package daemon import ( "fmt" "io" "strconv" "time" "github.com/Sirupsen/logrus" "github.com/docker/docker/daemon/logger" "github.com/docker/docker/pkg/stdcopy" ) // ContainerLogsConfig holds configs for logging operations. Exists // for users of the daemon to to pass it a logging configuration. type ContainerLogsConfig struct { // if true stream log output Follow bool // if true include timestamps for each line of log output Timestamps bool // return that many lines of log output from the end Tail string // filter logs by returning on those entries after this time Since time.Time // whether or not to show stdout and stderr as well as log entries. UseStdout, UseStderr bool OutStream io.Writer Stop <-chan bool } // ContainerLogs hooks up a container's stdout and stderr streams // configured with the given struct. func (daemon *Daemon) ContainerLogs(container *Container, config *ContainerLogsConfig) error { if !(config.UseStdout || config.UseStderr) { return fmt.Errorf("You must choose at least one stream") } outStream := config.OutStream errStream := outStream if !container.Config.Tty { errStream = stdcopy.NewStdWriter(outStream, stdcopy.Stderr) outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout) } cLog, err := container.getLogger() if err != nil { return err } logReader, ok := cLog.(logger.LogReader) if !ok { return logger.ErrReadLogsNotSupported } follow := config.Follow && container.IsRunning() tailLines, err := strconv.Atoi(config.Tail) if err != nil { tailLines = -1 } logrus.Debug("logs: begin stream") readConfig := logger.ReadConfig{ Since: config.Since, Tail: tailLines, Follow: follow, } logs := logReader.ReadLogs(readConfig) for { select { case err := <-logs.Err: logrus.Errorf("Error streaming logs: %v", err) return nil case <-config.Stop: logs.Close() return nil case msg, ok := <-logs.Msg: if !ok { logrus.Debugf("logs: end stream") return nil } logLine := msg.Line if config.Timestamps { logLine = append([]byte(msg.Timestamp.Format(logger.TimeFormat)+" "), logLine...) } if msg.Source == "stdout" && config.UseStdout { outStream.Write(logLine) } if msg.Source == "stderr" && config.UseStderr { errStream.Write(logLine) } } } }