3 * Copyright 2016 gRPC authors.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
19 //go:generate protoc --go_out=plugins=grpc:. grpc_reflection_v1alpha/reflection.proto
22 Package reflection implements server reflection service.
24 The service implemented is defined in:
25 https://github.com/grpc/grpc/blob/master/src/proto/grpc/reflection/v1alpha/reflection.proto.
27 To register server reflection on a gRPC server:
28 import "google.golang.org/grpc/reflection"
31 pb.RegisterYourOwnServer(s, &server{})
33 // Register reflection service on gRPC server.
34 reflection.Register(s)
39 package reflection // import "google.golang.org/grpc/reflection"
50 "github.com/golang/protobuf/proto"
51 dpb "github.com/golang/protobuf/protoc-gen-go/descriptor"
52 "google.golang.org/grpc"
53 "google.golang.org/grpc/codes"
54 rpb "google.golang.org/grpc/reflection/grpc_reflection_v1alpha"
57 type serverReflectionServer struct {
59 // TODO add more cache if necessary
60 serviceInfo map[string]grpc.ServiceInfo // cache for s.GetServiceInfo()
63 // Register registers the server reflection service on the given gRPC server.
64 func Register(s *grpc.Server) {
65 rpb.RegisterServerReflectionServer(s, &serverReflectionServer{
70 // protoMessage is used for type assertion on proto messages.
71 // Generated proto message implements function Descriptor(), but Descriptor()
72 // is not part of interface proto.Message. This interface is needed to
74 type protoMessage interface {
75 Descriptor() ([]byte, []int)
78 // fileDescForType gets the file descriptor for the given type.
79 // The given type should be a proto message.
80 func (s *serverReflectionServer) fileDescForType(st reflect.Type) (*dpb.FileDescriptorProto, error) {
81 m, ok := reflect.Zero(reflect.PtrTo(st)).Interface().(protoMessage)
83 return nil, fmt.Errorf("failed to create message from type: %v", st)
85 enc, _ := m.Descriptor()
87 return s.decodeFileDesc(enc)
90 // decodeFileDesc does decompression and unmarshalling on the given
91 // file descriptor byte slice.
92 func (s *serverReflectionServer) decodeFileDesc(enc []byte) (*dpb.FileDescriptorProto, error) {
93 raw, err := decompress(enc)
95 return nil, fmt.Errorf("failed to decompress enc: %v", err)
98 fd := new(dpb.FileDescriptorProto)
99 if err := proto.Unmarshal(raw, fd); err != nil {
100 return nil, fmt.Errorf("bad descriptor: %v", err)
105 // decompress does gzip decompression.
106 func decompress(b []byte) ([]byte, error) {
107 r, err := gzip.NewReader(bytes.NewReader(b))
109 return nil, fmt.Errorf("bad gzipped descriptor: %v", err)
111 out, err := ioutil.ReadAll(r)
113 return nil, fmt.Errorf("bad gzipped descriptor: %v", err)
118 func (s *serverReflectionServer) typeForName(name string) (reflect.Type, error) {
119 pt := proto.MessageType(name)
121 return nil, fmt.Errorf("unknown type: %q", name)
128 func (s *serverReflectionServer) fileDescContainingExtension(st reflect.Type, ext int32) (*dpb.FileDescriptorProto, error) {
129 m, ok := reflect.Zero(reflect.PtrTo(st)).Interface().(proto.Message)
131 return nil, fmt.Errorf("failed to create message from type: %v", st)
134 var extDesc *proto.ExtensionDesc
135 for id, desc := range proto.RegisteredExtensions(m) {
143 return nil, fmt.Errorf("failed to find registered extension for extension number %v", ext)
146 return s.decodeFileDesc(proto.FileDescriptor(extDesc.Filename))
149 func (s *serverReflectionServer) allExtensionNumbersForType(st reflect.Type) ([]int32, error) {
150 m, ok := reflect.Zero(reflect.PtrTo(st)).Interface().(proto.Message)
152 return nil, fmt.Errorf("failed to create message from type: %v", st)
155 exts := proto.RegisteredExtensions(m)
156 out := make([]int32, 0, len(exts))
157 for id := range exts {
158 out = append(out, id)
163 // fileDescEncodingByFilename finds the file descriptor for given filename,
164 // does marshalling on it and returns the marshalled result.
165 func (s *serverReflectionServer) fileDescEncodingByFilename(name string) ([]byte, error) {
166 enc := proto.FileDescriptor(name)
168 return nil, fmt.Errorf("unknown file: %v", name)
170 fd, err := s.decodeFileDesc(enc)
174 return proto.Marshal(fd)
177 // serviceMetadataForSymbol finds the metadata for name in s.serviceInfo.
178 // name should be a service name or a method name.
179 func (s *serverReflectionServer) serviceMetadataForSymbol(name string) (interface{}, error) {
180 if s.serviceInfo == nil {
181 s.serviceInfo = s.s.GetServiceInfo()
184 // Check if it's a service name.
185 if info, ok := s.serviceInfo[name]; ok {
186 return info.Metadata, nil
189 // Check if it's a method name.
190 pos := strings.LastIndex(name, ".")
191 // Not a valid method name.
193 return nil, fmt.Errorf("unknown symbol: %v", name)
196 info, ok := s.serviceInfo[name[:pos]]
197 // Substring before last "." is not a service name.
199 return nil, fmt.Errorf("unknown symbol: %v", name)
202 // Search the method name in info.Methods.
204 for _, m := range info.Methods {
205 if m.Name == name[pos+1:] {
211 return info.Metadata, nil
214 return nil, fmt.Errorf("unknown symbol: %v", name)
217 // parseMetadata finds the file descriptor bytes specified meta.
218 // For SupportPackageIsVersion4, m is the name of the proto file, we
219 // call proto.FileDescriptor to get the byte slice.
220 // For SupportPackageIsVersion3, m is a byte slice itself.
221 func parseMetadata(meta interface{}) ([]byte, bool) {
222 // Check if meta is the file name.
223 if fileNameForMeta, ok := meta.(string); ok {
224 return proto.FileDescriptor(fileNameForMeta), true
227 // Check if meta is the byte slice.
228 if enc, ok := meta.([]byte); ok {
235 // fileDescEncodingContainingSymbol finds the file descriptor containing the given symbol,
236 // does marshalling on it and returns the marshalled result.
237 // The given symbol can be a type, a service or a method.
238 func (s *serverReflectionServer) fileDescEncodingContainingSymbol(name string) ([]byte, error) {
240 fd *dpb.FileDescriptorProto
242 // Check if it's a type name.
243 if st, err := s.typeForName(name); err == nil {
244 fd, err = s.fileDescForType(st)
248 } else { // Check if it's a service name or a method name.
249 meta, err := s.serviceMetadataForSymbol(name)
251 // Metadata not found.
256 // Metadata not valid.
257 enc, ok := parseMetadata(meta)
259 return nil, fmt.Errorf("invalid file descriptor for symbol: %v", name)
262 fd, err = s.decodeFileDesc(enc)
268 return proto.Marshal(fd)
271 // fileDescEncodingContainingExtension finds the file descriptor containing given extension,
272 // does marshalling on it and returns the marshalled result.
273 func (s *serverReflectionServer) fileDescEncodingContainingExtension(typeName string, extNum int32) ([]byte, error) {
274 st, err := s.typeForName(typeName)
278 fd, err := s.fileDescContainingExtension(st, extNum)
282 return proto.Marshal(fd)
285 // allExtensionNumbersForTypeName returns all extension numbers for the given type.
286 func (s *serverReflectionServer) allExtensionNumbersForTypeName(name string) ([]int32, error) {
287 st, err := s.typeForName(name)
291 extNums, err := s.allExtensionNumbersForType(st)
298 // ServerReflectionInfo is the reflection service handler.
299 func (s *serverReflectionServer) ServerReflectionInfo(stream rpb.ServerReflection_ServerReflectionInfoServer) error {
301 in, err := stream.Recv()
309 out := &rpb.ServerReflectionResponse{
313 switch req := in.MessageRequest.(type) {
314 case *rpb.ServerReflectionRequest_FileByFilename:
315 b, err := s.fileDescEncodingByFilename(req.FileByFilename)
317 out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{
318 ErrorResponse: &rpb.ErrorResponse{
319 ErrorCode: int32(codes.NotFound),
320 ErrorMessage: err.Error(),
324 out.MessageResponse = &rpb.ServerReflectionResponse_FileDescriptorResponse{
325 FileDescriptorResponse: &rpb.FileDescriptorResponse{FileDescriptorProto: [][]byte{b}},
328 case *rpb.ServerReflectionRequest_FileContainingSymbol:
329 b, err := s.fileDescEncodingContainingSymbol(req.FileContainingSymbol)
331 out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{
332 ErrorResponse: &rpb.ErrorResponse{
333 ErrorCode: int32(codes.NotFound),
334 ErrorMessage: err.Error(),
338 out.MessageResponse = &rpb.ServerReflectionResponse_FileDescriptorResponse{
339 FileDescriptorResponse: &rpb.FileDescriptorResponse{FileDescriptorProto: [][]byte{b}},
342 case *rpb.ServerReflectionRequest_FileContainingExtension:
343 typeName := req.FileContainingExtension.ContainingType
344 extNum := req.FileContainingExtension.ExtensionNumber
345 b, err := s.fileDescEncodingContainingExtension(typeName, extNum)
347 out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{
348 ErrorResponse: &rpb.ErrorResponse{
349 ErrorCode: int32(codes.NotFound),
350 ErrorMessage: err.Error(),
354 out.MessageResponse = &rpb.ServerReflectionResponse_FileDescriptorResponse{
355 FileDescriptorResponse: &rpb.FileDescriptorResponse{FileDescriptorProto: [][]byte{b}},
358 case *rpb.ServerReflectionRequest_AllExtensionNumbersOfType:
359 extNums, err := s.allExtensionNumbersForTypeName(req.AllExtensionNumbersOfType)
361 out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{
362 ErrorResponse: &rpb.ErrorResponse{
363 ErrorCode: int32(codes.NotFound),
364 ErrorMessage: err.Error(),
368 out.MessageResponse = &rpb.ServerReflectionResponse_AllExtensionNumbersResponse{
369 AllExtensionNumbersResponse: &rpb.ExtensionNumberResponse{
370 BaseTypeName: req.AllExtensionNumbersOfType,
371 ExtensionNumber: extNums,
375 case *rpb.ServerReflectionRequest_ListServices:
376 if s.serviceInfo == nil {
377 s.serviceInfo = s.s.GetServiceInfo()
379 serviceResponses := make([]*rpb.ServiceResponse, 0, len(s.serviceInfo))
380 for n := range s.serviceInfo {
381 serviceResponses = append(serviceResponses, &rpb.ServiceResponse{
385 out.MessageResponse = &rpb.ServerReflectionResponse_ListServicesResponse{
386 ListServicesResponse: &rpb.ListServiceResponse{
387 Service: serviceResponses,
391 return grpc.Errorf(codes.InvalidArgument, "invalid MessageRequest: %v", in.MessageRequest)
394 if err := stream.Send(out); err != nil {