sahara/sahara/plugins/base.py

143 lines
3.7 KiB
Python

# Copyright (c) 2013 Mirantis Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import abc
from oslo.config import cfg
import six
from stevedore import enabled
from sahara import exceptions as ex
from sahara.i18n import _
from sahara.i18n import _LI
from sahara.openstack.common import log as logging
from sahara.utils import resources
LOG = logging.getLogger(__name__)
opts = [
cfg.ListOpt('plugins',
default=['vanilla', 'hdp', 'spark'],
help='List of plugins to be loaded. Sahara preserves the '
'order of the list when returning it.'),
]
CONF = cfg.CONF
CONF.register_opts(opts)
def required(fun):
return abc.abstractmethod(fun)
def required_with_default(fun):
return fun
def optional(fun):
fun.__not_implemented__ = True
return fun
@six.add_metaclass(abc.ABCMeta)
class PluginInterface(resources.BaseResource):
__resource_name__ = 'plugin'
name = 'plugin_interface'
@required
def get_title(self):
"""Plugin title
For example:
"Vanilla Provisioning"
"""
pass
@required_with_default
def get_description(self):
"""Optional description of the plugin
This information is targeted to be displayed in UI.
"""
pass
def to_dict(self):
return {
'name': self.name,
'title': self.get_title(),
'description': self.get_description(),
}
class PluginManager(object):
def __init__(self):
self.plugins = {}
self._load_cluster_plugins()
def _load_cluster_plugins(self):
config_plugins = CONF.plugins
extension_manager = enabled.EnabledExtensionManager(
check_func=lambda ext: ext.name in config_plugins,
namespace='sahara.cluster.plugins',
invoke_on_load=True
)
for ext in extension_manager.extensions:
if ext.name in self.plugins:
raise ex.ConfigurationError(
_("Plugin with name '%s' already exists.") % ext.name)
ext.obj.name = ext.name
self.plugins[ext.name] = ext.obj
LOG.info(_LI("Plugin '%(plugin_name)s' loaded %(entry_point)s"),
{'plugin_name': ext.name,
'entry_point': ext.entry_point_target})
if len(self.plugins) < len(config_plugins):
loaded_plugins = set(six.iterkeys(self.plugins))
requested_plugins = set(config_plugins)
raise ex.ConfigurationError(
_("Plugins couldn't be loaded: %s") %
", ".join(requested_plugins - loaded_plugins))
def get_plugins(self, base):
return [
self.plugins[plugin] for plugin in CONF.plugins
if not base or issubclass(self.plugins[plugin].__class__, base)
]
def get_plugin(self, plugin_name):
return self.plugins.get(plugin_name)
def is_plugin_implements(self, plugin_name, fun_name):
plugin = self.get_plugin(plugin_name)
fun = getattr(plugin, fun_name)
if not (fun and callable(fun)):
return False
return not hasattr(fun, '__not_implemented__')
PLUGINS = None
def setup_plugins():
global PLUGINS
PLUGINS = PluginManager()