Python oslo_utils.importutils.import_class() Examples

def get_client_class(api_name, version, version_map):
    """Returns the client class for the requested API version.

    :param api_name: the name of the API, e.g. 'compute', 'image', etc
    :param version: the requested API version
    :param version_map: a dict of client classes keyed by version
    :rtype: a client class for the requested API version
    """
    try:
        client_path = version_map[str(version)]
    except (KeyError, ValueError):
        msg = _("Invalid %(api_name)s client version '%(version)s'. must be "
                "one of: %(map_keys)s")
        msg = msg % {'api_name': api_name, 'version': version,
                     'map_keys': ', '.join(version_map.keys())}
        raise exceptions.UnsupportedVersion(message=msg)

    return importutils.import_class(client_path) 

def get_client_class(api_name, version, version_map):
    """Returns the client class for the requested API version.

    :param api_name: the name of the API, e.g. 'compute', 'image', etc
    :param version: the requested API version
    :param version_map: a dict of client classes keyed by version
    :rtype: a client class for the requested API version
    """
    try:
        client_path = version_map[str(version)]
    except (KeyError, ValueError):
        msg = _("Invalid %(api_name)s client version '%(version)s'. must be "
                "one of: %(map_keys)s")
        msg = msg % {'api_name': api_name, 'version': version,
                     'map_keys': ', '.join(version_map.keys())}
        raise exceptions.UnsupportedVersion(msg)

    return importutils.import_class(client_path) 

def _get_manager(self):
        """Initialize a Manager object appropriate for this service.

        Use the service name to look up a Manager subclass from the
        configuration and initialize an instance. If no class name
        is configured, just return None.

        :returns: a Manager instance, or None.

        """
        fl = '%s_manager' % self.name
        if fl not in CONF:
            return None

        manager_class_name = CONF.get(fl, None)
        if not manager_class_name:
            return None

        manager_class = importutils.import_class(manager_class_name)
        return manager_class() 

def API(configuration=None):
    conf = configuration or cfg.CONF
    conf.register_opts(key_manager_opts, group='key_manager')

    try:
        mgr = driver.DriverManager("castellan.drivers",
                                   conf.key_manager.backend,
                                   invoke_on_load=True,
                                   invoke_args=[conf])
        key_mgr = mgr.driver
    except exception.NoMatches:
        LOG.warning("Deprecation Warning : %s is not a stevedore based driver,"
                    " trying to load it as a class", conf.key_manager.backend)
        cls = importutils.import_class(conf.key_manager.backend)
        key_mgr = cls(configuration=conf)

    return migration.handle_migration(conf, key_mgr) 

def get_class(api_name, version, version_map):
        """Returns the client class for the requested API version

        :param api_name: the name of the API, e.g. 'compute', 'image', etc
        :param version: the requested API version
        :param version_map: a dict of client classes keyed by version
        :rtype: a client class for the requested API version
        """
        try:
            client_path = version_map[str(version)]
        except (KeyError, ValueError):
            msg = _("Invalid %(api_name)s client version '%(version)s'. "
                    "Must be one of: %(version_map)s") % {
                        'api_name': api_name,
                        'version': version,
                        'version_map': ', '.join(version_map.keys())}
            raise exceptions.UnsupportedVersion(msg)

        return importutils.import_class(client_path) 

def get_matching_classes(self, loadable_class_names):
        """Get loadable classes from a list of names.

        Each name can be a full module path or the full path to a
        method that returns classes to use.  The latter behavior
        is useful to specify a method that returns a list of
        classes to use in a default case.
        """

        classes = []
        for cls_name in loadable_class_names:
            obj = importutils.import_class(cls_name)
            if self._is_correct_class(obj):
                classes.append(obj)
            elif inspect.isfunction(obj):
                # Get list of classes from a function
                for cls in obj():
                    classes.append(cls)
            else:
                error_str = 'Not a class of the correct type'
                raise exception.ClassNotFound(class_name=cls_name,
                                              exception=error_str)
        return classes 

def get_class(api_name, version, version_map):
        """Returns the client class for the requested API version

        :param api_name: the name of the API, e.g. 'compute', 'image', etc
        :param version: the requested API version
        :param version_map: a dict of client classes keyed by version
        :rtype: a client class for the requested API version
        """
        try:
            client_path = version_map[str(version)]
        except (KeyError, ValueError):
            msg = _("Invalid %(api_name)s client version '%(version)s'. "
                    "Must be one of: %(version_map)s") % {
                        'api_name': api_name,
                        'version': version,
                        'version_map': ', '.join(version_map.keys())}
            raise exceptions.UnsupportedVersion(msg)

        return importutils.import_class(client_path) 

def get_class(api_name, version, version_map):
        """Returns the client class for the requested API version

        :param api_name: the name of the API, e.g. 'compute', 'image', etc
        :param version: the requested API version
        :param version_map: a dict of client classes keyed by version
        :rtype: a client class for the requested API version
        """
        try:
            client_path = version_map[str(version)]
        except (KeyError, ValueError):
            msg = _("Invalid %(api_name)s client version '%(version)s'. "
                    "Must be one of: %(version_map)s") % {
                        'api_name': api_name,
                        'version': version,
                        'version_map': ', '.join(version_map.keys())}
            raise exceptions.UnsupportedVersion(msg)

        return importutils.import_class(client_path) 

def get_class(api_name, version, version_map):
        """Returns the client class for the requested API version

        :param api_name: the name of the API, e.g. 'compute', 'image', etc
        :param version: the requested API version
        :param version_map: a dict of client classes keyed by version
        :rtype: a client class for the requested API version
        """
        try:
            client_path = version_map[str(version)]
        except (KeyError, ValueError):
            msg = _("Invalid %(api_name)s client version '%(version)s'. "
                    "Must be one of: %(version_map)s") % {
                        'api_name': api_name,
                        'version': version,
                        'version_map': ', '.join(version_map.keys())}
            raise exceptions.UnsupportedVersion(msg)

        return importutils.import_class(client_path) 

def __init__(self, host, binary, topic, manager, report_interval=None,
                 periodic_interval=None, periodic_fuzzy_delay=None,
                 service_name=None, coordination=False, *args, **kwargs):
        super(Service, self).__init__()
        if not rpc.initialized():
            rpc.init(CONF)
        self.host = host
        self.binary = binary
        self.topic = topic
        self.manager_class_name = manager
        manager_class = importutils.import_class(self.manager_class_name)
        self.manager = manager_class(host=self.host,
                                     service_name=service_name,
                                     *args, **kwargs)
        self.availability_zone = self.manager.availability_zone
        self.report_interval = report_interval
        self.periodic_interval = periodic_interval
        self.periodic_fuzzy_delay = periodic_fuzzy_delay
        self.saved_args, self.saved_kwargs = args, kwargs
        self.timers = []
        self.coordinator = coordination 

def load_extension(self, ext_factory):
        """Execute an extension factory.

        Loads an extension.  The 'ext_factory' is the name of a
        callable that will be imported and called with one
        argument--the extension manager.  The factory callable is
        expected to call the register() method at least once.
        """

        LOG.debug("Loading extension %s", ext_factory)

        if isinstance(ext_factory, six.string_types):
            # Load the factory
            factory = importutils.import_class(ext_factory)
        else:
            factory = ext_factory

        # Call it
        LOG.debug("Calling extension factory %s", ext_factory)
        factory(self) 

def load_extension(self, ext_factory):
        """Execute an extension factory.

        Loads an extension.  The 'ext_factory' is the name of a
        callable that will be imported and called with one
        argument--the extension manager.  The factory callable is
        expected to call the register() method at least once.
        """

        LOG.debug("Loading extension %s", ext_factory)

        # Load the factory
        factory = importutils.import_class(ext_factory)

        # Call it
        LOG.debug("Calling extension factory %s", ext_factory)
        factory(self) 

def _get_manager(self):
        """Initialize a Manager object appropriate for this service.

        Use the service name to look up a Manager subclass from the
        configuration and initialize an instance. If no class name
        is configured, just return None.

        :returns: a Manager instance, or None.

        """
        fl = '%s_manager' % self.name
        if fl not in CONF:
            return None

        manager_class_name = CONF.get(fl, None)
        if not manager_class_name:
            return None

        manager_class = importutils.import_class(manager_class_name)
        return manager_class() 

def __init__(self, host, binary, topic, manager, report_interval=None,
                 periodic_interval=None, periodic_fuzzy_delay=None,
                 service_name=None, *args, **kwargs):
        super(Service, self).__init__()

        rpc.init(CONF)

        self.host = host
        self.binary = binary
        self.topic = topic
        self.manager_class_name = manager
        manager_class = importutils.import_class(self.manager_class_name)
        self.manager = manager_class(host=self.host,
                                     service_name=service_name,
                                     *args, **kwargs)
        self.report_interval = report_interval
        self.periodic_interval = periodic_interval
        self.periodic_fuzzy_delay = periodic_fuzzy_delay
        self.basic_config_check()
        self.saved_args, self.saved_kwargs = args, kwargs
        self.timers = []

        self.rpcserver = None 

def setUp(self):
        super(FileSystemBankPluginTest, self).setUp()

        import_str = (
            "karbor.services.protection.bank_plugins."
            "file_system_bank_plugin.FileSystemBankPlugin"
        )
        plugin_config = cfg.ConfigOpts()
        plugin_config_fixture = self.useFixture(fixture.Config(plugin_config))
        plugin_config_fixture.load_raw_values(
            group='file_system_bank_plugin',
            file_system_bank_path=tempfile.mkdtemp(),
        )
        fs_bank_plugin_cls = importutils.import_class(
            import_str=import_str)
        self.fs_bank_plugin = fs_bank_plugin_cls(plugin_config) 

def get_matching_classes(self, loadable_class_names):
        """Get loadable classes from a list of names.

        Each name can be a full module path or the full path to a method that
        returns classes to use. The latter behavior is useful to specify a
        method that returns a list of classes to use in a default case.
        """

        classes = []
        for cls_name in loadable_class_names:
            obj = importutils.import_class(cls_name)
            if self._is_correct_class(obj):
                classes.append(obj)
            elif inspect.isfunction(obj):
                # Get list of classes from a function
                for cls in obj():
                    classes.append(cls)
            else:
                error_str = 'Not a class of the correct type'
                raise exception.ClassNotFound(class_name=cls_name,
                                              exception=error_str)
        return classes 

def all_generators():
    for mod_name in SUPPORTED_MODULES:
        prefix = mod_name.replace(' ', '')
        mod_namespace = mod_name.lower().replace(' ', '_')
        mod_cls_name = 'mistral_extra.actions.openstack.actions.%sAction' \
                       % prefix
        mod_action_cls = importutils.import_class(mod_cls_name)
        generator_cls_name = '%sActionGenerator' % prefix

        yield type(
            generator_cls_name,
            (base.OpenStackActionGenerator,),
            {
                'action_namespace': mod_namespace,
                'base_action_class': mod_action_cls
            }
        ) 

def load_driver(driver_cfg, namespace, *args, **kwargs):
    try:
        # Try to resolve by alias
        mgr = driver.DriverManager(namespace, driver_cfg)
        class_to_load = mgr.driver
    except RuntimeError:
        e1_info = sys.exc_info()
        # try with name
        try:
            class_to_load = importutils.import_class(driver_cfg)
        except (ImportError, ValueError):
            LOG.error("Error loading class %(class)s by alias e: %(e)s",
                      {'class': driver_cfg, 'e': e1_info},
                      exc_info=e1_info)
            LOG.error("Error loading class by class name",
                      exc_info=True)
            raise ImportError(_("Class not found."))
    return class_to_load(*args, **kwargs) 

def __init__(self, host, binary, topic, manager,
                 periodic_enable=None, periodic_fuzzy_delay=None,
                 periodic_interval_max=None):
        super(Service, self).__init__()

        if not rpc.initialized():
            rpc.init(CONF)

        self.host = host
        self.binary = binary
        self.topic = topic
        self.manager_class_name = manager
        manager_class = importutils.import_class(self.manager_class_name)
        self.rpcserver = None
        self.manager = manager_class(host=self.host)
        self.periodic_enable = periodic_enable
        self.periodic_fuzzy_delay = periodic_fuzzy_delay
        self.periodic_interval_max = periodic_interval_max 

def _get_manager(self):
        """Initialize a Manager object appropriate for this service.

        Use the service name to look up a Manager subclass from the
        configuration and initialize an instance. If no class name
        is configured, just return None.

        :returns: a Manager instance, or None.

        """
        fl = '%s_manager' % self.name
        if fl not in CONF:
            return None

        manager_class_name = CONF.get(fl, None)
        if not manager_class_name:
            return None

        manager_class = importutils.import_class(manager_class_name)
        return manager_class() 

def test_datasource_update_method_push(self):
        driver_names = ds_utils.get_push_drivers_names()
        push_drivers = ds_utils.get_drivers_by_name(driver_names)
        self.assertSequenceEqual({utils.import_class(
            self.conf[NOVA_INSTANCE_DATASOURCE].driver), utils.import_class(
            self.conf[ZABBIX_DATASOURCE_PUSH].driver)},
            set(d.__class__ for d in push_drivers)) 

def _fetch_factory(factory_name):
    try:
        return importutils.import_class(factory_name)
    except (ImportError, ValueError) as e:
        raise ImportError("Could not import factory %r: %s"
                          % (factory_name, e)) 

def __init__(self, host, binary, topic, manager, report_interval=None,
                 periodic_interval=None, periodic_fuzzy_delay=None,
                 *args, **kwargs):

        self.binary = binary
        self.manager_class_name = manager
        manager_class = importutils.import_class(self.manager_class_name)
        self.manager = manager_class(host=host, *args, **kwargs)
        self.report_interval = report_interval
        self.periodic_interval = periodic_interval
        self.periodic_fuzzy_delay = periodic_fuzzy_delay
        self.saved_args, self.saved_kwargs = args, kwargs
        self.timers = []
        super(Service, self).__init__(host, topic, manager=self.manager) 

def load_class_by_alias_or_classname(namespace, name):
    """Load class using stevedore alias or the class name.

    Load class using the stevedore driver manager
    :param namespace: namespace where the alias is defined
    :param name: alias or class name of the class to be loaded
    :returns: class if calls can be loaded
    :raises ImportError: if class cannot be loaded
    """
    if not name:
        LOG.error("Alias or class name is not set")
        raise ImportError(_("Class not found."))
    try:
        # Try to resolve class by alias
        mgr = driver.DriverManager(namespace, name)
        class_to_load = mgr.driver
    except RuntimeError:
        e1_info = sys.exc_info()
        # Fallback to class name
        try:
            class_to_load = importutils.import_class(name)
        except (ImportError, ValueError):
            LOG.error("Error loading class by alias",
                      exc_info=e1_info)
            LOG.error("Error loading class by class name",
                      exc_info=True)
            raise ImportError(_("Class not found."))
    return class_to_load 

def API(auth_url, configuration=None):
    conf = configuration or cfg.CONF
    conf.register_opts(key_manager_opts, group='key_manager')

    cls = importutils.import_class(conf.key_manager.api_class)
    return cls(auth_url) 

def _load_output_backend(self):
        backend = i_utils.import_class(CONF.output.backend)
        self._output = backend 

def monkey_patch():
    """If the CONF.monkey_patch set as True,
    this function patches a decorator
    for all functions in specified modules.
    You can set decorators for each modules
    using CONF.monkey_patch_modules.
    The format is "Module path:Decorator function".

    name - name of the function
    function - object of the function
    """
    # If CONF.monkey_patch is not True, this function do nothing.
    if not CONF.monkey_patch:
        return
    if six.PY2:
        is_method = inspect.ismethod
    else:
        def is_method(obj):
            # Unbound methods became regular functions on Python 3
            return inspect.ismethod(obj) or inspect.isfunction(obj)
    # Get list of modules and decorators
    for module_and_decorator in CONF.monkey_patch_modules:
        module, decorator_name = module_and_decorator.split(':')
        # import decorator function
        decorator = importutils.import_class(decorator_name)
        __import__(module)
        # Retrieve module information using pyclbr
        module_data = pyclbr.readmodule_ex(module)
        for key, value in module_data.items():
            # set the decorator for the class methods
            if isinstance(value, pyclbr.Class):
                clz = importutils.import_class("%s.%s" % (module, key))
                for method, func in inspect.getmembers(clz, is_method):
                    setattr(clz, method,
                            decorator("%s.%s.%s" % (module, key,
                                                    method), func))
            # set the decorator for the function
            if isinstance(value, pyclbr.Function):
                func = importutils.import_class("%s.%s" % (module, key))
                setattr(sys.modules[module], key,
                        decorator("%s.%s" % (module, key), func)) 

def _vmops(self):
        # We have to avoid a circular dependency.
        if not self._vmops_prop:
            self._vmops_prop = importutils.import_class(
                'compute_hyperv.nova.vmops.VMOps')()
        return self._vmops_prop 

def start(self):
        LOG.debug('IPABackend start')
        self.request = requests.Session()
        authclassname = cfg.CONF[self.name].ipa_auth_driver_class
        authclass = importutils.import_class(authclassname)
        self.request.auth = \
            authclass(cfg.CONF[self.name].ipa_client_keytab,
                      cfg.CONF[self.name].ipa_host)
        ipa_base_url = cfg.CONF[self.name].ipa_base_url
        if ipa_base_url.startswith("http"):  # full URL
            self.baseurl = ipa_base_url
        else:  # assume relative to https://host[:port]
            self.baseurl = "https://" + cfg.CONF[self.name].ipa_host
            ipa_port = cfg.CONF[self.name].ipa_port
            if ipa_port != IPA_DEFAULT_PORT:
                self.baseurl += ":" + str(ipa_port)
            self.baseurl += ipa_base_url
        ipa_json_url = cfg.CONF[self.name].ipa_json_url
        if ipa_json_url.startswith("http"):  # full URL
            self.jsonurl = ipa_json_url
        else:  # assume relative to https://host[:port]
            self.jsonurl = self.baseurl + ipa_json_url
        xtra_hdrs = {'Content-Type': 'application/json',
                     'Referer': self.baseurl}
        self.request.headers.update(xtra_hdrs)
        self.request.verify = cfg.CONF[self.name].ipa_ca_cert
        self.ntries = cfg.CONF[self.name].ipa_connect_retries
        self.force = cfg.CONF[self.name].ipa_force_ns_use 

def _block_dev_man(self):
        if not self._block_dev_man_prop:
            self._block_dev_man_prop = importutils.import_class(
                'compute_hyperv.nova.block_device_manager.'
                'BlockDeviceInfoManager')()
        return self._block_dev_man_prop