fix(gateway): stop rate limit tables dying with their creator (#2299)

fluxer_gateway/src/gateway/gateway_handler_rate_limit.erl

@@ -320,18 +320,17 @@ create_counter_table(Table) ->
 -spec create_table(atom()) -> created | exists.
 create_table(Table) ->
     try
-        _ = ets:new(Table, [
-            named_table,
-            public,
-            set,
-            {write_concurrency, true},
-            {read_concurrency, true}
-        ]),
+        _ = ets:new(Table, rate_table_options()),
         created
     catch
         error:badarg -> exists
     end.
 
+-spec rate_table_options() -> list().
+rate_table_options() ->
+    [named_table, public, set, {write_concurrency, true}, {read_concurrency, true}] ++
+        guild_ets_utils:heir_options().
+
 -spec rate_limits_disabled() -> boolean().
 rate_limits_disabled() ->
     case os:getenv("FLUXER_DISABLE_RATE_LIMITS") of
@@ -502,6 +501,41 @@ await_table_size(Table, Max, Attempts) ->
             await_table_size(Table, Max, Attempts - 1)
     end.
 
+shared_ip_bucket_survives_creating_process_death_test() ->
+    with_rate_limits_enabled(fun assert_shared_ip_bucket_survives_creator/0).
+
+assert_shared_ip_bucket_survives_creator() ->
+    drop_table(?SHARED_IP_RATE_TABLE),
+    {ok, _} = guild_ets_owner:start_link(),
+    try
+        assert_shared_ip_bucket_outlives_creator()
+    after
+        gen_server:stop(guild_ets_owner)
+    end.
+
+assert_shared_ip_bucket_outlives_creator() ->
+    IP = <<"198.51.100.70">>,
+    stop_table_owner(start_shared_ip_bucket_creator(IP)),
+    ?assertNotEqual(undefined, ets:whereis(?SHARED_IP_RATE_TABLE)),
+    Key = {IP, erlang:system_time(millisecond) div ?SHARED_IP_RATE_WINDOW_MS},
+    ?assertEqual([{Key, 1}], ets:lookup(?SHARED_IP_RATE_TABLE, Key)).
+
+start_shared_ip_bucket_creator(IP) ->
+    Parent = self(),
+    Pid = spawn(fun() -> create_shared_ip_bucket(Parent, IP) end),
+    receive
+        {owner_ready, Pid} -> Pid
+    after 1000 -> error(owner_start_timeout)
+    end.
+
+create_shared_ip_bucket(Parent, IP) ->
+    ok = check_shared_ip_rate(IP),
+    Parent ! {owner_ready, self()},
+    receive
+        stop -> ok
+    after 30000 -> ok
+    end.
+
 window_cleanup_loops_do_not_outlive_their_table_test() ->
     with_rate_limits_enabled(fun() ->
         with_fast_cleanup_timer(fun assert_window_cleanup_loops_do_not_leak/0)

fluxer_gateway/src/gateway/session_abuse_protection.erl

@@ -151,18 +151,17 @@ create_session_user_counts_table() ->
 -spec create_rate_table(atom()) -> created | exists.
 create_rate_table(Table) ->
     try
-        _ = ets:new(Table, [
-            named_table,
-            public,
-            set,
-            {write_concurrency, true},
-            {read_concurrency, true}
-        ]),
+        _ = ets:new(Table, rate_table_options()),
         created
     catch
         error:badarg -> exists
     end.
 
+-spec rate_table_options() -> list().
+rate_table_options() ->
+    [named_table, public, set, {write_concurrency, true}, {read_concurrency, true}] ++
+        guild_ets_utils:heir_options().
+
 -spec ensure_identify_table() -> ok.
 ensure_identify_table() ->
     case ets:whereis(?IDENTIFY_TABLE) of
@@ -313,6 +312,38 @@ prune_old_identify_entries_keeps_recent_buckets_test() ->
     ?assertNotEqual([], ets:lookup(?IDENTIFY_TABLE, RecentKey)),
     ets:delete(?IDENTIFY_TABLE, RecentKey).
 
+identify_bucket_survives_creating_process_death_test() ->
+    drop_identify_table(),
+    {ok, _} = guild_ets_owner:start_link(),
+    try
+        assert_identify_bucket_outlives_creator()
+    after
+        gen_server:stop(guild_ets_owner)
+    end.
+
+assert_identify_bucket_outlives_creator() ->
+    IP = <<"192.0.2.220">>,
+    stop_table_owner(start_identify_bucket_creator(IP)),
+    ?assertNotEqual(undefined, ets:whereis(?IDENTIFY_TABLE)),
+    Key = {IP, erlang:system_time(second) div ?IDENTIFY_WINDOW_SECS},
+    ?assertEqual([{Key, 1}], ets:lookup(?IDENTIFY_TABLE, Key)).
+
+start_identify_bucket_creator(IP) ->
+    Parent = self(),
+    Pid = spawn(fun() -> create_identify_bucket(Parent, IP) end),
+    receive
+        {owner_ready, Pid} -> Pid
+    after 1000 -> error(owner_start_timeout)
+    end.
+
+create_identify_bucket(Parent, IP) ->
+    ok = check_identify_rate(IP),
+    Parent ! {owner_ready, self()},
+    receive
+        stop -> ok
+    after 30000 -> ok
+    end.
+
 identify_cleanup_loops_do_not_outlive_their_table_test() ->
     meck:new(gateway_retry_timer, [passthrough]),
     meck:expect(gateway_retry_timer, wait, fun(_) -> timer:sleep(5) end),

fluxer_gateway/src/guild/guild_ets_utils.erl

@@ -3,7 +3,7 @@
 -module(guild_ets_utils).
 -typing([eqwalizer]).
 
--export([ensure_table/2]).
+-export([ensure_table/2, heir_options/0]).
 
 -spec ensure_table(atom(), list()) -> ok.
 ensure_table(TableName, Options) ->
@@ -14,6 +14,13 @@ ensure_table(TableName, Options) ->
             ensure_table_local(TableName, Options)
     end.
 
+-spec heir_options() -> list().
+heir_options() ->
+    case whereis(guild_ets_owner) of
+        Pid when is_pid(Pid), Pid =/= self() -> [{heir, Pid, inherited}];
+        _ -> []
+    end.
+
 -spec ensure_table_local(atom(), list()) -> ok.
 ensure_table_local(TableName, Options) ->
     case ets:whereis(TableName) of