# -*- coding: utf-8 -*-
# Copyright (c) 2010 Mark Sandstrom
# Copyright (c) 2011-2015 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.
import itertools
import logging
from . import compat
from . import utils
logger = logging.getLogger('factory.generate')
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, create, extra=None, 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.
create (bool): whether the model class should be 'built' or
'created'
extra (DeclarationDict or None): extracted key/value extracted from
the attribute prefix
"""
raise NotImplementedError('This is an abstract method')
[docs]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, create, extra=None, containers=()):
logger.debug("LazyAttribute: Evaluating %r on %r", self.function, obj)
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
[docs]class SelfAttribute(OrderedDeclaration):
"""Specific OrderedDeclaration copying values from other fields.
If the field name starts with two dots or more, the lookup will be anchored
in the related 'parent'.
Attributes:
depth (int): the number of steps to go up in the containers chain
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)
depth = len(attribute_name) - len(attribute_name.lstrip('.'))
attribute_name = attribute_name[depth:]
self.depth = depth
self.attribute_name = attribute_name
self.default = default
def evaluate(self, sequence, obj, create, extra=None, containers=()):
if self.depth > 1:
# Fetching from a parent
target = containers[self.depth - 2]
else:
target = obj
logger.debug("SelfAttribute: Picking attribute %r on %r", self.attribute_name, target)
return deepgetattr(target, self.attribute_name, self.default)
def __repr__(self):
return '<%s(%r, default=%r)>' % (
self.__class__.__name__,
self.attribute_name,
self.default,
)
[docs]class Iterator(OrderedDeclaration):
"""Fill this value using the values returned by an iterator.
Warning: the iterator should not end !
Attributes:
iterator (iterable): the iterator whose value should be used.
getter (callable or None): a function to parse returned values
"""
def __init__(self, iterator, cycle=True, getter=None):
super(Iterator, self).__init__()
self.getter = getter
self.iterator = None
if cycle:
self.iterator_builder = lambda: utils.ResetableIterator(itertools.cycle(iterator))
else:
self.iterator_builder = lambda: utils.ResetableIterator(iterator)
def evaluate(self, sequence, obj, create, extra=None, containers=()):
# Begin unrolling as late as possible.
# This helps with ResetableIterator(MyModel.objects.all())
if self.iterator is None:
self.iterator = self.iterator_builder()
logger.debug("Iterator: Fetching next value from %r", self.iterator)
value = next(iter(self.iterator))
if self.getter is None:
return value
return self.getter(value)
[docs] def reset(self):
"""Reset the internal iterator."""
self.iterator.reset()
[docs]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=int): # pylint: disable=W0622
super(Sequence, self).__init__()
self.function = function
self.type = type
def evaluate(self, sequence, obj, create, extra=None, containers=()):
logger.debug("Sequence: Computing next value of %r for seq=%s", self.function, sequence)
return self.function(self.type(sequence))
[docs]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, create, extra=None, containers=()):
logger.debug("LazyAttributeSequence: Computing next value of %r for seq=%s, obj=%r",
self.function, sequence, obj)
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, create, extra=None, 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 ParameteredAttribute(OrderedDeclaration):
"""Base class for attributes expecting parameters.
Attributes:
defaults (dict): Default values for the paramters.
May be overridden by call-time parameters.
Class attributes:
CONTAINERS_FIELD (str): name of the field, if any, where container
information (e.g for SubFactory) should be stored. If empty,
containers data isn't merged into generate() parameters.
"""
CONTAINERS_FIELD = '__containers'
# Whether to add the current object to the stack of containers
EXTEND_CONTAINERS = False
def __init__(self, **kwargs):
super(ParameteredAttribute, self).__init__()
self.defaults = kwargs
def _prepare_containers(self, obj, containers=()):
if self.EXTEND_CONTAINERS:
return (obj,) + tuple(containers)
return containers
def evaluate(self, sequence, obj, create, extra=None, containers=()):
"""Evaluate the current definition and fill its attributes.
Uses attributes definition in the following order:
- values defined when defining the ParameteredAttribute
- additional values defined when instantiating the containing factory
Args:
create (bool): whether the parent factory is being 'built' or
'created'
extra (containers.DeclarationDict): extra values that should
override the 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)
if self.CONTAINERS_FIELD:
containers = self._prepare_containers(obj, containers)
defaults[self.CONTAINERS_FIELD] = containers
return self.generate(sequence, obj, create, defaults)
def generate(self, sequence, obj, create, params): # pragma: no cover
"""Actually generate the related attribute.
Args:
sequence (int): the current sequence number
obj (LazyStub): the object being constructed
create (bool): whether the calling factory was in 'create' or
'build' mode
params (dict): parameters inherited from init and evaluation-time
overrides.
Returns:
Computed value for the current declaration.
"""
raise NotImplementedError()
class _FactoryWrapper(object):
"""Handle a 'factory' arg.
Such args can be either a Factory subclass, or a fully qualified import
path for that subclass (e.g 'myapp.factories.MyFactory').
"""
def __init__(self, factory_or_path):
self.factory = None
self.module = self.name = ''
if isinstance(factory_or_path, type):
self.factory = factory_or_path
else:
if not (compat.is_string(factory_or_path) and '.' in factory_or_path):
raise ValueError(
"A factory= argument must receive either a class "
"or the fully qualified path to a Factory subclass; got "
"%r instead." % factory_or_path)
self.module, self.name = factory_or_path.rsplit('.', 1)
def get(self):
if self.factory is None:
self.factory = utils.import_object(
self.module,
self.name,
)
return self.factory
def __repr__(self):
if self.factory is None:
return '<_FactoryImport: %s.%s>' % (self.module, self.name)
else:
return '<_FactoryImport: %s>' % self.factory.__class__
[docs]class SubFactory(ParameteredAttribute):
"""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
"""
EXTEND_CONTAINERS = True
def __init__(self, factory, **kwargs):
super(SubFactory, self).__init__(**kwargs)
self.factory_wrapper = _FactoryWrapper(factory)
def get_factory(self):
"""Retrieve the wrapped factory.Factory subclass."""
return self.factory_wrapper.get()
def generate(self, sequence, obj, create, params):
"""Evaluate the current definition and fill its attributes.
Args:
create (bool): whether the subfactory should call 'build' or
'create'
params (containers.DeclarationDict): extra values that should
override the wrapped factory's defaults
"""
subfactory = self.get_factory()
logger.debug("SubFactory: Instantiating %s.%s(%s), create=%r",
subfactory.__module__, subfactory.__name__,
utils.log_pprint(kwargs=params),
create,
)
return subfactory.simple_generate(create, **params)
[docs]class Dict(SubFactory):
"""Fill a dict with usual declarations."""
def __init__(self, params, dict_factory='factory.DictFactory'):
super(Dict, self).__init__(dict_factory, **dict(params))
def generate(self, sequence, obj, create, params):
dict_factory = self.get_factory()
logger.debug("Dict: Building dict(%s)", utils.log_pprint(kwargs=params))
return dict_factory.simple_generate(create,
__sequence=sequence,
**params)
[docs]class List(SubFactory):
"""Fill a list with standard declarations."""
def __init__(self, params, list_factory='factory.ListFactory'):
params = dict((str(i), v) for i, v in enumerate(params))
super(List, self).__init__(list_factory, **params)
def generate(self, sequence, obj, create, params):
list_factory = self.get_factory()
logger.debug('List: Building list(%s)',
utils.log_pprint(args=[v for _i, v in sorted(params.items())]),
)
return list_factory.simple_generate(create,
__sequence=sequence,
**params)
class ExtractionContext(object):
"""Private class holding all required context from extraction to postgen."""
def __init__(self, value=None, did_extract=False, extra=None, for_field=''):
self.value = value
self.did_extract = did_extract
self.extra = extra or {}
self.for_field = for_field
def __repr__(self):
return 'ExtractionContext(%r, %r, %r)' % (
self.value,
self.did_extract,
self.extra,
)
class PostGenerationDeclaration(object):
"""Declarations to be called once the model object has been generated."""
def extract(self, name, attrs):
"""Extract relevant attributes from a dict.
Args:
name (str): the name at which this PostGenerationDeclaration was
defined in the declarations
attrs (dict): the attribute dict from which values should be
extracted
Returns:
(object, dict): a tuple containing the attribute at 'name' (if
provided) and a dict of extracted attributes
"""
try:
extracted = attrs.pop(name)
did_extract = True
except KeyError:
extracted = None
did_extract = False
kwargs = utils.extract_dict(name, attrs)
return ExtractionContext(extracted, did_extract, kwargs, name)
def call(self, obj, create, extraction_context): # pragma: no cover
"""Call this hook; no return value is expected.
Args:
obj (object): the newly generated object
create (bool): whether the object was 'built' or 'created'
extraction_context: An ExtractionContext containing values
extracted from the containing factory's declaration
"""
raise NotImplementedError()
[docs]class PostGeneration(PostGenerationDeclaration):
"""Calls a given function once the object has been generated."""
def __init__(self, function):
super(PostGeneration, self).__init__()
self.function = function
def call(self, obj, create, extraction_context):
logger.debug('PostGeneration: Calling %s.%s(%s)',
self.function.__module__,
self.function.__name__,
utils.log_pprint(
(obj, create, extraction_context.value),
extraction_context.extra,
),
)
return self.function(obj, create,
extraction_context.value, **extraction_context.extra)
[docs]class PostGenerationMethodCall(PostGenerationDeclaration):
"""Calls a method of the generated object.
Attributes:
method_name (str): the method to call
method_args (list): arguments to pass to the method
method_kwargs (dict): keyword arguments to pass to the method
Example:
class UserFactory(factory.Factory):
...
password = factory.PostGenerationMethodCall('set_pass', password='')
"""
def __init__(self, method_name, *args, **kwargs):
super(PostGenerationMethodCall, self).__init__()
self.method_name = method_name
self.method_args = args
self.method_kwargs = kwargs
def call(self, obj, create, extraction_context):
if not extraction_context.did_extract:
passed_args = self.method_args
elif len(self.method_args) <= 1:
# Max one argument expected
passed_args = (extraction_context.value,)
else:
passed_args = tuple(extraction_context.value)
passed_kwargs = dict(self.method_kwargs)
passed_kwargs.update(extraction_context.extra)
method = getattr(obj, self.method_name)
logger.debug('PostGenerationMethodCall: Calling %r.%s(%s)',
obj,
self.method_name,
utils.log_pprint(passed_args, passed_kwargs),
)
return method(*passed_args, **passed_kwargs)