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# Copyright 2012 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.
"""
# 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
(UUID) as a parameter when dealing with relationships.
"""
try:
return obj.name
except AttributeError:
return obj
class Manager(object):
"""
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, body = self.api.json_request('GET', url)
if obj_class is None:
obj_class = self.resource_class
data = body[response_key]
return [obj_class(self, res, loaded=True) for res in data if res]
def _delete(self, url):
self.api.raw_request('DELETE', url)
def _update(self, url, body, response_key=None):
resp, body = self.api.json_request('PUT', url, body=body)
# PUT requests may not return a body
if body:
return self.resource_class(self, body[response_key])
class Resource(object):
"""
A resource represents a particular instance of an object (tenant, user,
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
"""
def __init__(self, manager, info, loaded=False):
self.manager = manager
self._info = info
self._add_details(info)
self._loaded = loaded
def _add_details(self, info):
for (k, v) in info.iteritems():
setattr(self, k, v)
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.name)
if new:
self._add_details(new._info)
def __eq__(self, other):
if not isinstance(other, self.__class__):
return False
if hasattr(self, 'name') and hasattr(other, 'name'):
return self.name == other.name
return self._info == other._info
def is_loaded(self):
return self._loaded
def set_loaded(self, val):
self._loaded = val
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