3b9d759b4b
- Clone of github.com/fluxerapp/fluxer (official upstream) - SELF_HOSTING.md: full VM rebuild procedure, architecture overview, service reference, step-by-step setup, troubleshooting, seattle reference - dev/.env.example: all env vars with secrets redacted and generation instructions - dev/livekit.yaml: LiveKit config template with placeholder keys - fluxer-seattle/: existing seattle deployment setup scripts
142 lines
4.2 KiB
Erlang
142 lines
4.2 KiB
Erlang
%% Copyright (C) 2026 Fluxer Contributors
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%%
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%% This file is part of Fluxer.
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%%
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%% Fluxer is free software: you can redistribute it and/or modify
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%% it under the terms of the GNU Affero General Public License as published by
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%% the Free Software Foundation, either version 3 of the License, or
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%% (at your option) any later version.
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%%
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%% Fluxer is distributed in the hope that it will be useful,
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%% but WITHOUT ANY WARRANTY; without even the implied warranty of
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%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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%% GNU Affero General Public License for more details.
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%%
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%% You should have received a copy of the GNU Affero General Public License
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%% along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
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-module(rendezvous_router).
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-export([select/2, group_keys/2]).
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-define(HASH_LIMIT, 16#FFFFFFFF).
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-spec select(term(), pos_integer()) -> non_neg_integer().
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select(Key, ShardCount) when ShardCount > 0 ->
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Indices = lists:seq(0, ShardCount - 1),
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{Index, _Weight} =
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lists:foldl(
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fun(CurrentIndex, {BestIndex, BestWeight}) ->
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Weight = weight(Key, CurrentIndex),
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case
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(Weight > BestWeight) orelse
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(Weight =:= BestWeight andalso CurrentIndex < BestIndex)
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of
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true ->
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{CurrentIndex, Weight};
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false ->
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{BestIndex, BestWeight}
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end
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end,
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{0, -1},
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Indices
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),
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Index;
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select(_Key, _ShardCount) ->
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0.
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-spec group_keys([term()], pos_integer()) -> [{non_neg_integer(), [term()]}].
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group_keys(Keys, ShardCount) when is_list(Keys), ShardCount > 0 ->
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Grouped =
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lists:foldl(
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fun(Key, Acc) ->
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Index = select(Key, ShardCount),
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Existing = maps:get(Index, Acc, []),
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maps:put(Index, [Key | Existing], Acc)
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end,
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#{},
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Keys
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),
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Sorted = lists:sort(
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fun({IdxA, _}, {IdxB, _}) -> IdxA =< IdxB end,
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[{Index, lists:usort(Group)} || {Index, Group} <- maps:to_list(Grouped)]
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),
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Sorted;
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group_keys(_Keys, _ShardCount) ->
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[].
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-spec weight(term(), non_neg_integer()) -> non_neg_integer().
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weight(Key, Index) ->
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erlang:phash2({Key, Index}, ?HASH_LIMIT).
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-ifdef(TEST).
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-include_lib("eunit/include/eunit.hrl").
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select_single_shard_test() ->
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?assertEqual(0, select(test_key, 1)),
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?assertEqual(0, select(any_key, 1)),
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?assertEqual(0, select(12345, 1)).
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select_valid_index_test_() ->
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[
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?_test(begin
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Index = select(test_key, N),
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?assert(Index >= 0),
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?assert(Index < N)
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end)
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|| N <- [2, 5, 10, 100]
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].
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select_stability_test_() ->
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[
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?_assertEqual(select(<<"abc">>, 8), select(<<"abc">>, 8)),
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?_assertEqual(select(12345, 3), select(12345, 3)),
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?_assertEqual(select({user, 1}, 10), select({user, 1}, 10))
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].
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select_distribution_test() ->
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Keys = lists:seq(1, 1000),
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ShardCount = 10,
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Distribution = lists:foldl(
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fun(Key, Acc) ->
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Index = select(Key, ShardCount),
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maps:update_with(Index, fun(V) -> V + 1 end, 1, Acc)
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end,
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#{},
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Keys
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),
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Counts = maps:values(Distribution),
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?assertEqual(ShardCount, maps:size(Distribution)),
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lists:foreach(fun(Count) -> ?assert(Count > 0) end, Counts).
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group_keys_empty_test() ->
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?assertEqual([], group_keys([], 4)).
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group_keys_single_test() ->
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Groups = group_keys([key1], 4),
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?assertEqual(1, length(Groups)).
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group_keys_deduplicates_test() ->
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Keys = [1, 2, 3, 1, 2],
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Groups = group_keys(Keys, 2),
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lists:foreach(
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fun({_Index, GroupKeys}) ->
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?assertEqual(GroupKeys, lists:usort(GroupKeys))
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end,
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Groups
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).
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group_keys_sorted_indices_test() ->
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Keys = lists:seq(1, 100),
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Groups = group_keys(Keys, 5),
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Indices = [I || {I, _} <- Groups],
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?assertEqual(Indices, lists:sort(Indices)).
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group_keys_all_keys_present_test() ->
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Keys = [a, b, c, d, e],
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Groups = group_keys(Keys, 3),
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AllGroupedKeys = lists:flatten([K || {_, K} <- Groups]),
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?assertEqual(lists:sort(Keys), lists:sort(AllGroupedKeys)).
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-endif.
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