code: def get_instance_jstack(cluster, environ, topology, instance, role=None):
    '''
    :param cluster:
    :param environ:
    :param topology:
    :param instance:
    :param role:
    :return:
    '''
    params = dict(
        cluster=cluster,
        environ=environ,
        topology=topology,
        instance=instance)
  
    if role is not None:
      params['role'] = role
  
    request_url = tornado.httputil.url_concat(
        create_url(JSTACK_URL_FMT), params)
  
    raise tornado.gen.Return((yield fetch_url_as_json(request_url))f get_instance_jstack(cluster, environ, topology, instance, role=None):
    '''
    :param cluster:
    :param environ:
    :param topology:
    :param instance:
    :param role:
    :return:
    '''
    params = dict(
        cluster=cluster,
        environ=environ,
        topology=topology,
        instance=instance)
  
    if role is not None:
      params['role'] = role
  
    request_url = tornado.httputil.url_concat(
        create_url(JSTACK_URL_FMT), params)
  
    raise tornado.gen.Return((yield fetch_url_as_json(request_url)))
docs: :param cluster:
    :param environ:
    :param topology:
    :param instance:
    :param role:
    :return: