openstack oslo.config配置解析模块

什么是oslo.config

    oslo.config是openstack解析命令行(CLI)或者配置文件(.conf)中配置信息的库.官网地址点击打开链接

    安装: $ sudo pip install oslo.config

cfg模块

    每一个配置项都是一个Opt类或其子类例如:

from oslo_config import cfg
from oslo_config import types

PortType = types.Integer(1, 65535)

common_opts = [
    cfg.StrOpt('bind_host',
               default='0.0.0.0',
               help='IP address to listen on.'),
    cfg.Opt('bind_port',
            type=PortType,
            default=9292,
            help='Port number to listen on.')
]

    选项类型

        选项可以有任意的类型,为了方便,在oslo.config.cfg中预先定义了选项类型的子类如下表

    

Type	Option
oslo_config.types.String	oslo_config.cfg.StrOpt oslo_config.cfg.SubComt
oslo_config.types.Boolean	oslo_config.cfg.BoolOpt
oslo_config.types.Integer	oslo_config.cfg.IntOpt oslo_config.cfg.PortOpt
oslo_config.types.Float	oslo_config.cfg.FloatOpt
oslo_config.types.List	oslo_config.cfg.ListOpt
oslo_config.types.Dict	oslo_config.cfg.DictOpt
oslo_config.types.IPAddress	oslo_config.cfg.IPOpt
oslo_config.types.Hostname	oslo_config.cfg.HostnameOp

        cfg模块也支持具有多个值的选项,使用oslo_config.cfg.MultiOpt类来定义.功能感觉和 oslo_config.types.List类似.     

    注册选项

        选项在使用前应该先注册,完善一下第一个例子:

from oslo_config import cfg
from oslo_config import types

PortType = types.Integer(1, 65535)
# 定义一组选项
common_opts = [
    cfg.StrOpt('bind_host',
               default='0.0.0.0',
               help='IP address to listen on.'),
    cfg.Opt('bind_port',
            type=PortType,
            default=9292,
            help='Port number to listen on.')
]


def add_common_opts(conf):   # 注册选项
        conf.register_opts(common_opts)


def get_bind_host(conf):   # 使用选项
        return conf.bind_host


def get_bind_port(conf):
        return conf.bind_port

# 创建配置类
cf = cfg.CONF
# 开始注册
add_common_opts(cf)
print(get_bind_host(cf))

        通过命令行配置

cli_opts = [
    cfg.BoolOpt('verbose',
                short='v',
                default=False,
                help='Print more verbose output'),
    cfg.BoolOpt('debug',
                short='d',
                default=False,
                help='Print debugging output'),
]

def add_common_opts(conf):
    conf.register_cli_opts(cli_opts)
cf = cfg.CONF
add_common_opts(cf)

      运行时加-h选项可看到定义的东西已经加上

usage: config.py [-h] [--config-dir DIR] [--config-file PATH] [--debug]
                 [--nodebug] [--noverbose] [--verbose] [--version]


optional arguments:
  -h, --help          show this help message and exit
  --config-dir DIR    Path to a config directory to pull *.conf files from.
                      This file set is sorted, so as to provide a predictable
                      parse order if individual options are over-ridden. The
                      set is parsed after the file(s) specified via previous
                      --config-file, arguments hence over-ridden options in
                      the directory take precedence.
  --config-file PATH  Path to a config file to use. Multiple config files can
                      be specified, with values in later files taking
                      precedence. Defaults to None.
  --debug, -d         Print debugging output.
  --nodebug           The inverse of --debug
  --noverbose         The inverse of --verbose
  --verbose, -v       Print more verbose output.
  --version           show program's version number and exit

       

         注册选项组

#定义选项组
rabbit_group = cfg.OptGroup(name='rabbit',
                            title='RabbitMQ options')
#定义两个选项
rabbit_host_opt = cfg.StrOpt('host',
                             default='localhost',
                             help='IP/hostname to listen on'),
rabbit_port_opt = cfg.IntOpt('port',
                             default=5672,
                             help='Port number to listen on')
#注册
def register_rabbit_opts(conf):
    conf.register_group(rabbit_group)
    # options can be registered under a group in either of these ways:
    #使用选项组的变量名注册
    conf.register_opt(rabbit_host_opt, group=rabbit_group)
    #使用选项组名注册
    conf.register_opt(rabbit_port_opt, group='rabbit')

        通过配置文件注册

        配置文件config.conf

[DEFAULT]
bind_host = 127.0.0.1
bind_port = 8000

        config.py

from oslo_config import cfg
from oslo_config import types

PortType = types.Integer(1, 65535)
# 定义一组选项
common_opts = [
    cfg.StrOpt('bind_host',
               default='0.0.0.0',
               help='IP address to listen on.'),
    cfg.Opt('bind_port',
            type=PortType,
            default=9292,
            help='Port number to listen on.')
]


def add_common_opts(conf):   # 注册选项
        conf.register_opts(common_opts)


def get_bind_host(conf):   # 使用选项
        return conf.bind_host


def get_bind_port(conf):
        return conf.bind_port

# 创建配置类
cf = cfg.CONF
# 开始注册
add_common_opts(cf)
cf(default_config_files=['config.conf'])
print(get_bind_host(cf))
print(get_bind_port(cf))

       运行结果:

127.0.0.1
8000

        成功的读取了配置文件的信息,若没有指定配置文件,则读取默认的配置信息.