dispatcher: add dispatch_filter

- presence: (basic) handle member lists when presence update.
    Note that the respective GUILD_UPDATE_MEMBER_LIST doesn't happen
    yet. we'll need roles beforehand.

litecord/dispatcher.py

@@ -106,6 +106,15 @@ class EventDispatcher:
         for key in keys:
             await self.dispatch(backend_str, key, *args, **kwargs)
 
+    async def dispatch_filter(self, backend_str: str,
+                              key: Any, func, *args):
+        """Dispatch to a backend that only accepts
+        (event, data) arguments with an optional filter
+        function."""
+        backend = self.backends[backend_str]
+        key = backend.KEY_TYPE(key)
+        return await backend.dispatch_filter(key, func, *args)
+
     async def reset(self, backend_str: str, key: Any):
         """Reset the bucket in the given backend."""
         backend = self.backends[backend_str]

litecord/gateway/websocket.py

@@ -685,26 +685,6 @@ class GatewayWebsocket:
                 }, ...
             ]
         }
-
-        # Implementation defails.
-
-        Lazy guilds are complicated to deal with in the backend level
-        as there are a lot of computation to be done for each request.
-
-        The current implementation is rudimentary and does not account
-        for any roles inside the guild.
-
-        A correct implementation would take account of roles and make
-        the correct groups on list_data:
-
-        For each channel in lazy_request['channels']:
-         - get all roles that have Read Messages on the channel:
-           - Also fetch their member counts, as it'll be important
-         - with the role list, order them like you normally would
-            (by their role priority)
-         - based on the channel's range's min and max and the ordered
-            role list, you can get the roles wanted for your list_data reply.
-         - make new groups ONLY when the role is hoisted.
         """
         data = payload['d']
 

litecord/presence.py

@@ -1,8 +1,11 @@
 from typing import List, Dict, Any
 from random import choice
 
+from logbook import Logger
 from quart import current_app as app
 
+log = Logger(__name__)
+
 
 def status_cmp(status: str, other_status: str) -> bool:
     """Compare if `status` is better than the `other_status`
@@ -100,11 +103,31 @@ class PresenceManager:
 
         game = state['game']
 
-        await self.dispatcher.dispatch_guild(
-            guild_id, 'PRESENCE_UPDATE', {
+        lazy_guild_store = self.dispatcher.backends['lazy_guild']
+        lists = lazy_guild_store.get_gml_guild(guild_id)
+
+        # shards that are in lazy guilds with 'everyone'
+        # enabled
+        in_lazy = []
+
+        for member_list in lists:
+            session_ids = await member_list.pres_update(
+                int(member['user']['id']),
+                member['roles'],
+                state['status'],
+                game
+            )
+
+            log.debug('Lazy Dispatch to {}',
+                      len(session_ids))
+
+            if member_list.channel_id == 'everyone':
+                in_lazy.extend(session_ids)
+
+        pres_update_payload = {
             'user': member['user'],
             'roles': member['roles'],
-                'guild_id': guild_id,
+            'guild_id': str(guild_id),
 
             'status': state['status'],
 
@@ -112,8 +135,18 @@ class PresenceManager:
             'game': game,
             'activities': [game] if game else []
         }
+
+        # everyone not in lazy guild mode
+        # gets a PRESENCE_UPDATE
+        await self.dispatcher.dispatch_filter(
+            'guild', guild_id,
+            lambda session_id: session_id not in in_lazy,
+
+            'PRESENCE_UPDATE', pres_update_payload
         )
 
+        return in_lazy
+
     async def dispatch_pres(self, user_id: int, state: dict):
         """Dispatch a new presence to all guilds the user is in.
 
@@ -122,10 +155,12 @@ class PresenceManager:
         if state['status'] == 'invisible':
             state['status'] = 'offline'
 
+        # TODO: shard-aware
         guild_ids = await self.storage.get_user_guilds(user_id)
 
         for guild_id in guild_ids:
-            await self.dispatch_guild_pres(guild_id, user_id, state)
+            await self.dispatch_guild_pres(
+                guild_id, user_id, state)
 
         # dispatch to all friends that are subscribed to them
         user = await self.storage.get_user(user_id)

litecord/pubsub/dispatcher.py

@@ -37,6 +37,14 @@ class Dispatcher:
         """Unsubscribe an elemtnt from the channel/key."""
         raise NotImplementedError
 
+    async def dispatch_filter(self, _key, _func, *_args):
+        """Selectively dispatch to the list of subscribed users.
+
+        The selection logic is completly arbitraty and up to the
+        Pub/Sub backend.
+        """
+        raise NotImplementedError
+
     async def dispatch(self, _key, *_args):
         """Dispatch an event to the given channel/key."""
         raise NotImplementedError

litecord/pubsub/guild.py

@@ -55,9 +55,10 @@ class GuildDispatcher(DispatcherWithState):
         # same thing happening from sub() happens on unsub()
         await self._chan_action('unsub', guild_id, user_id)
 
-    async def dispatch(self, guild_id: int,
+    async def dispatch_filter(self, guild_id: int, func,
                               event: str, data: Any):
-        """Dispatch an event to all subscribers of the guild."""
+        """Selectively dispatch to session ids that have
+        func(session_id) true."""
         user_ids = self.state[guild_id]
         dispatched = 0
 
@@ -74,8 +75,22 @@ class GuildDispatcher(DispatcherWithState):
                 await self.unsub(guild_id, user_id)
                 continue
 
+            # filter the ones that matter
+            states = list(filter(
+                lambda state: func(state.session_id), states
+            ))
+
             dispatched += await self._dispatch_states(
                 states, event, data)
 
         log.info('Dispatched {} {!r} to {} states',
                  guild_id, event, dispatched)
+
+    async def dispatch(self, guild_id: int,
+                       event: str, data: Any):
+        """Dispatch an event to all subscribers of the guild."""
+        await self.dispatch_filter(
+            guild_id,
+            lambda sess_id: True,
+            event, data,
+        )

litecord/pubsub/lazy_guild.py

@@ -256,6 +256,9 @@ class GuildMemberList:
         # subscribe the state to this list
         await self.sub(session_id)
 
+        # TODO: subscribe shard to 'everyone'
+        #       and forward the query to that list
+
         reply = {
             'guild_id': str(self.guild_id),
 
@@ -290,8 +293,14 @@ class GuildMemberList:
                 'items': items[start:end],
             })
 
+        # the first GUILD_MEMBER_LIST_UPDATE for a shard
+        # is dispatched here.
         await state.ws.dispatch('GUILD_MEMBER_LIST_UPDATE', reply)
 
+    async def pres_update(self, user_id: int, roles: List[str],
+                          status: str, game: dict) -> List[str]:
+        return list(self.state)
+
     async def dispatch(self, event: str, data: Any):
         """The dispatch() method here, instead of being
         about dispatching a single event to the subscribed
@@ -328,7 +337,14 @@ class LazyGuildDispatcher(Dispatcher):
         # {chan_id: gml, ...}
         self.state = {}
 
+        #: store which guilds have their
+        #  respective GMLs
+        # {guild_id: [chan_id, ...], ...}
+        self.guild_map = defaultdict(list)
+
     async def get_gml(self, channel_id: int):
+        """Get a guild list for a channel ID,
+        generating it if it doesn't exist."""
         try:
             return self.state[channel_id]
         except KeyError:
@@ -338,8 +354,16 @@ class LazyGuildDispatcher(Dispatcher):
 
             gml = GuildMemberList(guild_id, channel_id, self)
             self.state[channel_id] = gml
+            self.guild_map[guild_id].append(channel_id)
             return gml
 
+    def get_gml_guild(self, guild_id: int) -> List[GuildMemberList]:
+        """Get all member lists for a given guild."""
+        return list(map(
+            self.state.get,
+            self.guild_map[guild_id]
+        ))
+
     async def sub(self, chan_id, session_id):
         gml = await self.get_gml(chan_id)
         await gml.sub(session_id)