FileTailer.py

class FileTailer(object):
  def __init__(self, ip, port, username, password):
    self._ip, self._port, self._user, self._pass = ip, port, username, password
    self._stdout = None

  def start(self, remote_filepath, timeout_sec=60):
    if (not isinstance(timeout_sec, int)) or (timeout_sec < 0):
      timeout_sec = None
    if self._stdout is not None:
      self.close()
      self._stdout = None

    self._ssh = SSHClient()
    self._ssh.set_missing_host_key_policy(AutoAddPolicy())    
    self._ssh.connect(hostname=self._ip, port=self._port,
                      username=self._user, password=self._pass)
    _, self._stdout, _ = self._ssh.exec_command('tail -f {0}'.format(remote_filepath), 
                                                get_pty=True, timeout=timeout_sec)
    return self

  @property
  def is_readable(self):
    return (self._stdout is not None) and (not self._stdout.channel.closed)

  def readline(self):
    l = self._stdout.readline()
    if l != '':
      yield l

  def close(self):
    if self._stdout is not None:
      self._ssh.close()
      self._stdout.channel.close()



def tailer_test(filepath):
  tailer = FileTailer('192.168.100.16', 22, 'root', 'root')
  tailer.start(filepath, timeout_sec=-1)

  while tailer.is_readable:
    try:
      for l in tailer.readline():
        print l
    except KeyboardInterrupt as e:
      print 'Closed: KeyboardInterrupt'
      tailer.close()
      break
  else:
    print 'Closed: File is Not Readable Now'
    tailer.close()