package cmdio import ( "bufio" "context" "encoding/json" "fmt" "io" "os" "github.com/databricks/cli/libs/flags" ) // This is the interface for all io interactions with a user type Logger struct { // Mode for the logger. One of (append, inplace, json). Mode flags.ProgressLogFormat // Input stream (eg. stdin). Answers to questions prompted using the Ask() method // are read from here Reader bufio.Reader // Output stream where the logger writes to Writer io.Writer // If true, indicates no events have been printed by the logger yet. Used // by inplace logging for formatting isFirstEvent bool } func NewLogger(mode flags.ProgressLogFormat) *Logger { return &Logger{ Mode: mode, Writer: os.Stderr, Reader: *bufio.NewReader(os.Stdin), isFirstEvent: true, } } func Default() *Logger { return &Logger{ Mode: flags.ModeAppend, Writer: os.Stderr, Reader: *bufio.NewReader(os.Stdin), isFirstEvent: true, } } func Log(ctx context.Context, event Event) { logger, ok := FromContext(ctx) if !ok { logger = Default() } logger.Log(event) } func LogString(ctx context.Context, message string) { logger, ok := FromContext(ctx) if !ok { logger = Default() } logger.Log(&MessageEvent{ Message: message, }) } func LogError(ctx context.Context, err error) { logger, ok := FromContext(ctx) if !ok { logger = Default() } logger.Log(&ErrorEvent{ Error: err.Error(), }) } func Ask(ctx context.Context, question string) (bool, error) { logger, ok := FromContext(ctx) if !ok { logger = Default() } return logger.Ask(question) } func (l *Logger) Ask(question string) (bool, error) { if l.Mode == flags.ModeJson { return false, fmt.Errorf("question prompts are not supported in json mode") } l.Writer.Write([]byte(question)) ans, err := l.Reader.ReadString('\n') if err != nil { return false, err } if ans == "y\n" { return true, nil } else { return false, nil } } func (l *Logger) writeJson(event Event) { b, err := json.MarshalIndent(event, "", " ") if err != nil { // we panic because there we cannot catch this in jobs.RunNowAndWait panic(err) } l.Writer.Write([]byte(b)) l.Writer.Write([]byte("\n")) } func (l *Logger) writeAppend(event Event) { l.Writer.Write([]byte(event.String())) l.Writer.Write([]byte("\n")) } func (l *Logger) writeInplace(event Event) { if l.isFirstEvent { // save cursor location l.Writer.Write([]byte("\033[s")) } // move cursor to saved location l.Writer.Write([]byte("\033[u")) // clear from cursor to end of screen l.Writer.Write([]byte("\033[0J")) l.Writer.Write([]byte(event.String())) l.Writer.Write([]byte("\n")) l.isFirstEvent = false } func (l *Logger) Log(event Event) { switch l.Mode { case flags.ModeInplace: if event.IsInplaceSupported() { l.writeInplace(event) } else { l.writeAppend(event) } case flags.ModeJson: l.writeJson(event) case flags.ModeAppend: l.writeAppend(event) default: // we panic because errors are not captured in some log sides like // jobs.RunNowAndWait panic("unknown progress logger mode: " + l.Mode.String()) } }