634 lines
23 KiB
Python
634 lines
23 KiB
Python
# Copyright 2011 OpenStack Foundation.
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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 abc
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import imp
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import os
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from oslo_config import cfg
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import routes
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import six
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import webob.dec
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import webob.exc
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from tacker.api.v1 import attributes
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from tacker.common import exceptions
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import tacker.extensions
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from tacker.openstack.common import log as logging
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from tacker import policy
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from tacker import wsgi
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LOG = logging.getLogger(__name__)
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@six.add_metaclass(abc.ABCMeta)
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class PluginInterface(object):
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@classmethod
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def __subclasshook__(cls, klass):
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"""Checking plugin class.
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The __subclasshook__ method is a class method
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that will be called every time 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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if not cls.__abstractmethods__:
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return NotImplemented
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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_extended_resources(self, version):
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"""Retrieve extended resources or attributes for core resources.
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Extended attributes are implemented by a core plugin similarly
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to the attributes defined in the core, and can appear in
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request and response messages. Their names are scoped with the
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extension's prefix. The core API version is passed to this
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function, which must return a
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map[<resource_name>][<attribute_name>][<attribute_property>]
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specifying the extended resource attribute properties required
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by that API version.
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Extension can add resources and their attr definitions too.
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The returned map can be integrated into RESOURCE_ATTRIBUTE_MAP.
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"""
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return {}
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def get_plugin_interface(self):
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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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def update_attributes_map(self, extended_attributes,
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extension_attrs_map=None):
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"""Update attributes map for this extension.
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This is default method for extending an extension's attributes map.
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An extension can use this method and supplying its own resource
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attribute map in extension_attrs_map argument to extend all its
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attributes that needs to be extended.
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If an extension does not implement update_attributes_map, the method
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does nothing and just return.
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"""
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if not extension_attrs_map:
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return
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for resource, attrs in extension_attrs_map.iteritems():
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extended_attrs = extended_attributes.get(resource)
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if extended_attrs:
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attrs.update(extended_attrs)
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def get_alias_namespace_compatibility_map(self):
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"""Returns mappings between extension aliases and XML namespaces.
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The mappings are XML namespaces that should, for backward compatibility
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reasons, be added to the XML serialization of extended attributes.
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This allows an established extended attribute to be provided by
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another extension than the original one while keeping its old alias
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in the name.
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:return: A dictionary of extension_aliases and namespace strings.
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"""
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return {}
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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 dict(extension=self._translate(ext))
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def delete(self, request, id):
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msg = _('Resource not found.')
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raise webob.exc.HTTPNotFound(msg)
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def create(self, request):
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msg = _('Resource not found.')
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raise webob.exc.HTTPNotFound(msg)
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class ExtensionMiddleware(wsgi.Middleware):
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"""Extensions middleware for WSGI."""
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def __init__(self, application,
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ext_mgr=None):
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self.ext_mgr = (ext_mgr
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or ExtensionManager(get_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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path_prefix = resource.path_prefix
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if resource.parent:
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path_prefix = (resource.path_prefix +
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"/%s/{%s_id}" %
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(resource.parent["collection_name"],
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resource.parent["member_name"]))
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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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conditions = dict(method=[method])
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path = "/%s/%s" % (resource.collection, action)
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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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path_prefix=path_prefix)
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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 action.collection not 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 req_ext.key not 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 extension_middleware_factory(global_config, **local_config):
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"""Paste factory."""
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def _factory(app):
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ext_mgr = ExtensionManager.get_instance()
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return ExtensionMiddleware(app, 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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_instance = None
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@classmethod
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def get_instance(cls):
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if cls._instance is None:
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cls._instance = cls(get_extensions_path())
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return cls._instance
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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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policy.reset()
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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 ext in self.extensions.itervalues():
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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 ext in self.extensions.itervalues():
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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 ext in self.extensions.itervalues():
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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 extend_resources(self, version, attr_map):
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"""Extend resources with additional resources or attributes.
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:param: attr_map, the existing mapping from resource name to
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attrs definition.
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After this function, we will extend the attr_map if an extension
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wants to extend this map.
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"""
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update_exts = []
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processed_exts = set()
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exts_to_process = self.extensions.copy()
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# Iterate until there are unprocessed extensions or if no progress
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# is made in a whole iteration
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while exts_to_process:
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processed_ext_count = len(processed_exts)
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for ext_name, ext in exts_to_process.items():
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if not hasattr(ext, 'get_extended_resources'):
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del exts_to_process[ext_name]
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continue
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if hasattr(ext, 'update_attributes_map'):
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update_exts.append(ext)
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if hasattr(ext, 'get_required_extensions'):
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# Process extension only if all required extensions
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# have been processed already
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required_exts_set = set(ext.get_required_extensions())
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if required_exts_set - processed_exts:
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continue
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try:
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extended_attrs = ext.get_extended_resources(version)
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for resource, resource_attrs in extended_attrs.iteritems():
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if attr_map.get(resource, None):
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attr_map[resource].update(resource_attrs)
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else:
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attr_map[resource] = resource_attrs
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if extended_attrs:
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attributes.EXT_NSES[ext.get_alias()] = (
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ext.get_namespace())
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except AttributeError:
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LOG.exception(_("Error fetching extended attributes for "
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"extension '%s'"), ext.get_name())
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try:
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comp_map = ext.get_alias_namespace_compatibility_map()
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attributes.EXT_NSES_BC.update(comp_map)
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except AttributeError:
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LOG.info(_("Extension '%s' provides no backward "
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"compatibility map for extended attributes"),
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ext.get_name())
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processed_exts.add(ext_name)
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del exts_to_process[ext_name]
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if len(processed_exts) == processed_ext_count:
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# Exit loop as no progress was made
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break
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if exts_to_process:
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# NOTE(salv-orlando): Consider whether this error should be fatal
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LOG.error(_("It was impossible to process the following "
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"extensions: %s because of missing requirements."),
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','.join(exts_to_process.keys()))
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# Extending extensions' attributes map.
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for ext in update_exts:
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ext.update_attributes_map(attr_map)
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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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The extension name is constructed from the module_name. If your
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extension module is named widgets.py, the extension class within that
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module should be 'Widgets'.
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See tests/unit/extensions/foxinsocks.py for an example extension
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implementation.
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"""
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for path in self.path.split(':'):
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if os.path.exists(path):
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self._load_all_extensions_from_path(path)
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else:
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LOG.error(_("Extension path '%s' doesn't exist!"), path)
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def _load_all_extensions_from_path(self, path):
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# Sorting the extension list makes the order in which they
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# are loaded predictable across a cluster of load-balanced
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# Tacker Servers
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for f in sorted(os.listdir(path)):
|
|
try:
|
|
LOG.debug(_('Loading extension file: %s'), f)
|
|
mod_name, file_ext = os.path.splitext(os.path.split(f)[-1])
|
|
ext_path = os.path.join(path, f)
|
|
if file_ext.lower() == '.py' and not mod_name.startswith('_'):
|
|
mod = imp.load_source(mod_name, ext_path)
|
|
ext_name = mod_name[0].upper() + mod_name[1:]
|
|
new_ext_class = getattr(mod, ext_name, None)
|
|
if not new_ext_class:
|
|
LOG.warn(_('Did not find expected name '
|
|
'"%(ext_name)s" in %(file)s'),
|
|
{'ext_name': ext_name,
|
|
'file': ext_path})
|
|
continue
|
|
new_ext = new_ext_class()
|
|
self.add_extension(new_ext)
|
|
except Exception as exception:
|
|
LOG.warn(_("Extension file %(f)s wasn't loaded due to "
|
|
"%(exception)s"), {'f': f, 'exception': exception})
|
|
|
|
def add_extension(self, ext):
|
|
# Do nothing if the extension doesn't check out
|
|
if not self._check_extension(ext):
|
|
return
|
|
|
|
alias = ext.get_alias()
|
|
LOG.info(_('Loaded extension: %s'), alias)
|
|
|
|
if alias in self.extensions:
|
|
raise exceptions.DuplicatedExtension(alias=alias)
|
|
self.extensions[alias] = ext
|
|
|
|
|
|
class RequestExtension(object):
|
|
"""Extend requests and responses of core Tacker OpenStack API controllers.
|
|
|
|
Provide a way to add data to responses and handle custom request data
|
|
that is sent to core Tacker OpenStack API controllers.
|
|
"""
|
|
|
|
def __init__(self, method, url_route, handler):
|
|
self.url_route = url_route
|
|
self.handler = handler
|
|
self.conditions = dict(method=[method])
|
|
self.key = "%s-%s" % (method, url_route)
|
|
|
|
|
|
class ActionExtension(object):
|
|
"""Add custom actions to core Tacker OpenStack API controllers."""
|
|
|
|
def __init__(self, collection, action_name, handler):
|
|
self.collection = collection
|
|
self.action_name = action_name
|
|
self.handler = handler
|
|
|
|
|
|
class ResourceExtension(object):
|
|
"""Add top level resources to the OpenStack API in Tacker."""
|
|
|
|
def __init__(self, collection, controller, parent=None, path_prefix="",
|
|
collection_actions={}, member_actions={}, attr_map={}):
|
|
self.collection = collection
|
|
self.controller = controller
|
|
self.parent = parent
|
|
self.collection_actions = collection_actions
|
|
self.member_actions = member_actions
|
|
self.path_prefix = path_prefix
|
|
self.attr_map = attr_map
|
|
|
|
|
|
# Returns the extension paths from a config entry and the __path__
|
|
# of tacker.extensions
|
|
def get_extensions_path():
|
|
paths = ':'.join(tacker.extensions.__path__)
|
|
if cfg.CONF.api_extensions_path:
|
|
paths = ':'.join([cfg.CONF.api_extensions_path, paths])
|
|
|
|
return paths
|
|
|
|
|
|
def append_api_extensions_path(paths):
|
|
paths = [cfg.CONF.api_extensions_path] + paths
|
|
cfg.CONF.set_override('api_extensions_path',
|
|
':'.join([p for p in paths if p]))
|