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Diffstat (limited to 'cinderclient/base.py')
| -rw-r--r-- | cinderclient/base.py | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/cinderclient/base.py b/cinderclient/base.py new file mode 100644 index 0000000..02d3549 --- /dev/null +++ b/cinderclient/base.py @@ -0,0 +1,293 @@ +# Copyright 2010 Jacob Kaplan-Moss + +# Copyright 2011 OpenStack LLC. +# 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. + +""" +Base utilities to build API operation managers and objects on top of. +""" + +import contextlib +import hashlib +import os +from cinderclient import exceptions +from cinderclient import utils + + +# Python 2.4 compat +try: + all +except NameError: + def all(iterable): + return True not in (not x for x in iterable) + + +def getid(obj): + """ + Abstracts the common pattern of allowing both an object or an object's ID + as a parameter when dealing with relationships. + """ + try: + return obj.id + except AttributeError: + return obj + + +class Manager(utils.HookableMixin): + """ + Managers interact with a particular type of API (servers, flavors, images, + etc.) and provide CRUD operations for them. + """ + resource_class = None + + def __init__(self, api): + self.api = api + + def _list(self, url, response_key, obj_class=None, body=None): + resp = None + if body: + resp, body = self.api.client.post(url, body=body) + else: + resp, body = self.api.client.get(url) + + if obj_class is None: + obj_class = self.resource_class + + data = body[response_key] + # NOTE(ja): keystone returns values as list as {'values': [ ... ]} + # unlike other services which just return the list... + if isinstance(data, dict): + try: + data = data['values'] + except KeyError: + pass + + with self.completion_cache('human_id', obj_class, mode="w"): + with self.completion_cache('uuid', obj_class, mode="w"): + return [obj_class(self, res, loaded=True) + for res in data if res] + + @contextlib.contextmanager + def completion_cache(self, cache_type, obj_class, mode): + """ + The completion cache store items that can be used for bash + autocompletion, like UUIDs or human-friendly IDs. + + A resource listing will clear and repopulate the cache. + + A resource create will append to the cache. + + Delete is not handled because listings are assumed to be performed + often enough to keep the cache reasonably up-to-date. + """ + base_dir = utils.env('CINDERCLIENT_UUID_CACHE_DIR', + default="~/.cinderclient") + + # NOTE(sirp): Keep separate UUID caches for each username + endpoint + # pair + username = utils.env('OS_USERNAME', 'CINDER_USERNAME') + url = utils.env('OS_URL', 'CINDER_URL') + uniqifier = hashlib.md5(username + url).hexdigest() + + cache_dir = os.path.expanduser(os.path.join(base_dir, uniqifier)) + + try: + os.makedirs(cache_dir, 0755) + except OSError: + # NOTE(kiall): This is typicaly either permission denied while + # attempting to create the directory, or the directory + # already exists. Either way, don't fail. + pass + + resource = obj_class.__name__.lower() + filename = "%s-%s-cache" % (resource, cache_type.replace('_', '-')) + path = os.path.join(cache_dir, filename) + + cache_attr = "_%s_cache" % cache_type + + try: + setattr(self, cache_attr, open(path, mode)) + except IOError: + # NOTE(kiall): This is typicaly a permission denied while + # attempting to write the cache file. + pass + + try: + yield + finally: + cache = getattr(self, cache_attr, None) + if cache: + cache.close() + delattr(self, cache_attr) + + def write_to_completion_cache(self, cache_type, val): + cache = getattr(self, "_%s_cache" % cache_type, None) + if cache: + cache.write("%s\n" % val) + + def _get(self, url, response_key=None): + resp, body = self.api.client.get(url) + if response_key: + return self.resource_class(self, body[response_key], loaded=True) + else: + return self.resource_class(self, body, loaded=True) + + def _create(self, url, body, response_key, return_raw=False, **kwargs): + self.run_hooks('modify_body_for_create', body, **kwargs) + resp, body = self.api.client.post(url, body=body) + if return_raw: + return body[response_key] + + with self.completion_cache('human_id', self.resource_class, mode="a"): + with self.completion_cache('uuid', self.resource_class, mode="a"): + return self.resource_class(self, body[response_key]) + + def _delete(self, url): + resp, body = self.api.client.delete(url) + + def _update(self, url, body, **kwargs): + self.run_hooks('modify_body_for_update', body, **kwargs) + resp, body = self.api.client.put(url, body=body) + return body + + +class ManagerWithFind(Manager): + """ + Like a `Manager`, but with additional `find()`/`findall()` methods. + """ + def find(self, **kwargs): + """ + Find a single item with attributes matching ``**kwargs``. + + This isn't very efficient: it loads the entire list then filters on + the Python side. + """ + matches = self.findall(**kwargs) + num_matches = len(matches) + if num_matches == 0: + msg = "No %s matching %s." % (self.resource_class.__name__, kwargs) + raise exceptions.NotFound(404, msg) + elif num_matches > 1: + raise exceptions.NoUniqueMatch + else: + return matches[0] + + def findall(self, **kwargs): + """ + Find all items with attributes matching ``**kwargs``. + + This isn't very efficient: it loads the entire list then filters on + the Python side. + """ + found = [] + searches = kwargs.items() + + for obj in self.list(): + try: + if all(getattr(obj, attr) == value + for (attr, value) in searches): + found.append(obj) + except AttributeError: + continue + + return found + + def list(self): + raise NotImplementedError + + +class Resource(object): + """ + A resource represents a particular instance of an object (server, flavor, + etc). This is pretty much just a bag for attributes. + + :param manager: Manager object + :param info: dictionary representing resource attributes + :param loaded: prevent lazy-loading if set to True + """ + HUMAN_ID = False + + def __init__(self, manager, info, loaded=False): + self.manager = manager + self._info = info + self._add_details(info) + self._loaded = loaded + + # NOTE(sirp): ensure `id` is already present because if it isn't we'll + # enter an infinite loop of __getattr__ -> get -> __init__ -> + # __getattr__ -> ... + if 'id' in self.__dict__ and len(str(self.id)) == 36: + self.manager.write_to_completion_cache('uuid', self.id) + + human_id = self.human_id + if human_id: + self.manager.write_to_completion_cache('human_id', human_id) + + @property + def human_id(self): + """Subclasses may override this provide a pretty ID which can be used + for bash completion. + """ + if 'name' in self.__dict__ and self.HUMAN_ID: + return utils.slugify(self.name) + return None + + def _add_details(self, info): + for (k, v) in info.iteritems(): + try: + setattr(self, k, v) + except AttributeError: + # In this case we already defined the attribute on the class + pass + + def __getattr__(self, k): + if k not in self.__dict__: + #NOTE(bcwaldon): disallow lazy-loading if already loaded once + if not self.is_loaded(): + self.get() + return self.__getattr__(k) + + raise AttributeError(k) + else: + return self.__dict__[k] + + def __repr__(self): + reprkeys = sorted(k for k in self.__dict__.keys() if k[0] != '_' and + k != 'manager') + info = ", ".join("%s=%s" % (k, getattr(self, k)) for k in reprkeys) + return "<%s %s>" % (self.__class__.__name__, info) + + def get(self): + # set_loaded() first ... so if we have to bail, we know we tried. + self.set_loaded(True) + if not hasattr(self.manager, 'get'): + return + + new = self.manager.get(self.id) + if new: + self._add_details(new._info) + + def __eq__(self, other): + if not isinstance(other, self.__class__): + return False + if hasattr(self, 'id') and hasattr(other, 'id'): + return self.id == other.id + return self._info == other._info + + def is_loaded(self): + return self._loaded + + def set_loaded(self, val): + self._loaded = val |