code: def _update_file(self, seek_to_end=True):
          
          try:
              self.close()
              self._file = self.open()
          except IOError:
              pass
          else:
              if not self._file:
                  return
  
              self.active = True
              try:
                  st = os.stat(self._filename)
              except EnvironmentError, err:
                  if err.errno == errno.ENOENT:
                      self._log_info('file removed')
                      self.close()
  
              fid = self.get_file_id(st)
              if not self._fid:
                  self._fid = fid
  
              if fid != self._fid:
                  self._log_info('file rotated')
                  self.close()
              elif seek_to_end:
                  self._seek_to_end()
docs: Open the file for tailing