# 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 os
from novaclient import exceptions
# 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 to return the object's UUID first, if we have a UUID.
try:
if obj.uuid:
return obj.uuid
except AttributeError:
pass
try:
return obj.id
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 = 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 type(data) is dict:
data = data['values']
with self.uuid_cache(obj_class, mode="w"):
return [obj_class(self, res, loaded=True) for res in data if res]
@contextlib.contextmanager
def uuid_cache(self, obj_class, mode):
"""
Cache UUIDs for bash autocompletion.
The UUID cache works by checking to see whether an ID is UUID-like when
we create a resource object (e.g. a Image or a Server), and if it is,
we add it to a local cache file. We maintain one cache file per
resource type so that we can refresh them independently.
A resource listing will clear and repopulate the UUID cache.
A resource create will append to the UUID cache.
Delete is not handled because listings are assumed to be performed
often enough to keep the UUID cache reasonably up-to-date.
"""
resource = obj_class.__name__.lower()
filename = os.path.expanduser("~/.novaclient_cached_%s_uuids" %
resource)
try:
self._uuid_cache = open(filename, mode)
except IOError:
# NOTE(kiall): This is typicaly a permission denied while
# attempting to write the cache file.
pass
try:
yield
finally:
if hasattr(self, '_uuid_cache'):
self._uuid_cache.close()
del self._uuid_cache
def write_uuid_to_cache(self, uuid):
if hasattr(self, '_uuid_cache'):
self._uuid_cache.write("%s\n" % uuid)
def _get(self, url, response_key):
resp, body = self.api.client.get(url)
return self.resource_class(self, body[response_key])
def _create(self, url, body, response_key, return_raw=False):
resp, body = self.api.client.post(url, body=body)
if return_raw:
return body[response_key]
with self.uuid_cache(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):
resp, body = self.api.client.put(url, body=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.
"""
rl = self.findall(**kwargs)
try:
return rl[0]
except IndexError:
msg = "No %s matching %s." % (self.resource_class.__name__, kwargs)
raise exceptions.NotFound(404, msg)
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
class BootingManagerWithFind(ManagerWithFind):
"""Like a `ManagerWithFind`, but has the ability to boot servers."""
def _boot(self, resource_url, response_key, name, image, flavor,
ipgroup=None, meta=None, files=None, zone_blob=None,
reservation_id=None, return_raw=False, min_count=None,
max_count=None):
"""
Create (boot) a new server.
:param name: Something to name the server.
:param image: The :class:`Image` to boot with.
:param flavor: The :class:`Flavor` to boot onto.
:param ipgroup: An initial :class:`IPGroup` for this server.
:param meta: A dict of arbitrary key/value metadata to store for this
server. A maximum of five entries is allowed, and both
keys and values must be 255 characters or less.
:param files: A dict of files to overrwrite on the server upon boot.
Keys are file names (i.e. ``/etc/passwd``) and values
are the file contents (either as a string or as a
file-like object). A maximum of five entries is allowed,
and each file must be 10k or less.
:param zone_blob: a single (encrypted) string which is used internally
by Nova for routing between Zones. Users cannot populate
this field.
:param reservation_id: a UUID for the set of servers being requested.
:param return_raw: If True, don't try to coearse the result into
a Resource object.
"""
body = {"server": {
"name": name,
"imageId": getid(image),
"flavorId": getid(flavor),
}}
if ipgroup:
body["server"]["sharedIpGroupId"] = getid(ipgroup)
if meta:
body["server"]["metadata"] = meta
if reservation_id:
body["server"]["reservation_id"] = reservation_id
if zone_blob:
body["server"]["blob"] = zone_blob
if not min_count:
min_count = 1
if not max_count:
max_count = min_count
body["server"]["min_count"] = min_count
body["server"]["max_count"] = max_count
# Files are a slight bit tricky. They're passed in a "personality"
# list to the POST. Each item is a dict giving a file name and the
# base64-encoded contents of the file. We want to allow passing
# either an open file *or* some contents as files here.
if files:
personality = body['server']['personality'] = []
for filepath, file_or_string in files.items():
if hasattr(file_or_string, 'read'):
data = file_or_string.read()
else:
data = file_or_string
personality.append({
'path': filepath,
'contents': data.encode('base64'),
})
return self._create(resource_url, body, response_key,
return_raw=return_raw)
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
"""
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_uuid_to_cache(self.id)
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