# -*- coding: utf-8 -*- # Copyright 2014, 2015 OpenMarket Ltd # # 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. from twisted.internet import defer from synapse.util.logutils import log_function from synapse.util.async import run_on_reactor from synapse.types import StreamToken import synapse.metrics import logging logger = logging.getLogger(__name__) metrics = synapse.metrics.get_metrics_for(__name__) notified_events_counter = metrics.register_counter("notified_events") # TODO(paul): Should be shared somewhere def count(func, l): """Return the number of items in l for which func returns true.""" n = 0 for x in l: if func(x): n += 1 return n class _NotificationListener(object): """ This represents a single client connection to the events stream. The events stream handler will have yielded to the deferred, so to notify the handler it is sufficient to resolve the deferred. """ def __init__(self, deferred): self.deferred = deferred def notified(self): return self.deferred.called def notify(self, token): """ Inform whoever is listening about the new events. """ try: self.deferred.callback(token) except defer.AlreadyCalledError: pass class _NotifierUserStream(object): """This represents a user connected to the event stream. It tracks the most recent stream token for that user. At a given point a user may have a number of streams listening for events. This listener will also keep track of which rooms it is listening in so that it can remove itself from the indexes in the Notifier class. """ def __init__(self, user, rooms, current_token, time_now_ms, appservice=None): self.user = str(user) self.appservice = appservice self.listeners = set() self.rooms = set(rooms) self.current_token = current_token self.last_notified_ms = time_now_ms def notify(self, stream_key, stream_id, time_now_ms): """Notify any listeners for this user of a new event from an event source. Args: stream_key(str): The stream the event came from. stream_id(str): The new id for the stream the event came from. time_now_ms(int): The current time in milliseconds. """ self.current_token = self.current_token.copy_and_replace( stream_key, stream_id ) if self.listeners: self.last_notified_ms = time_now_ms listeners = self.listeners self.listeners = set() for listener in listeners: listener.notify(self.current_token) def remove(self, notifier): """ Remove this listener from all the indexes in the Notifier it knows about. """ for room in self.rooms: lst = notifier.room_to_user_streams.get(room, set()) lst.discard(self) notifier.user_to_user_stream.pop(self.user) if self.appservice: notifier.appservice_to_user_streams.get( self.appservice, set() ).discard(self) class Notifier(object): """ This class is responsible for notifying any listeners when there are new events available for it. Primarily used from the /events stream. """ UNUSED_STREAM_EXPIRY_MS = 10 * 60 * 1000 def __init__(self, hs): self.hs = hs self.user_to_user_stream = {} self.room_to_user_streams = {} self.appservice_to_user_streams = {} self.event_sources = hs.get_event_sources() self.store = hs.get_datastore() self.pending_new_room_events = [] self.clock = hs.get_clock() hs.get_distributor().observe( "user_joined_room", self._user_joined_room ) self.clock.looping_call( self.remove_expired_streams, self.UNUSED_STREAM_EXPIRY_MS ) # This is not a very cheap test to perform, but it's only executed # when rendering the metrics page, which is likely once per minute at # most when scraping it. def count_listeners(): all_user_streams = set() for x in self.room_to_user_streams.values(): all_user_streams |= x for x in self.user_to_user_stream: all_user_streams.add(x) for x in self.appservice_to_user_streams.values(): all_user_streams |= x return sum(len(stream.listeners) for stream in all_user_streams) metrics.register_callback("listeners", count_listeners) metrics.register_callback( "rooms", lambda: count(bool, self.room_to_user_streams.values()), ) metrics.register_callback( "users", lambda: len(self.user_to_user_stream), ) metrics.register_callback( "appservices", lambda: count(bool, self.appservice_to_user_streams.values()), ) @log_function @defer.inlineCallbacks def on_new_room_event(self, event, room_stream_id, max_room_stream_id, extra_users=[]): """ Used by handlers to inform the notifier something has happened in the room, room event wise. This triggers the notifier to wake up any listeners that are listening to the room, and any listeners for the users in the `extra_users` param. The events can be peristed out of order. The notifier will wait until all previous events have been persisted before notifying the client streams. """ yield run_on_reactor() self.pending_new_room_events.append(( event, room_stream_id, extra_users )) self._notify_pending_new_room_events(max_room_stream_id) def _notify_pending_new_room_events(self, max_room_stream_id): """Notify for the room events that were queued waiting for a previous event to be persisted. Args: max_room_stream_id(int): The highest stream_id below which all events have been persisted. """ pending = sorted(self.pending_new_room_events) self.pending_new_room_events = [] for event, room_stream_id, extra_users in pending: if room_stream_id > max_room_stream_id: self.pending_new_room_events.append(( event, room_stream_id, extra_users )) else: self._on_new_room_event(event, room_stream_id, extra_users) def _on_new_room_event(self, event, room_stream_id, extra_users=[]): """Notify any user streams that are interested in this room event""" # poke any interested application service. self.hs.get_handlers().appservice_handler.notify_interested_services( event ) room_id = event.room_id room_user_streams = self.room_to_user_streams.get(room_id, set()) user_streams = room_user_streams.copy() for user in extra_users: user_stream = self.user_to_user_stream.get(str(user)) if user_stream is not None: user_streams.add(user_stream) for appservice in self.appservice_to_user_streams: # TODO (kegan): Redundant appservice listener checks? # App services will already be in the room_to_user_streams set, but # that isn't enough. They need to be checked here in order to # receive *invites* for users they are interested in. Does this # make the room_to_user_streams check somewhat obselete? if appservice.is_interested(event): app_user_streams = self.appservice_to_user_streams.get( appservice, set() ) user_streams |= app_user_streams logger.debug("on_new_room_event listeners %s", user_streams) time_now_ms = self.clock.time_msec() for user_stream in user_streams: try: user_stream.notify( "room_key", "s%d" % (room_stream_id,), time_now_ms ) except: logger.exception("Failed to notify listener") @defer.inlineCallbacks @log_function def on_new_user_event(self, stream_key, new_token, users=[], rooms=[]): """ Used to inform listeners that something has happend presence/user event wise. Will wake up all listeners for the given users and rooms. """ yield run_on_reactor() user_streams = set() for user in users: user_stream = self.user_to_user_stream.get(str(user)) if user_stream is not None: user_streams.add(user_stream) for room in rooms: user_streams |= self.room_to_user_streams.get(room, set()) time_now_ms = self.clock.time_msec() for user_stream in user_streams: try: user_stream.notify(stream_key, new_token, time_now_ms) except: logger.exception("Failed to notify listener") @defer.inlineCallbacks def wait_for_events(self, user, rooms, timeout, callback, from_token=StreamToken("s0", "0", "0")): """Wait until the callback returns a non empty response or the timeout fires. """ deferred = defer.Deferred() time_now_ms = self.clock.time_msec() user = str(user) user_stream = self.user_to_user_stream.get(user) if user_stream is None: appservice = yield self.store.get_app_service_by_user_id(user) current_token = yield self.event_sources.get_current_token() rooms = yield self.store.get_rooms_for_user(user) user_stream = _NotifierUserStream( user=user, rooms=rooms, appservice=appservice, current_token=current_token, time_now_ms=time_now_ms, ) self._register_with_keys(user_stream) else: current_token = user_stream.current_token listener = [_NotificationListener(deferred)] if timeout and not current_token.is_after(from_token): user_stream.listeners.add(listener[0]) if current_token.is_after(from_token): result = yield callback(from_token, current_token) else: result = None timer = [None] if result: user_stream.listeners.discard(listener[0]) defer.returnValue(result) return if timeout: timed_out = [False] def _timeout_listener(): timed_out[0] = True timer[0] = None user_stream.listeners.discard(listener[0]) listener[0].notify(current_token) # We create multiple notification listeners so we have to manage # canceling the timeout ourselves. timer[0] = self.clock.call_later(timeout/1000., _timeout_listener) while not result and not timed_out[0]: new_token = yield deferred deferred = defer.Deferred() listener[0] = _NotificationListener(deferred) user_stream.listeners.add(listener[0]) result = yield callback(current_token, new_token) current_token = new_token if timer[0] is not None: try: self.clock.cancel_call_later(timer[0]) except: logger.exception("Failed to cancel notifer timer") defer.returnValue(result) @defer.inlineCallbacks def get_events_for(self, user, rooms, pagination_config, timeout): """ For the given user and rooms, return any new events for them. If there are no new events wait for up to `timeout` milliseconds for any new events to happen before returning. """ from_token = pagination_config.from_token if not from_token: from_token = yield self.event_sources.get_current_token() limit = pagination_config.limit @defer.inlineCallbacks def check_for_updates(before_token, after_token): events = [] end_token = from_token for name, source in self.event_sources.sources.items(): keyname = "%s_key" % name before_id = getattr(before_token, keyname) after_id = getattr(after_token, keyname) if before_id == after_id: continue stuff, new_key = yield source.get_new_events_for_user( user, getattr(from_token, keyname), limit, ) events.extend(stuff) end_token = end_token.copy_and_replace(keyname, new_key) if events: defer.returnValue((events, (from_token, end_token))) else: defer.returnValue(None) result = yield self.wait_for_events( user, rooms, timeout, check_for_updates, from_token=from_token ) if result is None: result = ([], (from_token, from_token)) defer.returnValue(result) @log_function def remove_expired_streams(self): time_now_ms = self.clock.time_msec() expired_streams = [] expire_before_ts = time_now_ms - self.UNUSED_STREAM_EXPIRY_MS for stream in self.user_to_user_stream.values(): if stream.listeners: continue if stream.last_notified_ms < expire_before_ts: expired_streams.append(stream) for expired_stream in expired_streams: expired_stream.remove(self) @log_function def _register_with_keys(self, user_stream): self.user_to_user_stream[user_stream.user] = user_stream for room in user_stream.rooms: s = self.room_to_user_streams.setdefault(room, set()) s.add(user_stream) if user_stream.appservice: self.appservice_to_user_stream.setdefault( user_stream.appservice, set() ).add(user_stream) def _user_joined_room(self, user, room_id): user = str(user) new_user_stream = self.user_to_user_stream.get(user) if new_user_stream is not None: room_streams = self.room_to_user_streams.setdefault(room_id, set()) room_streams.add(new_user_stream) new_user_stream.rooms.add(room_id)