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#!/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.
#
from abc import ABCMeta
from netmodel.model.attribute import Attribute
from netmodel.model.type import BaseType
from netmodel.model.mapper import ObjectSpecification
# Warning and error messages
E_UNK_RES_NAME = 'Unknown resource name for attribute {} in {} ({}) : {}'
class ObjectMetaclass(ABCMeta):
"""
Object metaclass allowing non-uniform attribute declaration.
"""
def __init__(cls, class_name, parents, attrs):
"""
Args:
cls: The class type we're registering.
class_name: A String containing the class_name.
parents: The parent class types of 'cls'.
attrs: The attribute (members) of 'cls'.
"""
super().__init__(class_name, parents, attrs)
cls._sanitize()
class Object(BaseType, metaclass = ObjectMetaclass):
def __init__(self, **kwargs):
"""
Object constructor.
Args:
kwargs: named arguments consisting in object attributes to be
initialized at construction.
"""
mandatory = { a.name for a in self.iter_attributes() if a.mandatory }
for key, value in kwargs.items():
attribute = self.get_attribute(key)
if issubclass(attribute.type, Object):
if attribute.is_collection:
new_value = list()
for x in value:
if isinstance(x, str):
resource = self._state.manager.by_name(x)
elif isinstance(x, UUID):
resource = self._state.manager.by_uuid(x)
else:
resource = x
if not resource:
raise LurchException(E_UNK_RES_NAME.format(key,
self.name, self.__class__.__name__, x))
new_value.append(resource._state.uuid)
value = new_value
else:
if isinstance(value, str):
resource = self._state.manager.by_name(value)
elif isinstance(value, UUID):
resource = self._state.manager.by_uuid(value)
else:
resource = value
if not resource:
raise LurchException(E_UNK_RES_NAME.format(key,
self.name, self.__class__.__name__, value))
value = resource._state.uuid
setattr(self, key, value)
mandatory -= { key }
# Check that all mandatory atttributes have been set
# Mandatory resource attributes will be marked as pending since they
# might be discovered
# Eventually, their absence will be discovered at runtime
if mandatory:
raise Exception('Mandatory attributes not set: %r' % (mandatory,))
# Assign backreferences (we need attribute to be initialized, so it has
# to be done at the end of __init__
for other_instance, attribute in self.iter_backrefs():
if attribute.is_collection:
collection = getattr(other_instance, attribute.name)
collection.append(self)
else:
setattr(other_instance, attribute.name, self)
#--------------------------------------------------------------------------
# Object model
#--------------------------------------------------------------------------
@classmethod
def get_attribute(cls, key):
return getattr(cls, key)
@classmethod
def _sanitize(cls):
"""Sanitize the object model to accomodate for multiple declaration
styles
In particular, this method:
- set names to all attributes
"""
cls._reverse_attributes = dict()
cur_reverse_attributes = dict()
for name, obj in vars(cls).items():
if not isinstance(obj, ObjectSpecification):
continue
if isinstance(obj, Attribute):
obj.name = name
# Remember whether a reverse_name is defined before loading
# inherited properties from parent
has_reverse = bool(obj.reverse_name)
# Handle overloaded attributes
# By recursion, it is sufficient to look into the parent
for base in cls.__bases__:
if hasattr(base, name):
parent_attribute = getattr(base, name)
obj.merge(parent_attribute)
assert obj.type
# Handle reverse attribute
#
# NOTE: we need to do this after merging to be sure we get all
# properties inherited from parent (eg. multiplicity)
if has_reverse:
a = {
'name' : obj.reverse_name,
'description' : obj.reverse_description,
'multiplicity' : Multiplicity.reverse(obj.multiplicity),
'auto' : obj.reverse_auto,
}
reverse_attribute = Attribute(cls, **a)
reverse_attribute.is_aggregate = True
cur_reverse_attributes[obj.type] = reverse_attribute
if not obj in cls._reverse_attributes:
cls._reverse_attributes[obj] = list()
cls._reverse_attributes[obj].append(reverse_attribute)
for cls, a in cur_reverse_attributes.items():
setattr(cls, a.name, a)
@classmethod
def iter_attributes(cls, aggregates = False):
for name in dir(cls):
attribute = getattr(cls, name)
if not isinstance(attribute, Attribute):
continue
if attribute.is_aggregate and not aggregates:
continue
yield attribute
def get_attributes(self, aggregates = False):
return list(self.iter_attributes(aggregates = aggregates))
def get_attribute_names(self, aggregates = False):
return set(a.name for a in self.iter_attributes(aggregates = \
aggregates))
def get_attribute_dict(self, field_names = None, aggregates = False,
uuid = True):
assert not field_names or field_names.is_star()
attributes = self.get_attributes(aggregates = aggregates)
ret = dict()
for a in attributes:
if not a.is_set(self):
continue
value = getattr(self, a.name)
if a.is_collection:
ret[a.name] = list()
for x in value:
if uuid and isinstance(x, Object):
x = x._state.uuid._uuid
ret[a.name].append(x)
else:
if uuid and isinstance(value, Object):
value = value._state.uuid._uuid
ret[a.name] = value
return ret
def get_tuple(self):
return (self.__class__, self._get_attribute_dict())
def format(self, fmt):
return fmt.format(**self.get_attribute_dict(uuid = False))
def iter_backrefs(self):
for base in self.__class__.mro():
if not hasattr(base, '_reverse_attributes'):
continue
for attr, rattrs in base._reverse_attributes.items():
instances = getattr(self, attr.name)
if not attr.is_collection:
instances = [instances]
for instance in instances:
# - instance = node
if instance in (None, NEVER_SET):
continue
for rattr in rattrs:
yield instance, rattr
#--------------------------------------------------------------------------
# Accessors
#--------------------------------------------------------------------------
@classmethod
def has_attribute(cls, name):
return name in [a.name for a in cls.attributes()]
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