495 lines
16 KiB
Python
495 lines
16 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# 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 functools
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import os
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import webob.dec
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import webob.exc
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import nova.api.openstack
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from nova.api.openstack import wsgi
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from nova.api.openstack import xmlutil
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from nova import exception
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from nova.openstack.common.gettextutils import _
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from nova.openstack.common import importutils
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from nova.openstack.common import log as logging
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import nova.policy
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LOG = logging.getLogger(__name__)
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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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# The name of the extension, e.g., 'Fox In Socks'
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name = None
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# The alias for the extension, e.g., 'FOXNSOX'
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alias = None
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# Description comes from the docstring for the class
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# The XML namespace for the extension, e.g.,
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# 'http://www.fox.in.socks/api/ext/pie/v1.0'
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namespace = None
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# The timestamp when the extension was last updated, e.g.,
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# '2011-01-22T13:25:27-06:00'
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updated = None
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def __init__(self, ext_mgr):
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"""Register extension with the extension manager."""
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ext_mgr.register(self)
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self.ext_mgr = ext_mgr
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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_controller_extensions(self):
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"""List of extensions.ControllerExtension extension objects.
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Controller extensions are used to extend existing controllers.
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"""
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controller_exts = []
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return controller_exts
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@classmethod
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def nsmap(cls):
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"""Synthesize a namespace map from extension."""
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# Start with a base nsmap
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nsmap = ext_nsmap.copy()
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# Add the namespace for the extension
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nsmap[cls.alias] = cls.namespace
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return nsmap
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@classmethod
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def xmlname(cls, name):
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"""Synthesize element and attribute names."""
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return '{%s}%s' % (cls.namespace, name)
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def make_ext(elem):
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elem.set('name')
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elem.set('namespace')
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elem.set('alias')
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elem.set('updated')
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desc = xmlutil.SubTemplateElement(elem, 'description')
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desc.text = 'description'
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xmlutil.make_links(elem, 'links')
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ext_nsmap = {None: xmlutil.XMLNS_COMMON_V10, 'atom': xmlutil.XMLNS_ATOM}
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class ExtensionTemplate(xmlutil.TemplateBuilder):
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def construct(self):
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root = xmlutil.TemplateElement('extension', selector='extension')
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make_ext(root)
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return xmlutil.MasterTemplate(root, 1, nsmap=ext_nsmap)
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class ExtensionsTemplate(xmlutil.TemplateBuilder):
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def construct(self):
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root = xmlutil.TemplateElement('extensions')
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elem = xmlutil.SubTemplateElement(root, 'extension',
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selector='extensions')
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make_ext(elem)
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return xmlutil.MasterTemplate(root, 1, nsmap=ext_nsmap)
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class ExtensionsResource(wsgi.Resource):
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def __init__(self, extension_manager):
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self.extension_manager = extension_manager
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super(ExtensionsResource, self).__init__(None)
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def _translate(self, ext):
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ext_data = {}
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ext_data['name'] = ext.name
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ext_data['alias'] = ext.alias
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ext_data['description'] = ext.__doc__
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ext_data['namespace'] = ext.namespace
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ext_data['updated'] = ext.updated
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ext_data['links'] = [] # TODO(dprince): implement extension links
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return ext_data
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@wsgi.serializers(xml=ExtensionsTemplate)
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def index(self, req):
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extensions = []
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for ext in self.extension_manager.sorted_extensions():
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extensions.append(self._translate(ext))
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return dict(extensions=extensions)
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@wsgi.serializers(xml=ExtensionTemplate)
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def show(self, req, id):
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try:
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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[id]
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except KeyError:
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raise webob.exc.HTTPNotFound()
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return dict(extension=self._translate(ext))
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def delete(self, req, id):
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raise webob.exc.HTTPNotFound()
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def create(self, req):
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raise webob.exc.HTTPNotFound()
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class ExtensionManager(object):
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"""Load extensions from the configured extension path.
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See nova/tests/api/openstack/volume/extensions/foxinsocks.py or an
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example extension implementation.
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"""
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def sorted_extensions(self):
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if self.sorted_ext_list is None:
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self.sorted_ext_list = sorted(self.extensions.iteritems())
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for _alias, ext in self.sorted_ext_list:
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yield ext
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def is_loaded(self, alias):
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return alias in self.extensions
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def register(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.alias
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LOG.audit(_('Loaded extension: %s'), alias)
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if alias in self.extensions:
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raise exception.NovaException("Found duplicate extension: %s"
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% alias)
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self.extensions[alias] = ext
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self.sorted_ext_list = None
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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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ExtensionsResource(self)))
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for ext in self.sorted_extensions():
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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_controller_extensions(self):
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"""Returns a list of ControllerExtension objects."""
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controller_exts = []
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for ext in self.sorted_extensions():
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try:
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get_ext_method = ext.get_controller_extensions
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except AttributeError:
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# NOTE(Vek): Extensions aren't required to have
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# controller extensions
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continue
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controller_exts.extend(get_ext_method())
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return controller_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.name)
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LOG.debug(_('Ext alias: %s'), extension.alias)
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LOG.debug(_('Ext description: %s'),
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' '.join(extension.__doc__.strip().split()))
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LOG.debug(_('Ext namespace: %s'), extension.namespace)
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LOG.debug(_('Ext updated: %s'), extension.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_extension(self, ext_factory):
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"""Execute an extension factory.
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Loads an extension. The 'ext_factory' is the name of a
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callable that will be imported and called with one
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argument--the extension manager. The factory callable is
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expected to call the register() method at least once.
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"""
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LOG.debug(_("Loading extension %s"), ext_factory)
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if isinstance(ext_factory, basestring):
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# Load the factory
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factory = importutils.import_class(ext_factory)
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else:
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factory = ext_factory
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# Call it
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LOG.debug(_("Calling extension factory %s"), ext_factory)
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factory(self)
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def _load_extensions(self):
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"""Load extensions specified on the command line."""
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extensions = list(self.cls_list)
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for ext_factory in extensions:
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try:
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self.load_extension(ext_factory)
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except Exception as exc:
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LOG.warn(_('Failed to load extension %(ext_factory)s: '
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'%(exc)s'),
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{'ext_factory': ext_factory, 'exc': exc})
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class ControllerExtension(object):
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"""Extend core controllers of nova OpenStack API.
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Provide a way to extend existing nova OpenStack API core
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controllers.
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"""
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def __init__(self, extension, collection, controller):
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self.extension = extension
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self.collection = collection
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self.controller = controller
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class ResourceExtension(object):
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"""Add top level resources to the OpenStack API in nova."""
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def __init__(self, collection, controller=None, parent=None,
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collection_actions=None, member_actions=None,
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custom_routes_fn=None, inherits=None, member_name=None):
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if not collection_actions:
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collection_actions = {}
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if not member_actions:
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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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self.custom_routes_fn = custom_routes_fn
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self.inherits = inherits
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self.member_name = member_name
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def load_standard_extensions(ext_mgr, logger, path, package, ext_list=None):
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"""Registers all standard API extensions."""
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# Walk through all the modules in our directory...
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our_dir = path[0]
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for dirpath, dirnames, filenames in os.walk(our_dir):
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# Compute the relative package name from the dirpath
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relpath = os.path.relpath(dirpath, our_dir)
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if relpath == '.':
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relpkg = ''
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else:
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relpkg = '.%s' % '.'.join(relpath.split(os.sep))
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# Now, consider each file in turn, only considering .py files
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for fname in filenames:
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root, ext = os.path.splitext(fname)
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# Skip __init__ and anything that's not .py
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if ext != '.py' or root == '__init__':
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continue
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# Try loading it
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classname = "%s%s" % (root[0].upper(), root[1:])
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classpath = ("%s%s.%s.%s" %
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(package, relpkg, root, classname))
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if ext_list is not None and classname not in ext_list:
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logger.debug("Skipping extension: %s" % classpath)
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continue
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try:
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ext_mgr.load_extension(classpath)
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except Exception as exc:
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logger.warn(_('Failed to load extension %(classpath)s: '
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'%(exc)s'),
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{'classpath': classpath, 'exc': exc})
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# Now, let's consider any subdirectories we may have...
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subdirs = []
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for dname in dirnames:
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# Skip it if it does not have __init__.py
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if not os.path.exists(os.path.join(dirpath, dname, '__init__.py')):
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continue
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# If it has extension(), delegate...
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ext_name = "%s%s.%s.extension" % (package, relpkg, dname)
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try:
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ext = importutils.import_class(ext_name)
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except ImportError:
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# extension() doesn't exist on it, so we'll explore
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# the directory for ourselves
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subdirs.append(dname)
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else:
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try:
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ext(ext_mgr)
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except Exception as exc:
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logger.warn(_('Failed to load extension %(ext_name)s:'
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'%(exc)s'),
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{'ext_name': ext_name, 'exc': exc})
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# Update the list of directories we'll explore...
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dirnames[:] = subdirs
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def extension_authorizer(api_name, extension_name):
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def authorize(context, target=None, action=None):
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if target is None:
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target = {'project_id': context.project_id,
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'user_id': context.user_id}
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if action is None:
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act = '%s_extension:%s' % (api_name, extension_name)
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else:
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act = '%s_extension:%s:%s' % (api_name, extension_name, action)
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nova.policy.enforce(context, act, target)
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return authorize
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def soft_extension_authorizer(api_name, extension_name):
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hard_authorize = extension_authorizer(api_name, extension_name)
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def authorize(context, action=None):
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try:
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hard_authorize(context, action=action)
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return True
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except exception.NotAuthorized:
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return False
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return authorize
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class V3APIExtensionBase(object):
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"""Abstract base class for all V3 API extensions.
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All V3 API extensions must derive from this class and implement
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the abstract methods get_resources and get_controller_extensions
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even if they just return an empty list. The extensions must also
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define the abstract properties.
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"""
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__metaclass__ = abc.ABCMeta
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def __init__(self, extension_info):
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self.extension_info = extension_info
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@abc.abstractmethod
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def get_resources(self):
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"""Return a list of resources extensions.
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The extensions should return a list of ResourceExtension
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objects. This list may be empty.
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"""
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pass
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@abc.abstractmethod
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def get_controller_extensions(self):
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"""Return a list of controller extensions.
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The extensions should return a list of ControllerExtension
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objects. This list may be empty.
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"""
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pass
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@abc.abstractproperty
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def name(self):
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"""Name of the extension."""
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pass
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@abc.abstractproperty
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def alias(self):
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"""Alias for the extension."""
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pass
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@abc.abstractproperty
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def namespace(self):
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"""Namespace for the extension."""
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pass
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@abc.abstractproperty
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def version(self):
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"""Version of the extension."""
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pass
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def expected_errors(errors):
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"""Decorator for v3 API methods which specifies expected exceptions.
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Specify which exceptions may occur when an API method is called. If an
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unexpected exception occurs then return a 500 instead and ask the user
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of the API to file a bug report.
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"""
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def decorator(f):
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@functools.wraps(f)
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def wrapped(*args, **kwargs):
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try:
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return f(*args, **kwargs)
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except Exception as exc:
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if isinstance(exc, webob.exc.WSGIHTTPException):
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if isinstance(errors, int):
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t_errors = (errors,)
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else:
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t_errors = errors
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if exc.code in t_errors:
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raise
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elif isinstance(exc, exception.PolicyNotAuthorized):
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# Note(cyeoh): Special case to handle
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# PolicyNotAuthorized exceptions so every
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# extension method does not need to wrap authorize
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# calls. ResourceExceptionHandler silently
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# converts NotAuthorized to HTTPForbidden
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raise
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LOG.exception(_("Unexpected exception in API method"))
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msg = _('Unexpected API Error. Please report this at '
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'http://bugs.launchpad.net/nova/ and attach the Nova '
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'API log if possible.\n%s') % type(exc)
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raise webob.exc.HTTPInternalServerError(explanation=msg)
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return wrapped
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return decorator
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