Sync notifier module from Oslo

Pull in the common notifier from Oslo-incubator into Keystone. This only
introduces the notifier module and it's dependencies. This change is
standalone and doesn't contain any code to implementation notifications,
just the initial sync.

blueprint notifications

Change-Id: If62d6012a92e944f3196dd20e6cdd3236e7ecae2

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