def GetJidFromHostLog(host_log_file):
  """Parse the me2me host log to obtain the JID that the host registered.

  Args:
    host_log_file: path to host-log file that should be parsed for a JID.

  Returns:
    host_jid: host-JID if found in host-log, else None
  """
  host_jid = None
  with open(host_log_file, 'r') as log_file:
    for line in log_file:
      # The host JID will be recorded in a line saying 'Signaling
      # connected'.
      if 'Signaling connected. ' in line:
        components = line.split(':')
        host_jid = components[-1].lstrip()
        break

  return host_jid