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
|
# -*- coding: utf-8 -*-
# Copyright (c) 2010 Mark Sandstrom
# Copyright (c) 2011 Raphaël Barrois
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
class OrderedDeclaration(object):
"""A factory declaration.
Ordered declarations mark an attribute as needing lazy evaluation.
This allows them to refer to attributes defined by other OrderedDeclarations
in the same factory.
"""
def evaluate(self, sequence, obj, containers=()):
"""Evaluate this declaration.
Args:
sequence (int): the current sequence counter to use when filling
the current instance
obj (containers.LazyStub): The object holding currently computed
attributes
containers (list of containers.LazyStub): The chain of SubFactory
which led to building this object.
"""
raise NotImplementedError('This is an abstract method')
class LazyAttribute(OrderedDeclaration):
"""Specific OrderedDeclaration computed using a lambda.
Attributes:
function (function): a function, expecting the current LazyStub and
returning the computed value.
"""
def __init__(self, function, *args, **kwargs):
super(LazyAttribute, self).__init__(*args, **kwargs)
self.function = function
def evaluate(self, sequence, obj, containers=()):
return self.function(obj)
class _UNSPECIFIED(object):
pass
def deepgetattr(obj, name, default=_UNSPECIFIED):
"""Try to retrieve the given attribute of an object, digging on '.'.
This is an extended getattr, digging deeper if '.' is found.
Args:
obj (object): the object of which an attribute should be read
name (str): the name of an attribute to look up.
default (object): the default value to use if the attribute wasn't found
Returns:
the attribute pointed to by 'name', splitting on '.'.
Raises:
AttributeError: if obj has no 'name' attribute.
"""
try:
if '.' in name:
attr, subname = name.split('.', 1)
return deepgetattr(getattr(obj, attr), subname, default)
else:
return getattr(obj, name)
except AttributeError:
if default is _UNSPECIFIED:
raise
else:
return default
class SelfAttribute(OrderedDeclaration):
"""Specific OrderedDeclaration copying values from other fields.
Attributes:
attribute_name (str): the name of the attribute to copy.
default (object): the default value to use if the attribute doesn't
exist.
"""
def __init__(self, attribute_name, default=_UNSPECIFIED, *args, **kwargs):
super(SelfAttribute, self).__init__(*args, **kwargs)
self.attribute_name = attribute_name
self.default = default
def evaluate(self, sequence, obj, containers=()):
return deepgetattr(obj, self.attribute_name, self.default)
class Sequence(OrderedDeclaration):
"""Specific OrderedDeclaration to use for 'sequenced' fields.
These fields are typically used to generate increasing unique values.
Attributes:
function (function): A function, expecting the current sequence counter
and returning the computed value.
type (function): A function converting an integer into the expected kind
of counter for the 'function' attribute.
"""
def __init__(self, function, type=str):
super(Sequence, self).__init__()
self.function = function
self.type = type
def evaluate(self, sequence, obj, containers=()):
return self.function(self.type(sequence))
class LazyAttributeSequence(Sequence):
"""Composite of a LazyAttribute and a Sequence.
Attributes:
function (function): A function, expecting the current LazyStub and the
current sequence counter.
type (function): A function converting an integer into the expected kind
of counter for the 'function' attribute.
"""
def evaluate(self, sequence, obj, containers=()):
return self.function(obj, self.type(sequence))
class ContainerAttribute(OrderedDeclaration):
"""Variant of LazyAttribute, also receives the containers of the object.
Attributes:
function (function): A function, expecting the current LazyStub and the
(optional) object having a subfactory containing this attribute.
strict (bool): Whether evaluating should fail when the containers are
not passed in (i.e used outside a SubFactory).
"""
def __init__(self, function, strict=True, *args, **kwargs):
super(ContainerAttribute, self).__init__(*args, **kwargs)
self.function = function
self.strict = strict
def evaluate(self, sequence, obj, containers=()):
"""Evaluate the current ContainerAttribute.
Args:
obj (LazyStub): a lazy stub of the object being constructed, if
needed.
containers (list of LazyStub): a list of lazy stubs of factories
being evaluated in a chain, each item being a future field of
next one.
"""
if self.strict and not containers:
raise TypeError(
"A ContainerAttribute in 'strict' mode can only be used "
"within a SubFactory.")
return self.function(obj, containers)
class SubFactory(OrderedDeclaration):
"""Base class for attributes based upon a sub-factory.
Attributes:
defaults (dict): Overrides to the defaults defined in the wrapped
factory
factory (base.Factory): the wrapped factory
"""
def __init__(self, factory, **kwargs):
super(SubFactory, self).__init__()
self.defaults = kwargs
self.factory = factory
def evaluate(self, create, extra, containers):
"""Evaluate the current definition and fill its attributes.
Uses attributes definition in the following order:
- attributes defined in the wrapped factory class
- values defined when defining the SubFactory
- additional values defined in attributes
Args:
create (bool): whether the subfactory should call 'build' or
'create'
extra (containers.DeclarationDict): extra values that should
override the wrapped factory's defaults
containers (list of LazyStub): List of LazyStub for the chain of
factories being evaluated, the calling stub being first.
"""
defaults = dict(self.defaults)
if extra:
defaults.update(extra)
defaults['__containers'] = containers
attrs = self.factory.attributes(create, defaults)
if create:
return self.factory.create(**attrs)
else:
return self.factory.build(**attrs)
# Decorators... in case lambdas don't cut it
def lazy_attribute(func):
return LazyAttribute(func)
def sequence(func):
return Sequence(func)
def lazy_attribute_sequence(func):
return LazyAttributeSequence(func)
def container_attribute(func):
return ContainerAttribute(func, strict=False)
|