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Diffstat (limited to 'vicn/core/attribute.py')
| -rw-r--r-- | vicn/core/attribute.py | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/vicn/core/attribute.py b/vicn/core/attribute.py new file mode 100644 index 00000000..f6ec7c70 --- /dev/null +++ b/vicn/core/attribute.py @@ -0,0 +1,270 @@ +#!/usr/bin/env python3 +# -*- coding: utf-8 -*- +# +# Copyright (c) 2017 Cisco and/or its affiliates. +# +# 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. +# + +import abc +import copy +import logging +import operator +import types + +from netmodel.model.mapper import ObjectSpecification +from netmodel.model.type import Type, Self +from netmodel.util.meta import inheritors +from netmodel.util.misc import is_iterable +from vicn.core.exception import VICNListException +from vicn.core.requirement import Requirement, RequirementList +from vicn.core.sa_collections import InstrumentedList +from vicn.core.state import UUID, NEVER_SET, Operations + +log = logging.getLogger(__name__) + +#------------------------------------------------------------------------------ +# Attribute Multiplicity +#------------------------------------------------------------------------------ + +class Multiplicity: + OneToOne = '1_1' + OneToMany = '1_N' + ManyToOne = 'N_1' + ManyToMany = 'N_N' + + + @staticmethod + def reverse(value): + reverse_map = { + Multiplicity.OneToOne: Multiplicity.OneToOne, + Multiplicity.OneToMany: Multiplicity.ManyToOne, + Multiplicity.ManyToOne: Multiplicity.OneToMany, + Multiplicity.ManyToMany: Multiplicity.ManyToMany, + } + return reverse_map[value] + + +# Default attribute properties values (default to None) +DEFAULT = { + 'multiplicity' : Multiplicity.OneToOne, + 'mandatory' : False, +} + +#------------------------------------------------------------------------------ +# Attribute +#------------------------------------------------------------------------------ + +class Attribute(abc.ABC, ObjectSpecification): + properties = [ + 'name', + 'type', + 'key', + 'description', + 'default', + 'choices', + 'mandatory', + 'multiplicity', + 'ro', + 'auto', + 'func', + 'requirements', + 'reverse_name', + 'reverse_description', + 'reverse_auto' + ] + + def __init__(self, *args, **kwargs): + for key in Attribute.properties: + value = kwargs.pop(key, NEVER_SET) + setattr(self, key, value) + + if len(args) == 1: + self.type, = args + elif len(args) == 2: + self.name, self.type = args + + # self.type is optional since the type can be inherited. Although we + # will have to verify the attribute is complete at some point + if self.type: + if isinstance(self.type, str): + self.type = Type.from_string(self.type) + assert self.type is Self or Type.exists(self.type) + + # Post processing attribute properties + if self.requirements is not NEVER_SET: + self.requirements = RequirementList(self.requirements) + + self.is_aggregate = False + + self._reverse_attributes = list() + + #-------------------------------------------------------------------------- + # Display + #-------------------------------------------------------------------------- + + def __repr__(self): + return '<Attribute {}>'.format(self.name) + + __str__ = __repr__ + + # The following functions are required to allow comparing attributes, and + # using them as dict keys + + def __eq__(self, other): + return self.name == other.name + + def __hash__(self): + return hash(self.name) + + #-------------------------------------------------------------------------- + # Descriptor protocol + # + # see. https://docs.python.org/3/howto/descriptor.html + #-------------------------------------------------------------------------- + + def __get__(self, instance, owner=None): + if not instance: + return self + + return instance.get(self.name, blocking=False) + + def __set__(self, instance, value): + if not instance: + raise NotImplementedError('Setting default value not implemented') + + instance.set(self.name, value, blocking=False) + + def __delete__(self, instance): + raise NotImplementedError + + #-------------------------------------------------------------------------- + + def do_list_add(self, instance, value): + if instance.is_local_attribute(self.name): + from vicn.core.resource import Resource + if isinstance(value, Resource): + value = value.get_uuid() + return value + else: + try: + cur_value = vars(instance)[self.name] + if self.is_collection: + # copy the list + cur_value = list(cur_value) + except KeyError as e: + cur_value = None + if self.is_collection: + cur_value = list() + + instance._state.dirty[self.name].trigger(Operations.LIST_ADD, + value, cur_value) + + # prevent instrumented list to perform operation + raise VICNListException + + def do_list_remove(self, instance, value): + if instance.is_local_attribute(self.name): + from vicn.core.resource import Resource + if isinstance(value, Resource): + value = value.get_uuid() + return value + else: + cur_value = vars(instance)[self.name] + if self.is_collection: + # copy the list + cur_value = list(cur_value) + instance._state.dirty[self.name].trigger(Operations.LIST_REMOVE, + value, cur_value) + + # prevent instrumented list to perform operation + raise VICNListException + + def do_list_clear(self, instance): + if instance.is_local_attribute(self.name): + return + else: + cur_value = vars(instance)[self.name] + if self.is_collection: + # copy the list + cur_value = list(cur_value) + instance._state.dirty[self.name].trigger(Operations.LIST_CLEAR, + value, cur_value) + + # prevent instrumented list to perform operation + raise VICNListException + + def handle_getitem(self, instance, item): + if isinstance(item, UUID): + from vicn.core.resource_mgr import ResourceManager + return ResourceManager().by_uuid(item) + return item + + #-------------------------------------------------------------------------- + # Accessors + #-------------------------------------------------------------------------- + + def __getattribute__(self, name): + value = super().__getattribute__(name) + if value is NEVER_SET: + if name == 'default': + return list() if self.is_collection else None + return DEFAULT.get(name, None) + return value + + def has_reverse_attribute(self): + return self.reverse_name and self.multiplicity + + @property + def is_collection(self): + return self.multiplicity in (Multiplicity.OneToMany, + Multiplicity.ManyToMany) + + def is_set(self, instance): + return instance.is_set(self.name) + + #-------------------------------------------------------------------------- + # Operations + #-------------------------------------------------------------------------- + + def merge(self, parent): + for prop in Attribute.properties: + # NOTE: we cannot use getattr otherwise we get the default value, + # and we never override + value = vars(self).get(prop, NEVER_SET) + if value is not NEVER_SET and not is_iterable(value): + continue + + parent_value = vars(parent).get(prop, NEVER_SET) + if parent_value is NEVER_SET: + continue + + if parent_value: + if is_iterable(value): + value.extend(parent_value) + else: + setattr(self, prop, parent_value) + +#------------------------------------------------------------------------------ + +class Reference: + """ + Value reference. + + Attribute value refers to attribute value on a different resource. + Use resource = Self to point to another attribute of the same resource. + """ + + def __init__(self, resource, attribute=None): + self._resource = resource + self._attribute = attribute |