def _get_impl():
"""Delay import of rpc_backend until configuration is loaded."""
global _RPCIMPL
if _RPCIMPL is None:
try:
_RPCIMPL = importutils.import_module(CONF.rpc_backend)
except ImportError:
# For backwards compatibility with older nova config.
impl = CONF.rpc_backend.replace("nova.rpc", "nova.openstack.common.rpc")
_RPCIMPL = importutils.import_module(impl)
return _RPCIMPL
def _get_drivers():
"""Instantiate, cache, and return drivers based on the CONF."""
global _drivers
if _drivers is None:
_drivers = {}
for notification_driver in CONF.notification_driver:
try:
driver = importutils.import_module(notification_driver)
_drivers[notification_driver] = driver
except ImportError:
LOG.exception(_("Failed to load notifier %s. "
"These notifications will not be sent.") %
notification_driver)
return _drivers.values()
def deserialize_remote_exception(conf, data):
failure = jsonutils.loads(str(data))
trace = failure.get('tb', [])
message = failure.get('message', "") + "\n" + "\n".join(trace)
name = failure.get('class')
module = failure.get('module')
# NOTE(ameade): We DO NOT want to allow just any module to be imported, in
# order to prevent arbitrary code execution.
if module not in conf.allowed_rpc_exception_modules:
return RemoteError(name, failure.get('message'), trace)
try:
mod = importutils.import_module(module)
klass = getattr(mod, name)
if not issubclass(klass, Exception):
raise TypeError("Can only deserialize Exceptions")
failure = klass(*failure.get('args', []), **failure.get('kwargs', {}))
except (AttributeError, TypeError, ImportError):
return RemoteError(name, failure.get('message'), trace)
ex_type = type(failure)
str_override = lambda self: message
new_ex_type = type(ex_type.__name__ + _REMOTE_POSTFIX, (ex_type,),
{'__str__': str_override, '__unicode__': str_override})
new_ex_type.__module__ = '%s%s' % (module, _REMOTE_POSTFIX)
try:
# NOTE(ameade): Dynamically create a new exception type and swap it in
# as the new type for the exception. This only works on user defined
# Exceptions and not core python exceptions. This is important because
# we cannot necessarily change an exception message so we must override
# the __str__ method.
failure.__class__ = new_ex_type
except TypeError:
# NOTE(ameade): If a core exception then just add the traceback to the
# first exception argument.
failure.args = (message,) + failure.args[1:]
return failure