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 _import_module(mod_str):
try:
if mod_str.startswith('bin.'):
imp.load_source(mod_str[4:], os.path.join('bin', mod_str[4:]))
return sys.modules[mod_str[4:]]
else:
return importutils.import_module(mod_str)
except ImportError as ie:
sys.stderr.write("%s\n" % str(ie))
return None
except Exception:
return None
def add_driver(notification_driver):
"""Add a notification driver at runtime."""
# Make sure the driver list is initialized.
_get_drivers()
if isinstance(notification_driver, basestring):
# Load and add
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)
else:
# Driver is already loaded; just add the object.
_drivers[notification_driver] = notification_driver
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)
def str_override(self):
return message
new_ex_type = type(ex_type.__name__ + "_Remote", (ex_type, ), {
'__str__': str_override,
'__unicode__': str_override
})
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
def __get_backend(self):
"""Get the actual backend. May be a module or an instance of
a class. Doesn't matter to us. We do this synchronized as it's
possible multiple greenthreads started very quickly trying to do
DB calls and eventlet can switch threads before self.__backend gets
assigned.
"""
if self.__backend:
# Another thread assigned it
return self.__backend
backend_name = CONF.database.backend
self.__use_tpool = CONF.database.use_tpool
if self.__use_tpool:
from eventlet import tpool
self.__tpool = tpool
# Import the untranslated name if we don't have a
# mapping.
backend_path = self.__backend_mapping.get(backend_name, backend_name)
backend_mod = importutils.import_module(backend_path)
self.__backend = backend_mod.get_backend()
return self.__backend