Add a NotifierUserStream to hold all the notification listeners for a user

synapse/notifier.py

@@ -43,28 +43,18 @@ def count(func, l):
 
 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.
-
-    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, deferred, appservice=None):
-        self.user = user
-        self.appservice = appservice
+    def __init__(self, deferred):
         self.deferred = deferred
-        self.rooms = rooms
-        self.timer = None
 
     def notified(self):
         return self.deferred.called
 
-    def notify(self, notifier):
-        """ Inform whoever is listening about the new events. This will
-        also remove this listener from all the indexes in the Notifier
-        it knows about.
+    def notify(self):
+        """ Inform whoever is listening about the new events.
         """
 
         try:
@@ -72,27 +62,45 @@ class _NotificationListener(object):
         except defer.AlreadyCalledError:
             pass
 
-        # Should the following be done be using intrusively linked lists?
-        # -- erikj
+
+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, appservice=None):
+        self.user = user
+        self.appservice = appservice
+        self.listeners = set()
+        self.rooms = rooms
+        self.current_token = current_token
+
+    def notify(self, new_token):
+        for listener in self.listeners:
+            listener.notify(new_token)
+        self.listeners.clear()
+
+    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_listeners.get(room, set())
+            lst = notifier.room_to_user_streams.get(room, set())
             lst.discard(self)
 
-        notifier.user_to_listeners.get(self.user, set()).discard(self)
+        notifier.user_to_user_streams.get(self.user, set()).discard(self)
 
         if self.appservice:
-            notifier.appservice_to_listeners.get(
+            notifier.appservice_to_user_streams.get(
                 self.appservice, set()
             ).discard(self)
 
-        # Cancel the timeout for this notifer if one exists.
-        if self.timer is not None:
-            try:
-                notifier.clock.cancel_call_later(self.timer)
-            except:
-                logger.warn("Failed to cancel notifier timer")
-
 
 class Notifier(object):
     """ This class is responsible for notifying any listeners when there are
@@ -104,11 +112,12 @@ class Notifier(object):
     def __init__(self, hs):
         self.hs = hs
 
-        self.room_to_listeners = {}
-        self.user_to_listeners = {}
-        self.appservice_to_listeners = {}
+        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.clock = hs.get_clock()
 
@@ -120,34 +129,34 @@ class Notifier(object):
         # when rendering the metrics page, which is likely once per minute at
         # most when scraping it.
         def count_listeners():
-            all_listeners = set()
+            all_user_streams = set()
 
-            for x in self.room_to_listeners.values():
-                all_listeners |= x
-            for x in self.user_to_listeners.values():
-                all_listeners |= x
-            for x in self.appservice_to_listeners.values():
-                all_listeners |= x
+            for x in self.room_to_user_streams.values():
+                all_user_streams |= x
+            for x in self.user_to_user_streams.values():
+                all_user_streams |= x
+            for x in self.appservice_to_user_streams.values():
+                all_user_streams |= x
 
-            return len(all_listeners)
+            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_listeners.values()),
+            lambda: count(bool, self.room_to_user_streams.values()),
         )
         metrics.register_callback(
             "users",
-            lambda: count(bool, self.user_to_listeners.values()),
+            lambda: len(self.user_to_user_stream),
         )
         metrics.register_callback(
             "appservices",
-            lambda: count(bool, self.appservice_to_listeners.values()),
+            lambda: count(bool, self.appservice_to_user_streams.values()),
         )
 
     @log_function
     @defer.inlineCallbacks
-    def on_new_room_event(self, event, extra_users=[]):
+    def on_new_room_event(self, event, new_token, extra_users=[]):
         """ Used by handlers to inform the notifier something has happened
         in the room, room event wise.
 
@@ -155,6 +164,7 @@ class Notifier(object):
         listening to the room, and any listeners for the users in the
         `extra_users` param.
         """
+        assert isinstance(new_token, StreamToken)
         yield run_on_reactor()
         # poke any interested application service.
         self.hs.get_handlers().appservice_handler.notify_interested_services(
@@ -163,72 +173,60 @@ class Notifier(object):
 
         room_id = event.room_id
 
-        room_listeners = self.room_to_listeners.get(room_id, set())
+        room_user_streams = self.room_to_user_streams.get(room_id, set())
 
-        _discard_if_notified(room_listeners)
-
-        listeners = room_listeners.copy()
+        user_streams = room_user_streams.copy()
 
         for user in extra_users:
-            user_listeners = self.user_to_listeners.get(user, set())
+            user_stream = self.user_to_user_stream.get(user)
+            if user_stream is not None:
+                user_streams.add(user_stream)
 
-            _discard_if_notified(user_listeners)
-
-            listeners |= user_listeners
-
-        for appservice in self.appservice_to_listeners:
+        for appservice in self.appservice_to_user_streams:
             # TODO (kegan): Redundant appservice listener checks?
-            # App services will already be in the room_to_listeners set, but
+            # 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_listeners check somewhat obselete?
+            # make the room_to_user_streams check somewhat obselete?
             if appservice.is_interested(event):
-                app_listeners = self.appservice_to_listeners.get(
+                app_user_streams = self.appservice_to_user_streams.get(
                     appservice, set()
                 )
+                user_streams |= app_user_streams
 
-                _discard_if_notified(app_listeners)
-
-                listeners |= app_listeners
-
-        logger.debug("on_new_room_event listeners %s", listeners)
+        logger.debug("on_new_room_event listeners %s", user_streams)
 
         with PreserveLoggingContext():
-            for listener in listeners:
+            for user_stream in user_streams:
                 try:
-                    listener.notify(self)
+                    user_stream.notify(new_token)
                 except:
                     logger.exception("Failed to notify listener")
 
     @defer.inlineCallbacks
     @log_function
-    def on_new_user_event(self, users=[], rooms=[]):
+    def on_new_user_event(self, 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.
         """
+        assert isinstance(new_token, StreamToken)
         yield run_on_reactor()
-        listeners = set()
+        user_streams = set()
 
         for user in users:
-            user_listeners = self.user_to_listeners.get(user, set())
-
-            _discard_if_notified(user_listeners)
-
-            listeners |= user_listeners
+            user_stream = self.user_to_user_stream.get(user)
+            if user_stream:
+                user_stream.add(user_stream)
 
         for room in rooms:
-            room_listeners = self.room_to_listeners.get(room, set())
-
-            _discard_if_notified(room_listeners)
-
-            listeners |= room_listeners
+            user_streams |= self.room_to_user_streams.get(room, set())
 
         with PreserveLoggingContext():
-            for listener in listeners:
+            for user_stream in user_streams:
                 try:
-                    listener.notify(self)
+                    user_streams.notify(new_token)
                 except:
                     logger.exception("Failed to notify listener")
 
@@ -240,21 +238,32 @@ class Notifier(object):
         """
 
         deferred = defer.Deferred()
-        appservice = yield self.hs.get_datastore().get_app_service_by_user_id(
-            user.to_string()
-        )
 
-        listener = [_NotificationListener(
-            user=user,
-            rooms=rooms,
-            deferred=deferred,
-            appservice=appservice,
-        )]
+        user_stream = self.user_to_user_streams.get(user)
+        if user_stream is None:
+            appservice = yield self.store.get_app_service_by_user_id(
+                user.to_string()
+            )
+            current_token = yield self.event_sources.get_current_token()
+            user_stream = _NotifierUserStream(
+                user=user,
+                rooms=rooms,
+                appservice=appservice,
+                current_token=current_token,
+            )
+            self._register_with_keys(user_stream)
+        else:
+            current_token = user_stream.current_token
 
-        if timeout:
-            self._register_with_keys(listener[0])
+        if timeout and not current_token.is_after(from_token):
+            listener = [_NotificationListener(deferred)]
+            user_stream.listeners.add(listener[0])
+
+        if current_token.is_after(from_token):
+            result = yield callback(from_token, current_token)
+        else:
+            result = None
 
-        result = yield callback()
         timer = [None]
 
         if timeout:
@@ -263,23 +272,19 @@ class Notifier(object):
             def _timeout_listener():
                 timed_out[0] = True
                 timer[0] = None
-                listener[0].notify(self)
+                listener[0].notify(user_stream)
 
             # 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]:
-                yield deferred
+                new_token = yield deferred
                 deferred = defer.Deferred()
-                listener[0] = _NotificationListener(
-                    user=user,
-                    rooms=rooms,
-                    deferred=deferred,
-                    appservice=appservice,
-                )
-                self._register_with_keys(listener[0])
-                result = yield callback()
+                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:
@@ -302,7 +307,7 @@ class Notifier(object):
         limit = pagination_config.limit
 
         @defer.inlineCallbacks
-        def check_for_updates():
+        def check_for_updates(start_token, end_token):
             events = []
             end_token = from_token
             for name, source in self.event_sources.sources.items():
@@ -328,26 +333,23 @@ class Notifier(object):
         defer.returnValue(result)
 
     @log_function
-    def _register_with_keys(self, listener):
-        for room in listener.rooms:
-            s = self.room_to_listeners.setdefault(room, set())
-            s.add(listener)
+    def _register_with_keys(self, user_stream):
+        self.user_to_user_stream[user_stream.user] = user_stream
 
-        self.user_to_listeners.setdefault(listener.user, set()).add(listener)
+        for room in user_stream.rooms:
+            s = self.room_to_user_stream.setdefault(room, set())
+            s.add(user_stream)
 
-        if listener.appservice:
-            self.appservice_to_listeners.setdefault(
-                listener.appservice, set()
-            ).add(listener)
+        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):
-        new_listeners = self.user_to_listeners.get(user, set())
-
-        listeners = self.room_to_listeners.setdefault(room_id, set())
-        listeners |= new_listeners
-
-        for l in new_listeners:
-            l.rooms.add(room_id)
+        new_user_stream = self.user_to_user_stream.get(user)
+        room_streams = self.room_to_user_streams.setdefault(room_id, set())
+        room_streams.add(new_user_stream)
+        new_user_stream.rooms.add(room_id)
 
 
 def _discard_if_notified(listener_set):