diff --git a/reflection.go b/reflection.go new file mode 100644 index 0000000..fc78268 --- /dev/null +++ b/reflection.go @@ -0,0 +1,486 @@ +/* + * + * Copyright 2016 gRPC authors. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + */ + +/* +Package reflection implements server reflection service. + +The service implemented is defined in: +https://github.com/grpc/grpc/blob/master/src/proto/grpc/reflection/v1alpha/reflection.proto. + +To register server reflection on a gRPC server: + import "google.golang.org/grpc/reflection" + + s := grpc.NewServer() + pb.RegisterYourOwnServer(s, &server{}) + + // Register reflection service on gRPC server. + reflection.Register(s) + + s.Serve(lis) + +*/ +package grpc + +import ( + "bytes" + "compress/gzip" + "fmt" + "io" + "io/ioutil" + "reflect" + "sort" + "sync" + + "github.com/golang/protobuf/proto" + dpb "github.com/golang/protobuf/protoc-gen-go/descriptor" + "google.golang.org/grpc" + "google.golang.org/grpc/codes" + rpb "google.golang.org/grpc/reflection/grpc_reflection_v1alpha" + "google.golang.org/grpc/status" +) + +type serverReflectionServer struct { + rpb.UnimplementedServerReflectionServer + s *grpc.Server + + initSymbols sync.Once + serviceNames []string + symbols map[string]*dpb.FileDescriptorProto // map of fully-qualified names to files +} + +// Register registers the server reflection service on the given gRPC server. +func Register(s *grpc.Server) { + rpb.RegisterServerReflectionServer(s, &serverReflectionServer{ + s: s, + }) +} + +// protoMessage is used for type assertion on proto messages. +// Generated proto message implements function Descriptor(), but Descriptor() +// is not part of interface proto.Message. This interface is needed to +// call Descriptor(). +type protoMessage interface { + Descriptor() ([]byte, []int) +} + +func (s *serverReflectionServer) getSymbols() (svcNames []string, symbolIndex map[string]*dpb.FileDescriptorProto) { + s.initSymbols.Do(func() { + serviceInfo := s.s.GetServiceInfo() + + s.symbols = map[string]*dpb.FileDescriptorProto{} + s.serviceNames = make([]string, 0, len(serviceInfo)) + processed := map[string]struct{}{} + for svc, info := range serviceInfo { + s.serviceNames = append(s.serviceNames, svc) + fdenc, ok := parseMetadata(info.Metadata) + if !ok { + continue + } + fd, err := decodeFileDesc(fdenc) + if err != nil { + continue + } + s.processFile(fd, processed) + } + sort.Strings(s.serviceNames) + }) + + return s.serviceNames, s.symbols +} + +func (s *serverReflectionServer) processFile(fd *dpb.FileDescriptorProto, processed map[string]struct{}) { + filename := fd.GetName() + if _, ok := processed[filename]; ok { + return + } + processed[filename] = struct{}{} + + prefix := fd.GetPackage() + + for _, msg := range fd.MessageType { + s.processMessage(fd, prefix, msg) + } + for _, en := range fd.EnumType { + s.processEnum(fd, prefix, en) + } + for _, ext := range fd.Extension { + s.processField(fd, prefix, ext) + } + for _, svc := range fd.Service { + svcName := fqn(prefix, svc.GetName()) + s.symbols[svcName] = fd + for _, meth := range svc.Method { + name := fqn(svcName, meth.GetName()) + s.symbols[name] = fd + } + } + + for _, dep := range fd.Dependency { + fdenc := proto.FileDescriptor(dep) + fdDep, err := decodeFileDesc(fdenc) + if err != nil { + continue + } + s.processFile(fdDep, processed) + } +} + +func (s *serverReflectionServer) processMessage(fd *dpb.FileDescriptorProto, prefix string, msg *dpb.DescriptorProto) { + msgName := fqn(prefix, msg.GetName()) + s.symbols[msgName] = fd + + for _, nested := range msg.NestedType { + s.processMessage(fd, msgName, nested) + } + for _, en := range msg.EnumType { + s.processEnum(fd, msgName, en) + } + for _, ext := range msg.Extension { + s.processField(fd, msgName, ext) + } + for _, fld := range msg.Field { + s.processField(fd, msgName, fld) + } + for _, oneof := range msg.OneofDecl { + oneofName := fqn(msgName, oneof.GetName()) + s.symbols[oneofName] = fd + } +} + +func (s *serverReflectionServer) processEnum(fd *dpb.FileDescriptorProto, prefix string, en *dpb.EnumDescriptorProto) { + enName := fqn(prefix, en.GetName()) + s.symbols[enName] = fd + + for _, val := range en.Value { + valName := fqn(enName, val.GetName()) + s.symbols[valName] = fd + } +} + +func (s *serverReflectionServer) processField(fd *dpb.FileDescriptorProto, prefix string, fld *dpb.FieldDescriptorProto) { + fldName := fqn(prefix, fld.GetName()) + s.symbols[fldName] = fd +} + +func fqn(prefix, name string) string { + if prefix == "" { + return name + } + return prefix + "." + name +} + +// fileDescForType gets the file descriptor for the given type. +// The given type should be a proto message. +func (s *serverReflectionServer) fileDescForType(st reflect.Type) (*dpb.FileDescriptorProto, error) { + m, ok := reflect.Zero(reflect.PtrTo(st)).Interface().(protoMessage) + if !ok { + return nil, fmt.Errorf("failed to create message from type: %v", st) + } + enc, _ := m.Descriptor() + + return decodeFileDesc(enc) +} + +// decodeFileDesc does decompression and unmarshalling on the given +// file descriptor byte slice. +func decodeFileDesc(enc []byte) (*dpb.FileDescriptorProto, error) { + raw, err := decompress(enc) + if err != nil { + return nil, fmt.Errorf("failed to decompress enc: %v", err) + } + + fd := new(dpb.FileDescriptorProto) + if err := proto.Unmarshal(raw, fd); err != nil { + return nil, fmt.Errorf("bad descriptor: %v", err) + } + return fd, nil +} + +// decompress does gzip decompression. +func decompress(b []byte) ([]byte, error) { + r, err := gzip.NewReader(bytes.NewReader(b)) + if err != nil { + return nil, fmt.Errorf("bad gzipped descriptor: %v", err) + } + out, err := ioutil.ReadAll(r) + if err != nil { + return nil, fmt.Errorf("bad gzipped descriptor: %v", err) + } + return out, nil +} + +func typeForName(name string) (reflect.Type, error) { + pt := proto.MessageType(name) + if pt == nil { + return nil, fmt.Errorf("unknown type: %q", name) + } + st := pt.Elem() + + return st, nil +} + +func fileDescContainingExtension(st reflect.Type, ext int32) (*dpb.FileDescriptorProto, error) { + m, ok := reflect.Zero(reflect.PtrTo(st)).Interface().(proto.Message) + if !ok { + return nil, fmt.Errorf("failed to create message from type: %v", st) + } + + var extDesc *proto.ExtensionDesc + for id, desc := range proto.RegisteredExtensions(m) { + if id == ext { + extDesc = desc + break + } + } + + if extDesc == nil { + return nil, fmt.Errorf("failed to find registered extension for extension number %v", ext) + } + + return decodeFileDesc(proto.FileDescriptor(extDesc.Filename)) +} + +func (s *serverReflectionServer) allExtensionNumbersForType(st reflect.Type) ([]int32, error) { + m, ok := reflect.Zero(reflect.PtrTo(st)).Interface().(proto.Message) + if !ok { + return nil, fmt.Errorf("failed to create message from type: %v", st) + } + + exts := proto.RegisteredExtensions(m) + out := make([]int32, 0, len(exts)) + for id := range exts { + out = append(out, id) + } + return out, nil +} + +// fileDescWithDependencies returns a slice of serialized fileDescriptors in +// wire format ([]byte). The fileDescriptors will include fd and all the +// transitive dependencies of fd with names not in sentFileDescriptors. +func fileDescWithDependencies(fd *dpb.FileDescriptorProto, sentFileDescriptors map[string]bool) ([][]byte, error) { + r := [][]byte{} + queue := []*dpb.FileDescriptorProto{fd} + for len(queue) > 0 { + currentfd := queue[0] + queue = queue[1:] + if sent := sentFileDescriptors[currentfd.GetName()]; len(r) == 0 || !sent { + sentFileDescriptors[currentfd.GetName()] = true + currentfdEncoded, err := proto.Marshal(currentfd) + if err != nil { + return nil, err + } + r = append(r, currentfdEncoded) + } + for _, dep := range currentfd.Dependency { + fdenc := proto.FileDescriptor(dep) + fdDep, err := decodeFileDesc(fdenc) + if err != nil { + continue + } + queue = append(queue, fdDep) + } + } + return r, nil +} + +// fileDescEncodingByFilename finds the file descriptor for given filename, +// finds all of its previously unsent transitive dependencies, does marshalling +// on them, and returns the marshalled result. +func (s *serverReflectionServer) fileDescEncodingByFilename(name string, sentFileDescriptors map[string]bool) ([][]byte, error) { + enc := proto.FileDescriptor(name) + if enc == nil { + return nil, fmt.Errorf("unknown file: %v", name) + } + fd, err := decodeFileDesc(enc) + if err != nil { + return nil, err + } + return fileDescWithDependencies(fd, sentFileDescriptors) +} + +// parseMetadata finds the file descriptor bytes specified meta. +// For SupportPackageIsVersion4, m is the name of the proto file, we +// call proto.FileDescriptor to get the byte slice. +// For SupportPackageIsVersion3, m is a byte slice itself. +func parseMetadata(meta interface{}) ([]byte, bool) { + // Check if meta is the file name. + if fileNameForMeta, ok := meta.(string); ok { + return proto.FileDescriptor(fileNameForMeta), true + } + + // Check if meta is the byte slice. + if enc, ok := meta.([]byte); ok { + return enc, true + } + + return nil, false +} + +// fileDescEncodingContainingSymbol finds the file descriptor containing the +// given symbol, finds all of its previously unsent transitive dependencies, +// does marshalling on them, and returns the marshalled result. The given symbol +// can be a type, a service or a method. +func (s *serverReflectionServer) fileDescEncodingContainingSymbol(name string, sentFileDescriptors map[string]bool) ([][]byte, error) { + _, symbols := s.getSymbols() + fd := symbols[name] + if fd == nil { + // Check if it's a type name that was not present in the + // transitive dependencies of the registered services. + if st, err := typeForName(name); err == nil { + fd, err = s.fileDescForType(st) + if err != nil { + return nil, err + } + } + } + + if fd == nil { + return nil, fmt.Errorf("unknown symbol: %v", name) + } + + return fileDescWithDependencies(fd, sentFileDescriptors) +} + +// fileDescEncodingContainingExtension finds the file descriptor containing +// given extension, finds all of its previously unsent transitive dependencies, +// does marshalling on them, and returns the marshalled result. +func (s *serverReflectionServer) fileDescEncodingContainingExtension(typeName string, extNum int32, sentFileDescriptors map[string]bool) ([][]byte, error) { + st, err := typeForName(typeName) + if err != nil { + return nil, err + } + fd, err := fileDescContainingExtension(st, extNum) + if err != nil { + return nil, err + } + return fileDescWithDependencies(fd, sentFileDescriptors) +} + +// allExtensionNumbersForTypeName returns all extension numbers for the given type. +func (s *serverReflectionServer) allExtensionNumbersForTypeName(name string) ([]int32, error) { + st, err := typeForName(name) + if err != nil { + return nil, err + } + extNums, err := s.allExtensionNumbersForType(st) + if err != nil { + return nil, err + } + return extNums, nil +} + +// ServerReflectionInfo is the reflection service handler. +func (s *serverReflectionServer) ServerReflectionInfo(stream rpb.ServerReflection_ServerReflectionInfoServer) error { + sentFileDescriptors := make(map[string]bool) + for { + in, err := stream.Recv() + if err == io.EOF { + return nil + } + if err != nil { + return err + } + + out := &rpb.ServerReflectionResponse{ + ValidHost: in.Host, + OriginalRequest: in, + } + switch req := in.MessageRequest.(type) { + case *rpb.ServerReflectionRequest_FileByFilename: + b, err := s.fileDescEncodingByFilename(req.FileByFilename, sentFileDescriptors) + if err != nil { + out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{ + ErrorResponse: &rpb.ErrorResponse{ + ErrorCode: int32(codes.NotFound), + ErrorMessage: err.Error(), + }, + } + } else { + out.MessageResponse = &rpb.ServerReflectionResponse_FileDescriptorResponse{ + FileDescriptorResponse: &rpb.FileDescriptorResponse{FileDescriptorProto: b}, + } + } + case *rpb.ServerReflectionRequest_FileContainingSymbol: + b, err := s.fileDescEncodingContainingSymbol(req.FileContainingSymbol, sentFileDescriptors) + if err != nil { + out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{ + ErrorResponse: &rpb.ErrorResponse{ + ErrorCode: int32(codes.NotFound), + ErrorMessage: err.Error(), + }, + } + } else { + out.MessageResponse = &rpb.ServerReflectionResponse_FileDescriptorResponse{ + FileDescriptorResponse: &rpb.FileDescriptorResponse{FileDescriptorProto: b}, + } + } + case *rpb.ServerReflectionRequest_FileContainingExtension: + typeName := req.FileContainingExtension.ContainingType + extNum := req.FileContainingExtension.ExtensionNumber + b, err := s.fileDescEncodingContainingExtension(typeName, extNum, sentFileDescriptors) + if err != nil { + out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{ + ErrorResponse: &rpb.ErrorResponse{ + ErrorCode: int32(codes.NotFound), + ErrorMessage: err.Error(), + }, + } + } else { + out.MessageResponse = &rpb.ServerReflectionResponse_FileDescriptorResponse{ + FileDescriptorResponse: &rpb.FileDescriptorResponse{FileDescriptorProto: b}, + } + } + case *rpb.ServerReflectionRequest_AllExtensionNumbersOfType: + extNums, err := s.allExtensionNumbersForTypeName(req.AllExtensionNumbersOfType) + if err != nil { + out.MessageResponse = &rpb.ServerReflectionResponse_ErrorResponse{ + ErrorResponse: &rpb.ErrorResponse{ + ErrorCode: int32(codes.NotFound), + ErrorMessage: err.Error(), + }, + } + } else { + out.MessageResponse = &rpb.ServerReflectionResponse_AllExtensionNumbersResponse{ + AllExtensionNumbersResponse: &rpb.ExtensionNumberResponse{ + BaseTypeName: req.AllExtensionNumbersOfType, + ExtensionNumber: extNums, + }, + } + } + case *rpb.ServerReflectionRequest_ListServices: + svcNames, _ := s.getSymbols() + serviceResponses := make([]*rpb.ServiceResponse, len(svcNames)) + for i, n := range svcNames { + serviceResponses[i] = &rpb.ServiceResponse{ + Name: n, + } + } + out.MessageResponse = &rpb.ServerReflectionResponse_ListServicesResponse{ + ListServicesResponse: &rpb.ListServiceResponse{ + Service: serviceResponses, + }, + } + default: + return status.Errorf(codes.InvalidArgument, "invalid MessageRequest: %v", in.MessageRequest) + } + + if err := stream.Send(out); err != nil { + return err + } + } +}