假定我们有一个项目需求，希望用Rpc作为内部API的通讯，同时也想对外提供Restful Api，写两套又太繁琐不符合

于是我们想到了Grpc以及Grpc Gateway，这就是我们所需要的

准备环境

假设以及安装好go环境以及grpc所需的组件

• Golang
• Grpc
• Protoc Plugin
• Protocol Buffers
• Grpc-gateway

准备构建所需组件

// +build toolspackage toolsimport (_ "github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway"_ "github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger"_ "github.com/golang/protobuf/protoc-gen-go"
)

运行go mod tidy以解决版本。通过运行安装

 go install \github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway \github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger \github.com/golang/protobuf/protoc-gen-go

这将在$GOBIN目录中放置三个二进制文件；

• protoc-gen-grpc-gateway-
• protoc-gen-swagger
• protoc-gen-go

对原有的RPC服务进行改造

your_history_service.proto:

syntax = "proto3";
package example;
message StringMessage {string value = 1;
}service YourService {rpc Echo(StringMessage) returns (StringMessage) {}
}

your_new_service.proto:

 syntax = "proto3";package example;
+
+import "google/api/annotations.proto";
+message StringMessage {string value = 1;}service YourService {
-  rpc Echo(StringMessage) returns (StringMessage) {}
+  rpc Echo(StringMessage) returns (StringMessage) {
+    option (google.api.http) = {
+      post: "/v1/example/echo"
+      body: "*"
+    };
+  }}

您将需要向protoc编译器提供所需的第三方protobuf文件。它们包含在此存储库中的third_party/googleapis文件夹下，建议将它们复制到protoc生成文件结构中。如果您已按照Buf样式指南的要求来构造原型文件，则可以将文件复制到顶级./google文件夹中。

上述话是官方文档中所介绍，我将下述目录下的复制粘贴到protoc文件的根目录下
E:\GOPATH\pkg\mod\github.com\grpc-ecosystem\grpc-gateway@v1.14.6\third_party\googleapis

生成rpc存根

1.这是生成RPC存根serveric.pd.go的命令

protoc -I. --go_out=plugins=grpc,paths=source_relative:./gen/go/ your/service/v1/your_service.proto

2.使用生成反向代理 protoc-gen-grpc-gateway

protoc -I. --grpc-gateway_out=logtostderr=true,paths=source_relative:./gen/go \your/service/v1/your_service.proto

示例代码

/*
@Time : 2020/6/8 10:21
@Author : zhb
@File : serviceHttp
@Software: GoLand
*/
package mainimport ("context""flag""github.com/golang/glog""github.com/grpc-ecosystem/grpc-gateway/runtime"pb "grpcDemo/protoc""net/http"
)var (// command-line options:// gRPC server endpointgrpcServerEndpoint = flag.String("grpc-server-endpoint", "localhost:9090", "gRPC server endpoint")
)type SearchServiceHttp struct{}func (s *SearchServiceHttp) Search(ctx context.Context, r *pb.SearchRequest) (*pb.SearchResponse, error) {return &pb.SearchResponse{Query: r.GetQuery() + " Server"}, nil
}func run() error {ctx := context.Background()ctx, cancel := context.WithCancel(ctx)defer cancel()// Register gRPC server endpoint// Note: Make sure the gRPC server is running properly and accessiblemux := runtime.NewServeMux()//opts := []grpc.DialOption{grpc.WithInsecure()}err := pb.RegisterSearchServiceHandlerServer(ctx, mux, &SearchServiceHttp{})if err != nil {return err}// Start HTTP server (and proxy calls to gRPC server endpoint)return http.ListenAndServe(":8081", mux)
}func main() {flag.Parse()defer glog.Flush()if err := run(); err != nil {glog.Fatal(err)}
}

完整代码示例