oslo.config库是openstack读取配置的一个公共库，其实它就是是一套解析配置文件的框架。


[root@devstack oslo_config_practice]# cat app.py  # 来看个例子

from oslo_config import cfg

# 创建一个组
test_group_1 = cfg.OptGroup(name='DEFAULT',
                            title='group1')
# 再创建一个组                            
test_group_2 = cfg.OptGroup(name='nova',
                            title='group2')
group1_opts = [
    cfg.BoolOpt('enable_tunneling', default=False,
                help=('True enables, False disables')),
    cfg.IPOpt('bind_host', default='0.0.0.0',
              help='IP address the API server will listen on.'),
    cfg.StrOpt('query_scope', default='one',
               choices=['one', 'sub'],
               help='The LDAP scope for queries, "one" represents '
                    'oneLevel/singleLevel and "sub" represents '
                    'subtree/wholeSubtree options.'),
    cfg.StrOrIPOpt('glance_api_host', default='localhost',
                  help='glance api server fqdn'),
]
group2_opts = [
    cfg.StrOpt('bind_address', default='0.0.0.0',
               help=('Server listen on.')),
    cfg.ListOpt('service_plugins', default=[],
                help=("The service plugins Neutron will use")),
    cfg.DictOpt('notification_service_id',
                default={'mysql': '2f3ff068-2bfb-4f70-9a9d-a6bb65bc084b',
                         'percona': 'fd1723f5-68d2-409c-994f-a4a197892a17',
                         'pxc': '75a628c3-f81b-4ffb-b10a-4087c26bc854',
                         'redis': 'b216ffc5-1947-456c-a4cf-70f94c05f7d0',
                         'cassandra': '459a230d-4e97-4344-9067-2a54a310b0ed',
                         'couchbase': 'fa62fe68-74d9-4779-a24e-36f19602c415',
                         'mongodb': 'c8c907af-7375-456f-b929-b637ff9209ee',
                         'postgresql': 'ac277e0d-4f21-40aa-b347-1ea31e571720',
                         'couchdb': 'f0a9ab7b-66f7-4352-93d7-071521d44c7c',
                         'vertica': 'a8d805ae-a3b2-c4fd-gb23-b62cee5201ae',
                         'db2': 'e040cd37-263d-4869-aaa6-c62aa97523b5',
                         'mariadb': '7a4f82cc-10d2-4bc6-aadc-d9aacc2a3cb5'},
                help='Unique ID to tag notification events.'),
    cfg.IntOpt('glance_request_timeout', default=None,
               help='http/https timeout value for glance operations. If no '
                    'value (None) is supplied here, the glanceclient default '
                    'value is used.'),
    cfg.PortOpt('bind_port', default=9696,
                help=("The port to bind to")),
    cfg.FloatOpt('pi', default=0.0,
                 help=('The value of Pi')),
    cfg.MultiStrOpt('osapi_volume_extension',
                    default=['cinder.api.contrib.standard_extensions'],
                    help='osapi volume extension to load')
]
CONF = cfg.CONF
CONF.register_group(test_group_1)   # 登记test_group_1
CONF.register_opts(group1_opts, test_group_1) # 配置项登记到test_group_1
CONF.register_group(test_group_2)   # 登记test_group_2
CONF.register_opts(group2_opts, test_group_2)  # 配置项登记到test_group_2
if __name__ == "__main__":
    CONF(default_config_files=[
         'app_1.conf', 'app_2.conf'])
         
    print('(DEFAULT) enable_tunneling: {}'.format(CONF.DEFAULT.enable_tunneling))
    print('(DEFAULT) bind_host: {}'.format(CONF.DEFAULT.bind_host))
    print('(DEFAULT) query_scope: {}'.format(CONF.DEFAULT.query_scope))
    print('(DEFAULT) glance_api_host: {}'.format(CONF.DEFAULT.glance_api_host))
    print('(nova) bind_address:{}'.format(CONF.nova.bind_address))
    print('(nova) service_plugins: {}'.format(CONF.nova.service_plugins))
    print('(nova) notification_service_id: {}'.format(CONF.nova.notification_service_id))
    print('(nova) glance_request_timeout: {}'.format(CONF.nova.glance_request_timeout))
    print('(nova) bind_port: {}'.format(CONF.nova.bind_port))
    print('(nova) pi: {}'.format(CONF.nova.pi))
    print('(nova) osapi_volume_extension: {}'.format(CONF.nova.osapi_volume_extension))
    
[root@devstack oslo_config_practice]# cat app_1.conf
[DEFAULT]
enable_tunneling = true
bind_host = 192.168.1.1
query_scope = one
glance_api_host = 102.34.43.5

[root@devstack oslo_config_practice]# cat app_2.conf
[nova]
bind_address = 127.0.0.1
service_plugins = ['router','lb']
notification_service_id = {'mysql': '2f3ff068-2bfb-4f70-9a9d-a6bb65bc084b'}
glance_request_timeout = 300
bind_port = 9696
pi = 3.14
osapi_volume_extension = cinder.api.contrib.standard_extensions
osapi_volume_extension = cinder.api.contrib.standard_extensions_2222


参考链接

http://docs.openstack.org/developer/oslo.config/

http://ronaldbradford.com/blog/understanding-the-different-openstack-tox-configs-2015-04-30/   tox使用教程