def deserialize_msg(msg):
# NOTE(russellb): Hang on to your hats, this road is about to
# get a little bumpy.
#
# Robustness Principle:
# "Be strict in what you send, liberal in what you accept."
#
# At this point we have to do a bit of guessing about what it
# is we just received. Here is the set of possibilities:
#
# 1) We received a dict. This could be 2 things:
#
# a) Inspect it to see if it looks like a standard message envelope.
# If so, great!
#
# b) If it doesn't look like a standard message envelope, it could either
# be a notification (which we don't wrap), or a message from before
# we added a message envelope (referred to as version 1.0).
# Just return the message as-is.
#
# 2) It's any other non-dict type. Just return it and hope for the best.
# This case covers return values from rpc.call() from before message
# envelopes were used. (messages to call a method were always a dict)
if not isinstance(msg, dict):
# See #2 above.
return msg
base_envelope_keys = (_VERSION_KEY, _MESSAGE_KEY)
if not all(map(lambda key: key in msg, base_envelope_keys)):
# See #1.b above.
return msg
# At this point we think we have the message envelope
# format we were expecting. (#1.a above)
if not version_is_compatible(_RPC_ENVELOPE_VERSION, msg[_VERSION_KEY]):
raise UnsupportedRpcEnvelopeVersion(version=msg[_VERSION_KEY])
raw_msg = jsonutils.loads(msg[_MESSAGE_KEY])
return raw_msg
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 not module 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('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", (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 _from_json(self, datastring):
try:
return jsonutils.loads(datastring)
except ValueError:
msg = _("cannot understand JSON")
raise exception.MalformedRequestBody(reason=msg)