package ipc import ( "bytes" "io" "io/ioutil" "net" "os" "reflect" "github.com/docker/docker-registry/storagedriver" "github.com/docker/libchan" "github.com/docker/libchan/spdy" ) // StorageDriverServer runs a new IPC server handling requests for the given // storagedriver.StorageDriver // This explicitly uses file descriptor 3 for IPC communication, as storage drivers are spawned in // client.go // // To create a new out-of-process driver, create a main package which calls StorageDriverServer with // a storagedriver.StorageDriver func StorageDriverServer(driver storagedriver.StorageDriver) error { childSocket := os.NewFile(3, "childSocket") defer childSocket.Close() conn, err := net.FileConn(childSocket) if err != nil { panic(err) } defer conn.Close() if transport, err := spdy.NewServerTransport(conn); err != nil { panic(err) } else { for { receiver, err := transport.WaitReceiveChannel() if err == io.EOF { return nil } else if err != nil { panic(err) } go receive(driver, receiver) } } } // receive receives new storagedriver.StorageDriver method requests and creates a new goroutine to // handle each request // Requests are expected to be of type ipc.Request as the parameters are unknown until the request // type is deserialized func receive(driver storagedriver.StorageDriver, receiver libchan.Receiver) { for { var request Request err := receiver.Receive(&request) if err == io.EOF { return } else if err != nil { panic(err) } go handleRequest(driver, request) } } // handleRequest handles storagedriver.StorageDriver method requests as defined in client.go // Responds to requests using the Request.ResponseChannel func handleRequest(driver storagedriver.StorageDriver, request Request) { switch request.Type { case "Version": err := request.ResponseChannel.Send(&VersionResponse{Version: storagedriver.CurrentVersion}) if err != nil { panic(err) } case "GetContent": path, _ := request.Parameters["Path"].(string) content, err := driver.GetContent(path) var response ReadStreamResponse if err != nil { response = ReadStreamResponse{Error: WrapError(err)} } else { response = ReadStreamResponse{Reader: ioutil.NopCloser(bytes.NewReader(content))} } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } case "PutContent": path, _ := request.Parameters["Path"].(string) reader, _ := request.Parameters["Reader"].(io.ReadCloser) contents, err := ioutil.ReadAll(reader) defer reader.Close() if err == nil { err = driver.PutContent(path, contents) } response := WriteStreamResponse{ Error: WrapError(err), } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } case "ReadStream": path, _ := request.Parameters["Path"].(string) // Depending on serialization method, Offset may be convereted to any int/uint type offset := reflect.ValueOf(request.Parameters["Offset"]).Convert(reflect.TypeOf(uint64(0))).Uint() reader, err := driver.ReadStream(path, offset) var response ReadStreamResponse if err != nil { response = ReadStreamResponse{Error: WrapError(err)} } else { response = ReadStreamResponse{Reader: ioutil.NopCloser(reader)} } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } case "WriteStream": path, _ := request.Parameters["Path"].(string) // Depending on serialization method, Offset may be convereted to any int/uint type offset := reflect.ValueOf(request.Parameters["Offset"]).Convert(reflect.TypeOf(uint64(0))).Uint() // Depending on serialization method, Size may be convereted to any int/uint type size := reflect.ValueOf(request.Parameters["Size"]).Convert(reflect.TypeOf(uint64(0))).Uint() reader, _ := request.Parameters["Reader"].(io.ReadCloser) err := driver.WriteStream(path, offset, size, reader) response := WriteStreamResponse{ Error: WrapError(err), } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } case "CurrentSize": path, _ := request.Parameters["Path"].(string) position, err := driver.CurrentSize(path) response := CurrentSizeResponse{ Position: position, Error: WrapError(err), } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } case "List": path, _ := request.Parameters["Path"].(string) keys, err := driver.List(path) response := ListResponse{ Keys: keys, Error: WrapError(err), } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } case "Move": sourcePath, _ := request.Parameters["SourcePath"].(string) destPath, _ := request.Parameters["DestPath"].(string) err := driver.Move(sourcePath, destPath) response := MoveResponse{ Error: WrapError(err), } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } case "Delete": path, _ := request.Parameters["Path"].(string) err := driver.Delete(path) response := DeleteResponse{ Error: WrapError(err), } err = request.ResponseChannel.Send(&response) if err != nil { panic(err) } default: panic(request) } }