def mro(self):
if not self._is_resource(self.__name__, self.__bases__):
# Not a resource; perform the normal MRO.
return super(ResourceBase, self).mro()
# Retrieve the normal MRO.
mro = super(ResourceBase, self).mro()
# Remove all connectors from the mro.
for cls in list(mro):
if cls in connector_set:
mro.remove(cls)
# Attempt to resolve a list of connectors.
meta = self.__dict__.get('meta')
if meta:
cmap = CONNECTORS
for key, ref in six.iteritems(meta.connectors):
if key not in self.connectors:
continue
name = cmap[key]['resource'][0].format(ref)
module = utils.import_module(name)
if module:
klass = getattr(module, cmap[key]['resource'][1], None)
if klass:
# Found a connector class for this connector.
# Find where in the MRO it should go.
# It needs to go directly after the resource base
# for which it is a connector for.
for index, cls in enumerate(mro):
if key in getattr(cls, 'connectors', []):
break
# Let us forever know this is a connector class.
connector_set.update(set(klass.__mro__) - set(mro))
# Insert the connector class.
for cls in klass.__mro__:
if cls not in mro:
index += 1
mro.insert(index, cls)
# Return the constructed MRO.
return mro
def apply_connectors(meta, name, bases, metadata, base_meta):
# Apply the declared connectors. What this entails is inserting the
# connector base classes at the correct location in the base class list.
# The correct location would be directly before one of the base resource
# classes.
# What is not implemented (and will not be) is replacing existing
# connectors. You may have an inheritance chain of as many "abstract"
# resources as warranted but as soon as a connector is supplied on a
# non-abstract resource then that connector is "locked-in" so-to-speak.
# Order the connectors found in meta by the order declared above.
connectors = OrderedDict()
for key in reversed(CONNECTORS):
if key in meta.connectors:
connectors[key] = meta.connectors[key]
meta.connectors = connectors
# Iterate through the declared connectors.
cmap = CONNECTORS
new_bases = list(bases)
offset = 0
for key, ref in six.iteritems(meta.connectors):
try:
# Resolve an optional options class that may be provided by
# the connector.
options = utils.import_module(cmap[key]['options'][0].format(ref))
options = getattr(options, cmap[key]['options'][1])
options_instance = options(metadata, name, base_meta)
meta.__dict__.update(**options_instance.__dict__)
except (AttributeError, KeyError):
pass
try:
# Resolve the connector itself.
module = utils.import_module(cmap[key]['resource'][0].format(ref))
class_ = getattr(module, cmap[key]['resource'][1], None)
# Ensure the connector has not already been applied.
applied = False
for base in bases:
if issubclass(base, class_):
applied = True
if applied:
continue
# Find where to insert this connector.
module_key = 'armet.resources.%s' % cmap[key]['resource'][2]
module = utils.import_module(module_key)
armet_resource = getattr(module, cmap[key]['resource'][1])
for index, base in enumerate(bases):
if issubclass(base, armet_resource):
new_bases.insert(index + offset, class_)
offset += 1
break
except (AttributeError, KeyError):
pass
return tuple(new_bases)
def __new__(cls, name, bases, attrs):
if not cls._is_resource(name, bases):
# This is not an actual resource.
return super(ResourceBase, cls).__new__(cls, name, bases, attrs)
# Gather the attributes of all options classes.
# Start with the base configuration.
metadata = armet.use().copy()
values = lambda x: {n: getattr(x, n) for n in dir(x)}
# Expand the options class with the gathered metadata.
base_meta = []
cls._gather_metadata(base_meta, bases)
# Apply the configuration from each class in the chain.
for meta in base_meta:
metadata.update(**values(meta))
cur_meta = {}
if attrs.get('Meta'):
# Apply the configuration from the current class.
cur_meta = values(attrs['Meta'])
metadata.update(**cur_meta)
# Gather and construct the options object.
meta = attrs['meta'] = cls.options(metadata, name, cur_meta, base_meta)
# Construct the class object.
self = super(ResourceBase, cls).__new__(cls, name, bases, attrs)
# Generate a serializer map that maps media ranges to serializer
# names.
self._serializer_map = smap = {}
for key in self.meta.allowed_serializers:
serializer = self.meta.serializers[key]
for media_type in serializer.media_types:
smap[media_type] = key
# Generate a deserializer map that maps media ranges to deserializer
# names.
self._deserializer_map = dmap = {}
for key in self.meta.allowed_deserializers:
deserializer = self.meta.deserializers[key]
for media_type in deserializer.media_types:
dmap[media_type] = key
# Filter the available connectors according to the
# metaclass restriction set.
for key in list(meta.connectors.keys()):
if key not in cls.connectors:
del meta.connectors[key]
# Iterate through the available connectors.
iterator = six.iteritems(meta.connectors)
self.connectors = connectors = []
cmap = CONNECTORS
for key, ref in iterator:
options = utils.import_module(cmap[key]['options'][0].format(ref))
if options:
options = getattr(options, cmap[key]['options'][1], None)
if options:
# Available options to parse for this connector;
# instantiate the options class and apply all
# available options.
options_instance = options(metadata, name, base_meta)
meta.__dict__.update(**options_instance.__dict__)
module = utils.import_module(cmap[key]['resource'][0].format(ref))
if module:
klass = getattr(module, cmap[key]['resource'][1], None)
if klass:
# Found a connector class for this connector
connectors.append(klass)
# Return the constructed instance.
return self
