package libpod import ( "context" "fmt" "os" "github.com/containers/podman/v3/libpod/define" "github.com/containers/podman/v3/libpod/events" "github.com/containers/podman/v3/libpod/logs" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) // Log is a runtime function that can read one or more container logs. func (r *Runtime) Log(ctx context.Context, containers []*Container, options *logs.LogOptions, logChannel chan *logs.LogLine) error { for _, ctr := range containers { if err := ctr.ReadLog(ctx, options, logChannel); err != nil { return err } } return nil } // ReadLog reads a containers log based on the input options and returns log lines over a channel. func (c *Container) ReadLog(ctx context.Context, options *logs.LogOptions, logChannel chan *logs.LogLine) error { switch c.LogDriver() { case define.NoLogging: return errors.Wrapf(define.ErrNoLogs, "this container is using the 'none' log driver, cannot read logs") case define.JournaldLogging: return c.readFromJournal(ctx, options, logChannel) case define.JSONLogging: // TODO provide a separate implementation of this when Conmon // has support. fallthrough case define.KubernetesLogging, "": return c.readFromLogFile(ctx, options, logChannel) default: return errors.Wrapf(define.ErrInternal, "unrecognized log driver %q, cannot read logs", c.LogDriver()) } } func (c *Container) readFromLogFile(ctx context.Context, options *logs.LogOptions, logChannel chan *logs.LogLine) error { t, tailLog, err := logs.GetLogFile(c.LogPath(), options) if err != nil { // If the log file does not exist, this is not fatal. if os.IsNotExist(errors.Cause(err)) { return nil } return errors.Wrapf(err, "unable to read log file %s for %s ", c.ID(), c.LogPath()) } options.WaitGroup.Add(1) if len(tailLog) > 0 { for _, nll := range tailLog { nll.CID = c.ID() nll.CName = c.Name() if nll.Since(options.Since) { logChannel <- nll } } } go func() { defer options.WaitGroup.Done() var partial string for line := range t.Lines { select { case <-ctx.Done(): // the consumer has cancelled return default: // fallthrough } nll, err := logs.NewLogLine(line.Text) if err != nil { logrus.Error(err) continue } if nll.Partial() { partial += nll.Msg continue } else if !nll.Partial() && len(partial) > 0 { nll.Msg = partial + nll.Msg partial = "" } nll.CID = c.ID() nll.CName = c.Name() if nll.Since(options.Since) { logChannel <- nll } } }() // Check if container is still running or paused if options.Follow { state, err := c.State() if err != nil || state != define.ContainerStateRunning { // If the container isn't running or if we encountered // an error getting its state, instruct the logger to // read the file until EOF. tailError := t.StopAtEOF() if tailError != nil && fmt.Sprintf("%v", tailError) != "tail: stop at eof" { logrus.Error(tailError) } if errors.Cause(err) != define.ErrNoSuchCtr { logrus.Error(err) } return nil } // The container is running, so we need to wait until the container exited go func() { eventChannel := make(chan *events.Event) eventOptions := events.ReadOptions{ EventChannel: eventChannel, Filters: []string{"event=died", "container=" + c.ID()}, Stream: true, } go func() { if err := c.runtime.Events(ctx, eventOptions); err != nil { logrus.Errorf("Error waiting for container to exit: %v", err) } }() // Now wait for the died event and signal to finish // reading the log until EOF. <-eventChannel tailError := t.StopAtEOF() if tailError != nil && fmt.Sprintf("%v", tailError) != "tail: stop at eof" { logrus.Error(tailError) } }() } return nil }