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67 lines
2.1 KiB
Erlang
67 lines
2.1 KiB
Erlang
%%--------------------------------------------------------------------
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%% Copyright (c) 2019-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
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%%
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%% Licensed under the Apache License, Version 2.0 (the "License");
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%% you may not use this file except in compliance with the License.
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%% You may obtain a copy of the License at
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%%
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%% http://www.apache.org/licenses/LICENSE-2.0
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%%
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%% Unless required by applicable law or agreed to in writing, software
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%% distributed under the License is distributed on an "AS IS" BASIS,
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%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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%% See the License for the specific language governing permissions and
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%% limitations under the License.
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%%--------------------------------------------------------------------
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-module(emqx_cm_locker).
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-include("emqx.hrl").
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-include("types.hrl").
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-export([start_link/0]).
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-export([ trans/2
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, trans/3
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, lock/1
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, lock/2
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, unlock/1
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]).
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-spec(start_link() -> startlink_ret()).
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start_link() ->
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ekka_locker:start_link(?MODULE).
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-spec(trans(emqx_types:clientid(), fun(([node()]) -> any())) -> any()).
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trans(ClientId, Fun) ->
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trans(ClientId, Fun, undefined).
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-spec(trans(maybe(emqx_types:clientid()),
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fun(([node()])-> any()), ekka_locker:piggyback()) -> any()).
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trans(undefined, Fun, _Piggyback) ->
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Fun([]);
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trans(ClientId, Fun, Piggyback) ->
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case lock(ClientId, Piggyback) of
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{true, Nodes} ->
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try Fun(Nodes) after unlock(ClientId) end;
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{false, _Nodes} ->
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{error, client_id_unavailable}
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end.
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-spec(lock(emqx_types:clientid()) -> ekka_locker:lock_result()).
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lock(ClientId) ->
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ekka_locker:acquire(?MODULE, ClientId, strategy()).
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-spec(lock(emqx_types:clientid(), ekka_locker:piggyback()) -> ekka_locker:lock_result()).
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lock(ClientId, Piggyback) ->
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ekka_locker:acquire(?MODULE, ClientId, strategy(), Piggyback).
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-spec(unlock(emqx_types:clientid()) -> {boolean(), [node()]}).
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unlock(ClientId) ->
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ekka_locker:release(?MODULE, ClientId, strategy()).
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-spec(strategy() -> local | leader | quorum | all).
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strategy() ->
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emqx:get_env(session_locking_strategy, quorum).
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