532 lines
19 KiB
Python
532 lines
19 KiB
Python
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2011 OpenStack LLC.
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# Copyright 2011 Justin Santa Barbara
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import imp
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import logging
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import os
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import routes
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import webob.dec
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import webob.exc
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from gettext import gettext as _
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from abc import ABCMeta
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from quantum.common import exceptions
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from quantum.manager import QuantumManager
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from quantum.common import wsgi
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LOG = logging.getLogger('quantum.common.extensions')
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class PluginInterface(object):
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__metaclass__ = ABCMeta
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@classmethod
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def __subclasshook__(cls, klass):
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"""
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The __subclasshook__ method is a class method
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that will be called everytime a class is tested
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using issubclass(klass, PluginInterface).
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In that case, it will check that every method
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marked with the abstractmethod decorator is
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provided by the plugin class.
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"""
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for method in cls.__abstractmethods__:
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if any(method in base.__dict__ for base in klass.__mro__):
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continue
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return NotImplemented
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return True
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class ExtensionDescriptor(object):
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"""Base class that defines the contract for extensions.
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Note that you don't have to derive from this class to have a valid
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extension; it is purely a convenience.
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"""
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def get_name(self):
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"""The name of the extension.
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e.g. 'Fox In Socks'
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"""
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raise NotImplementedError()
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def get_alias(self):
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"""The alias for the extension.
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e.g. 'FOXNSOX'
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"""
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raise NotImplementedError()
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def get_description(self):
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"""Friendly description for the extension.
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e.g. 'The Fox In Socks Extension'
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"""
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raise NotImplementedError()
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def get_namespace(self):
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"""The XML namespace for the extension.
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e.g. 'http://www.fox.in.socks/api/ext/pie/v1.0'
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"""
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raise NotImplementedError()
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def get_updated(self):
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"""The timestamp when the extension was last updated.
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e.g. '2011-01-22T13:25:27-06:00'
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"""
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# NOTE(justinsb): Not sure of the purpose of this is, vs the XML NS
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raise NotImplementedError()
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def get_resources(self):
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"""List of extensions.ResourceExtension extension objects.
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Resources define new nouns, and are accessible through URLs.
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"""
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resources = []
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return resources
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def get_actions(self):
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"""List of extensions.ActionExtension extension objects.
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Actions are verbs callable from the API.
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"""
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actions = []
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return actions
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def get_request_extensions(self):
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"""List of extensions.RequestException extension objects.
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Request extensions are used to handle custom request data.
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"""
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request_exts = []
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return request_exts
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def get_plugin_interface(self):
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"""
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Returns an abstract class which defines contract for the plugin.
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The abstract class should inherit from extesnions.PluginInterface,
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Methods in this abstract class should be decorated as abstractmethod
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"""
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return None
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class ActionExtensionController(wsgi.Controller):
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def __init__(self, application):
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self.application = application
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self.action_handlers = {}
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def add_action(self, action_name, handler):
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self.action_handlers[action_name] = handler
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def action(self, request, id):
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input_dict = self._deserialize(request.body,
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request.get_content_type())
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for action_name, handler in self.action_handlers.iteritems():
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if action_name in input_dict:
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return handler(input_dict, request, id)
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# no action handler found (bump to downstream application)
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response = self.application
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return response
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class RequestExtensionController(wsgi.Controller):
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def __init__(self, application):
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self.application = application
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self.handlers = []
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def add_handler(self, handler):
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self.handlers.append(handler)
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def process(self, request, *args, **kwargs):
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res = request.get_response(self.application)
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# currently request handlers are un-ordered
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for handler in self.handlers:
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response = handler(request, res)
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return response
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class ExtensionController(wsgi.Controller):
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def __init__(self, extension_manager):
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self.extension_manager = extension_manager
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def _translate(self, ext):
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ext_data = {}
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ext_data['name'] = ext.get_name()
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ext_data['alias'] = ext.get_alias()
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ext_data['description'] = ext.get_description()
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ext_data['namespace'] = ext.get_namespace()
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ext_data['updated'] = ext.get_updated()
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ext_data['links'] = [] # TODO(dprince): implement extension links
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return ext_data
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def index(self, request):
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extensions = []
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for _alias, ext in self.extension_manager.extensions.iteritems():
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extensions.append(self._translate(ext))
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return dict(extensions=extensions)
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def show(self, request, id):
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# NOTE(dprince): the extensions alias is used as the 'id' for show
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ext = self.extension_manager.extensions.get(id, None)
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if not ext:
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raise webob.exc.HTTPNotFound(
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_("Extension with alias %s does not exist") % id)
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return self._translate(ext)
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def delete(self, request, id):
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raise webob.exc.HTTPNotFound()
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def create(self, request):
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raise webob.exc.HTTPNotFound()
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class ExtensionMiddleware(wsgi.Middleware):
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"""Extensions middleware for WSGI."""
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def __init__(self, application, config_params,
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ext_mgr=None):
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self.ext_mgr = (ext_mgr
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or ExtensionManager(
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config_params.get('api_extensions_path', '')))
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mapper = routes.Mapper()
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# extended resources
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for resource in self.ext_mgr.get_resources():
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LOG.debug(_('Extended resource: %s'),
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resource.collection)
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for action, method in resource.collection_actions.iteritems():
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path_prefix = ""
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parent = resource.parent
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conditions = dict(method=[method])
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path = "/%s/%s" % (resource.collection, action)
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if parent:
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path_prefix = "/%s/{%s_id}" % (parent["collection_name"],
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parent["member_name"])
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with mapper.submapper(controller=resource.controller,
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action=action,
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path_prefix=path_prefix,
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conditions=conditions) as submap:
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submap.connect(path)
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submap.connect("%s.:(format)" % path)
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mapper.resource(resource.collection, resource.collection,
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controller=resource.controller,
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member=resource.member_actions,
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parent_resource=resource.parent)
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# extended actions
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action_controllers = self._action_ext_controllers(application,
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self.ext_mgr, mapper)
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for action in self.ext_mgr.get_actions():
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LOG.debug(_('Extended action: %s'), action.action_name)
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controller = action_controllers[action.collection]
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controller.add_action(action.action_name, action.handler)
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# extended requests
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req_controllers = self._request_ext_controllers(application,
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self.ext_mgr, mapper)
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for request_ext in self.ext_mgr.get_request_extensions():
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LOG.debug(_('Extended request: %s'), request_ext.key)
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controller = req_controllers[request_ext.key]
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controller.add_handler(request_ext.handler)
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self._router = routes.middleware.RoutesMiddleware(self._dispatch,
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mapper)
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super(ExtensionMiddleware, self).__init__(application)
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@classmethod
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def factory(cls, global_config, **local_config):
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"""Paste factory."""
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def _factory(app):
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return cls(app, global_config, **local_config)
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return _factory
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def _action_ext_controllers(self, application, ext_mgr, mapper):
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"""Return a dict of ActionExtensionController-s by collection."""
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action_controllers = {}
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for action in ext_mgr.get_actions():
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if not action.collection in action_controllers.keys():
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controller = ActionExtensionController(application)
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mapper.connect("/%s/:(id)/action.:(format)" %
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action.collection,
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action='action',
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controller=controller,
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conditions=dict(method=['POST']))
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mapper.connect("/%s/:(id)/action" % action.collection,
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action='action',
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controller=controller,
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conditions=dict(method=['POST']))
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action_controllers[action.collection] = controller
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return action_controllers
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def _request_ext_controllers(self, application, ext_mgr, mapper):
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"""Returns a dict of RequestExtensionController-s by collection."""
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request_ext_controllers = {}
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for req_ext in ext_mgr.get_request_extensions():
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if not req_ext.key in request_ext_controllers.keys():
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controller = RequestExtensionController(application)
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mapper.connect(req_ext.url_route + '.:(format)',
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action='process',
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controller=controller,
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conditions=req_ext.conditions)
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mapper.connect(req_ext.url_route,
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action='process',
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controller=controller,
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conditions=req_ext.conditions)
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request_ext_controllers[req_ext.key] = controller
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return request_ext_controllers
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@webob.dec.wsgify(RequestClass=wsgi.Request)
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def __call__(self, req):
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"""Route the incoming request with router."""
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req.environ['extended.app'] = self.application
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return self._router
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@staticmethod
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@webob.dec.wsgify(RequestClass=wsgi.Request)
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def _dispatch(req):
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"""Dispatch the request.
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Returns the routed WSGI app's response or defers to the extended
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application.
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"""
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match = req.environ['wsgiorg.routing_args'][1]
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if not match:
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return req.environ['extended.app']
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app = match['controller']
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return app
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def plugin_aware_extension_middleware_factory(global_config, **local_config):
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"""Paste factory."""
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def _factory(app):
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extensions_path = global_config.get('api_extensions_path', '')
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ext_mgr = PluginAwareExtensionManager(extensions_path,
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QuantumManager.get_plugin())
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return ExtensionMiddleware(app, global_config, ext_mgr=ext_mgr)
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return _factory
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class ExtensionManager(object):
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"""Load extensions from the configured extension path.
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See tests/unit/extensions/foxinsocks.py for an
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example extension implementation.
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"""
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def __init__(self, path):
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LOG.info(_('Initializing extension manager.'))
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self.path = path
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self.extensions = {}
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self._load_all_extensions()
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def get_resources(self):
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"""Returns a list of ResourceExtension objects."""
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resources = []
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resources.append(ResourceExtension('extensions',
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ExtensionController(self)))
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for alias, ext in self.extensions.iteritems():
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try:
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resources.extend(ext.get_resources())
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except AttributeError:
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# NOTE(dprince): Extension aren't required to have resource
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# extensions
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pass
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return resources
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def get_actions(self):
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"""Returns a list of ActionExtension objects."""
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actions = []
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for alias, ext in self.extensions.iteritems():
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try:
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actions.extend(ext.get_actions())
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except AttributeError:
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# NOTE(dprince): Extension aren't required to have action
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# extensions
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pass
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return actions
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def get_request_extensions(self):
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"""Returns a list of RequestExtension objects."""
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request_exts = []
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for alias, ext in self.extensions.iteritems():
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try:
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request_exts.extend(ext.get_request_extensions())
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except AttributeError:
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# NOTE(dprince): Extension aren't required to have request
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# extensions
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pass
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return request_exts
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def _check_extension(self, extension):
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"""Checks for required methods in extension objects."""
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try:
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LOG.debug(_('Ext name: %s'), extension.get_name())
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LOG.debug(_('Ext alias: %s'), extension.get_alias())
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LOG.debug(_('Ext description: %s'), extension.get_description())
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LOG.debug(_('Ext namespace: %s'), extension.get_namespace())
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LOG.debug(_('Ext updated: %s'), extension.get_updated())
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except AttributeError as ex:
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LOG.exception(_("Exception loading extension: %s"), unicode(ex))
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return False
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return True
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def _load_all_extensions(self):
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"""Load extensions from the configured path.
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Load extensions from the configured path. The extension name is
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constructed from the module_name. If your extension module was named
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widgets.py the extension class within that module should be
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'Widgets'.
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See tests/unit/extensions/foxinsocks.py for an example
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extension implementation.
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"""
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if os.path.exists(self.path):
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self._load_all_extensions_from_path(self.path)
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def _load_all_extensions_from_path(self, path):
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for f in os.listdir(path):
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try:
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LOG.info(_('Loading extension file: %s'), f)
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mod_name, file_ext = os.path.splitext(os.path.split(f)[-1])
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ext_path = os.path.join(path, f)
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if file_ext.lower() == '.py' and not mod_name.startswith('_'):
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mod = imp.load_source(mod_name, ext_path)
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ext_name = mod_name[0].upper() + mod_name[1:]
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new_ext_class = getattr(mod, ext_name, None)
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if not new_ext_class:
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LOG.warn(_('Did not find expected name '
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'"%(ext_name)s" in %(file)s'),
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{'ext_name': ext_name,
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'file': ext_path})
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continue
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new_ext = new_ext_class()
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self.add_extension(new_ext)
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except Exception as exception:
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LOG.warn("extension file %s wasnt loaded due to %s",
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f, exception)
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def add_extension(self, ext):
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# Do nothing if the extension doesn't check out
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if not self._check_extension(ext):
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return
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alias = ext.get_alias()
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LOG.warn(_('Loaded extension: %s'), alias)
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if alias in self.extensions:
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raise exceptions.Error("Found duplicate extension: %s"
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% alias)
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self.extensions[alias] = ext
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class PluginAwareExtensionManager(ExtensionManager):
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def __init__(self, path, plugin):
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self.plugin = plugin
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super(PluginAwareExtensionManager, self).__init__(path)
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def _check_extension(self, extension):
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"""Checks if plugin supports extension and implements the
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extension contract."""
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extension_is_valid = super(PluginAwareExtensionManager,
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self)._check_extension(extension)
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return (extension_is_valid and
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self._plugin_supports(extension) and
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self._plugin_implements_interface(extension))
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def _plugin_supports(self, extension):
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alias = extension.get_alias()
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supports_extension = (hasattr(self.plugin,
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"supported_extension_aliases") and
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alias in self.plugin.supported_extension_aliases)
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if not supports_extension:
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LOG.warn("extension %s not supported by plugin %s",
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alias, self.plugin)
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return supports_extension
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def _plugin_implements_interface(self, extension):
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if(not hasattr(extension, "get_plugin_interface") or
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extension.get_plugin_interface() is None):
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return True
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plugin_has_interface = isinstance(self.plugin,
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extension.get_plugin_interface())
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if not plugin_has_interface:
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LOG.warn("plugin %s does not implement extension's"
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"plugin interface %s" % (self.plugin,
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extension.get_alias()))
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return plugin_has_interface
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class RequestExtension(object):
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"""Extend requests and responses of core Quantum OpenStack API controllers.
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Provide a way to add data to responses and handle custom request data
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that is sent to core Quantum OpenStack API controllers.
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"""
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def __init__(self, method, url_route, handler):
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self.url_route = url_route
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self.handler = handler
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self.conditions = dict(method=[method])
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self.key = "%s-%s" % (method, url_route)
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class ActionExtension(object):
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"""Add custom actions to core Quantum OpenStack API controllers."""
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def __init__(self, collection, action_name, handler):
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self.collection = collection
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self.action_name = action_name
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self.handler = handler
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class ResourceExtension(object):
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"""Add top level resources to the OpenStack API in Quantum."""
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def __init__(self, collection, controller, parent=None,
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collection_actions={}, member_actions={}):
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self.collection = collection
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self.controller = controller
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self.parent = parent
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self.collection_actions = collection_actions
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self.member_actions = member_actions
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