8da14f68d3
The decaying timer can now just use the functionality of the oslo_utils stop watch to avoid having to maintain similar information itself; now it just becomes a thin layer ontop of that object that provides its functionality. Change-Id: I1b014b821a6b980590ca5b4d850a515d55c42208
350 lines
12 KiB
Python
350 lines
12 KiB
Python
# Copyright 2010 United States Government as represented by the
|
|
# Administrator of the National Aeronautics and Space Administration.
|
|
# All Rights Reserved.
|
|
# Copyright 2011 Red Hat, Inc.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
|
# not use this file except in compliance with the License. You may obtain
|
|
# a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
# License for the specific language governing permissions and limitations
|
|
# under the License.
|
|
|
|
import copy
|
|
import logging
|
|
import sys
|
|
import traceback
|
|
|
|
from oslo_serialization import jsonutils
|
|
from oslo_utils import timeutils
|
|
import six
|
|
|
|
import oslo_messaging
|
|
from oslo_messaging._i18n import _
|
|
from oslo_messaging import _utils as utils
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
_EXCEPTIONS_MODULE = 'exceptions' if six.PY2 else 'builtins'
|
|
|
|
|
|
'''RPC Envelope Version.
|
|
|
|
This version number applies to the top level structure of messages sent out.
|
|
It does *not* apply to the message payload, which must be versioned
|
|
independently. For example, when using rpc APIs, a version number is applied
|
|
for changes to the API being exposed over rpc. This version number is handled
|
|
in the rpc proxy and dispatcher modules.
|
|
|
|
This version number applies to the message envelope that is used in the
|
|
serialization done inside the rpc layer. See serialize_msg() and
|
|
deserialize_msg().
|
|
|
|
The current message format (version 2.0) is very simple. It is:
|
|
|
|
{
|
|
'oslo.version': <RPC Envelope Version as a String>,
|
|
'oslo.message': <Application Message Payload, JSON encoded>
|
|
}
|
|
|
|
Message format version '1.0' is just considered to be the messages we sent
|
|
without a message envelope.
|
|
|
|
So, the current message envelope just includes the envelope version. It may
|
|
eventually contain additional information, such as a signature for the message
|
|
payload.
|
|
|
|
We will JSON encode the application message payload. The message envelope,
|
|
which includes the JSON encoded application message body, will be passed down
|
|
to the messaging libraries as a dict.
|
|
'''
|
|
_RPC_ENVELOPE_VERSION = '2.0'
|
|
|
|
_VERSION_KEY = 'oslo.version'
|
|
_MESSAGE_KEY = 'oslo.message'
|
|
|
|
_REMOTE_POSTFIX = '_Remote'
|
|
|
|
|
|
class RPCException(Exception):
|
|
msg_fmt = _("An unknown RPC related exception occurred.")
|
|
|
|
def __init__(self, message=None, **kwargs):
|
|
self.kwargs = kwargs
|
|
|
|
if not message:
|
|
try:
|
|
message = self.msg_fmt % kwargs
|
|
|
|
except Exception:
|
|
# kwargs doesn't match a variable in the message
|
|
# log the issue and the kwargs
|
|
LOG.exception(_('Exception in string format operation'))
|
|
for name, value in six.iteritems(kwargs):
|
|
LOG.error("%s: %s", name, value)
|
|
# at least get the core message out if something happened
|
|
message = self.msg_fmt
|
|
|
|
super(RPCException, self).__init__(message)
|
|
|
|
|
|
class Timeout(RPCException):
|
|
"""Signifies that a timeout has occurred.
|
|
|
|
This exception is raised if the rpc_response_timeout is reached while
|
|
waiting for a response from the remote side.
|
|
"""
|
|
msg_fmt = _('Timeout while waiting on RPC response - '
|
|
'topic: "%(topic)s", RPC method: "%(method)s" '
|
|
'info: "%(info)s"')
|
|
|
|
def __init__(self, info=None, topic=None, method=None):
|
|
"""Initiates Timeout object.
|
|
|
|
:param info: Extra info to convey to the user
|
|
:param topic: The topic that the rpc call was sent to
|
|
:param rpc_method_name: The name of the rpc method being
|
|
called
|
|
"""
|
|
self.info = info
|
|
self.topic = topic
|
|
self.method = method
|
|
super(Timeout, self).__init__(
|
|
None,
|
|
info=info or _('<unknown>'),
|
|
topic=topic or _('<unknown>'),
|
|
method=method or _('<unknown>'))
|
|
|
|
|
|
class DuplicateMessageError(RPCException):
|
|
msg_fmt = _("Found duplicate message(%(msg_id)s). Skipping it.")
|
|
|
|
|
|
class InvalidRPCConnectionReuse(RPCException):
|
|
msg_fmt = _("Invalid reuse of an RPC connection.")
|
|
|
|
|
|
class UnsupportedRpcVersion(RPCException):
|
|
msg_fmt = _("Specified RPC version, %(version)s, not supported by "
|
|
"this endpoint.")
|
|
|
|
|
|
class UnsupportedRpcEnvelopeVersion(RPCException):
|
|
msg_fmt = _("Specified RPC envelope version, %(version)s, "
|
|
"not supported by this endpoint.")
|
|
|
|
|
|
class RpcVersionCapError(RPCException):
|
|
msg_fmt = _("Specified RPC version cap, %(version_cap)s, is too low")
|
|
|
|
|
|
class Connection(object):
|
|
"""A connection, returned by rpc.create_connection().
|
|
|
|
This class represents a connection to the message bus used for rpc.
|
|
An instance of this class should never be created by users of the rpc API.
|
|
Use rpc.create_connection() instead.
|
|
"""
|
|
def close(self):
|
|
"""Close the connection.
|
|
|
|
This method must be called when the connection will no longer be used.
|
|
It will ensure that any resources associated with the connection, such
|
|
as a network connection, and cleaned up.
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
|
|
def serialize_remote_exception(failure_info, log_failure=True):
|
|
"""Prepares exception data to be sent over rpc.
|
|
|
|
Failure_info should be a sys.exc_info() tuple.
|
|
|
|
"""
|
|
tb = traceback.format_exception(*failure_info)
|
|
failure = failure_info[1]
|
|
if log_failure:
|
|
LOG.error(_("Returning exception %s to caller"),
|
|
six.text_type(failure))
|
|
LOG.error(tb)
|
|
|
|
kwargs = {}
|
|
if hasattr(failure, 'kwargs'):
|
|
kwargs = failure.kwargs
|
|
|
|
# NOTE(matiu): With cells, it's possible to re-raise remote, remote
|
|
# exceptions. Lets turn it back into the original exception type.
|
|
cls_name = six.text_type(failure.__class__.__name__)
|
|
mod_name = six.text_type(failure.__class__.__module__)
|
|
if (cls_name.endswith(_REMOTE_POSTFIX) and
|
|
mod_name.endswith(_REMOTE_POSTFIX)):
|
|
cls_name = cls_name[:-len(_REMOTE_POSTFIX)]
|
|
mod_name = mod_name[:-len(_REMOTE_POSTFIX)]
|
|
|
|
data = {
|
|
'class': cls_name,
|
|
'module': mod_name,
|
|
'message': six.text_type(failure),
|
|
'tb': tb,
|
|
'args': failure.args,
|
|
'kwargs': kwargs
|
|
}
|
|
|
|
json_data = jsonutils.dumps(data)
|
|
|
|
return json_data
|
|
|
|
|
|
def deserialize_remote_exception(data, allowed_remote_exmods):
|
|
failure = jsonutils.loads(six.text_type(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 != _EXCEPTIONS_MODULE and module not in allowed_remote_exmods:
|
|
return oslo_messaging.RemoteError(name, failure.get('message'), trace)
|
|
|
|
try:
|
|
__import__(module)
|
|
mod = sys.modules[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 oslo_messaging.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
|
|
|
|
|
|
class CommonRpcContext(object):
|
|
def __init__(self, **kwargs):
|
|
self.values = kwargs
|
|
|
|
def __getattr__(self, key):
|
|
try:
|
|
return self.values[key]
|
|
except KeyError:
|
|
raise AttributeError(key)
|
|
|
|
def to_dict(self):
|
|
return copy.deepcopy(self.values)
|
|
|
|
@classmethod
|
|
def from_dict(cls, values):
|
|
return cls(**values)
|
|
|
|
def deepcopy(self):
|
|
return self.from_dict(self.to_dict())
|
|
|
|
def update_store(self):
|
|
# local.store.context = self
|
|
pass
|
|
|
|
|
|
class ClientException(Exception):
|
|
"""Encapsulates actual exception expected to be hit by a RPC proxy object.
|
|
|
|
Merely instantiating it records the current exception information, which
|
|
will be passed back to the RPC client without exceptional logging.
|
|
"""
|
|
def __init__(self):
|
|
self._exc_info = sys.exc_info()
|
|
|
|
|
|
def serialize_msg(raw_msg):
|
|
# NOTE(russellb) See the docstring for _RPC_ENVELOPE_VERSION for more
|
|
# information about this format.
|
|
msg = {_VERSION_KEY: _RPC_ENVELOPE_VERSION,
|
|
_MESSAGE_KEY: jsonutils.dumps(raw_msg)}
|
|
|
|
return msg
|
|
|
|
|
|
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, 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 utils.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
|
|
|
|
|
|
class DecayingTimer(object):
|
|
def __init__(self, duration=None):
|
|
self._watch = timeutils.StopWatch(duration=duration)
|
|
|
|
def start(self):
|
|
self._watch.start()
|
|
|
|
def check_return(self, timeout_callback=None, *args, **kwargs):
|
|
maximum = kwargs.pop('maximum', None)
|
|
left = self._watch.leftover(return_none=True)
|
|
if left is None:
|
|
return maximum
|
|
if left <= 0 and timeout_callback is not None:
|
|
timeout_callback(*args, **kwargs)
|
|
return left if maximum is None else min(left, maximum)
|