498 lines
18 KiB
Python
498 lines
18 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# All Rights Reserved.
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# Copyright 2011 Red Hat, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import copy
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import sys
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import traceback
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from oslo.config import cfg
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from quantum.openstack.common.gettextutils import _
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from quantum.openstack.common import importutils
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from quantum.openstack.common import jsonutils
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from quantum.openstack.common import local
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from quantum.openstack.common import log as logging
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CONF = cfg.CONF
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LOG = logging.getLogger(__name__)
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'''RPC Envelope Version.
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This version number applies to the top level structure of messages sent out.
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It does *not* apply to the message payload, which must be versioned
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independently. For example, when using rpc APIs, a version number is applied
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for changes to the API being exposed over rpc. This version number is handled
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in the rpc proxy and dispatcher modules.
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This version number applies to the message envelope that is used in the
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serialization done inside the rpc layer. See serialize_msg() and
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deserialize_msg().
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The current message format (version 2.0) is very simple. It is:
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{
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'oslo.version': <RPC Envelope Version as a String>,
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'oslo.message': <Application Message Payload, JSON encoded>
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}
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Message format version '1.0' is just considered to be the messages we sent
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without a message envelope.
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So, the current message envelope just includes the envelope version. It may
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eventually contain additional information, such as a signature for the message
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payload.
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We will JSON encode the application message payload. The message envelope,
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which includes the JSON encoded application message body, will be passed down
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to the messaging libraries as a dict.
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'''
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_RPC_ENVELOPE_VERSION = '2.0'
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_VERSION_KEY = 'oslo.version'
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_MESSAGE_KEY = 'oslo.message'
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# TODO(russellb) Turn this on after Grizzly.
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_SEND_RPC_ENVELOPE = False
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class RPCException(Exception):
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message = _("An unknown RPC related exception occurred.")
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def __init__(self, message=None, **kwargs):
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self.kwargs = kwargs
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if not message:
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try:
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message = self.message % kwargs
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except Exception:
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# kwargs doesn't match a variable in the message
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# log the issue and the kwargs
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LOG.exception(_('Exception in string format operation'))
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for name, value in kwargs.iteritems():
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LOG.error("%s: %s" % (name, value))
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# at least get the core message out if something happened
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message = self.message
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super(RPCException, self).__init__(message)
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class RemoteError(RPCException):
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"""Signifies that a remote class has raised an exception.
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Contains a string representation of the type of the original exception,
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the value of the original exception, and the traceback. These are
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sent to the parent as a joined string so printing the exception
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contains all of the relevant info.
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"""
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message = _("Remote error: %(exc_type)s %(value)s\n%(traceback)s.")
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def __init__(self, exc_type=None, value=None, traceback=None):
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self.exc_type = exc_type
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self.value = value
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self.traceback = traceback
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super(RemoteError, self).__init__(exc_type=exc_type,
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value=value,
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traceback=traceback)
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class Timeout(RPCException):
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"""Signifies that a timeout has occurred.
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This exception is raised if the rpc_response_timeout is reached while
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waiting for a response from the remote side.
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"""
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message = _("Timeout while waiting on RPC response.")
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class DuplicateMessageError(RPCException):
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message = _("Found duplicate message(%(msg_id)s). Skipping it.")
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class InvalidRPCConnectionReuse(RPCException):
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message = _("Invalid reuse of an RPC connection.")
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class UnsupportedRpcVersion(RPCException):
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message = _("Specified RPC version, %(version)s, not supported by "
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"this endpoint.")
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class UnsupportedRpcEnvelopeVersion(RPCException):
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message = _("Specified RPC envelope version, %(version)s, "
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"not supported by this endpoint.")
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class Connection(object):
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"""A connection, returned by rpc.create_connection().
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This class represents a connection to the message bus used for rpc.
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An instance of this class should never be created by users of the rpc API.
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Use rpc.create_connection() instead.
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"""
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def close(self):
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"""Close the connection.
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This method must be called when the connection will no longer be used.
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It will ensure that any resources associated with the connection, such
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as a network connection, and cleaned up.
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"""
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raise NotImplementedError()
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def create_consumer(self, topic, proxy, fanout=False):
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"""Create a consumer on this connection.
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A consumer is associated with a message queue on the backend message
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bus. The consumer will read messages from the queue, unpack them, and
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dispatch them to the proxy object. The contents of the message pulled
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off of the queue will determine which method gets called on the proxy
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object.
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:param topic: This is a name associated with what to consume from.
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Multiple instances of a service may consume from the same
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topic. For example, all instances of nova-compute consume
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from a queue called "compute". In that case, the
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messages will get distributed amongst the consumers in a
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round-robin fashion if fanout=False. If fanout=True,
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every consumer associated with this topic will get a
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copy of every message.
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:param proxy: The object that will handle all incoming messages.
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:param fanout: Whether or not this is a fanout topic. See the
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documentation for the topic parameter for some
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additional comments on this.
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"""
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raise NotImplementedError()
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def create_worker(self, topic, proxy, pool_name):
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"""Create a worker on this connection.
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A worker is like a regular consumer of messages directed to a
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topic, except that it is part of a set of such consumers (the
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"pool") which may run in parallel. Every pool of workers will
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receive a given message, but only one worker in the pool will
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be asked to process it. Load is distributed across the members
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of the pool in round-robin fashion.
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:param topic: This is a name associated with what to consume from.
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Multiple instances of a service may consume from the same
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topic.
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:param proxy: The object that will handle all incoming messages.
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:param pool_name: String containing the name of the pool of workers
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"""
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raise NotImplementedError()
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def join_consumer_pool(self, callback, pool_name, topic, exchange_name):
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"""Register as a member of a group of consumers for a given topic from
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the specified exchange.
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Exactly one member of a given pool will receive each message.
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A message will be delivered to multiple pools, if more than
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one is created.
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:param callback: Callable to be invoked for each message.
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:type callback: callable accepting one argument
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:param pool_name: The name of the consumer pool.
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:type pool_name: str
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:param topic: The routing topic for desired messages.
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:type topic: str
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:param exchange_name: The name of the message exchange where
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the client should attach. Defaults to
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the configured exchange.
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:type exchange_name: str
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"""
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raise NotImplementedError()
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def consume_in_thread(self):
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"""Spawn a thread to handle incoming messages.
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Spawn a thread that will be responsible for handling all incoming
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messages for consumers that were set up on this connection.
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Message dispatching inside of this is expected to be implemented in a
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non-blocking manner. An example implementation would be having this
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thread pull messages in for all of the consumers, but utilize a thread
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pool for dispatching the messages to the proxy objects.
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"""
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raise NotImplementedError()
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def _safe_log(log_func, msg, msg_data):
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"""Sanitizes the msg_data field before logging."""
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SANITIZE = {'set_admin_password': [('args', 'new_pass')],
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'run_instance': [('args', 'admin_password')],
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'route_message': [('args', 'message', 'args', 'method_info',
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'method_kwargs', 'password'),
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('args', 'message', 'args', 'method_info',
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'method_kwargs', 'admin_password')]}
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has_method = 'method' in msg_data and msg_data['method'] in SANITIZE
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has_context_token = '_context_auth_token' in msg_data
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has_token = 'auth_token' in msg_data
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if not any([has_method, has_context_token, has_token]):
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return log_func(msg, msg_data)
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msg_data = copy.deepcopy(msg_data)
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if has_method:
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for arg in SANITIZE.get(msg_data['method'], []):
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try:
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d = msg_data
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for elem in arg[:-1]:
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d = d[elem]
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d[arg[-1]] = '<SANITIZED>'
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except KeyError, e:
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LOG.info(_('Failed to sanitize %(item)s. Key error %(err)s'),
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{'item': arg,
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'err': e})
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if has_context_token:
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msg_data['_context_auth_token'] = '<SANITIZED>'
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if has_token:
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msg_data['auth_token'] = '<SANITIZED>'
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return log_func(msg, msg_data)
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def serialize_remote_exception(failure_info, log_failure=True):
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"""Prepares exception data to be sent over rpc.
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Failure_info should be a sys.exc_info() tuple.
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"""
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tb = traceback.format_exception(*failure_info)
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failure = failure_info[1]
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if log_failure:
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LOG.error(_("Returning exception %s to caller"), unicode(failure))
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LOG.error(tb)
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kwargs = {}
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if hasattr(failure, 'kwargs'):
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kwargs = failure.kwargs
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data = {
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'class': str(failure.__class__.__name__),
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'module': str(failure.__class__.__module__),
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'message': unicode(failure),
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'tb': tb,
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'args': failure.args,
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'kwargs': kwargs
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}
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json_data = jsonutils.dumps(data)
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return json_data
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def deserialize_remote_exception(conf, data):
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failure = jsonutils.loads(str(data))
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trace = failure.get('tb', [])
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message = failure.get('message', "") + "\n" + "\n".join(trace)
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name = failure.get('class')
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module = failure.get('module')
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# NOTE(ameade): We DO NOT want to allow just any module to be imported, in
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# order to prevent arbitrary code execution.
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if module not in conf.allowed_rpc_exception_modules:
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return RemoteError(name, failure.get('message'), trace)
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try:
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mod = importutils.import_module(module)
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klass = getattr(mod, name)
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if not issubclass(klass, Exception):
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raise TypeError("Can only deserialize Exceptions")
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failure = klass(**failure.get('kwargs', {}))
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except (AttributeError, TypeError, ImportError):
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return RemoteError(name, failure.get('message'), trace)
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ex_type = type(failure)
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str_override = lambda self: message
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new_ex_type = type(ex_type.__name__ + "_Remote", (ex_type,),
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{'__str__': str_override, '__unicode__': str_override})
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try:
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# NOTE(ameade): Dynamically create a new exception type and swap it in
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# as the new type for the exception. This only works on user defined
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# Exceptions and not core python exceptions. This is important because
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# we cannot necessarily change an exception message so we must override
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# the __str__ method.
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failure.__class__ = new_ex_type
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except TypeError:
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# NOTE(ameade): If a core exception then just add the traceback to the
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# first exception argument.
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failure.args = (message,) + failure.args[1:]
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return failure
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class CommonRpcContext(object):
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def __init__(self, **kwargs):
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self.values = kwargs
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def __getattr__(self, key):
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try:
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return self.values[key]
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except KeyError:
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raise AttributeError(key)
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def to_dict(self):
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return copy.deepcopy(self.values)
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@classmethod
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def from_dict(cls, values):
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return cls(**values)
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def deepcopy(self):
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return self.from_dict(self.to_dict())
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def update_store(self):
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local.store.context = self
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def elevated(self, read_deleted=None, overwrite=False):
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"""Return a version of this context with admin flag set."""
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# TODO(russellb) This method is a bit of a nova-ism. It makes
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# some assumptions about the data in the request context sent
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# across rpc, while the rest of this class does not. We could get
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# rid of this if we changed the nova code that uses this to
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# convert the RpcContext back to its native RequestContext doing
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# something like nova.context.RequestContext.from_dict(ctxt.to_dict())
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context = self.deepcopy()
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context.values['is_admin'] = True
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context.values.setdefault('roles', [])
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if 'admin' not in context.values['roles']:
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context.values['roles'].append('admin')
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if read_deleted is not None:
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context.values['read_deleted'] = read_deleted
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return context
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class ClientException(Exception):
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"""This encapsulates some actual exception that is expected to be
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hit by an RPC proxy object. Merely instantiating it records the
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current exception information, which will be passed back to the
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RPC client without exceptional logging."""
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def __init__(self):
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self._exc_info = sys.exc_info()
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def catch_client_exception(exceptions, func, *args, **kwargs):
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try:
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return func(*args, **kwargs)
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except Exception, e:
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if type(e) in exceptions:
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raise ClientException()
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else:
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raise
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def client_exceptions(*exceptions):
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"""Decorator for manager methods that raise expected exceptions.
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Marking a Manager method with this decorator allows the declaration
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of expected exceptions that the RPC layer should not consider fatal,
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and not log as if they were generated in a real error scenario. Note
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that this will cause listed exceptions to be wrapped in a
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ClientException, which is used internally by the RPC layer."""
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def outer(func):
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def inner(*args, **kwargs):
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return catch_client_exception(exceptions, func, *args, **kwargs)
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return inner
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return outer
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def version_is_compatible(imp_version, version):
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"""Determine whether versions are compatible.
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:param imp_version: The version implemented
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:param version: The version requested by an incoming message.
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"""
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version_parts = version.split('.')
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imp_version_parts = imp_version.split('.')
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if int(version_parts[0]) != int(imp_version_parts[0]): # Major
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return False
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if int(version_parts[1]) > int(imp_version_parts[1]): # Minor
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return False
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return True
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def serialize_msg(raw_msg, force_envelope=False):
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if not _SEND_RPC_ENVELOPE and not force_envelope:
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return raw_msg
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# NOTE(russellb) See the docstring for _RPC_ENVELOPE_VERSION for more
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# information about this format.
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msg = {_VERSION_KEY: _RPC_ENVELOPE_VERSION,
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_MESSAGE_KEY: jsonutils.dumps(raw_msg)}
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return msg
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def deserialize_msg(msg):
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# NOTE(russellb): Hang on to your hats, this road is about to
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# get a little bumpy.
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#
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# Robustness Principle:
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# "Be strict in what you send, liberal in what you accept."
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#
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# At this point we have to do a bit of guessing about what it
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# is we just received. Here is the set of possibilities:
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#
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# 1) We received a dict. This could be 2 things:
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#
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# a) Inspect it to see if it looks like a standard message envelope.
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# If so, great!
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#
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# b) If it doesn't look like a standard message envelope, it could either
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# be a notification, or a message from before we added a message
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# envelope (referred to as version 1.0).
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# Just return the message as-is.
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#
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# 2) It's any other non-dict type. Just return it and hope for the best.
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# This case covers return values from rpc.call() from before message
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# envelopes were used. (messages to call a method were always a dict)
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if not isinstance(msg, dict):
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# See #2 above.
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return msg
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base_envelope_keys = (_VERSION_KEY, _MESSAGE_KEY)
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if not all(map(lambda key: key in msg, base_envelope_keys)):
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# See #1.b above.
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return msg
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# At this point we think we have the message envelope
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# format we were expecting. (#1.a above)
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if not version_is_compatible(_RPC_ENVELOPE_VERSION, msg[_VERSION_KEY]):
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raise UnsupportedRpcEnvelopeVersion(version=msg[_VERSION_KEY])
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raw_msg = jsonutils.loads(msg[_MESSAGE_KEY])
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return raw_msg
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