1 files changed, 316 insertions, 0 deletions
diff --git a/openstack/common/rpc/common.py b/openstack/common/rpc/common.py
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+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# 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 openstack.common import cfg
+from openstack.common import importutils
+from openstack.common import jsonutils
+from openstack.common import local
+
+
+LOG = logging.getLogger(__name__)
+
+
+class RPCException(Exception):
+    message = _("An unknown RPC related exception occurred.")
+
+    def __init__(self, message=None, **kwargs):
+        self.kwargs = kwargs
+
+        if not message:
+            try:
+                message = self.message % kwargs
+
+            except Exception as e:
+                # 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 kwargs.iteritems():
+                    LOG.error("%s: %s" % (name, value))
+                # at least get the core message out if something happened
+                message = self.message
+
+        super(RPCException, self).__init__(message)
+
+
+class RemoteError(RPCException):
+    """Signifies that a remote class has raised an exception.
+
+    Contains a string representation of the type of the original exception,
+    the value of the original exception, and the traceback.  These are
+    sent to the parent as a joined string so printing the exception
+    contains all of the relevant info.
+
+    """
+    message = _("Remote error: %(exc_type)s %(value)s\n%(traceback)s.")
+
+    def __init__(self, exc_type=None, value=None, traceback=None):
+        self.exc_type = exc_type
+        self.value = value
+        self.traceback = traceback
+        super(RemoteError, self).__init__(exc_type=exc_type,
+                                          value=value,
+                                          traceback=traceback)
+
+
+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.
+    """
+    message = _("Timeout while waiting on RPC response.")
+
+
+class InvalidRPCConnectionReuse(RPCException):
+    message = _("Invalid reuse of an RPC connection.")
+
+
+class UnsupportedRpcVersion(RPCException):
+    message = _("Specified RPC version, %(version)s, not supported by "
+                "this endpoint.")
+
+
+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 create_consumer(self, conf, topic, proxy, fanout=False):
+        """Create a consumer on this connection.
+
+        A consumer is associated with a message queue on the backend message
+        bus.  The consumer will read messages from the queue, unpack them, and
+        dispatch them to the proxy object.  The contents of the message pulled
+        off of the queue will determine which method gets called on the proxy
+        object.
+
+        :param conf:  An openstack.common.cfg configuration object.
+        :param topic: This is a name associated with what to consume from.
+                      Multiple instances of a service may consume from the same
+                      topic. For example, all instances of nova-compute consume
+                      from a queue called "compute".  In that case, the
+                      messages will get distributed amongst the consumers in a
+                      round-robin fashion if fanout=False.  If fanout=True,
+                      every consumer associated with this topic will get a
+                      copy of every message.
+        :param proxy: The object that will handle all incoming messages.
+        :param fanout: Whether or not this is a fanout topic.  See the
+                       documentation for the topic parameter for some
+                       additional comments on this.
+        """
+        raise NotImplementedError()
+
+    def create_worker(self, conf, topic, proxy, pool_name):
+        """Create a worker on this connection.
+
+        A worker is like a regular consumer of messages directed to a
+        topic, except that it is part of a set of such consumers (the
+        "pool") which may run in parallel. Every pool of workers will
+        receive a given message, but only one worker in the pool will
+        be asked to process it. Load is distributed across the members
+        of the pool in round-robin fashion.
+
+        :param conf:  An openstack.common.cfg configuration object.
+        :param topic: This is a name associated with what to consume from.
+                      Multiple instances of a service may consume from the same
+                      topic.
+        :param proxy: The object that will handle all incoming messages.
+        :param pool_name: String containing the name of the pool of workers
+        """
+        raise NotImplementedError()
+
+    def consume_in_thread(self):
+        """Spawn a thread to handle incoming messages.
+
+        Spawn a thread that will be responsible for handling all incoming
+        messages for consumers that were set up on this connection.
+
+        Message dispatching inside of this is expected to be implemented in a
+        non-blocking manner.  An example implementation would be having this
+        thread pull messages in for all of the consumers, but utilize a thread
+        pool for dispatching the messages to the proxy objects.
+        """
+        raise NotImplementedError()
+
+
+def _safe_log(log_func, msg, msg_data):
+    """Sanitizes the msg_data field before logging."""
+    SANITIZE = {
+                'set_admin_password': ('new_pass',),
+                'run_instance': ('admin_password',),
+               }
+
+    has_method = 'method' in msg_data and msg_data['method'] in SANITIZE
+    has_context_token = '_context_auth_token' in msg_data
+    has_token = 'auth_token' in msg_data
+
+    if not any([has_method, has_context_token, has_token]):
+        return log_func(msg, msg_data)
+
+    msg_data = copy.deepcopy(msg_data)
+
+    if has_method:
+        method = msg_data['method']
+        if method in SANITIZE:
+            args_to_sanitize = SANITIZE[method]
+            for arg in args_to_sanitize:
+                try:
+                    msg_data['args'][arg] = "<SANITIZED>"
+                except KeyError:
+                    pass
+
+    if has_context_token:
+        msg_data['_context_auth_token'] = '<SANITIZED>'
+
+    if has_token:
+        msg_data['auth_token'] = '<SANITIZED>'
+
+    return log_func(msg, msg_data)
+
+
+def serialize_remote_exception(failure_info):
+    """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]
+    LOG.error(_("Returning exception %s to caller"), unicode(failure))
+    LOG.error(tb)
+
+    kwargs = {}
+    if hasattr(failure, 'kwargs'):
+        kwargs = failure.kwargs
+
+    data = {
+        'class': str(failure.__class__.__name__),
+        'module': str(failure.__class__.__module__),
+        'message': unicode(failure),
+        'tb': tb,
+        'args': failure.args,
+        'kwargs': kwargs
+    }
+
+    json_data = jsonutils.dumps(data)
+
+    return json_data
+
+
+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 as e:
+        # 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
+
+    def elevated(self, read_deleted=None, overwrite=False):
+        """Return a version of this context with admin flag set."""
+        # TODO(russellb) This method is a bit of a nova-ism.  It makes
+        # some assumptions about the data in the request context sent
+        # across rpc, while the rest of this class does not.  We could get
+        # rid of this if we changed the nova code that uses this to
+        # convert the RpcContext back to its native RequestContext doing
+        # something like nova.context.RequestContext.from_dict(ctxt.to_dict())
+
+        context = self.deepcopy()
+        context.values['is_admin'] = True
+
+        context.values.setdefault('roles', [])
+
+        if 'admin' not in context.values['roles']:
+            context.values['roles'].append('admin')
+
+        if read_deleted is not None:
+            context.values['read_deleted'] = read_deleted
+
+        return context