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Diffstat (limited to 'keystone/openstack/common/rpc/amqp.py')
| -rw-r--r-- | keystone/openstack/common/rpc/amqp.py | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/keystone/openstack/common/rpc/amqp.py b/keystone/openstack/common/rpc/amqp.py new file mode 100644 index 00000000..3bcedbdb --- /dev/null +++ b/keystone/openstack/common/rpc/amqp.py @@ -0,0 +1,615 @@ +# 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 - 2012, 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. + +""" +Shared code between AMQP based openstack.common.rpc implementations. + +The code in this module is shared between the rpc implemenations based on AMQP. +Specifically, this includes impl_kombu and impl_qpid. impl_carrot also uses +AMQP, but is deprecated and predates this code. +""" + +import collections +import inspect +import sys +import uuid + +from eventlet import greenpool +from eventlet import pools +from eventlet import queue +from eventlet import semaphore +from oslo.config import cfg + +from keystone.openstack.common import excutils +from keystone.openstack.common.gettextutils import _ # noqa +from keystone.openstack.common import local +from keystone.openstack.common import log as logging +from keystone.openstack.common.rpc import common as rpc_common + + +amqp_opts = [ + cfg.BoolOpt('amqp_durable_queues', + default=False, + deprecated_name='rabbit_durable_queues', + deprecated_group='DEFAULT', + help='Use durable queues in amqp.'), + cfg.BoolOpt('amqp_auto_delete', + default=False, + help='Auto-delete queues in amqp.'), +] + +cfg.CONF.register_opts(amqp_opts) + +UNIQUE_ID = '_unique_id' +LOG = logging.getLogger(__name__) + + +class Pool(pools.Pool): + """Class that implements a Pool of Connections.""" + def __init__(self, conf, connection_cls, *args, **kwargs): + self.connection_cls = connection_cls + self.conf = conf + kwargs.setdefault("max_size", self.conf.rpc_conn_pool_size) + kwargs.setdefault("order_as_stack", True) + super(Pool, self).__init__(*args, **kwargs) + self.reply_proxy = None + + # TODO(comstud): Timeout connections not used in a while + def create(self): + LOG.debug(_('Pool creating new connection')) + return self.connection_cls(self.conf) + + def empty(self): + while self.free_items: + self.get().close() + # Force a new connection pool to be created. + # Note that this was added due to failing unit test cases. The issue + # is the above "while loop" gets all the cached connections from the + # pool and closes them, but never returns them to the pool, a pool + # leak. The unit tests hang waiting for an item to be returned to the + # pool. The unit tests get here via the tearDown() method. In the run + # time code, it gets here via cleanup() and only appears in service.py + # just before doing a sys.exit(), so cleanup() only happens once and + # the leakage is not a problem. + self.connection_cls.pool = None + + +_pool_create_sem = semaphore.Semaphore() + + +def get_connection_pool(conf, connection_cls): + with _pool_create_sem: + # Make sure only one thread tries to create the connection pool. + if not connection_cls.pool: + connection_cls.pool = Pool(conf, connection_cls) + return connection_cls.pool + + +class ConnectionContext(rpc_common.Connection): + """The class that is actually returned to the create_connection() caller. + + This is essentially a wrapper around Connection that supports 'with'. + It can also return a new Connection, or one from a pool. + + The function will also catch when an instance of this class is to be + deleted. With that we can return Connections to the pool on exceptions + and so forth without making the caller be responsible for catching them. + If possible the function makes sure to return a connection to the pool. + """ + + def __init__(self, conf, connection_pool, pooled=True, server_params=None): + """Create a new connection, or get one from the pool.""" + self.connection = None + self.conf = conf + self.connection_pool = connection_pool + if pooled: + self.connection = connection_pool.get() + else: + self.connection = connection_pool.connection_cls( + conf, + server_params=server_params) + self.pooled = pooled + + def __enter__(self): + """When with ConnectionContext() is used, return self.""" + return self + + def _done(self): + """If the connection came from a pool, clean it up and put it back. + If it did not come from a pool, close it. + """ + if self.connection: + if self.pooled: + # Reset the connection so it's ready for the next caller + # to grab from the pool + self.connection.reset() + self.connection_pool.put(self.connection) + else: + try: + self.connection.close() + except Exception: + pass + self.connection = None + + def __exit__(self, exc_type, exc_value, tb): + """End of 'with' statement. We're done here.""" + self._done() + + def __del__(self): + """Caller is done with this connection. Make sure we cleaned up.""" + self._done() + + def close(self): + """Caller is done with this connection.""" + self._done() + + def create_consumer(self, topic, proxy, fanout=False): + self.connection.create_consumer(topic, proxy, fanout) + + def create_worker(self, topic, proxy, pool_name): + self.connection.create_worker(topic, proxy, pool_name) + + def join_consumer_pool(self, callback, pool_name, topic, exchange_name, + ack_on_error=True): + self.connection.join_consumer_pool(callback, + pool_name, + topic, + exchange_name, + ack_on_error) + + def consume_in_thread(self): + self.connection.consume_in_thread() + + def __getattr__(self, key): + """Proxy all other calls to the Connection instance.""" + if self.connection: + return getattr(self.connection, key) + else: + raise rpc_common.InvalidRPCConnectionReuse() + + +class ReplyProxy(ConnectionContext): + """Connection class for RPC replies / callbacks.""" + def __init__(self, conf, connection_pool): + self._call_waiters = {} + self._num_call_waiters = 0 + self._num_call_waiters_wrn_threshhold = 10 + self._reply_q = 'reply_' + uuid.uuid4().hex + super(ReplyProxy, self).__init__(conf, connection_pool, pooled=False) + self.declare_direct_consumer(self._reply_q, self._process_data) + self.consume_in_thread() + + def _process_data(self, message_data): + msg_id = message_data.pop('_msg_id', None) + waiter = self._call_waiters.get(msg_id) + if not waiter: + LOG.warn(_('No calling threads waiting for msg_id : %(msg_id)s' + ', message : %(data)s'), {'msg_id': msg_id, + 'data': message_data}) + LOG.warn(_('_call_waiters: %s') % str(self._call_waiters)) + else: + waiter.put(message_data) + + def add_call_waiter(self, waiter, msg_id): + self._num_call_waiters += 1 + if self._num_call_waiters > self._num_call_waiters_wrn_threshhold: + LOG.warn(_('Number of call waiters is greater than warning ' + 'threshhold: %d. There could be a MulticallProxyWaiter ' + 'leak.') % self._num_call_waiters_wrn_threshhold) + self._num_call_waiters_wrn_threshhold *= 2 + self._call_waiters[msg_id] = waiter + + def del_call_waiter(self, msg_id): + self._num_call_waiters -= 1 + del self._call_waiters[msg_id] + + def get_reply_q(self): + return self._reply_q + + +def msg_reply(conf, msg_id, reply_q, connection_pool, reply=None, + failure=None, ending=False, log_failure=True): + """Sends a reply or an error on the channel signified by msg_id. + + Failure should be a sys.exc_info() tuple. + + """ + with ConnectionContext(conf, connection_pool) as conn: + if failure: + failure = rpc_common.serialize_remote_exception(failure, + log_failure) + + msg = {'result': reply, 'failure': failure} + if ending: + msg['ending'] = True + _add_unique_id(msg) + # If a reply_q exists, add the msg_id to the reply and pass the + # reply_q to direct_send() to use it as the response queue. + # Otherwise use the msg_id for backward compatibilty. + if reply_q: + msg['_msg_id'] = msg_id + conn.direct_send(reply_q, rpc_common.serialize_msg(msg)) + else: + conn.direct_send(msg_id, rpc_common.serialize_msg(msg)) + + +class RpcContext(rpc_common.CommonRpcContext): + """Context that supports replying to a rpc.call.""" + def __init__(self, **kwargs): + self.msg_id = kwargs.pop('msg_id', None) + self.reply_q = kwargs.pop('reply_q', None) + self.conf = kwargs.pop('conf') + super(RpcContext, self).__init__(**kwargs) + + def deepcopy(self): + values = self.to_dict() + values['conf'] = self.conf + values['msg_id'] = self.msg_id + values['reply_q'] = self.reply_q + return self.__class__(**values) + + def reply(self, reply=None, failure=None, ending=False, + connection_pool=None, log_failure=True): + if self.msg_id: + msg_reply(self.conf, self.msg_id, self.reply_q, connection_pool, + reply, failure, ending, log_failure) + if ending: + self.msg_id = None + + +def unpack_context(conf, msg): + """Unpack context from msg.""" + context_dict = {} + for key in list(msg.keys()): + # NOTE(vish): Some versions of python don't like unicode keys + # in kwargs. + key = str(key) + if key.startswith('_context_'): + value = msg.pop(key) + context_dict[key[9:]] = value + context_dict['msg_id'] = msg.pop('_msg_id', None) + context_dict['reply_q'] = msg.pop('_reply_q', None) + context_dict['conf'] = conf + ctx = RpcContext.from_dict(context_dict) + rpc_common._safe_log(LOG.debug, _('unpacked context: %s'), ctx.to_dict()) + return ctx + + +def pack_context(msg, context): + """Pack context into msg. + + Values for message keys need to be less than 255 chars, so we pull + context out into a bunch of separate keys. If we want to support + more arguments in rabbit messages, we may want to do the same + for args at some point. + + """ + if isinstance(context, dict): + context_d = dict([('_context_%s' % key, value) + for (key, value) in context.iteritems()]) + else: + context_d = dict([('_context_%s' % key, value) + for (key, value) in context.to_dict().iteritems()]) + + msg.update(context_d) + + +class _MsgIdCache(object): + """This class checks any duplicate messages.""" + + # NOTE: This value is considered can be a configuration item, but + # it is not necessary to change its value in most cases, + # so let this value as static for now. + DUP_MSG_CHECK_SIZE = 16 + + def __init__(self, **kwargs): + self.prev_msgids = collections.deque([], + maxlen=self.DUP_MSG_CHECK_SIZE) + + def check_duplicate_message(self, message_data): + """AMQP consumers may read same message twice when exceptions occur + before ack is returned. This method prevents doing it. + """ + if UNIQUE_ID in message_data: + msg_id = message_data[UNIQUE_ID] + if msg_id not in self.prev_msgids: + self.prev_msgids.append(msg_id) + else: + raise rpc_common.DuplicateMessageError(msg_id=msg_id) + + +def _add_unique_id(msg): + """Add unique_id for checking duplicate messages.""" + unique_id = uuid.uuid4().hex + msg.update({UNIQUE_ID: unique_id}) + LOG.debug(_('UNIQUE_ID is %s.') % (unique_id)) + + +class _ThreadPoolWithWait(object): + """Base class for a delayed invocation manager. + + Used by the Connection class to start up green threads + to handle incoming messages. + """ + + def __init__(self, conf, connection_pool): + self.pool = greenpool.GreenPool(conf.rpc_thread_pool_size) + self.connection_pool = connection_pool + self.conf = conf + + def wait(self): + """Wait for all callback threads to exit.""" + self.pool.waitall() + + +class CallbackWrapper(_ThreadPoolWithWait): + """Wraps a straight callback. + + Allows it to be invoked in a green thread. + """ + + def __init__(self, conf, callback, connection_pool): + """Initiates CallbackWrapper object. + + :param conf: cfg.CONF instance + :param callback: a callable (probably a function) + :param connection_pool: connection pool as returned by + get_connection_pool() + """ + super(CallbackWrapper, self).__init__( + conf=conf, + connection_pool=connection_pool, + ) + self.callback = callback + + def __call__(self, message_data): + self.pool.spawn_n(self.callback, message_data) + + +class ProxyCallback(_ThreadPoolWithWait): + """Calls methods on a proxy object based on method and args.""" + + def __init__(self, conf, proxy, connection_pool): + super(ProxyCallback, self).__init__( + conf=conf, + connection_pool=connection_pool, + ) + self.proxy = proxy + self.msg_id_cache = _MsgIdCache() + + def __call__(self, message_data): + """Consumer callback to call a method on a proxy object. + + Parses the message for validity and fires off a thread to call the + proxy object method. + + Message data should be a dictionary with two keys: + method: string representing the method to call + args: dictionary of arg: value + + Example: {'method': 'echo', 'args': {'value': 42}} + + """ + # It is important to clear the context here, because at this point + # the previous context is stored in local.store.context + if hasattr(local.store, 'context'): + del local.store.context + rpc_common._safe_log(LOG.debug, _('received %s'), message_data) + self.msg_id_cache.check_duplicate_message(message_data) + ctxt = unpack_context(self.conf, message_data) + method = message_data.get('method') + args = message_data.get('args', {}) + version = message_data.get('version') + namespace = message_data.get('namespace') + if not method: + LOG.warn(_('no method for message: %s') % message_data) + ctxt.reply(_('No method for message: %s') % message_data, + connection_pool=self.connection_pool) + return + self.pool.spawn_n(self._process_data, ctxt, version, method, + namespace, args) + + def _process_data(self, ctxt, version, method, namespace, args): + """Process a message in a new thread. + + If the proxy object we have has a dispatch method + (see rpc.dispatcher.RpcDispatcher), pass it the version, + method, and args and let it dispatch as appropriate. If not, use + the old behavior of magically calling the specified method on the + proxy we have here. + """ + ctxt.update_store() + try: + rval = self.proxy.dispatch(ctxt, version, method, namespace, + **args) + # Check if the result was a generator + if inspect.isgenerator(rval): + for x in rval: + ctxt.reply(x, None, connection_pool=self.connection_pool) + else: + ctxt.reply(rval, None, connection_pool=self.connection_pool) + # This final None tells multicall that it is done. + ctxt.reply(ending=True, connection_pool=self.connection_pool) + except rpc_common.ClientException as e: + LOG.debug(_('Expected exception during message handling (%s)') % + e._exc_info[1]) + ctxt.reply(None, e._exc_info, + connection_pool=self.connection_pool, + log_failure=False) + except Exception: + # sys.exc_info() is deleted by LOG.exception(). + exc_info = sys.exc_info() + LOG.error(_('Exception during message handling'), + exc_info=exc_info) + ctxt.reply(None, exc_info, connection_pool=self.connection_pool) + + +class MulticallProxyWaiter(object): + def __init__(self, conf, msg_id, timeout, connection_pool): + self._msg_id = msg_id + self._timeout = timeout or conf.rpc_response_timeout + self._reply_proxy = connection_pool.reply_proxy + self._done = False + self._got_ending = False + self._conf = conf + self._dataqueue = queue.LightQueue() + # Add this caller to the reply proxy's call_waiters + self._reply_proxy.add_call_waiter(self, self._msg_id) + self.msg_id_cache = _MsgIdCache() + + def put(self, data): + self._dataqueue.put(data) + + def done(self): + if self._done: + return + self._done = True + # Remove this caller from reply proxy's call_waiters + self._reply_proxy.del_call_waiter(self._msg_id) + + def _process_data(self, data): + result = None + self.msg_id_cache.check_duplicate_message(data) + if data['failure']: + failure = data['failure'] + result = rpc_common.deserialize_remote_exception(self._conf, + failure) + elif data.get('ending', False): + self._got_ending = True + else: + result = data['result'] + return result + + def __iter__(self): + """Return a result until we get a reply with an 'ending' flag.""" + if self._done: + raise StopIteration + while True: + try: + data = self._dataqueue.get(timeout=self._timeout) + result = self._process_data(data) + except queue.Empty: + self.done() + raise rpc_common.Timeout() + except Exception: + with excutils.save_and_reraise_exception(): + self.done() + if self._got_ending: + self.done() + raise StopIteration + if isinstance(result, Exception): + self.done() + raise result + yield result + + +def create_connection(conf, new, connection_pool): + """Create a connection.""" + return ConnectionContext(conf, connection_pool, pooled=not new) + + +_reply_proxy_create_sem = semaphore.Semaphore() + + +def multicall(conf, context, topic, msg, timeout, connection_pool): + """Make a call that returns multiple times.""" + LOG.debug(_('Making synchronous call on %s ...'), topic) + msg_id = uuid.uuid4().hex + msg.update({'_msg_id': msg_id}) + LOG.debug(_('MSG_ID is %s') % (msg_id)) + _add_unique_id(msg) + pack_context(msg, context) + + with _reply_proxy_create_sem: + if not connection_pool.reply_proxy: + connection_pool.reply_proxy = ReplyProxy(conf, connection_pool) + msg.update({'_reply_q': connection_pool.reply_proxy.get_reply_q()}) + wait_msg = MulticallProxyWaiter(conf, msg_id, timeout, connection_pool) + with ConnectionContext(conf, connection_pool) as conn: + conn.topic_send(topic, rpc_common.serialize_msg(msg), timeout) + return wait_msg + + +def call(conf, context, topic, msg, timeout, connection_pool): + """Sends a message on a topic and wait for a response.""" + rv = multicall(conf, context, topic, msg, timeout, connection_pool) + # NOTE(vish): return the last result from the multicall + rv = list(rv) + if not rv: + return + return rv[-1] + + +def cast(conf, context, topic, msg, connection_pool): + """Sends a message on a topic without waiting for a response.""" + LOG.debug(_('Making asynchronous cast on %s...'), topic) + _add_unique_id(msg) + pack_context(msg, context) + with ConnectionContext(conf, connection_pool) as conn: + conn.topic_send(topic, rpc_common.serialize_msg(msg)) + + +def fanout_cast(conf, context, topic, msg, connection_pool): + """Sends a message on a fanout exchange without waiting for a response.""" + LOG.debug(_('Making asynchronous fanout cast...')) + _add_unique_id(msg) + pack_context(msg, context) + with ConnectionContext(conf, connection_pool) as conn: + conn.fanout_send(topic, rpc_common.serialize_msg(msg)) + + +def cast_to_server(conf, context, server_params, topic, msg, connection_pool): + """Sends a message on a topic to a specific server.""" + _add_unique_id(msg) + pack_context(msg, context) + with ConnectionContext(conf, connection_pool, pooled=False, + server_params=server_params) as conn: + conn.topic_send(topic, rpc_common.serialize_msg(msg)) + + +def fanout_cast_to_server(conf, context, server_params, topic, msg, + connection_pool): + """Sends a message on a fanout exchange to a specific server.""" + _add_unique_id(msg) + pack_context(msg, context) + with ConnectionContext(conf, connection_pool, pooled=False, + server_params=server_params) as conn: + conn.fanout_send(topic, rpc_common.serialize_msg(msg)) + + +def notify(conf, context, topic, msg, connection_pool, envelope): + """Sends a notification event on a topic.""" + LOG.debug(_('Sending %(event_type)s on %(topic)s'), + dict(event_type=msg.get('event_type'), + topic=topic)) + _add_unique_id(msg) + pack_context(msg, context) + with ConnectionContext(conf, connection_pool) as conn: + if envelope: + msg = rpc_common.serialize_msg(msg) + conn.notify_send(topic, msg) + + +def cleanup(connection_pool): + if connection_pool: + connection_pool.empty() + + +def get_control_exchange(conf): + return conf.control_exchange |