wait after container exit in logs cmd instead of json_logger for unprocessed data

Signed-off-by: Mrudul Harwani <[email protected]>

Author: mharwani

pkg/cmd/container/logs.go

@@ -22,6 +22,7 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/errdefs"
@@ -90,6 +91,8 @@ func Logs(ctx context.Context, client *containerd.Client, container string, opti
 						// Setup goroutine to send stop event if container task finishes:
 						go func() {
 							<-waitCh
+							// wait 100ms to let logViewer process data sent after container exit, if any
+							time.Sleep(100 * time.Millisecond)
 							logrus.Debugf("container task has finished, sending kill signal to log viewer")
 							stopChannel <- os.Interrupt
 						}()

pkg/logging/json_logger.go

@@ -157,46 +157,37 @@ func viewLogsJSONFileDirect(lvopts LogViewOptions, jsonLogFilePath string, stdou
 			return fmt.Errorf("error occurred while trying to seek JSON logfile %q at position %d: %s", jsonLogFilePath, lastPos, err)
 		}
 		fin.Close()
-
-		readFromLastPos := func() error {
-			// Re-open the file and seek to the last-consumed offset.
-			fin, err = os.OpenFile(jsonLogFilePath, os.O_RDONLY, 0400)
-			if err != nil {
-				fin.Close()
-				return fmt.Errorf("error occurred while trying to re-open JSON logfile %q: %s", jsonLogFilePath, err)
-			}
-			_, err = fin.Seek(lastPos, 0)
-			if err != nil {
-				fin.Close()
-				return fmt.Errorf("error occurred while trying to seek JSON logfile %q at position %d: %s", jsonLogFilePath, lastPos, err)
-			}
-
-			err = jsonfile.Decode(stdout, stderr, fin, lvopts.Timestamps, lvopts.Since, lvopts.Until, 0)
-			if err != nil {
-				fin.Close()
-				return fmt.Errorf("error occurred while doing follow-up decoding of JSON logfile %q at starting position %d: %s", jsonLogFilePath, lastPos, err)
-			}
-
-			// Record current file seek position before looping again.
-			lastPos, err = fin.Seek(0, io.SeekCurrent)
-			if err != nil {
-				fin.Close()
-				return fmt.Errorf("error occurred while trying to seek JSON logfile %q at current position: %s", jsonLogFilePath, err)
-			}
-			fin.Close()
-			return nil
-		}
-
 		for {
 			select {
 			case <-stopChannel:
-				logrus.Debugf("received stop signal, re-reading JSON logfile and returning")
-				// read final logs before returning
-				return readFromLastPos()
+				logrus.Debugf("received stop signal while re-reading JSON logfile, returning")
+				return nil
 			default:
-				if err = readFromLastPos(); err != nil {
-					return err
+				// Re-open the file and seek to the last-consumed offset.
+				fin, err = os.OpenFile(jsonLogFilePath, os.O_RDONLY, 0400)
+				if err != nil {
+					fin.Close()
+					return fmt.Errorf("error occurred while trying to re-open JSON logfile %q: %s", jsonLogFilePath, err)
 				}
+				_, err = fin.Seek(lastPos, 0)
+				if err != nil {
+					fin.Close()
+					return fmt.Errorf("error occurred while trying to seek JSON logfile %q at position %d: %s", jsonLogFilePath, lastPos, err)
+				}
+
+				err = jsonfile.Decode(stdout, stderr, fin, lvopts.Timestamps, lvopts.Since, lvopts.Until, 0)
+				if err != nil {
+					fin.Close()
+					return fmt.Errorf("error occurred while doing follow-up decoding of JSON logfile %q at starting position %d: %s", jsonLogFilePath, lastPos, err)
+				}
+
+				// Record current file seek position before looping again.
+				lastPos, err = fin.Seek(0, io.SeekCurrent)
+				if err != nil {
+					fin.Close()
+					return fmt.Errorf("error occurred while trying to seek JSON logfile %q at current position: %s", jsonLogFilePath, err)
+				}
+				fin.Close()
 			}
 			// Give the OS a second to breathe before re-opening the file:
 			time.Sleep(time.Second)
@@ -233,8 +224,6 @@ func viewLogsJSONFileThroughTailExec(lvopts LogViewOptions, jsonLogFilePath stri
 	// Setup killing goroutine:
 	go func() {
 		<-stopChannel
-		// sleep 100ms to get logs post container exit
-		time.Sleep(100 * time.Millisecond)
 		logrus.Debugf("killing tail logs process with PID: %d", cmd.Process.Pid)
 		cmd.Process.Kill()
 	}()