OpenStack Block Storage (Cinder)
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# Copyright 2011 OpenStack Foundation
# Copyright 2013 IBM Corp.
# 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
# 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.
from collections import abc
import functools
import inspect
import math
import time
from oslo_log import log as logging
from oslo_serialization import jsonutils
from oslo_utils import encodeutils
from oslo_utils import excutils
from oslo_utils import strutils
import six
from six.moves import http_client
import webob
import webob.exc
from cinder.api.openstack import api_version_request as api_version
from cinder.api.openstack import versioned_method
from cinder import exception
from cinder import i18n
from cinder.i18n import _
from cinder import utils
from cinder.wsgi import common as wsgi
LOG = logging.getLogger(__name__)
'application/vnd.openstack.volume+json': 'json',
'application/json': 'json',
# name of attribute to keep version method information
VER_METHOD_ATTR = 'versioned_methods'
# Name of header used by clients to request a specific version
# of the REST API
class Request(webob.Request):
"""Add some OpenStack API-specific logic to the base webob.Request."""
def __init__(self, *args, **kwargs):
super(Request, self).__init__(*args, **kwargs)
self._resource_cache = {}
if not hasattr(self, 'api_version_request'):
self.api_version_request = api_version.APIVersionRequest()
def cache_resource(self, resource_to_cache, id_attribute='id', name=None):
"""Cache the given resource.
Allow API methods to cache objects, such as results from a DB query,
to be used by API extensions within the same API request.
The resource_to_cache can be a list or an individual resource,
but ultimately resources are cached individually using the given
Different resources types might need to be cached during the same
request, they can be cached using the name parameter. For example:
Controller 1:
request.cache_resource(db_volumes, 'volumes')
request.cache_resource(db_volume_types, 'types')
Controller 2:
db_volumes = request.cached_resource('volumes')
db_type_1 = request.cached_resource_by_id('1', 'types')
If no name is given, a default name will be used for the resource.
An instance of this class only lives for the lifetime of a
single API request, so there's no need to implement full
cache management.
if not isinstance(resource_to_cache, list):
resource_to_cache = [resource_to_cache]
if not name:
name = self.path
cached_resources = self._resource_cache.setdefault(name, {})
for resource in resource_to_cache:
cached_resources[resource[id_attribute]] = resource
def cached_resource(self, name=None):
"""Get the cached resources cached under the given resource name.
Allow an API extension to get previously stored objects within
the same API request.
Note that the object data will be slightly stale.
:returns: a dict of id_attribute to the resource from the cached
resources, an empty map if an empty collection was cached,
or None if nothing has been cached yet under this name
if not name:
name = self.path
if name not in self._resource_cache:
# Nothing has been cached for this key yet
return None
return self._resource_cache[name]
def cached_resource_by_id(self, resource_id, name=None):
"""Get a resource by ID cached under the given resource name.
Allow an API extension to get a previously stored object
within the same API request. This is basically a convenience method
to lookup by ID on the dictionary of all cached resources.
Note that the object data will be slightly stale.
:returns: the cached resource or None if the item is not in the cache
resources = self.cached_resource(name)
if not resources:
# Nothing has been cached yet for this key yet
return None
return resources.get(resource_id)
def cache_db_items(self, key, items, item_key='id'):
"""Get cached database items.
Allow API methods to store objects from a DB query to be
used by API extensions within the same API request.
An instance of this class only lives for the lifetime of a
single API request, so there's no need to implement full
cache management.
self.cache_resource(items, item_key, key)
def get_db_items(self, key):
"""Get database items.
Allow an API extension to get previously stored objects within
the same API request.
Note that the object data will be slightly stale.
return self.cached_resource(key)
def get_db_item(self, key, item_key):
"""Get database item.
Allow an API extension to get a previously stored object
within the same API request.
Note that the object data will be slightly stale.
return self.get_db_items(key).get(item_key)
def cache_db_volumes(self, volumes):
# NOTE(mgagne) Cache it twice for backward compatibility reasons
self.cache_db_items('volumes', volumes, 'id')
self.cache_db_items(self.path, volumes, 'id')
def cache_db_volume(self, volume):
# NOTE(mgagne) Cache it twice for backward compatibility reasons
self.cache_db_items('volumes', [volume], 'id')
self.cache_db_items(self.path, [volume], 'id')
def get_db_volumes(self):
return (self.get_db_items('volumes') or
def get_db_volume(self, volume_id):
return (self.get_db_item('volumes', volume_id) or
self.get_db_item(self.path, volume_id))
def cache_db_volume_types(self, volume_types):
self.cache_db_items('volume_types', volume_types, 'id')
def cache_db_volume_type(self, volume_type):
self.cache_db_items('volume_types', [volume_type], 'id')
def get_db_volume_types(self):
return self.get_db_items('volume_types')
def get_db_volume_type(self, volume_type_id):
return self.get_db_item('volume_types', volume_type_id)
def cache_db_snapshots(self, snapshots):
self.cache_db_items('snapshots', snapshots, 'id')
def cache_db_snapshot(self, snapshot):
self.cache_db_items('snapshots', [snapshot], 'id')
def get_db_snapshots(self):
return self.get_db_items('snapshots')
def get_db_snapshot(self, snapshot_id):
return self.get_db_item('snapshots', snapshot_id)
def cache_db_backups(self, backups):
self.cache_db_items('backups', backups, 'id')
def cache_db_backup(self, backup):
self.cache_db_items('backups', [backup], 'id')
def get_db_backups(self):
return self.get_db_items('backups')
def get_db_backup(self, backup_id):
return self.get_db_item('backups', backup_id)
def best_match_content_type(self):
"""Determine the requested response content-type."""
if 'cinder.best_content_type' not in self.environ:
# Calculate the best MIME type
content_type = None
# Check URL path suffix
parts = self.path.rsplit('.', 1)
if len(parts) > 1:
possible_type = 'application/' + parts[1]
if possible_type in SUPPORTED_CONTENT_TYPES:
content_type = possible_type
if not content_type:
content_type = self.accept.best_match(SUPPORTED_CONTENT_TYPES)
self.environ['cinder.best_content_type'] = (content_type or
return self.environ['cinder.best_content_type']
def get_content_type(self):
"""Determine content type of the request body.
Does not do any body introspection, only checks header
if "Content-Type" not in self.headers:
return None
content_type = self.content_type
if content_type not in allowed_types:
raise exception.InvalidContentType(content_type=content_type)
return content_type
def best_match_language(self):
"""Determines best available locale from the Accept-Language header.
:returns: the best language match or None if the 'Accept-Language'
header was not available in the request.
if not self.accept_language:
return None
all_languages = i18n.get_available_languages()
return self.accept_language.best_match(all_languages)
def set_api_version_request(self, url):
"""Set API version request based on the request header information.
Microversions starts with /v3, so if a client sends a request for
version 1.0 or 2.0 with the /v3 endpoint, throw an exception.
Sending a header with any microversion to a /v2 endpoint will
be ignored.
Note that a microversion must be set for the legacy endpoint. This
will appear as 2.0 for /v2.
if API_VERSION_REQUEST_HEADER in self.headers and 'v3' in url:
hdr_string = self.headers[API_VERSION_REQUEST_HEADER]
# 'latest' is a special keyword which is equivalent to requesting
# the maximum version of the API supported
hdr_string_list = hdr_string.split(",")
volume_version = None
for hdr in hdr_string_list:
service, volume_version = hdr.split()
if not volume_version:
raise exception.VersionNotFoundForAPIMethod(
if volume_version == 'latest':
self.api_version_request = api_version.max_api_version()
self.api_version_request = api_version.APIVersionRequest(
# Check that the version requested is within the global
# minimum/maximum of supported API versions
if not self.api_version_request.matches(
raise exception.InvalidGlobalAPIVersion(
if 'v2' in url:
self.api_version_request = api_version.legacy_api_version2()
self.api_version_request = api_version.APIVersionRequest(
class ActionDispatcher(object):
"""Maps method name to local methods through action name."""
def dispatch(self, *args, **kwargs):
"""Find and call local method."""
action = kwargs.pop('action', 'default')
action_method = getattr(self, six.text_type(action), self.default)
return action_method(*args, **kwargs)
def default(self, data):
raise NotImplementedError()
class TextDeserializer(ActionDispatcher):
"""Default request body deserialization."""
def deserialize(self, datastring, action='default'):
return self.dispatch(datastring, action=action)
def default(self, datastring):
return {}
class JSONDeserializer(TextDeserializer):
def _from_json(self, datastring):
return jsonutils.loads(datastring)
except ValueError:
msg = _("cannot understand JSON")
raise exception.MalformedRequestBody(reason=msg)
def default(self, datastring):
return {'body': self._from_json(datastring)}
class DictSerializer(ActionDispatcher):
"""Default request body serialization."""
def serialize(self, data, action='default'):
return self.dispatch(data, action=action)
def default(self, data):
return ""
class JSONDictSerializer(DictSerializer):
"""Default JSON request body serialization."""
def default(self, data):
return jsonutils.dump_as_bytes(data)
def serializers(**serializers):
"""Attaches serializers to a method.
This decorator associates a dictionary of serializers with a
method. Note that the function attributes are directly
manipulated; the method is not wrapped.
def decorator(func):
if not hasattr(func, 'wsgi_serializers'):
func.wsgi_serializers = {}
return func
return decorator
def deserializers(**deserializers):
"""Attaches deserializers to a method.
This decorator associates a dictionary of deserializers with a
method. Note that the function attributes are directly
manipulated; the method is not wrapped.
def decorator(func):
if not hasattr(func, 'wsgi_deserializers'):
func.wsgi_deserializers = {}
return func
return decorator
def response(code):
"""Attaches response code to a method.
This decorator associates a response code with a method. Note
that the function attributes are directly manipulated; the method
is not wrapped.
def decorator(func):
func.wsgi_code = code
return func
return decorator
class ResponseObject(object):
"""Bundles a response object with appropriate serializers.
Object that app methods may return in order to bind alternate
serializers with a response object to be serialized. Its use is
def __init__(self, obj, code=None, headers=None, **serializers):
"""Binds serializers with an object.
Takes keyword arguments akin to the @serializer() decorator
for specifying serializers. Serializers specified will be
given preference over default serializers or method-specific
serializers on return.
self.obj = obj
self.serializers = serializers
self._default_code = http_client.OK
self._code = code
self._headers = headers or {}
self.serializer = None
self.media_type = None
def __getitem__(self, key):
"""Retrieves a header with the given name."""
return self._headers[key.lower()]
def __setitem__(self, key, value):
"""Sets a header with the given name to the given value."""
self._headers[key.lower()] = value
def __delitem__(self, key):
"""Deletes the header with the given name."""
del self._headers[key.lower()]
def _bind_method_serializers(self, meth_serializers):
"""Binds method serializers with the response object.
Binds the method serializers with the response object.
Serializers specified to the constructor will take precedence
over serializers specified to this method.
:param meth_serializers: A dictionary with keys mapping to
response types and values containing
serializer objects.
# We can't use update because that would be the wrong
# precedence
for mtype, serializer in meth_serializers.items():
self.serializers.setdefault(mtype, serializer)
def get_serializer(self, content_type, default_serializers=None):
"""Returns the serializer for the wrapped object.
Returns the serializer for the wrapped object subject to the
indicated content type. If no serializer matching the content
type is attached, an appropriate serializer drawn from the
default serializers will be used. If no appropriate
serializer is available, raises InvalidContentType.
default_serializers = default_serializers or {}
mtype = _MEDIA_TYPE_MAP.get(content_type, content_type)
if mtype in self.serializers:
return mtype, self.serializers[mtype]
return mtype, default_serializers[mtype]
except (KeyError, TypeError):
raise exception.InvalidContentType(content_type=content_type)
def preserialize(self, content_type, default_serializers=None):
"""Prepares the serializer that will be used to serialize.
Determines the serializer that will be used and prepares an
instance of it for later call. This allows the serializer to
be accessed by extensions for, e.g., template extension.
mtype, serializer = self.get_serializer(content_type,
self.media_type = mtype
self.serializer = serializer()
def attach(self, **kwargs):
"""Attach slave templates to serializers."""
if self.media_type in kwargs:
def serialize(self, request, content_type, default_serializers=None):
"""Serializes the wrapped object.
Utility method for serializing the wrapped object. Returns a
webob.Response object.
if self.serializer:
serializer = self.serializer
_mtype, _serializer = self.get_serializer(content_type,
serializer = _serializer()
response = webob.Response()
response.status_int = self.code
for hdr, value in self._headers.items():
response.headers[hdr] = six.text_type(value)
response.headers['Content-Type'] = six.text_type(content_type)
if self.obj is not None:
body = serializer.serialize(self.obj)
if isinstance(body, six.text_type):
body = body.encode('utf-8')
response.body = body
return response
def code(self):
"""Retrieve the response status."""
return self._code or self._default_code
def headers(self):
"""Retrieve the headers."""
return self._headers.copy()
def action_peek_json(body):
"""Determine action to invoke."""
decoded = jsonutils.loads(body)
except ValueError:
msg = _("cannot understand JSON")
raise exception.MalformedRequestBody(reason=msg)
# Make sure there's exactly one key...
if len(decoded) != 1:
msg = _("too many body keys")
raise exception.MalformedRequestBody(reason=msg)
# Return the action and the decoded body...
return list(decoded.keys())[0]
class ResourceExceptionHandler(object):
"""Context manager to handle Resource exceptions.
Used when processing exceptions generated by API implementation
methods (or their extensions). Converts most exceptions to Fault
exceptions, with the appropriate logging.
def __enter__(self):
return None
def __exit__(self, ex_type, ex_value, ex_traceback):
if not ex_value:
return True
if isinstance(ex_value, exception.NotAuthorized):
msg = six.text_type(ex_value)
raise Fault(webob.exc.HTTPForbidden(explanation=msg))
elif isinstance(ex_value, exception.VersionNotFoundForAPIMethod):
elif isinstance(ex_value, (exception.Invalid, exception.NotFound)):
raise Fault(exception.ConvertedException(
code=ex_value.code, explanation=six.text_type(ex_value)))
elif isinstance(ex_value, TypeError):
LOG.exception('Exception handling resource:')
raise Fault(webob.exc.HTTPBadRequest())
elif isinstance(ex_value, Fault):"Fault thrown: %s", ex_value)
elif isinstance(ex_value, webob.exc.HTTPException):"HTTP exception thrown: %s", ex_value)
raise Fault(ex_value)
# We didn't handle the exception
return False
class Resource(wsgi.Application):
"""WSGI app that handles (de)serialization and controller dispatch.
WSGI app that reads routing information supplied by RoutesMiddleware
and calls the requested action method upon its controller. All
controller action methods must accept a 'req' argument, which is the
incoming wsgi.Request. If the operation is a PUT or POST, the controller
method must also accept a 'body' argument (the deserialized request body).
They may raise a webob.exc exception or return a dict, which will be
serialized by requested content type.
Exceptions derived from webob.exc.HTTPException will be automatically
wrapped in Fault() to provide API friendly error responses.
support_api_request_version = True
def __init__(self, controller, action_peek=None, **deserializers):
"""Initialize Resource.
:param controller: object that implement methods created by routes lib
:param action_peek: dictionary of routines for peeking into an action
request body to determine the desired action
self.controller = controller
default_deserializers = dict(json=JSONDeserializer)
self.default_deserializers = default_deserializers
self.default_serializers = dict(json=JSONDictSerializer)
self.action_peek = dict(json=action_peek_json)
self.action_peek.update(action_peek or {})
# Copy over the actions dictionary
self.wsgi_actions = {}
if controller:
# Save a mapping of extensions
self.wsgi_extensions = {}
self.wsgi_action_extensions = {}
def register_actions(self, controller):
"""Registers controller actions with this resource."""
actions = getattr(controller, 'wsgi_actions', {})
for key, method_name in actions.items():
self.wsgi_actions[key] = getattr(controller, method_name)
def register_extensions(self, controller):
"""Registers controller extensions with this resource."""
extensions = getattr(controller, 'wsgi_extensions', [])
for method_name, action_name in extensions:
# Look up the extending method
extension = getattr(controller, method_name)
if action_name:
# Extending an action...
if action_name not in self.wsgi_action_extensions:
self.wsgi_action_extensions[action_name] = []
# Extending a regular method
if method_name not in self.wsgi_extensions:
self.wsgi_extensions[method_name] = []
def get_action_args(self, request_environment):
"""Parse dictionary created by routes library."""
# NOTE(Vek): Check for get_action_args() override in the
# controller
if hasattr(self.controller, 'get_action_args'):
return self.controller.get_action_args(request_environment)
args = request_environment['wsgiorg.routing_args'][1].copy()
except (KeyError, IndexError, AttributeError):
return {}
del args['controller']
except KeyError:
del args['format']
except KeyError:
return args
def get_body(self, request):
if len(request.body) == 0:
LOG.debug("Empty body provided in request")
return None, ''
content_type = request.get_content_type()
if not content_type:
LOG.debug("No Content-Type provided in request")
return None, ''
return content_type, request.body
def deserialize(self, meth, content_type, body):
meth_deserializers = getattr(meth, 'wsgi_deserializers', {})
mtype = _MEDIA_TYPE_MAP.get(content_type, content_type)
if mtype in meth_deserializers:
deserializer = meth_deserializers[mtype]
deserializer = self.default_deserializers[mtype]
except (KeyError, TypeError):
raise exception.InvalidContentType(content_type=content_type)
return deserializer().deserialize(body)
def pre_process_extensions(self, extensions, request, action_args):
# List of callables for post-processing extensions
post = []
for ext in extensions:
if inspect.isgeneratorfunction(ext):
response = None
# If it's a generator function, the part before the
# yield is the preprocessing stage
with ResourceExceptionHandler():
gen = ext(req=request, **action_args)
response = next(gen)
except Fault as ex:
response = ex
# We had a response...
if response:
return response, []
# No response, queue up generator for post-processing
# Regular functions only perform post-processing
# Run post-processing in the reverse order
return None, reversed(post)
def post_process_extensions(self, extensions, resp_obj, request,
for ext in extensions:
response = None
if inspect.isgenerator(ext):
# If it's a generator, run the second half of
# processing
with ResourceExceptionHandler():
response = ext.send(resp_obj)
except StopIteration:
# Normal exit of generator
except Fault as ex:
response = ex
# Regular functions get post-processing...
with ResourceExceptionHandler():
response = ext(req=request, resp_obj=resp_obj,
except exception.VersionNotFoundForAPIMethod:
# If an attached extension (@wsgi.extends) for the
# method has no version match its not an error. We
# just don't run the extends code
except Fault as ex:
response = ex
# We had a response...
if response:
return response
return None
def __call__(self, request):
"""WSGI method that controls (de)serialization and method dispatch.""""%(method)s %(url)s",
{"method": request.method,
"url": request.url})
if self.support_api_request_version:
# Set the version of the API requested based on the header
except exception.InvalidAPIVersionString as e:
return Fault(webob.exc.HTTPBadRequest(
except exception.InvalidGlobalAPIVersion as e:
return Fault(webob.exc.HTTPNotAcceptable(
# Identify the action, its arguments, and the requested
# content type
action_args = self.get_action_args(request.environ)
action = action_args.pop('action', None)
# NOTE(sdague): we filter out InvalidContentTypes early so we
# know everything is good from here on out.
content_type, body = self.get_body(request)
accept = request.best_match_content_type()
except exception.InvalidContentType:
msg = _("Unsupported Content-Type")
return Fault(webob.exc.HTTPUnsupportedMediaType(explanation=msg))
# NOTE(Vek): Splitting the function up this way allows for
# auditing by external tools that wrap the existing
# function. If we try to audit __call__(), we can
# run into troubles due to the @webob.dec.wsgify()
# decorator.
return self._process_stack(request, action, action_args,
content_type, body, accept)
def _process_stack(self, request, action, action_args,
content_type, body, accept):
"""Implement the processing stack."""
# Get the implementing method
meth, extensions = self.get_method(request, action,
content_type, body)
except (AttributeError, TypeError):
return Fault(webob.exc.HTTPNotFound())
except KeyError as ex:
msg = (_("There is no such action: %s. Verify the request body "
"and Content-Type header and try again.") % ex.args[0])
return Fault(webob.exc.HTTPBadRequest(explanation=msg))
except exception.MalformedRequestBody:
msg = _("Malformed request body")
return Fault(webob.exc.HTTPBadRequest(explanation=msg))
if body:
decoded_body = encodeutils.safe_decode(body, errors='ignore')
msg = ("Action: '%(action)s', calling method: %(meth)s, body: "
"%(body)s") % {'action': action,
'body': decoded_body,
'meth': meth.__name__}
LOG.debug("Calling method '%(meth)s'",
{'meth': meth.__name__})
# Now, deserialize the request body...
if content_type:
contents = self.deserialize(meth, content_type, body)
contents = {}
except exception.InvalidContentType:
msg = _("Unsupported Content-Type")
return Fault(webob.exc.HTTPBadRequest(explanation=msg))
except exception.MalformedRequestBody:
msg = _("Malformed request body")
return Fault(webob.exc.HTTPBadRequest(explanation=msg))
# Update the action args
project_id = action_args.pop("project_id", None)
context = request.environ.get('cinder.context')
if (context and project_id and (project_id != context.project_id)):
msg = _("Malformed request url")
return Fault(webob.exc.HTTPBadRequest(explanation=msg))
# Run pre-processing extensions
response, post = self.pre_process_extensions(extensions,
request, action_args)
if not response:
with ResourceExceptionHandler():
action_result = self.dispatch(meth, request, action_args)
except Fault as ex:
response = ex
if not response:
# No exceptions; convert action_result into a
# ResponseObject
resp_obj = None
if isinstance(action_result, dict) or action_result is None:
resp_obj = ResponseObject(action_result)
elif isinstance(action_result, ResponseObject):
resp_obj = action_result
response = action_result
# Run post-processing extensions
if resp_obj:
_set_request_id_header(request, resp_obj)
# Do a preserialize to set up the response object
serializers = getattr(meth, 'wsgi_serializers', {})
if hasattr(meth, 'wsgi_code'):
resp_obj._default_code = meth.wsgi_code
resp_obj.preserialize(accept, self.default_serializers)
# Process post-processing extensions
response = self.post_process_extensions(post, resp_obj,
request, action_args)
if resp_obj and not response:
response = resp_obj.serialize(request, accept,
msg_dict = dict(url=request.url, status=response.status_int)
msg = "%(url)s returned with HTTP %(status)s"
except AttributeError as e:
msg_dict = dict(url=request.url, e=e)
msg = "%(url)s returned a fault: %(e)s", msg_dict)
if hasattr(response, 'headers'):
for hdr, val in response.headers.items():
# Headers must be utf-8 strings
val = utils.convert_str(val)
response.headers[hdr] = val
if (request.api_version_request and
not _is_legacy_endpoint(request)):
response.headers[API_VERSION_REQUEST_HEADER] = (
response.headers['Vary'] = API_VERSION_REQUEST_HEADER
return response
def get_method(self, request, action, content_type, body):
"""Look up the action-specific method and its extensions."""
# Look up the method
if not self.controller:
meth = getattr(self, action)
meth = getattr(self.controller, action)
except AttributeError as e:
with excutils.save_and_reraise_exception(e) as ctxt:
if (not self.wsgi_actions or action not in ['action',
LOG.exception('Get method error.')
ctxt.reraise = False
return meth, self.wsgi_extensions.get(action, [])
if action == 'action':
# OK, it's an action; figure out which action...
mtype = _MEDIA_TYPE_MAP.get(content_type)
action_name = self.action_peek[mtype](body)
LOG.debug("Action body: %s", body)
action_name = action
# Look up the action method
return (self.wsgi_actions[action_name],
self.wsgi_action_extensions.get(action_name, []))
def dispatch(self, method, request, action_args):
"""Dispatch a call to the action-specific method."""
return method(req=request, **action_args)
except exception.VersionNotFoundForAPIMethod:
# We deliberately don't return any message information
# about the exception to the user so it looks as if
# the method is simply not implemented.
return Fault(webob.exc.HTTPNotFound())
def action(name):
"""Mark a function as an action.
The given name will be taken as the action key in the body.
This is also overloaded to allow extensions to provide
non-extending definitions of create and delete operations.
def decorator(func):
func.wsgi_action = name
return func
return decorator
def extends(*args, **kwargs):
"""Indicate a function extends an operation.
Can be used as either::
def index(...):
or as::
def _action_resize(...):
def decorator(func):
# Store enough information to find what we're extending
func.wsgi_extends = (func.__name__, kwargs.get('action'))
return func
# If we have positional arguments, call the decorator
if args:
return decorator(*args)
# OK, return the decorator instead
return decorator
class ControllerMetaclass(type):
"""Controller metaclass.
This metaclass automates the task of assembling a dictionary
mapping action keys to method names.
def __new__(mcs, name, bases, cls_dict):
"""Adds the wsgi_actions dictionary to the class."""
# Find all actions
actions = {}
extensions = []
# NOTE(geguileo): We'll keep a list of versioned methods that have been
# added by the new metaclass (dictionary in attribute VER_METHOD_ATTR
# on Controller class) and all the versioned methods from the different
# base classes so we can consolidate them.
versioned_methods = []
# NOTE(cyeoh): This resets the VER_METHOD_ATTR attribute
# between API controller class creations. This allows us
# to use a class decorator on the API methods that doesn't
# require naming explicitly what method is being versioned as
# it can be implicit based on the method decorated. It is a bit
# ugly.
if bases != (object,) and VER_METHOD_ATTR in vars(Controller):
# Get the versioned methods that this metaclass creation has added
# to the Controller class
versioned_methods.append(getattr(Controller, VER_METHOD_ATTR))
# Remove them so next metaclass has a clean start
delattr(Controller, VER_METHOD_ATTR)
# start with wsgi actions from base classes
for base in bases:
actions.update(getattr(base, 'wsgi_actions', {}))
# Get the versioned methods that this base has
if VER_METHOD_ATTR in vars(base):
versioned_methods.append(getattr(base, VER_METHOD_ATTR))
for key, value in cls_dict.items():
if not isinstance(value, abc.Callable):
if getattr(value, 'wsgi_action', None):
actions[value.wsgi_action] = key
elif getattr(value, 'wsgi_extends', None):
# Add the actions and extensions to the class dict
cls_dict['wsgi_actions'] = actions
cls_dict['wsgi_extensions'] = extensions
if versioned_methods:
cls_dict[VER_METHOD_ATTR] = mcs.consolidate_vers(versioned_methods)
return super(ControllerMetaclass, mcs).__new__(mcs, name, bases,
def consolidate_vers(versioned_methods):
"""Consolidates a list of versioned methods dictionaries."""
if not versioned_methods:
return {}
result = versioned_methods.pop(0)
for base_methods in versioned_methods:
for name, methods in base_methods.items():
method_list = result.setdefault(name, [])
return result
class Controller(object):
"""Default controller."""
_view_builder_class = None
def __init__(self, view_builder=None):
"""Initialize controller with a view builder instance."""
if view_builder:
self._view_builder = view_builder
elif self._view_builder_class:
self._view_builder = self._view_builder_class()
self._view_builder = None
def __getattribute__(self, key):
def version_select(*args, **kwargs):
"""Select and call the matching version of the specified method.
Look for the method which matches the name supplied and version
constraints and calls it with the supplied arguments.
:returns: Returns the result of the method called
:raises VersionNotFoundForAPIMethod: if there is no method which
matches the name and version constraints
# The first arg to all versioned methods is always the request
# object. The version for the request is attached to the
# request object
if len(args) == 0:
version_request = kwargs['req'].api_version_request
version_request = args[0].api_version_request
func_list = self.versioned_methods[key]
for func in func_list:
if version_request.matches_versioned_method(func):
# Update the version_select wrapper function so
# other decorator attributes like wsgi.response
# are still respected.
functools.update_wrapper(version_select, func.func)
return func.func(self, *args, **kwargs)
# No version match
raise exception.VersionNotFoundForAPIMethod(
version_meth_dict = object.__getattribute__(self, VER_METHOD_ATTR)
except AttributeError:
# No versioning on this class
return object.__getattribute__(self, key)
if (version_meth_dict and key in
object.__getattribute__(self, VER_METHOD_ATTR)):
return version_select
return object.__getattribute__(self, key)
# NOTE(cyeoh): This decorator MUST appear first (the outermost
# decorator) on an API method for it to work correctly
def api_version(cls, min_ver, max_ver=None, experimental=False):
"""Decorator for versioning API methods.
Add the decorator to any method which takes a request object
as the first parameter and belongs to a class which inherits from
:param min_ver: string representing minimum version
:param max_ver: optional string representing maximum version
def decorator(f):
obj_min_ver = api_version.APIVersionRequest(min_ver)
if max_ver:
obj_max_ver = api_version.APIVersionRequest(max_ver)
obj_max_ver = api_version.APIVersionRequest()
# Add to list of versioned methods registered
func_name = f.__name__
new_func = versioned_method.VersionedMethod(
func_name, obj_min_ver, obj_max_ver, experimental, f)
func_dict = getattr(cls, VER_METHOD_ATTR, {})
if not func_dict:
setattr(cls, VER_METHOD_ATTR, func_dict)
func_list = func_dict.get(func_name, [])
if not func_list:
func_dict[func_name] = func_list
# Ensure the list is sorted by minimum version (reversed)
# so later when we work through the list in order we find
# the method which has the latest version which supports
# the version requested.
# TODO(cyeoh): Add check to ensure that there are no overlapping
# ranges of valid versions as that is ambiguous
# NOTE(geguileo): To avoid PEP8 errors when defining multiple
# microversions of the same method in the same class we add the
# api_version decorator to the function so it can be used instead,
# thus preventing method redefinition errors.
f.api_version = cls.api_version
return f
return decorator
def assert_valid_body(body, entity_name):
fail_msg = _(
"Missing required element '%s' in request body.") % entity_name
if not (body and entity_name in body):
raise webob.exc.HTTPBadRequest(explanation=fail_msg)
def is_dict(d):
return True
except AttributeError:
return False
if not is_dict(body[entity_name]):
raise webob.exc.HTTPBadRequest(explanation=fail_msg)
def validate_name_and_description(body, check_length=True):
for attribute in ['name', 'description',
'display_name', 'display_description']:
value = body.get(attribute)
if value is not None:
if isinstance(value, six.string_types):
body[attribute] = value.strip()
if check_length:
utils.check_string_length(body[attribute], attribute,
min_length=0, max_length=255)
except exception.InvalidInput as error:
raise webob.exc.HTTPBadRequest(explanation=error.msg)
def validate_string_length(value, entity_name, min_length=0,
max_length=None, remove_whitespaces=False):
"""Check the length of specified string.
:param value: the value of the string
:param entity_name: the name of the string
:param min_length: the min_length of the string
:param max_length: the max_length of the string
:param remove_whitespaces: True if trimming whitespaces is needed
else False
if isinstance(value, six.string_types) and remove_whitespaces:
value = value.strip()
utils.check_string_length(value, entity_name,
except exception.InvalidInput as error:
raise webob.exc.HTTPBadRequest(explanation=error.msg)
class Fault(webob.exc.HTTPException):
"""Wrap webob.exc.HTTPException to provide API friendly response."""
_fault_names = {http_client.BAD_REQUEST: "badRequest",
http_client.UNAUTHORIZED: "unauthorized",
http_client.FORBIDDEN: "forbidden",
http_client.NOT_FOUND: "itemNotFound",
http_client.METHOD_NOT_ALLOWED: "badMethod",
http_client.CONFLICT: "conflictingRequest",
http_client.REQUEST_ENTITY_TOO_LARGE: "overLimit",
http_client.UNSUPPORTED_MEDIA_TYPE: "badMediaType",
http_client.NOT_IMPLEMENTED: "notImplemented",
http_client.SERVICE_UNAVAILABLE: "serviceUnavailable"}
def __init__(self, exception):
"""Create a Fault for the given webob.exc.exception."""
self.wrapped_exc = exception
self.status_int = exception.status_int
def __call__(self, req):
"""Generate a WSGI response based on the exception passed to ctor."""
# Replace the body with fault details.
locale = req.best_match_language()
code = self.wrapped_exc.status_int
fault_name = self._fault_names.get(code, "computeFault")
explanation = self.wrapped_exc.explanation
fault_data = {
fault_name: {
'code': code,
'message': i18n.translate(explanation, locale)}}
if code == http_client.REQUEST_ENTITY_TOO_LARGE:
retry = self.wrapped_exc.headers.get('Retry-After', None)
if retry:
fault_data[fault_name]['retryAfter'] = retry
if req.api_version_request and not _is_legacy_endpoint(req):
self.wrapped_exc.headers[API_VERSION_REQUEST_HEADER] = (
VOLUME_SERVICE + ' ' + req.api_version_request.get_string())
self.wrapped_exc.headers['Vary'] = API_VERSION_REQUEST_HEADER
content_type = req.best_match_content_type()
serializer = {
'application/json': JSONDictSerializer(),
body = serializer.serialize(fault_data)
if isinstance(body, six.text_type):
body = body.encode('utf-8')
self.wrapped_exc.body = body
self.wrapped_exc.content_type = content_type
_set_request_id_header(req, self.wrapped_exc.headers)
return self.wrapped_exc
def __str__(self):
return self.wrapped_exc.__str__()
def _set_request_id_header(req, headers):
context = req.environ.get('cinder.context')
if context:
headers['x-compute-request-id'] = context.request_id
def _is_legacy_endpoint(request):
version_str = request.api_version_request.get_string()
return '1.0' in version_str or '2.0' in version_str
class OverLimitFault(webob.exc.HTTPException):
"""Rate-limited request response."""
def __init__(self, message, details, retry_time):
"""Initialize new `OverLimitFault` with relevant information."""
hdrs = OverLimitFault._retry_after(retry_time)
self.wrapped_exc = webob.exc.HTTPRequestEntityTooLarge(headers=hdrs)
self.content = {
"overLimitFault": {
"code": self.wrapped_exc.status_int,
"message": message,
"details": details,
def _retry_after(retry_time):
delay = int(math.ceil(retry_time - time.time()))
retry_after = delay if delay > 0 else 0
headers = {'Retry-After': '%d' % retry_after}
return headers
def __call__(self, request):
"""Serializes the wrapped exception conforming to our error format."""
content_type = request.best_match_content_type()
def translate(msg):
locale = request.best_match_language()
return i18n.translate(msg, locale)
self.content['overLimitFault']['message'] = \
self.content['overLimitFault']['details'] = \
serializer = {
'application/json': JSONDictSerializer(),
content = serializer.serialize(self.content)
self.wrapped_exc.body = content
return self.wrapped_exc