How to use the jumbo.utils.session.svars function in jumbo

raise RuntimeError(
            'addbundle: invalid arguments. Name required.')

    (active, available) = list_bundles()

    if name in active:
        raise Warning('addbundle: bundle `% s` already active. '
                      'Nothing to be done.' % name)
        # IDEA: --force option (case of bundle called multiple time)
    if name not in available:
        raise RuntimeError('addbundle: bundle `%s` does not exist.' % name)

    if position == 'last':
        ss.svars['bundles'].append(name)
    elif position == 'first':
        ss.svars['bundles'].insert(0, name)
    else:
        if not position.isdigit():
            raise RuntimeError(
                'addbundle: invalid value for position. '
                'Can be `last` (default), `first`, or a number.')

        ss.svars['bundles'].insert(int(position), name)

    services.config = services.load_services_conf(cluster=cluster)
    ss.dump_config(services.get_services_components_hosts(),
                   services.config)

ip = None
    for node in ss.svars['nodes']:
        for comp in node['components']:
            if comp == 'AMBARI_SERVER':
                ip = node['ip']
                break

    if ip:
        cmd = ('curl -u admin:admin -H "X-Requested-By: ambari" '
               '-X PUT '
               '-d \'{\"RequestInfo\": '
               '{\"context\":\"Start all services\"}, '
               '\"Body\":{\"ServiceInfo\": '
               '{\"state\":\"STARTED\"}}}\' ' +
               ip + ':8080/api/v1/clusters/' +
               ss.svars['domain'].replace('.', '') + '/services')

        retries = 0
        accepted = False
        res = subprocess.Popen(cmd,
                               shell=True,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.STDOUT)
        for line in res.stdout:
            if "Accepted" in line.decode('utf-8').rstrip():
                accepted = True
                break

        while not accepted and retries < max_retries:
            print('Server is not up yet. Retrying to start services...')
            time.sleep(5)
            res = subprocess.Popen(cmd,

def list_components(*, node, cluster):
    """List the components installed on a node of a specified cluster.

    :param node: Machine name
    :type node: str
    :param cluster: Cluster name
    :type cluster: str
    :raises ex.LoadError: [description]
    :return: The list of the components installed on the node
    :rtype: list
    """

    if not nodes.check_node(cluster=cluster, node=node):
        raise ex.LoadError('node', node, 'NotExist')

    if cluster != ss.svars['cluster']:
        try:
            with open(JUMBODIR + cluster + '/jumbo_config', 'r') as clf:
                cluster_conf = json.load(clf)
        except IOError as e:
            raise ex.LoadError('cluster', cluster, e.strerror)
    else:
        cluster_conf = ss.svars

    for m in cluster_conf['nodes']:
        if m['name'] == node:
            m_conf = m
            break

    return m_conf['components']

:raises ex.LoadError: [description]
    :return: The list of the components installed on the node
    :rtype: list
    """

    if not nodes.check_node(cluster=cluster, node=node):
        raise ex.LoadError('node', node, 'NotExist')

    if cluster != ss.svars['cluster']:
        try:
            with open(JUMBODIR + cluster + '/jumbo_config', 'r') as clf:
                cluster_conf = json.load(clf)
        except IOError as e:
            raise ex.LoadError('cluster', cluster, e.strerror)
    else:
        cluster_conf = ss.svars

    for m in cluster_conf['nodes']:
        if m['name'] == node:
            m_conf = m
            break

    return m_conf['components']

ss.clear()
    data_dir = os.path.dirname(os.path.abspath(__file__)) + '/data/'
    config_dir = os.path.dirname(os.path.abspath(__file__)) + '/config/'
    if template:
        try:
            with open(config_dir + 'templates/' + template + '.json') \
                    as template_file:
                ss.svars = json.load(template_file)
        except:
            raise ex.LoadError('template', template, 'NotExist')

    pathlib.Path(JUMBODIR + cluster).mkdir(parents=True)

    dir_util.copy_tree(data_dir, JUMBODIR + cluster)
    dir_util._path_created = {}
    ss.svars['cluster'] = cluster
    ss.svars['domain'] = domain if domain else '%s.local' % cluster

    services_components_hosts = None
    if template:
        services_components_hosts = services.get_services_components_hosts()

    ss.dump_config(services_components_hosts)
    return True

raise ex.CreationError('node', name, 'IP', ip, 'Exists')


    changed = []

    for i, m in enumerate(ss.svars['nodes']):
        if m['name'] == name:
            if ip:
                changed.append(["IP", ss.svars['nodes'][i]['ip'], ip])
                ss.svars['nodes'][i]['ip'] = ip
            if ram:
                changed.append(["RAM", ss.svars['nodes'][i]['ram'], ram])
                ss.svars['nodes'][i]['ram'] = ram
            if cpus:
                changed.append(["CPUs", ss.svars['nodes'][i]['cpus'], cpus])
                ss.svars['nodes'][i]['cpus'] = cpus

    ss.dump_config()

    return changed

:param name: Service name
    :type name: str
    :param ha: Weither the service is in HA, defaults to False
    :raises ex.LoadError: If the service doesn't exist
    :return: The misssing services and components needed to install the service
    :rtype: dict
    """

    req = 'ha' if ha else 'default'
    missing_serv = []
    missing_comp = {}
    for s in config['services']:
        if s['name'] == name:
            for req_s in s['requirements']['services'][req]:
                if req_s not in ss.svars['services']:
                    missing_serv.append(req_s)
                missing_comp.update(check_service_req_comp(req_s))
            return missing_serv, missing_comp
    raise ex.LoadError('service', name, 'NotExist')

allowed_chars = string.ascii_letters + string.digits + '-'
    for l in cluster:
        if l not in allowed_chars:
            raise ex.CreationError('cluster', cluster, 'name',
                                   'Allowed characters: ' + allowed_chars,
                                   'NameNotAllowed')

    ss.clear()
    data_dir = os.path.dirname(os.path.abspath(__file__)) + '/data/'
    config_dir = os.path.dirname(os.path.abspath(__file__)) + '/config/'
    if template:
        try:
            with open(config_dir + 'templates/' + template + '.json') \
                    as template_file:
                ss.svars = json.load(template_file)
        except:
            raise ex.LoadError('template', template, 'NotExist')

    pathlib.Path(JUMBODIR + cluster).mkdir(parents=True)

    dir_util.copy_tree(data_dir, JUMBODIR + cluster)
    dir_util._path_created = {}
    ss.svars['cluster'] = cluster
    ss.svars['domain'] = domain if domain else '%s.local' % cluster

    services_components_hosts = None
    if template:
        services_components_hosts = services.get_services_components_hosts()

    ss.dump_config(services_components_hosts)
    return True