perf(push): batch badge count invalidation per mention chunk (#2178)

fluxer_gateway/src/gateway/gateway_rpc_push.erl

@@ -12,6 +12,8 @@ execute_method(<<"push.sync_user_blocked_ids">>, P) ->
     do_sync_user_blocked_ids(P);
 execute_method(<<"push.invalidate_badge_count">>, P) ->
     do_invalidate_badge_count(P);
+execute_method(<<"push.invalidate_badge_counts">>, P) ->
+    do_invalidate_badge_counts(P);
 execute_method(<<"push.clear_channel_notifications">>, P) ->
     do_clear_channel_notifications(P);
 execute_method(<<"push.invalidate_subscriptions">>, P) ->
@@ -43,6 +45,19 @@ do_invalidate_badge_count(#{<<"user_id">> := UBin}) ->
     fanout_local_cache_mutation(push, invalidate_user_badge_count_local, [UserId]),
     true.
 
+-spec do_invalidate_badge_counts(map()) -> true.
+do_invalidate_badge_counts(#{<<"user_ids">> := UserIdsRaw}) ->
+    UserIds = lists:usort(validation:snowflake_list_or_throw(<<"user_ids">>, UserIdsRaw)),
+    gateway_rpc_guild_routing:validate_batch_size(length(UserIds)),
+    fanout_badge_count_invalidation(UserIds).
+
+-spec fanout_badge_count_invalidation([pos_integer()]) -> true.
+fanout_badge_count_invalidation([]) ->
+    true;
+fanout_badge_count_invalidation(UserIds) ->
+    fanout_local_cache_mutation(push, invalidate_user_badge_counts_local, [UserIds]),
+    true.
+
 -spec do_clear_channel_notifications(map()) -> true.
 do_clear_channel_notifications(#{
     <<"user_id">> := UBin,
@@ -79,3 +94,24 @@ fanout_local_cache_mutation(Module, Function, Args) ->
             ),
             ok
     end.
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+
+invalidate_badge_counts_rejects_oversized_batch_test() ->
+    UserIds = [integer_to_binary(UserId) || UserId <- lists:seq(1000, 1200)],
+    ?assertError(
+        {gateway_rpc_error, _},
+        execute_method(<<"push.invalidate_badge_counts">>, #{<<"user_ids">> => UserIds})
+    ).
+
+invalidate_badge_counts_rejects_invalid_snowflakes_test() ->
+    ?assertError(
+        {validation, _},
+        execute_method(<<"push.invalidate_badge_counts">>, #{<<"user_ids">> => [<<"nope">>]})
+    ).
+
+invalidate_badge_counts_accepts_an_empty_batch_test() ->
+    ?assert(execute_method(<<"push.invalidate_badge_counts">>, #{<<"user_ids">> => []})).
+
+-endif.

fluxer_gateway/src/push/push.erl

@@ -16,6 +16,7 @@
     invalidate_user_subscriptions_local/1,
     invalidate_user_badge_count/1,
     invalidate_user_badge_count_local/1,
+    invalidate_user_badge_counts_local/1,
     clear_channel_notifications/3
 ]).
 -export([get_cache_stats/0]).
@@ -172,6 +173,15 @@ invalidate_user_badge_count_local(UserId) ->
         push_ets_cache:delete_badge_count(UserId)
     end).
 
+-spec invalidate_user_badge_counts_local(term()) -> ok.
+invalidate_user_badge_counts_local(UserIds) ->
+    case integer_list(UserIds) of
+        {ok, TypedUserIds} ->
+            lists:foreach(fun invalidate_user_badge_count_local/1, TypedUserIds);
+        error ->
+            ok
+    end.
+
 -spec maybe_cast(term(), term()) -> ok.
 maybe_cast(Key, Msg) ->
     case is_push_noop() of
@@ -551,6 +561,25 @@ sync_user_blocked_ids_local_updates_local_cache_test() ->
         ?assertEqual([20, 30], push_ets_cache:get_blocked_ids(10))
     end).
 
+invalidate_user_badge_counts_local_deletes_every_cached_entry_test() ->
+    push_ets_cache:init(),
+    push_ets_cache:put_badge_count(10, 5, 1000),
+    push_ets_cache:put_badge_count(11, 7, 1000),
+    with_registered_push(fun() ->
+        ok = invalidate_user_badge_counts_local([10, 11])
+    end),
+    ?assertEqual(undefined, push_ets_cache:get_badge_count(10)),
+    ?assertEqual(undefined, push_ets_cache:get_badge_count(11)).
+
+invalidate_user_badge_counts_local_ignores_untyped_ids_test() ->
+    push_ets_cache:init(),
+    push_ets_cache:put_badge_count(12, 5, 1000),
+    with_registered_push(fun() ->
+        ok = invalidate_user_badge_counts_local([<<"12">>])
+    end),
+    ?assertEqual({5, 1000}, push_ets_cache:get_badge_count(12)),
+    push_ets_cache:delete_badge_count(12).
+
 invalidate_user_subscriptions_local_deletes_local_cache_test() ->
     push_ets_cache:init(),
     push_ets_cache:put_subscriptions(10, [#{<<"endpoint">> => <<"test">>}]),