r.URL.Path)
http.NotFound(w, r)
return
} p := strings.TrimPrefix(r.URL.Path, "/swagger/")
p = path.Join("../protos", p) log.Printf("Serving swagger-file: %s", p) http.ServeFile(w, r, p)
} func serveSwaggerUI(mux *http.ServeMux) {
fileServer := http.FileServer(&assetfs.AssetFS{
Asset: swagger.Asset,
AssetDir: swagger.AssetDir,
Prefix: "third_party/swagger-ui",
})
prefix := "/swagger-ui/"
mux.Handle(prefix, http.StripPrefix(prefix, fileServer))
} func main() {
defer glog.Flush() if err := run(); err != nil {
glog.Fatal(err)
}
}

结果如下:

gRPC+gRPC Gateway+swagger小记-LMLPHP

总结

通过grpc-gateway的方式来访问grpc服务,还是挺方便的,不过性能会有所折损。

参考

https://segmentfault.com/a/1190000013513469

05-22 19:10