logs: Seek the file only if it is large enough

logs.go

@@ -60,15 +60,27 @@ func Logtail(b BatchSystem, jobName, outputType string, nBytes int) error {
  logFile = job.ErrorFile
  }
 
+ location := &tail.SeekInfo{
+ Offset: 0,
+ Whence: io.SeekStart,
+ }
+
+ // If the file exists and it is large enough, truncate by seeking
+ if fi, err := os.Stat(logFile); err == nil {
+ if fi.Size() > int64(nBytes) {
+ location = &tail.SeekInfo{
+ Offset: -int64(nBytes),
+ Whence: io.SeekEnd,
+ }
+ }
+ }
+
  tailConfig := tail.Config{
- Follow: true,
- ReOpen: true,
- Poll: true, // On many cluster filesystems, inotify doesn't work
- Location: &tail.SeekInfo{
- Offset: -int64(nBytes),
- Whence: io.SeekEnd,
- },
- Logger: tail.DiscardingLogger,
+ Follow: true,
+ ReOpen: true,
+ Poll: true, // On many cluster filesystems, inotify doesn't work
+ Location: location,
+ Logger: tail.DiscardingLogger,
  }
 
  consoleWriter := zerolog.ConsoleWriter{