package daemon import ( "bytes" "encoding/json" "fmt" "io" "os" "strconv" "sync" log "github.com/Sirupsen/logrus" "github.com/docker/docker/engine" "github.com/docker/docker/pkg/jsonlog" "github.com/docker/docker/pkg/tailfile" "github.com/docker/docker/pkg/timeutils" ) func (daemon *Daemon) ContainerLogs(job *engine.Job) error { if len(job.Args) != 1 { return fmt.Errorf("Usage: %s CONTAINER\n", job.Name) } var ( name = job.Args[0] stdout = job.GetenvBool("stdout") stderr = job.GetenvBool("stderr") tail = job.Getenv("tail") follow = job.GetenvBool("follow") times = job.GetenvBool("timestamps") lines = -1 format string ) if !(stdout || stderr) { return fmt.Errorf("You must choose at least one stream") } if times { format = timeutils.RFC3339NanoFixed } if tail == "" { tail = "all" } container, err := daemon.Get(name) if err != nil { return err } if container.LogDriverType() != "json-file" { return fmt.Errorf("\"logs\" endpoint is supported only for \"json-file\" logging driver") } cLog, err := container.ReadLog("json") if err != nil && os.IsNotExist(err) { // Legacy logs log.Debugf("Old logs format") if stdout { cLog, err := container.ReadLog("stdout") if err != nil { log.Errorf("Error reading logs (stdout): %s", err) } else if _, err := io.Copy(job.Stdout, cLog); err != nil { log.Errorf("Error streaming logs (stdout): %s", err) } } if stderr { cLog, err := container.ReadLog("stderr") if err != nil { log.Errorf("Error reading logs (stderr): %s", err) } else if _, err := io.Copy(job.Stderr, cLog); err != nil { log.Errorf("Error streaming logs (stderr): %s", err) } } } else if err != nil { log.Errorf("Error reading logs (json): %s", err) } else { if tail != "all" { var err error lines, err = strconv.Atoi(tail) if err != nil { log.Errorf("Failed to parse tail %s, error: %v, show all logs", tail, err) lines = -1 } } if lines != 0 { if lines > 0 { f := cLog.(*os.File) ls, err := tailfile.TailFile(f, lines) if err != nil { return err } tmp := bytes.NewBuffer([]byte{}) for _, l := range ls { fmt.Fprintf(tmp, "%s\n", l) } cLog = tmp } dec := json.NewDecoder(cLog) l := &jsonlog.JSONLog{} for { if err := dec.Decode(l); err == io.EOF { break } else if err != nil { log.Errorf("Error streaming logs: %s", err) break } logLine := l.Log if times { // format can be "" or time format, so here can't be error logLine, _ = l.Format(format) } if l.Stream == "stdout" && stdout { io.WriteString(job.Stdout, logLine) } if l.Stream == "stderr" && stderr { io.WriteString(job.Stderr, logLine) } l.Reset() } } } if follow && container.IsRunning() { errors := make(chan error, 2) wg := sync.WaitGroup{} if stdout { wg.Add(1) stdoutPipe := container.StdoutLogPipe() defer stdoutPipe.Close() go func() { errors <- jsonlog.WriteLog(stdoutPipe, job.Stdout, format) wg.Done() }() } if stderr { wg.Add(1) stderrPipe := container.StderrLogPipe() defer stderrPipe.Close() go func() { errors <- jsonlog.WriteLog(stderrPipe, job.Stderr, format) wg.Done() }() } wg.Wait() close(errors) for err := range errors { if err != nil { log.Errorf("%s", err) } } } return nil }