1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
|
#!/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
import sys
from netmodel.model.attribute import Attribute, Multiplicity
from netmodel.model.key import Key
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(type):
"""
Object metaclass allowing non-uniform attribute declaration.
"""
def __new__(mcls, name, bases, attrs):
cls = super(ObjectMetaclass, mcls).__new__(mcls, name, bases, attrs)
if (sys.version_info < (3, 6)):
# Before Python 3.6, descriptor protocol does not include __set_name__.
# We use a metaclass to emulate the functionality.
for attr, obj in attrs.items():
if isinstance(obj, ObjectSpecification):
obj.__set_name__(cls, attr)
return cls
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):
"""
This methods performs sanitization of the object declaration.
More specifically:
- it goes over all attributes and sets their name based on the python
object attribute name.
- it establishes mutual object relationships through reverse attributes.
"""
cls._reverse_attributes = dict()
cur_reverse_attributes = dict()
for name, obj in vars(cls).items():
if not isinstance(obj, Attribute):
continue
# 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, "No type for obj={} cls={}, base={}".format(obj, cls, base)
# Handle reverse attribute
#
# NOTE: we need to do this after merging to be sure we get all
# properties inherited from parent (eg. multiplicity)
#
# See "Reverse attributes" section in BaseResource docstring.
#
# Continueing with the same example, let's detail how it is handled:
#
# Original declaration:
# >>>
# class Group(Resource):
# resources = Attribute(Resource, description = 'Resources belonging to the group',
# multiplicity = Multiplicity.ManyToMany,
# default = [],
# reverse_name = 'groups',
# reverse_description = 'Groups to which the resource belongs')
# <<<
#
# Local variables:
# cls = <class 'vicn.resource.group.Group'>
# obj = <Attribute resources>
# obj.type = <class 'vicn.core.Resource'>
# reverse_attribute = <Attribute groups>
#
# Result:
# 1) Group._reverse_attributes =
# { <Attribute resources> : [<Attribute groups>, ...], ...}
# 2) Add attribute <Attribute groups> to class Resource
# 3) Resource._reverse_attributes =
# { <Attribute groups> : [<Attribute resources], ...], ...}
#
if has_reverse:
a = {
'name' : obj.reverse_name,
'description' : obj.reverse_description,
'multiplicity' : Multiplicity.reverse(obj.multiplicity),
'reverse_name' : obj.name,
'reverse_description' : obj.description,
'auto' : obj.reverse_auto,
}
# We need to use the same class as the Attribute !
reverse_attribute = obj.__class__(cls, **a)
reverse_attribute.is_aggregate = True
# 1) Store the reverse attributes to be later inserted in the
# remote class, at the end of the function
# TODO : clarify the reasons to perform this in two steps
cur_reverse_attributes[obj.type] = reverse_attribute
# 2)
if not obj in cls._reverse_attributes:
cls._reverse_attributes[obj] = list()
cls._reverse_attributes[obj].append(reverse_attribute)
# 3)
if not reverse_attribute in obj.type._reverse_attributes:
obj.type._reverse_attributes[reverse_attribute] = list()
obj.type._reverse_attributes[reverse_attribute].append(obj)
# Insert newly created reverse attributes in the remote class
for kls, a in cur_reverse_attributes.items():
setattr(kls, 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
@classmethod
def iter_keys(cls):
for name in dir(cls):
key = getattr(cls, name)
if not isinstance(key, Key):
continue
yield key
@classmethod
def get_keys(cls):
return list(cls.iter_keys())
def get_key_dicts(self):
return [{attribute: self.get(attribute.name) for attribute in key} for key in self.iter_keys()]
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()]
def get(self, attribute_name):
raise NotImplementedError
def set(self, attribute_name, value):
raise NotImplementedError
|