505 lines
18 KiB
Python
505 lines
18 KiB
Python
# Copyright 2013 IBM Corp.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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#
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# Copyright (c) 2013-2014 Wind River Systems, Inc.
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#
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"""Sm common internal object model"""
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import collections
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from sm_api.common import exception
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from sm_api.objects import utils as obj_utils
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from sm_api.openstack.common import context
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from sm_api.openstack.common import log as logging
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from sm_api.openstack.common.rpc import common as rpc_common
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from sm_api.openstack.common.rpc import serializer as rpc_serializer
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LOG = logging.getLogger('object')
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def get_attrname(name):
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"""Return the mangled name of the attribute's underlying storage."""
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return '_%s' % name
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def make_class_properties(cls):
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# NOTE(danms): Inherit Sm_apiObject's base fields only
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cls.fields.update(Sm_apiObject.fields)
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for name, typefn in cls.fields.items():
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def getter(self, name=name):
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attrname = get_attrname(name)
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if not hasattr(self, attrname):
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self.obj_load_attr(name)
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return getattr(self, attrname)
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def setter(self, value, name=name, typefn=typefn):
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self._changed_fields.add(name)
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try:
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return setattr(self, get_attrname(name), typefn(value))
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except Exception:
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attr = "%s.%s" % (self.obj_name(), name)
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LOG.exception(_('Error setting %(attr)s') %
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{'attr': attr})
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raise
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setattr(cls, name, property(getter, setter))
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class Sm_apiObjectMetaclass(type):
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"""Metaclass that allows tracking of object classes."""
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# NOTE(danms): This is what controls whether object operations are
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# remoted. If this is not None, use it to remote things over RPC.
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indirection_api = None
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def __init__(cls, names, bases, dict_):
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if not hasattr(cls, '_obj_classes'):
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# This will be set in the 'Sm_apiObject' class.
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cls._obj_classes = collections.defaultdict(list)
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else:
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# Add the subclass to Sm_apiObject._obj_classes
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make_class_properties(cls)
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cls._obj_classes[cls.obj_name()].append(cls)
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# These are decorators that mark an object's method as remotable.
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# If the metaclass is configured to forward object methods to an
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# indirection service, these will result in making an RPC call
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# instead of directly calling the implementation in the object. Instead,
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# the object implementation on the remote end will perform the
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# requested action and the result will be returned here.
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def remotable_classmethod(fn):
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"""Decorator for remotable classmethods."""
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def wrapper(cls, context, *args, **kwargs):
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if Sm_apiObject.indirection_api:
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result = Sm_apiObject.indirection_api.object_class_action(
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context, cls.obj_name(), fn.__name__, cls.version,
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args, kwargs)
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else:
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result = fn(cls, context, *args, **kwargs)
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if isinstance(result, Sm_apiObject):
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result._context = context
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return result
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return classmethod(wrapper)
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# See comment above for remotable_classmethod()
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#
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# Note that this will use either the provided context, or the one
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# stashed in the object. If neither are present, the object is
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# "orphaned" and remotable methods cannot be called.
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def remotable(fn):
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"""Decorator for remotable object methods."""
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def wrapper(self, *args, **kwargs):
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ctxt = self._context
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try:
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if isinstance(args[0], (context.RequestContext,
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rpc_common.CommonRpcContext)):
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ctxt = args[0]
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args = args[1:]
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except IndexError:
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pass
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if ctxt is None:
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raise exception.OrphanedObjectError(method=fn.__name__,
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objtype=self.obj_name())
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if Sm_apiObject.indirection_api:
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updates, result = Sm_apiObject.indirection_api.object_action(
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ctxt, self, fn.__name__, args, kwargs)
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for key, value in updates.items():
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if key in self.fields:
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self[key] = self._attr_from_primitive(key, value)
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self._changed_fields = set(updates.get('obj_what_changed', []))
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return result
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else:
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return fn(self, ctxt, *args, **kwargs)
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return wrapper
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# Object versioning rules
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#
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# Each service has its set of objects, each with a version attached. When
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# a client attempts to call an object method, the server checks to see if
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# the version of that object matches (in a compatible way) its object
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# implementation. If so, cool, and if not, fail.
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def check_object_version(server, client):
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try:
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client_major, _client_minor = client.split('.')
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server_major, _server_minor = server.split('.')
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client_minor = int(_client_minor)
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server_minor = int(_server_minor)
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except ValueError:
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raise exception.IncompatibleObjectVersion(
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_('Invalid version string'))
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if client_major != server_major:
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raise exception.IncompatibleObjectVersion(
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dict(client=client_major, server=server_major))
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if client_minor > server_minor:
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raise exception.IncompatibleObjectVersion(
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dict(client=client_minor, server=server_minor))
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class Sm_apiObject(object):
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"""Base class and object factory.
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This forms the base of all objects that can be remoted or instantiated
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via RPC. Simply defining a class that inherits from this base class
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will make it remotely instantiatable. Objects should implement the
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necessary "get" classmethod routines as well as "save" object methods
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as appropriate.
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"""
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__metaclass__ = Sm_apiObjectMetaclass
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# Version of this object (see rules above check_object_version())
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version = '1.0'
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# The fields present in this object as key:typefn pairs. For example:
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#
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# fields = { 'foo': int,
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# 'bar': str,
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# 'baz': lambda x: str(x).ljust(8),
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# }
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#
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# NOTE(danms): The base Sm_apiObject class' fields will be inherited
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# by subclasses, but that is a special case. Objects inheriting from
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# other objects will not receive this merging of fields contents.
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fields = {}
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# JKUNG until avail 'created_at': obj_utils.datetime_or_str_or_none,
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# 'updated_at': obj_utils.datetime_or_str_or_none,
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# }
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obj_extra_fields = []
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def __init__(self):
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self._changed_fields = set()
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self._context = None
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@classmethod
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def obj_name(cls):
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"""Return a canonical name for this object which will be used over
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the wire for remote hydration.
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"""
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return cls.__name__
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@classmethod
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def obj_class_from_name(cls, objname, objver):
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"""Returns a class from the registry based on a name and version."""
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if objname not in cls._obj_classes:
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LOG.error(_('Unable to instantiate unregistered object type '
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'%(objtype)s') % dict(objtype=objname))
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raise exception.UnsupportedObjectError(objtype=objname)
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compatible_match = None
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for objclass in cls._obj_classes[objname]:
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if objclass.version == objver:
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return objclass
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try:
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check_object_version(objclass.version, objver)
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compatible_match = objclass
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except exception.IncompatibleObjectVersion:
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pass
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if compatible_match:
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return compatible_match
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raise exception.IncompatibleObjectVersion(objname=objname,
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objver=objver)
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_attr_created_at_from_primitive = obj_utils.dt_deserializer
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_attr_updated_at_from_primitive = obj_utils.dt_deserializer
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def _attr_from_primitive(self, attribute, value):
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"""Attribute deserialization dispatcher.
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This calls self._attr_foo_from_primitive(value) for an attribute
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foo with value, if it exists, otherwise it assumes the value
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is suitable for the attribute's setter method.
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"""
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handler = '_attr_%s_from_primitive' % attribute
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if hasattr(self, handler):
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return getattr(self, handler)(value)
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return value
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@classmethod
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def obj_from_primitive(cls, primitive, context=None):
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"""Simple base-case hydration.
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This calls self._attr_from_primitive() for each item in fields.
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"""
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if primitive['sm_api_object.namespace'] != 'sm_api':
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# NOTE(danms): We don't do anything with this now, but it's
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# there for "the future"
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raise exception.UnsupportedObjectError(
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objtype='%s.%s' % (primitive['sm_api_object.namespace'],
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primitive['sm_api_object.name']))
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objname = primitive['sm_api_object.name']
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objver = primitive['sm_api_object.version']
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objdata = primitive['sm_api_object.data']
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objclass = cls.obj_class_from_name(objname, objver)
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self = objclass()
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self._context = context
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for name in self.fields:
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if name in objdata:
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setattr(self, name,
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self._attr_from_primitive(name, objdata[name]))
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changes = primitive.get('sm_api_object.changes', [])
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self._changed_fields = set([x for x in changes if x in self.fields])
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return self
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_attr_created_at_to_primitive = obj_utils.dt_serializer('created_at')
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_attr_updated_at_to_primitive = obj_utils.dt_serializer('updated_at')
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def _attr_to_primitive(self, attribute):
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"""Attribute serialization dispatcher.
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This calls self._attr_foo_to_primitive() for an attribute foo,
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if it exists, otherwise it assumes the attribute itself is
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primitive-enough to be sent over the RPC wire.
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"""
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handler = '_attr_%s_to_primitive' % attribute
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if hasattr(self, handler):
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return getattr(self, handler)()
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else:
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return getattr(self, attribute)
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def obj_to_primitive(self):
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"""Simple base-case dehydration.
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This calls self._attr_to_primitive() for each item in fields.
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"""
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primitive = dict()
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for name in self.fields:
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if hasattr(self, get_attrname(name)):
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primitive[name] = self._attr_to_primitive(name)
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obj = {'sm_api_object.name': self.obj_name(),
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'sm_api_object.namespace': 'sm_api',
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'sm_api_object.version': self.version,
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'sm_api_object.data': primitive}
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if self.obj_what_changed():
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obj['sm_api_object.changes'] = list(self.obj_what_changed())
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return obj
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def obj_load_attr(self, attrname):
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"""Load an additional attribute from the real object.
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This should use self._conductor, and cache any data that might
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be useful for future load operations.
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"""
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raise NotImplementedError(
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_("Cannot load '%(attrname)s' in the base class") %
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{'attrname': attrname})
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def save(self, context):
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"""Save the changed fields back to the store.
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This is optional for subclasses, but is presented here in the base
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class for consistency among those that do.
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"""
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raise NotImplementedError('Cannot save anything in the base class')
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def obj_what_changed(self):
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"""Returns a set of fields that have been modified."""
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return self._changed_fields
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def obj_reset_changes(self, fields=None):
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"""Reset the list of fields that have been changed.
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Note that this is NOT "revert to previous values"
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"""
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if fields:
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self._changed_fields -= set(fields)
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else:
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self._changed_fields.clear()
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# dictish syntactic sugar
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def iteritems(self):
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"""For backwards-compatibility with dict-based objects.
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NOTE(danms): May be removed in the future.
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"""
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for name in self.fields.keys() + self.obj_extra_fields:
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if (hasattr(self, get_attrname(name)) or
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name in self.obj_extra_fields):
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yield name, getattr(self, name)
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items = lambda self: list(self.items())
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def __getitem__(self, name):
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"""For backwards-compatibility with dict-based objects.
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NOTE(danms): May be removed in the future.
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"""
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return getattr(self, name)
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def __setitem__(self, name, value):
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"""For backwards-compatibility with dict-based objects.
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NOTE(danms): May be removed in the future.
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"""
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setattr(self, name, value)
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def __contains__(self, name):
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"""For backwards-compatibility with dict-based objects.
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NOTE(danms): May be removed in the future.
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"""
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return hasattr(self, get_attrname(name))
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def get(self, key, value=None):
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"""For backwards-compatibility with dict-based objects.
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NOTE(danms): May be removed in the future.
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"""
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return self[key]
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def update(self, updates):
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"""For backwards-compatibility with dict-base objects.
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NOTE(danms): May be removed in the future.
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"""
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for key, value in updates.items():
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self[key] = value
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def as_dict(self):
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return dict((k, getattr(self, k))
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for k in self.fields
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if hasattr(self, k))
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@classmethod
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def get_defaults(cls):
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"""Return a dict of its fields with their default value."""
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return dict((k, v(None))
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for k, v in cls.fields.items()
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if k != "id" and callable(v))
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class ObjectListBase(object):
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"""Mixin class for lists of objects.
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This mixin class can be added as a base class for an object that
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is implementing a list of objects. It adds a single field of 'objects',
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which is the list store, and behaves like a list itself. It supports
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serialization of the list of objects automatically.
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"""
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fields = {
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'objects': list,
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}
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def __iter__(self):
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"""List iterator interface."""
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return iter(self.objects)
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def __len__(self):
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"""List length."""
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return len(self.objects)
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def __getitem__(self, index):
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"""List index access."""
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if isinstance(index, slice):
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new_obj = self.__class__()
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new_obj.objects = self.objects[index]
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# NOTE(danms): We must be mixed in with an Sm_apiObject!
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new_obj.obj_reset_changes()
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new_obj._context = self._context
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return new_obj
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return self.objects[index]
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def __contains__(self, value):
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"""List membership test."""
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return value in self.objects
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def count(self, value):
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"""List count of value occurrences."""
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return self.objects.count(value)
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def index(self, value):
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"""List index of value."""
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return self.objects.index(value)
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def _attr_objects_to_primitive(self):
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"""Serialization of object list."""
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return [x.obj_to_primitive() for x in self.objects]
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def _attr_objects_from_primitive(self, value):
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"""Deserialization of object list."""
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objects = []
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for entity in value:
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obj = Sm_apiObject.obj_from_primitive(entity,
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context=self._context)
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objects.append(obj)
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return objects
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class Sm_apiObjectSerializer(rpc_serializer.Serializer):
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"""A Sm_apiObject-aware Serializer.
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This implements the Oslo Serializer interface and provides the
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ability to serialize and deserialize Sm_apiObject entities. Any service
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that needs to accept or return Sm_apiObjects as arguments or result values
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should pass this to its RpcProxy and RpcDispatcher objects.
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"""
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def _process_iterable(self, context, action_fn, values):
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"""Process an iterable, taking an action on each value.
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:param:context: Request context
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:param:action_fn: Action to take on each item in values
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:param:values: Iterable container of things to take action on
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:returns: A new container of the same type (except set) with
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items from values having had action applied.
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"""
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iterable = values.__class__
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if iterable == set:
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# NOTE(danms): A set can't have an unhashable value inside, such as
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# a dict. Convert sets to tuples, which is fine, since we can't
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# send them over RPC anyway.
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iterable = tuple
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return iterable([action_fn(context, value) for value in values])
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def serialize_entity(self, context, entity):
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if isinstance(entity, (tuple, list, set)):
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entity = self._process_iterable(context, self.serialize_entity,
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entity)
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elif (hasattr(entity, 'obj_to_primitive') and
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callable(entity.obj_to_primitive)):
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entity = entity.obj_to_primitive()
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return entity
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def deserialize_entity(self, context, entity):
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if isinstance(entity, dict) and 'sm_api_object.name' in entity:
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entity = Sm_apiObject.obj_from_primitive(entity, context=context)
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elif isinstance(entity, (tuple, list, set)):
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entity = self._process_iterable(context, self.deserialize_entity,
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entity)
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return entity
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def obj_to_primitive(obj):
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"""Recursively turn an object into a python primitive.
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An Sm_apiObject becomes a dict, and anything that implements ObjectListBase
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becomes a list.
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"""
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if isinstance(obj, ObjectListBase):
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return [obj_to_primitive(x) for x in obj]
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elif isinstance(obj, Sm_apiObject):
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result = {}
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for key, value in obj.items():
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result[key] = obj_to_primitive(value)
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return result
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else:
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return obj
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