logs: k8s-file: restore poll sleep

Commit 84b55eec2796 attempted to fix a race waiting for the container
died event.  Previously, Podman slept for duration of the polling
frequence which I considerred to be a mistake.  As it turns out, I was
mistaken since the file logger will, in fact, NOT read until EOF and
then stop logging but stop logging immediately _after_ it woke up.

[NO TESTS NEEDED] as the race condition cannot be hit reliably.

Fixes: #10675
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/libpod/container_log.go b/libpod/container_log.go
index 8bbb7ebe8..43b3f7736 100644
--- a/libpod/container_log.go
+++ b/libpod/container_log.go
@@ -4,10 +4,12 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"time"
 
 	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/libpod/events"
 	"github.com/containers/podman/v3/libpod/logs"
+	"github.com/hpcloud/tail/watch"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
@@ -93,11 +95,14 @@ func (c *Container) readFromLogFile(ctx context.Context, options *logs.LogOption
 	}()
 	// Check if container is still running or paused
 	if options.Follow {
+		// If the container isn't running or if we encountered an error
+		// getting its state, instruct the logger to read the file
+		// until EOF.
 		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.
+			// Make sure to wait at least for the poll duration
+			// before stopping the file logger (see #10675).
+			time.Sleep(watch.POLL_DURATION)
 			tailError := t.StopAtEOF()
 			if tailError != nil && fmt.Sprintf("%v", tailError) != "tail: stop at eof" {
 				logrus.Errorf("Error stopping logger: %v", tailError)
@@ -124,6 +129,9 @@ func (c *Container) readFromLogFile(ctx context.Context, options *logs.LogOption
 			// Now wait for the died event and signal to finish
 			// reading the log until EOF.
 			<-eventChannel
+			// Make sure to wait at least for the poll duration
+			// before stopping the file logger (see #10675).
+			time.Sleep(watch.POLL_DURATION)
 			tailError := t.StopAtEOF()
 			if tailError != nil && fmt.Sprintf("%v", tailError) != "tail: stop at eof" {
 				logrus.Errorf("Error stopping logger: %v", tailError)