package daemon import ( "fmt" "io" "strconv" "time" "golang.org/x/net/context" "github.com/Sirupsen/logrus" "github.com/docker/docker/api/types/backend" "github.com/docker/docker/container" "github.com/docker/docker/daemon/logger" "github.com/docker/docker/daemon/logger/jsonfilelog" "github.com/docker/docker/pkg/ioutils" "github.com/docker/docker/pkg/stdcopy" containertypes "github.com/docker/engine-api/types/container" timetypes "github.com/docker/engine-api/types/time" ) // ContainerLogs hooks up a container's stdout and stderr streams // configured with the given struct. func (daemon *Daemon) ContainerLogs(ctx context.Context, containerName string, config *backend.ContainerLogsConfig, started chan struct{}) error { container, err := daemon.GetContainer(containerName) if err != nil { return err } if !(config.ShowStdout || config.ShowStderr) { return fmt.Errorf("You must choose at least one stream") } cLog, err := daemon.getLogger(container) 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") var since time.Time if config.Since != "" { s, n, err := timetypes.ParseTimestamps(config.Since, 0) if err != nil { return err } since = time.Unix(s, n) } readConfig := logger.ReadConfig{ Since: since, Tail: tailLines, Follow: follow, } logs := logReader.ReadLogs(readConfig) wf := ioutils.NewWriteFlusher(config.OutStream) defer wf.Close() close(started) wf.Flush() var outStream io.Writer = wf errStream := outStream if !container.Config.Tty { errStream = stdcopy.NewStdWriter(outStream, stdcopy.Stderr) outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout) } for { select { case err := <-logs.Err: logrus.Errorf("Error streaming logs: %v", err) return nil case <-ctx.Done(): logs.Close() return nil case msg, ok := <-logs.Msg: if !ok { logrus.Debugf("logs: end stream") logs.Close() return nil } logLine := msg.Line if config.Timestamps { logLine = append([]byte(msg.Timestamp.Format(logger.TimeFormat)+" "), logLine...) } if msg.Source == "stdout" && config.ShowStdout { outStream.Write(logLine) } if msg.Source == "stderr" && config.ShowStderr { errStream.Write(logLine) } } } } func (daemon *Daemon) getLogger(container *container.Container) (logger.Logger, error) { if container.LogDriver != nil && container.IsRunning() { return container.LogDriver, nil } cfg := daemon.getLogConfig(container.HostConfig.LogConfig) if err := logger.ValidateLogOpts(cfg.Type, cfg.Config); err != nil { return nil, err } return container.StartLogger(cfg) } // StartLogging initializes and starts the container logging stream. func (daemon *Daemon) StartLogging(container *container.Container) error { cfg := daemon.getLogConfig(container.HostConfig.LogConfig) if cfg.Type == "none" { return nil // do not start logging routines } if err := logger.ValidateLogOpts(cfg.Type, cfg.Config); err != nil { return err } l, err := container.StartLogger(cfg) if err != nil { return fmt.Errorf("Failed to initialize logging driver: %v", err) } copier := logger.NewCopier(container.ID, map[string]io.Reader{"stdout": container.StdoutPipe(), "stderr": container.StderrPipe()}, l) container.LogCopier = copier copier.Run() container.LogDriver = l // set LogPath field only for json-file logdriver if jl, ok := l.(*jsonfilelog.JSONFileLogger); ok { container.LogPath = jl.LogPath() } return nil } // getLogConfig returns the log configuration for the container. func (daemon *Daemon) getLogConfig(cfg containertypes.LogConfig) containertypes.LogConfig { if cfg.Type != "" || len(cfg.Config) > 0 { // container has log driver configured if cfg.Type == "" { cfg.Type = jsonfilelog.Name } return cfg } // Use daemon's default log config for containers return daemon.defaultLogConfig }