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OpenStack Study: common.py**** CubicPower OpenStack Study ****
# 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 sys import traceback from oslo.config import cfg import six from neutron.openstack.common.gettextutils import _, _LE from neutron.openstack.common import importutils from neutron.openstack.common import jsonutils from neutron.openstack.common import local from neutron.openstack.common import log as logging from neutron.openstack.common import versionutils CONF = cfg.CONF LOG = logging.getLogger(__name__) _RPC_ENVELOPE_VERSION = '2.0' '''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': 'oslo.message': } 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. ''' _VERSION_KEY = 'oslo.version' _MESSAGE_KEY = 'oslo.message' _REMOTE_POSTFIX = '_Remote'
**** CubicPower OpenStack Study **** class RPCException(Exception): msg_fmt = _("An unknown RPC related exception occurred.")
**** CubicPower OpenStack Study **** 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(_LE('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)
**** CubicPower OpenStack Study **** 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. """ msg_fmt = _("Remote error: %(exc_type)s %(value)s\n%(traceback)s.")
**** CubicPower OpenStack Study **** 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)
**** CubicPower OpenStack Study **** 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"')
**** CubicPower OpenStack Study **** 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 _(' topic=topic or _(' method=method or _('
**** CubicPower OpenStack Study **** class DuplicateMessageError(RPCException): msg_fmt = _("Found duplicate message(%(msg_id)s). Skipping it.")
**** CubicPower OpenStack Study **** class InvalidRPCConnectionReuse(RPCException): msg_fmt = _("Invalid reuse of an RPC connection.")
**** CubicPower OpenStack Study **** class UnsupportedRpcVersion(RPCException): msg_fmt = _("Specified RPC version, %(version)s, not supported by " "this endpoint.")
**** CubicPower OpenStack Study **** class UnsupportedRpcEnvelopeVersion(RPCException): msg_fmt = _("Specified RPC envelope version, %(version)s, " "not supported by this endpoint.")
**** CubicPower OpenStack Study **** class RpcVersionCapError(RPCException): msg_fmt = _("Specified RPC version cap, %(version_cap)s, is too low")
**** CubicPower OpenStack Study **** 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. """
**** CubicPower OpenStack Study **** 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()
**** CubicPower OpenStack Study **** def create_consumer(self, 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 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()
**** CubicPower OpenStack Study **** def create_worker(self, 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 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()
**** CubicPower OpenStack Study **** def join_consumer_pool(self, callback, pool_name, topic, exchange_name): """Register as a member of a group of consumers. Uses given topic from the specified exchange. Exactly one member of a given pool will receive each message. A message will be delivered to multiple pools, if more than one is created. :param callback: Callable to be invoked for each message. :type callback: callable accepting one argument :param pool_name: The name of the consumer pool. :type pool_name: str :param topic: The routing topic for desired messages. :type topic: str :param exchange_name: The name of the message exchange where the client should attach. Defaults to the configured exchange. :type exchange_name: str """ raise NotImplementedError()
**** CubicPower OpenStack Study **** 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 = ['_context_auth_token', 'auth_token', 'new_pass']
**** CubicPower OpenStack Study **** def _safe_log(log_func, msg, msg_data): """Sanitizes the msg_data field before logging.""" SANITIZE = ['_context_auth_token', 'auth_token', 'new_pass']
**** CubicPower OpenStack Study **** def _fix_passwords(d): """Sanitizes the password fields in the dictionary.""" for k in six.iterkeys(d): if k.lower().find('password') != -1: d[k] = ' elif k.lower() in SANITIZE: d[k] = ' elif isinstance(d[k], list): for e in d[k]: if isinstance(e, dict): _fix_passwords(e) elif isinstance(d[k], dict): _fix_passwords(d[k]) return d return log_func(msg, _fix_passwords(copy.deepcopy(msg_data))) 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(_LE("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 = str(failure.__class__.__name__) mod_name = str(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(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) 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
**** CubicPower OpenStack Study **** 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(_LE("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 = str(failure.__class__.__name__) mod_name = str(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
**** CubicPower OpenStack Study **** 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) 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
**** CubicPower OpenStack Study **** class CommonRpcContext(object):
**** CubicPower OpenStack Study **** def __init__(self, **kwargs): self.values = kwargs
**** CubicPower OpenStack Study **** def __getattr__(self, key): try: return self.values[key] except KeyError: raise AttributeError(key)
**** CubicPower OpenStack Study **** def to_dict(self): return copy.deepcopy(self.values) @classmethod
**** CubicPower OpenStack Study **** def from_dict(cls, values): return cls(**values)
**** CubicPower OpenStack Study **** def deepcopy(self): return self.from_dict(self.to_dict())
**** CubicPower OpenStack Study **** def update_store(self): local.store.context = self
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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. """
**** CubicPower OpenStack Study **** def __init__(self): self._exc_info = sys.exc_info() def catch_client_exception(exceptions, func, *args, **kwargs): try: return func(*args, **kwargs) except Exception as e: if type(e) in exceptions: raise ClientException() else: raise def client_exceptions(*exceptions): """Decorator for manager methods that raise expected exceptions. Marking a Manager method with this decorator allows the declaration of expected exceptions that the RPC layer should not consider fatal, and not log as if they were generated in a real error scenario. Note that this will cause listed exceptions to be wrapped in a ClientException, which is used internally by the RPC layer. """
**** CubicPower OpenStack Study **** def catch_client_exception(exceptions, func, *args, **kwargs): try: return func(*args, **kwargs) except Exception as e: if type(e) in exceptions: raise ClientException() else: raise
**** CubicPower OpenStack Study **** def client_exceptions(*exceptions): """Decorator for manager methods that raise expected exceptions. Marking a Manager method with this decorator allows the declaration of expected exceptions that the RPC layer should not consider fatal, and not log as if they were generated in a real error scenario. Note that this will cause listed exceptions to be wrapped in a ClientException, which is used internally by the RPC layer. """
**** CubicPower OpenStack Study **** def outer(func): def inner(*args, **kwargs): return catch_client_exception(exceptions, func, *args, **kwargs) return inner return outer # TODO(sirp): we should deprecate this in favor of # using `versionutils.is_compatible` directly def version_is_compatible(imp_version, version): """Determine whether versions are compatible. :param imp_version: The version implemented :param version: The version requested by an incoming message. """ return versionutils.is_compatible(version, imp_version) 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 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
**** CubicPower OpenStack Study **** def inner(*args, **kwargs): return catch_client_exception(exceptions, func, *args, **kwargs) return inner return outer # TODO(sirp): we should deprecate this in favor of # using `versionutils.is_compatible` directly def version_is_compatible(imp_version, version): """Determine whether versions are compatible. :param imp_version: The version implemented :param version: The version requested by an incoming message. """ return versionutils.is_compatible(version, imp_version) 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 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
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