# 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. """ The :class:`~openstack.resource.Resource` class is a base class that represent a remote resource. The attributes that comprise a request or response for this resource are specified as class members on the Resource subclass where their values are of a component type, including :class:`~openstack.resource2.Body`, :class:`~openstack.resource2.Header`, and :class:`~openstack.resource2.URI`. For update management, :class:`~openstack.resource2.Resource` employs a series of :class:`~openstack.resource2._ComponentManager` instances to look after the attributes of that particular component type. This is particularly useful for Body and Header types, so that only the values necessary are sent in requests to the server. When making requests, each of the managers are looked at to gather the necessary URI, body, and header data to build a request to be sent via keystoneauth's sessions. Responses from keystoneauth are then converted into this Resource class' appropriate components and types and then returned to the caller. """ import collections import itertools import time from openstack import exceptions from openstack import format from openstack import utils class _BaseComponent(object): # The name this component is being tracked as in the Resource key = None def __init__(self, name, type=None, default=None, alternate_id=False): """A typed descriptor for a component that makes up a Resource :param name: The name this component exists as on the server :param type: The type this component is expected to be by the server. By default this is None, meaning any value you specify will work. If you specify type=dict and then set a component to a string, __set__ will fail, for example. :param default: Typically None, but any other default can be set. :param alternate_id: When `True`, this property is known internally as a value that can be sent with requests that require an ID but when `id` is not a name the Resource has. This is a relatively uncommon case, and this setting should only be used once per Resource. """ self.name = name self.type = type self.default = default self.alternate_id = alternate_id def __get__(self, instance, owner): if instance is None: return None attributes = getattr(instance, self.key) try: value = attributes[self.name] except KeyError: return self.default # self.type() should not be called on None objects. if value is None: return None if self.type and not isinstance(value, self.type): if issubclass(self.type, format.Formatter): value = self.type.deserialize(value) else: value = self.type(value) return value def __set__(self, instance, value): if (self.type and not isinstance(value, self.type) and value != self.default): if issubclass(self.type, format.Formatter): value = self.type.serialize(value) else: value = str(self.type(value)) # validate to fail fast attributes = getattr(instance, self.key) attributes[self.name] = value def __delete__(self, instance): try: attributes = getattr(instance, self.key) del attributes[self.name] except KeyError: pass class Body(_BaseComponent): """Body attributes""" key = "_body" class Header(_BaseComponent): """Header attributes""" key = "_header" class URI(_BaseComponent): """URI attributes""" key = "_uri" class _ComponentManager(collections.MutableMapping): """Storage of a component type""" def __init__(self, attributes=None, synchronized=False): self.attributes = dict() if attributes is None else attributes.copy() self._dirty = set() if synchronized else set(self.attributes.keys()) def __getitem__(self, key): return self.attributes[key] def __setitem__(self, key, value): try: orig = self.attributes[key] except KeyError: changed = True else: changed = orig != value if changed: self.attributes[key] = value self._dirty.add(key) def __delitem__(self, key): del self.attributes[key] self._dirty.add(key) def __iter__(self): return iter(self.attributes) def __len__(self): return len(self.attributes) @property def dirty(self): """Return a dict of modified attributes""" return dict((key, self.attributes.get(key, None)) for key in self._dirty) def clean(self): """Signal that the resource no longer has modified attributes""" self._dirty = set() class _Request(object): """Prepared components that go into a KSA request""" def __init__(self, uri, body, headers): self.uri = uri self.body = body self.headers = headers class QueryParameters(object): def __init__(self, *names, **mappings): """Create a dict of accepted query parameters :param names: List of strings containing client-side query parameter names. Each name in the list maps directly to the name expected by the server. :param mappings: Key-value pairs where the key is the client-side name we'll accept here and the value is the name the server expects, e.g, changes_since=changes-since """ self._mapping = dict({name: name for name in names}, **mappings) def _transpose(self, query): """Transpose the keys in query based on the mapping :param dict query: Collection of key-value pairs where each key is the client-side parameter name to be transposed to its server side name. """ result = {} for key, value in self._mapping.items(): if key in query: result[value] = query[key] return result class Resource(object): #: Singular form of key for resource. resource_key = None #: Plural form of key for resource. resources_key = None #: The ID of this resource. id = Body("id") #: The name of this resource. name = Body("name") #: The location of this resource. location = Header("Location") #: Mapping of accepted query parameter names. _query_mapping = QueryParameters() #: The base part of the URI for this resource. base_path = "" #: The service associated with this resource to find the service URL. service = None #: Allow create operation for this resource. allow_create = False #: Allow get operation for this resource. allow_get = False #: Allow update operation for this resource. allow_update = False #: Allow delete operation for this resource. allow_delete = False #: Allow list operation for this resource. allow_list = False #: Allow head operation for this resource. allow_head = False #: Use PATCH for update operations on this resource. patch_update = False #: Use PUT for create operations on this resource. put_create = False def __init__(self, synchronized=False, **attrs): # NOTE: _collect_attrs modifies **attrs in place, removing # items as they match up with any of the body, header, # or uri mappings. body, header, uri = self._collect_attrs(attrs) # TODO(briancurtin): at this point if attrs has anything left # they're not being set anywhere. Log this? Raise exception? # How strict should we be here? Should strict be an option? self._body = _ComponentManager(attributes=body, synchronized=synchronized) self._header = _ComponentManager(attributes=header, synchronized=synchronized) self._uri = _ComponentManager(attributes=uri, synchronized=synchronized) def __repr__(self): pairs = ["%s=%s" % (k, v) for k, v in dict(itertools.chain( self._body.attributes.items(), self._header.attributes.items(), self._uri.attributes.items())).items()] args = ", ".join(pairs) return "%s.%s(%s)" % ( self.__module__, self.__class__.__name__, args) def __eq__(self, comparand): """Return True if another resource has the same contents""" return all([self._body.attributes == comparand._body.attributes, self._header.attributes == comparand._header.attributes, self._uri.attributes == comparand._uri.attributes]) def __getattribute__(self, name): """Return an attribute on this instance This is mostly a pass-through except for a specialization on the 'id' name, as this can exist under a different name via the `alternate_id` argument to resource.Body. """ if name == "id": if name in self._body: return self._body[name] else: return self._body[self._alternate_id()] else: return object.__getattribute__(self, name) def _update(self, **attrs): """Given attributes, update them on this instance This is intended to be used from within the proxy layer when updating instances that may have already been created. """ body, header, uri = self._collect_attrs(attrs) self._body.update(body) self._header.update(header) self._uri.update(uri) def _collect_attrs(self, attrs): """Given attributes, return a dict per type of attribute This method splits up **attrs into separate dictionaries that correspond to the relevant body, header, and uri attributes that exist on this class. """ body = self._consume_attrs(self._body_mapping(), attrs) header = self._consume_attrs(self._header_mapping(), attrs) uri = self._consume_attrs(self._uri_mapping(), attrs) return body, header, uri def _consume_attrs(self, mapping, attrs): """Given a mapping and attributes, return relevant matches This method finds keys in attrs that exist in the mapping, then both transposes them to their server-side equivalent key name to be returned, and finally pops them out of attrs. This allows us to only calculate their place and existence in a particular type of Resource component one time, rather than looking at the same source dict several times. """ relevant_attrs = {} consumed_keys = [] for key in attrs: if key in mapping: # Convert client-side key names into server-side. relevant_attrs[mapping[key]] = attrs[key] consumed_keys.append(key) elif key in mapping.values(): # Server-side names can be stored directly. relevant_attrs[key] = attrs[key] consumed_keys.append(key) for key in consumed_keys: attrs.pop(key) return relevant_attrs @classmethod def _get_mapping(cls, component): """Return a dict of attributes of a given component on the class""" mapping = {} # Since we're looking at class definitions we need to include # subclasses, so check the whole MRO. for klass in cls.__mro__: for key, value in klass.__dict__.items(): if isinstance(value, component): # Make sure base classes don't end up overwriting # mappings we've found previously in subclasses. if key not in mapping: mapping[key] = value.name return mapping @classmethod def _body_mapping(cls): """Return all Body members of this class""" return cls._get_mapping(Body) @classmethod def _header_mapping(cls): """Return all Header members of this class""" return cls._get_mapping(Header) @classmethod def _uri_mapping(cls): """Return all URI members of this class""" return cls._get_mapping(URI) @classmethod def _alternate_id(cls): """Return the name of any value known as an alternate_id NOTE: This will only ever return the first such alternate_id. Only one alternate_id should be specified. Returns an empty string if no name exists, as this method is consumed by _get_id and passed to getattr. """ for value in cls.__dict__.values(): if isinstance(value, Body): if value.alternate_id: return value.name return "" @staticmethod def _get_id(value): """If a value is a Resource, return the canonical ID This will return either the value specified by `id` or `alternate_id` in that order if `value` is a Resource. If `value` is anything other than a Resource, likely to be a string already representing an ID, it is returned. """ if isinstance(value, Resource): # Don't check _alternate_id unless we need to. It's an uncommon # case and it involves looping through the class' dict. id = value.id or getattr(value, value._alternate_id(), None) return id else: return value @classmethod def new(cls, **kwargs): """Create a new instance of this resource. Internally set flags such that it is marked as not present on the server. :param dict kwargs: Each of the named arguments will be set as attributes on the resulting Resource object. """ return cls(synchronized=False, **kwargs) @classmethod def existing(cls, **kwargs): """Create an instance of an existing remote resource. It is marked as an exact replication of a resource present on a server. :param dict kwargs: Each of the named arguments will be set as attributes on the resulting Resource object. """ return cls(synchronized=True, **kwargs) def to_dict(self, body=True, headers=True, ignore_none=False): """Return a dictionary of this resource's contents :param bool body: Include the :class:`~openstack.resource2.Body` attributes in the returned dictionary. :param bool headers: Include the :class:`~openstack.resource2.Header` attributes in the returned dictionary. :param bool ignore_none: When True, exclude key/value pairs where the value is None. This will exclude attributes that the server hasn't returned. :return: A dictionary of key/value pairs where keys are named as they exist as attributes of this class. """ mapping = {} components = [] if body: components.append(Body) if headers: components.append(Header) if not components: raise ValueError( "At least one of `body` or `headers` must be True") # isinstance stricly requires this to be a tuple components = tuple(components) # NOTE: This is similar to the implementation in _get_mapping # but is slightly different in that we're looking at an instance # and we're mapping names on this class to their actual stored # values. # Since we're looking at class definitions we need to include # subclasses, so check the whole MRO. for klass in self.__class__.__mro__: for key, value in klass.__dict__.items(): if isinstance(value, components): # Make sure base classes don't end up overwriting # mappings we've found previously in subclasses. if key not in mapping: value = getattr(self, key, None) if ignore_none and value is None: continue mapping[key] = value return mapping def _prepare_request(self, requires_id=True, prepend_key=False): """Prepare a request to be sent to the server Create operations don't require an ID, but all others do, so only try to append an ID when it's needed with requires_id. Create and update operations sometimes require their bodies to be contained within an dict -- if the instance contains a resource_key and prepend_key=True, the body will be wrapped in a dict with that key. Return a _Request object that contains the constructed URI as well a body and headers that are ready to send. Only dirty body and header contents will be returned. """ body = self._body.dirty if prepend_key and self.resource_key is not None: body = {self.resource_key: body} headers = self._header.dirty uri = self.base_path % self._uri.attributes if requires_id: id = self._get_id(self) if id is None: raise exceptions.InvalidRequest( "Request requires an ID but none was found") uri = utils.urljoin(uri, id) return _Request(uri, body, headers) def _filter_component(self, component, mapping): """Filter the keys in component based on a mapping This method converts a dict of server-side data to contain only the appropriate keys for attributes on this instance. """ return {k: v for k, v in component.items() if k in mapping.values()} def _translate_response(self, response, has_body=True): """Given a KSA response, inflate this instance with its data DELETE operations don't return a body, so only try to work with a body when has_body is True. This method updates attributes that correspond to headers and body on this instance and clears the dirty set. """ if has_body: body = response.json() if self.resource_key and self.resource_key in body: body = body[self.resource_key] body = self._filter_component(body, self._body_mapping()) self._body.attributes.update(body) self._body.clean() headers = self._filter_component(response.headers, self._header_mapping()) self._header.attributes.update(headers) self._header.clean() def create(self, session, prepend_key=True): """Create a remote resource based on this instance. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :param prepend_key: A boolean indicating whether the resource_key should be prepended in a resource creation request. Default to True. :return: This :class:`Resource` instance. :raises: :exc:`~openstack.exceptions.MethodNotSupported` if :data:`Resource.allow_create` is not set to ``True``. """ if not self.allow_create: raise exceptions.MethodNotSupported(self, "create") if self.put_create: request = self._prepare_request(requires_id=True, prepend_key=prepend_key) response = session.put(request.uri, endpoint_filter=self.service, json=request.body, headers=request.headers) else: request = self._prepare_request(requires_id=False, prepend_key=prepend_key) response = session.post(request.uri, endpoint_filter=self.service, json=request.body, headers=request.headers) self._translate_response(response) return self def get(self, session, requires_id=True): """Get a remote resource based on this instance. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :param boolean requires_id: A boolean indicating whether resource ID should be part of the requested URI. :return: This :class:`Resource` instance. :raises: :exc:`~openstack.exceptions.MethodNotSupported` if :data:`Resource.allow_get` is not set to ``True``. """ if not self.allow_get: raise exceptions.MethodNotSupported(self, "get") request = self._prepare_request(requires_id=requires_id) response = session.get(request.uri, endpoint_filter=self.service) self._translate_response(response) return self def head(self, session): """Get headers from a remote resource based on this instance. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :return: This :class:`Resource` instance. :raises: :exc:`~openstack.exceptions.MethodNotSupported` if :data:`Resource.allow_head` is not set to ``True``. """ if not self.allow_head: raise exceptions.MethodNotSupported(self, "head") request = self._prepare_request() response = session.head(request.uri, endpoint_filter=self.service, headers={"Accept": ""}) self._translate_response(response) return self def update(self, session, prepend_key=True, has_body=True): """Update the remote resource based on this instance. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :param prepend_key: A boolean indicating whether the resource_key should be prepended in a resource update request. Default to True. :return: This :class:`Resource` instance. :raises: :exc:`~openstack.exceptions.MethodNotSupported` if :data:`Resource.allow_update` is not set to ``True``. """ # Only try to update if we actually have anything to update. if not any([self._body.dirty, self._header.dirty]): return self if not self.allow_update: raise exceptions.MethodNotSupported(self, "update") request = self._prepare_request(prepend_key=prepend_key) if self.patch_update: response = session.patch(request.uri, endpoint_filter=self.service, json=request.body, headers=request.headers) else: response = session.put(request.uri, endpoint_filter=self.service, json=request.body, headers=request.headers) self._translate_response(response, has_body=has_body) return self def delete(self, session): """Delete the remote resource based on this instance. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :return: This :class:`Resource` instance. :raises: :exc:`~openstack.exceptions.MethodNotSupported` if :data:`Resource.allow_update` is not set to ``True``. """ if not self.allow_delete: raise exceptions.MethodNotSupported(self, "delete") request = self._prepare_request() response = session.delete(request.uri, endpoint_filter=self.service, headers={"Accept": ""}) self._translate_response(response, has_body=False) return self @classmethod def list(cls, session, paginated=False, **params): """This method is a generator which yields resource objects. This resource object list generator handles pagination and takes query params for response filtering. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :param bool paginated: ``True`` if a GET to this resource returns a paginated series of responses, or ``False`` if a GET returns only one page of data. **When paginated is False only one page of data will be returned regardless of the API's support of pagination.** :param dict params: These keyword arguments are passed through the :meth:`~openstack.resource2.QueryParamter._transpose` method to find if any of them match expected query parameters to be sent in the *params* argument to :meth:`~openstack.session.Session.get`. They are additionally checked against the :data:`~openstack.resource2.Resource.base_path` format string to see if any path fragments need to be filled in by the contents of this argument. :return: A generator of :class:`Resource` objects. :raises: :exc:`~openstack.exceptions.MethodNotSupported` if :data:`Resource.allow_list` is not set to ``True``. """ if not cls.allow_list: raise exceptions.MethodNotSupported(cls, "list") more_data = True query_params = cls._query_mapping._transpose(params) uri = cls.base_path % params while more_data: resp = session.get(uri, endpoint_filter=cls.service, headers={"Accept": "application/json"}, params=query_params) resp = resp.json() if cls.resources_key: resp = resp[cls.resources_key] if not resp: more_data = False # Keep track of how many items we've yielded. If we yielded # less than our limit, we don't need to do an extra request # to get back an empty data set, which acts as a sentinel. yielded = 0 new_marker = None for data in resp: # Do not allow keys called "self" through. Glance chose # to name a key "self", so we need to pop it out because # we can't send it through cls.existing and into the # Resource initializer. "self" is already the first # argument and is practically a reserved word. data.pop("self", None) value = cls.existing(**data) new_marker = value.id yielded += 1 yield value if not paginated: return if "limit" in query_params and yielded < query_params["limit"]: return query_params["limit"] = yielded query_params["marker"] = new_marker @classmethod def _get_one_match(cls, name_or_id, results): """Given a list of results, return the match""" the_result = None for maybe_result in results: id_value = cls._get_id(maybe_result) name_value = maybe_result.name if (id_value == name_or_id) or (name_value == name_or_id): # Only allow one resource to be found. If we already # found a match, raise an exception to show it. if the_result is None: the_result = maybe_result else: msg = "More than one %s exists with the name '%s'." msg = (msg % (cls.__name__, name_or_id)) raise exceptions.DuplicateResource(msg) return the_result @classmethod def find(cls, session, name_or_id, ignore_missing=True, **params): """Find a resource by its name or id. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :param name_or_id: This resource's identifier, if needed by the request. The default is ``None``. :param bool ignore_missing: When set to ``False`` :class:`~openstack.exceptions.ResourceNotFound` will be raised when the resource does not exist. When set to ``True``, None will be returned when attempting to find a nonexistent resource. :param dict params: Any additional parameters to be passed into underlying methods, such as to :meth:`~openstack.resource2.Resource.existing` in order to pass on URI parameters. :return: The :class:`Resource` object matching the given name or id or None if nothing matches. :raises: :class:`openstack.exceptions.DuplicateResource` if more than one resource is found for this request. :raises: :class:`openstack.exceptions.ResourceNotFound` if nothing is found and ignore_missing is ``False``. """ # Try to short-circuit by looking directly for a matching ID. try: match = cls.existing(id=name_or_id, **params) return match.get(session) except exceptions.NotFoundException: pass data = cls.list(session, **params) result = cls._get_one_match(name_or_id, data) if result is not None: return result if ignore_missing: return None raise exceptions.ResourceNotFound( "No %s found for %s" % (cls.__name__, name_or_id)) def wait_for_status(session, resource, status, failures, interval, wait): """Wait for the resource to be in a particular status. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :param resource: The resource to wait on to reach the status. The resource must have a status attribute. :type resource: :class:`~openstack.resource.Resource` :param status: Desired status of the resource. :param list failures: Statuses that would indicate the transition failed such as 'ERROR'. :param interval: Number of seconds to wait between checks. :param wait: Maximum number of seconds to wait for transition. :return: Method returns self on success. :raises: :class:`~openstack.exceptions.ResourceTimeout` transition to status failed to occur in wait seconds. :raises: :class:`~openstack.exceptions.ResourceFailure` resource transitioned to one of the failure states. :raises: :class:`~AttributeError` if the resource does not have a status attribute """ if resource.status == status: return resource total_sleep = 0 if failures is None: failures = [] while total_sleep < wait: resource.get(session) if resource.status == status: return resource if resource.status in failures: msg = ("Resource %s transitioned to failure state %s" % (resource.id, resource.status)) raise exceptions.ResourceFailure(msg) time.sleep(interval) total_sleep += interval msg = "Timeout waiting for %s to transition to %s" % (resource.id, status) raise exceptions.ResourceTimeout(msg) def wait_for_delete(session, resource, interval, wait): """Wait for the resource to be deleted. :param session: The session to use for making this request. :type session: :class:`~openstack.session.Session` :param resource: The resource to wait on to be deleted. :type resource: :class:`~openstack.resource.Resource` :param interval: Number of seconds to wait between checks. :param wait: Maximum number of seconds to wait for the delete. :return: Method returns self on success. :raises: :class:`~openstack.exceptions.ResourceTimeout` transition to status failed to occur in wait seconds. """ total_sleep = 0 while total_sleep < wait: try: resource.get(session) except exceptions.NotFoundException: return resource time.sleep(interval) total_sleep += interval msg = "Timeout waiting for %s delete" % (resource.id) raise exceptions.ResourceTimeout(msg)