fluxer/fluxer_gateway/src/presence/presence_cache_shard.erl
2026-02-17 12:22:36 +00:00

150 lines
4.9 KiB
Erlang

%% Copyright (C) 2026 Fluxer Contributors
%%
%% This file is part of Fluxer.
%%
%% Fluxer is free software: you can redistribute it and/or modify
%% it under the terms of the GNU Affero General Public License as published by
%% the Free Software Foundation, either version 3 of the License, or
%% (at your option) any later version.
%%
%% Fluxer is distributed in the hope that it will be useful,
%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
%% GNU Affero General Public License for more details.
%%
%% You should have received a copy of the GNU Affero General Public License
%% along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
-module(presence_cache_shard).
-behaviour(gen_server).
-include_lib("fluxer_gateway/include/timeout_config.hrl").
-export([start_link/1, table_name/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
-type state() :: #{table := atom(), shard_index := non_neg_integer()}.
-define(TABLE_PREFIX, presence_cache).
-spec start_link(non_neg_integer()) -> {ok, pid()} | {error, term()}.
start_link(ShardIndex) ->
gen_server:start_link(?MODULE, #{shard_index => ShardIndex}, []).
-spec table_name(non_neg_integer()) -> atom().
table_name(Index) ->
list_to_atom(atom_to_list(?TABLE_PREFIX) ++ "_" ++ integer_to_list(Index)).
-spec init(map()) -> {ok, state()}.
init(#{shard_index := ShardIndex}) ->
process_flag(trap_exit, true),
TableName = table_name(ShardIndex),
ensure_table(TableName),
{ok, #{table => TableName, shard_index => ShardIndex}}.
-spec handle_call(term(), gen_server:from(), state()) -> {reply, term(), state()}.
handle_call({put, UserId, Presence}, _From, State) ->
Table = maps:get(table, State),
{reply, do_put(Table, UserId, Presence), State};
handle_call({delete, UserId}, _From, State) ->
Table = maps:get(table, State),
ets:delete(Table, UserId),
{reply, ok, State};
handle_call({get, UserId}, _From, State) ->
Table = maps:get(table, State),
Reply =
case catch ets:lookup(Table, UserId) of
[{_, Presence}] -> {ok, Presence};
_ -> not_found
end,
{reply, Reply, State};
handle_call({bulk_get, UserIds}, _From, State) ->
Table = maps:get(table, State),
Presences =
lists:filtermap(
fun(Uid) ->
case catch ets:lookup(Table, Uid) of
[{_, Presence}] -> {true, Presence};
_ -> false
end
end,
lists:usort(UserIds)
),
{reply, Presences, State};
handle_call(_Request, _From, State) ->
{reply, ok, State}.
-spec handle_cast(term(), state()) -> {noreply, state()}.
handle_cast(_Msg, State) ->
{noreply, State}.
-spec handle_info(term(), state()) -> {noreply, state()}.
handle_info(_Info, State) ->
{noreply, State}.
-spec terminate(term(), state()) -> ok.
terminate(_Reason, _State) ->
ok.
-spec code_change(term(), term(), term()) -> {ok, state()}.
code_change(_OldVsn, State, _Extra) when is_map(State) ->
{ok, State};
code_change(_OldVsn, {state, Table, ShardIndex}, _Extra) ->
{ok, #{table => Table, shard_index => ShardIndex}}.
-spec do_put(atom(), integer(), map()) -> ok.
do_put(Table, UserId, Presence) ->
Status = maps:get(<<"status">>, Presence, <<"offline">>),
case Status of
<<"invisible">> ->
ets:delete(Table, UserId),
ok;
<<"offline">> ->
ets:delete(Table, UserId),
ok;
_ ->
ets:insert(Table, {UserId, Presence}),
ok
end.
-spec ensure_table(atom()) -> ok.
ensure_table(Table) ->
case ets:info(Table) of
undefined ->
ets:new(Table, [named_table, public, set, {read_concurrency, true}]),
ok;
_ ->
ok
end.
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
table_name_test() ->
?assertEqual(presence_cache_0, table_name(0)),
?assertEqual(presence_cache_5, table_name(5)).
do_put_online_inserts_test() ->
Table = test_cache_table,
ets:new(Table, [named_table, public, set]),
?assertEqual(ok, do_put(Table, 1, #{<<"status">> => <<"online">>})),
?assertMatch([{1, _}], ets:lookup(Table, 1)),
ets:delete(Table).
do_put_offline_deletes_test() ->
Table = test_cache_table_2,
ets:new(Table, [named_table, public, set]),
ets:insert(Table, {1, #{<<"status">> => <<"online">>}}),
?assertEqual(ok, do_put(Table, 1, #{<<"status">> => <<"offline">>})),
?assertEqual([], ets:lookup(Table, 1)),
ets:delete(Table).
do_put_invisible_deletes_test() ->
Table = test_cache_table_3,
ets:new(Table, [named_table, public, set]),
ets:insert(Table, {1, #{<<"status">> => <<"online">>}}),
?assertEqual(ok, do_put(Table, 1, #{<<"status">> => <<"invisible">>})),
?assertEqual([], ets:lookup(Table, 1)),
ets:delete(Table).
-endif.