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OpenStack Study: extensions.py**** CubicPower OpenStack Study ****
# Copyright 2011 OpenStack Foundation # Copyright 2011 Justin Santa Barbara # All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. import os from oslo.config import cfg import webob.dec import webob.exc import cinder.api.openstack from cinder.api.openstack import wsgi from cinder.api import xmlutil from cinder import exception from cinder.openstack.common import importutils from cinder.openstack.common import log as logging import cinder.policy CONF = cfg.CONF LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** class ExtensionDescriptor(object): """Base class that
**** CubicPower OpenStack Study **** def __init__(self, ext_mgr): """Register extension with the extension manager.""" ext_mgr.register(self) self.ext_mgr = ext_mgr
**** CubicPower OpenStack Study **** def get_resources(self): """List of extensions.ResourceExtension extension objects. Resources define new nouns, and are accessible through URLs. """ resources = [] return resources
**** CubicPower OpenStack Study **** def get_controller_extensions(self): """List of extensions.ControllerExtension extension objects. Controller extensions are used to extend existing controllers. """ controller_exts = [] return controller_exts @classmethod
**** CubicPower OpenStack Study **** def nsmap(cls): """Synthesize a namespace map from extension.""" # Start with a base nsmap nsmap = ext_nsmap.copy() # Add the namespace for the extension nsmap[cls.alias] = cls.namespace return nsmap @classmethod
**** CubicPower OpenStack Study **** def xmlname(cls, name): """Synthesize element and attribute names.""" return '{%s}%s' % (cls.namespace, name) def make_ext(elem): elem.set('name') elem.set('namespace') elem.set('alias') elem.set('updated') desc = xmlutil.SubTemplateElement(elem, 'description') desc.text = 'description' xmlutil.make_links(elem, 'links') ext_nsmap = {None: xmlutil.XMLNS_COMMON_V10, 'atom': xmlutil.XMLNS_ATOM}
**** CubicPower OpenStack Study **** def make_ext(elem): elem.set('name') elem.set('namespace') elem.set('alias') elem.set('updated') desc = xmlutil.SubTemplateElement(elem, 'description') desc.text = 'description' xmlutil.make_links(elem, 'links') ext_nsmap = {None: xmlutil.XMLNS_COMMON_V10, 'atom': xmlutil.XMLNS_ATOM}
**** CubicPower OpenStack Study **** class ExtensionTemplate(xmlutil.TemplateBuilder):
**** CubicPower OpenStack Study **** def construct(self): root = xmlutil.TemplateElement('extension', selector='extension') make_ext(root) return xmlutil.MasterTemplate(root, 1, nsmap=ext_nsmap)
**** CubicPower OpenStack Study **** class ExtensionsTemplate(xmlutil.TemplateBuilder):
**** CubicPower OpenStack Study **** def construct(self): root = xmlutil.TemplateElement('extensions') elem = xmlutil.SubTemplateElement(root, 'extension', selector='extensions') make_ext(elem) return xmlutil.MasterTemplate(root, 1, nsmap=ext_nsmap)
**** CubicPower OpenStack Study **** class ExtensionsResource(wsgi.Resource):
**** CubicPower OpenStack Study **** def __init__(self, extension_manager): self.extension_manager = extension_manager super(ExtensionsResource, self).__init__(None)
**** CubicPower OpenStack Study **** def _translate(self, ext): ext_data = {} ext_data['name'] = ext.name ext_data['alias'] = ext.alias ext_data['description'] = ext.__doc__ ext_data['namespace'] = ext.namespace ext_data['updated'] = ext.updated ext_data['links'] = [] # TODO(dprince): implement extension links return ext_data @wsgi.serializers(xml=ExtensionsTemplate)
**** CubicPower OpenStack Study **** def index(self, req): extensions = [] for _alias, ext in self.extension_manager.extensions.iteritems(): extensions.append(self._translate(ext)) return dict(extensions=extensions) @wsgi.serializers(xml=ExtensionTemplate)
**** CubicPower OpenStack Study **** def show(self, req, id): try: # NOTE(dprince): the extensions alias is used as the 'id' for show ext = self.extension_manager.extensions[id] except KeyError: raise webob.exc.HTTPNotFound() return dict(extension=self._translate(ext))
**** CubicPower OpenStack Study **** def delete(self, req, id): raise webob.exc.HTTPNotFound()
**** CubicPower OpenStack Study **** def create(self, req): raise webob.exc.HTTPNotFound()
**** CubicPower OpenStack Study **** class ExtensionManager(object): """Load extensions from the configured extension path. See cinder/tests/api/extensions/foxinsocks/extension.py for an example extension implementation. """
**** CubicPower OpenStack Study **** def __init__(self): LOG.audit(_('Initializing extension manager.')) self.cls_list = CONF.osapi_volume_extension self.extensions = {} self._load_extensions()
**** CubicPower OpenStack Study **** def is_loaded(self, alias): return alias in self.extensions
**** CubicPower OpenStack Study **** def register(self, ext): # Do nothing if the extension doesn't check out if not self._check_extension(ext): return alias = ext.alias LOG.audit(_('Loaded extension: %s'), alias) if alias in self.extensions: raise exception.Error("Found duplicate extension: %s" % alias) self.extensions[alias] = ext
**** CubicPower OpenStack Study **** def get_resources(self): """Returns a list of ResourceExtension objects.""" resources = [] resources.append(ResourceExtension('extensions', ExtensionsResource(self))) for ext in self.extensions.values(): try: resources.extend(ext.get_resources()) except AttributeError: # NOTE(dprince): Extension aren't required to have resource # extensions pass return resources
**** CubicPower OpenStack Study **** def get_controller_extensions(self): """Returns a list of ControllerExtension objects.""" controller_exts = [] for ext in self.extensions.values(): try: get_ext_method = ext.get_controller_extensions except AttributeError: # NOTE(Vek): Extensions aren't required to have # controller extensions continue controller_exts.extend(get_ext_method()) return controller_exts
**** CubicPower OpenStack Study **** def _check_extension(self, extension): """Checks for required methods in extension objects.""" try: LOG.debug(_('Ext name: %s'), extension.name) LOG.debug(_('Ext alias: %s'), extension.alias) LOG.debug(_('Ext description: %s'), ' '.join(extension.__doc__.strip().split())) LOG.debug(_('Ext namespace: %s'), extension.namespace) LOG.debug(_('Ext updated: %s'), extension.updated) except AttributeError as ex: LOG.exception(_("Exception loading extension: %s"), unicode(ex)) return False return True
**** CubicPower OpenStack Study **** def load_extension(self, ext_factory): """Execute an extension factory. Loads an extension. The 'ext_factory' is the name of a callable that will be imported and called with one argument--the extension manager. The factory callable is expected to call the register() method at least once. """ LOG.debug(_("Loading extension %s"), ext_factory) # Load the factory factory = importutils.import_class(ext_factory) # Call it LOG.debug(_("Calling extension factory %s"), ext_factory) factory(self)
**** CubicPower OpenStack Study **** def _load_extensions(self): """Load extensions specified on the command line.""" extensions = list(self.cls_list) # NOTE(thingee): Backwards compat for the old extension loader path. # We can drop this post-grizzly in the H release. old_contrib_path = ('cinder.api.openstack.volume.contrib.' 'standard_extensions') new_contrib_path = 'cinder.api.contrib.standard_extensions' if old_contrib_path in extensions: LOG.warn(_('osapi_volume_extension is set to deprecated path: %s'), old_contrib_path) LOG.warn(_('Please set your flag or cinder.conf settings for ' 'osapi_volume_extension to: %s'), new_contrib_path) extensions = [e.replace(old_contrib_path, new_contrib_path) for e in extensions] for ext_factory in extensions: try: self.load_extension(ext_factory) except Exception as exc: LOG.warn(_('Failed to load extension %(ext_factory)s: ' '%(exc)s'), {'ext_factory': ext_factory, 'exc': exc})
**** CubicPower OpenStack Study **** class ControllerExtension(object): """Extend core controllers of cinder OpenStack API. Provide a way to extend existing cinder OpenStack API core controllers. """
**** CubicPower OpenStack Study **** def __init__(self, extension, collection, controller): self.extension = extension self.collection = collection self.controller = controller
**** CubicPower OpenStack Study **** class ResourceExtension(object): """Add top level resources to the OpenStack API in cinder."""
**** CubicPower OpenStack Study **** def __init__(self, collection, controller, parent=None, collection_actions=None, member_actions=None, custom_routes_fn=None): if not collection_actions: collection_actions = {} if not member_actions: member_actions = {} self.collection = collection self.controller = controller self.parent = parent self.collection_actions = collection_actions self.member_actions = member_actions self.custom_routes_fn = custom_routes_fn def load_standard_extensions(ext_mgr, logger, path, package, ext_list=None): """Registers all standard API extensions.""" # Walk through all the modules in our directory... our_dir = path[0] for dirpath, dirnames, filenames in os.walk(our_dir): # Compute the relative package name from the dirpath relpath = os.path.relpath(dirpath, our_dir) if relpath == '.': relpkg = '' else: relpkg = '.%s' % '.'.join(relpath.split(os.sep)) # Now, consider each file in turn, only considering .py files for fname in filenames: root, ext = os.path.splitext(fname) # Skip __init__ and anything that's not .py if ext != '.py' or root == '__init__': continue # Try loading it classname = "%s%s" % (root[0].upper(), root[1:]) classpath = ("%s%s.%s.%s" % (package, relpkg, root, classname)) if ext_list is not None and classname not in ext_list: logger.debug("Skipping extension: %s" % classpath) continue try: ext_mgr.load_extension(classpath) except Exception as exc: logger.warn(_('Failed to load extension %(classpath)s: ' '%(exc)s'), {'classpath': classpath, 'exc': exc}) # Now, let's consider any subdirectories we may have... subdirs = [] for dname in dirnames: # Skip it if it does not have __init__.py if not os.path.exists(os.path.join(dirpath, dname, '__init__.py')): continue # If it has extension(), delegate... ext_name = ("%s%s.%s.extension" % (package, relpkg, dname)) try: ext = importutils.import_class(ext_name) except ImportError: # extension() doesn't exist on it, so we'll explore # the directory for ourselves subdirs.append(dname) else: try: ext(ext_mgr) except Exception as exc: logger.warn(_('Failed to load extension %(ext_name)s: ' '%(exc)s'), {'ext_name': ext_name, 'exc': exc}) # Update the list of directories we'll explore... dirnames[:] = subdirs def extension_authorizer(api_name, extension_name):
**** CubicPower OpenStack Study **** def load_standard_extensions(ext_mgr, logger, path, package, ext_list=None): """Registers all standard API extensions.""" # Walk through all the modules in our directory... our_dir = path[0] for dirpath, dirnames, filenames in os.walk(our_dir): # Compute the relative package name from the dirpath relpath = os.path.relpath(dirpath, our_dir) if relpath == '.': relpkg = '' else: relpkg = '.%s' % '.'.join(relpath.split(os.sep)) # Now, consider each file in turn, only considering .py files for fname in filenames: root, ext = os.path.splitext(fname) # Skip __init__ and anything that's not .py if ext != '.py' or root == '__init__': continue # Try loading it classname = "%s%s" % (root[0].upper(), root[1:]) classpath = ("%s%s.%s.%s" % (package, relpkg, root, classname)) if ext_list is not None and classname not in ext_list: logger.debug("Skipping extension: %s" % classpath) continue try: ext_mgr.load_extension(classpath) except Exception as exc: logger.warn(_('Failed to load extension %(classpath)s: ' '%(exc)s'), {'classpath': classpath, 'exc': exc}) # Now, let's consider any subdirectories we may have... subdirs = [] for dname in dirnames: # Skip it if it does not have __init__.py if not os.path.exists(os.path.join(dirpath, dname, '__init__.py')): continue # If it has extension(), delegate... ext_name = ("%s%s.%s.extension" % (package, relpkg, dname)) try: ext = importutils.import_class(ext_name) except ImportError: # extension() doesn't exist on it, so we'll explore # the directory for ourselves subdirs.append(dname) else: try: ext(ext_mgr) except Exception as exc: logger.warn(_('Failed to load extension %(ext_name)s: ' '%(exc)s'), {'ext_name': ext_name, 'exc': exc}) # Update the list of directories we'll explore... dirnames[:] = subdirs
**** CubicPower OpenStack Study **** def extension_authorizer(api_name, extension_name):
**** CubicPower OpenStack Study **** def authorize(context, target=None): if target is None: target = {'project_id': context.project_id, 'user_id': context.user_id} action = '%s_extension:%s' % (api_name, extension_name) cinder.policy.enforce(context, action, target) return authorize def soft_extension_authorizer(api_name, extension_name): hard_authorize = extension_authorizer(api_name, extension_name)
**** CubicPower OpenStack Study **** def soft_extension_authorizer(api_name, extension_name): hard_authorize = extension_authorizer(api_name, extension_name)
**** CubicPower OpenStack Study **** def authorize(context): try: hard_authorize(context) return True except exception.NotAuthorized: return False return authorize
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