175 lines
6.4 KiB
Erlang
175 lines
6.4 KiB
Erlang
%%%-----------------------------------------------------------------------------
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%%% @Copyright (C) 2012-2015, Feng Lee <feng@emqtt.io>
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%%%
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%%% Permission is hereby granted, free of charge, to any person obtaining a copy
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%%% of this software and associated documentation files (the "Software"), to deal
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%%% in the Software without restriction, including without limitation the rights
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%%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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%%% copies of the Software, and to permit persons to whom the Software is
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%%% furnished to do so, subject to the following conditions:
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%%%
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%%% The above copyright notice and this permission notice shall be included in all
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%%% copies or substantial portions of the Software.
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%%%
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%%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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%%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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%%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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%%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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%%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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%%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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%%% SOFTWARE.
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%%%-----------------------------------------------------------------------------
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%%% @doc
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%%% emqttd bridge.
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%%%
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%%% @end
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%%%-----------------------------------------------------------------------------
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-module(emqttd_bridge).
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-author('feng@emqtt.io').
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-behaviour(gen_server).
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-include("emqttd_packet.hrl").
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%% API Function Exports
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-export([start_link/3]).
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%% gen_server Function Exports
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-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
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terminate/2, code_change/3]).
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-define(PING_DOWN_INTERVAL, 1000).
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-record(state, {node, subtopic,
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qos,
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topic_suffix = <<>>,
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topic_prefix = <<>>,
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max_queue_len = 0,
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ping_down_interval = ?PING_DOWN_INTERVAL,
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status = up}).
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-type option() :: {max_queue_len, pos_integer()} |
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{qos, mqtt_qos()} |
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{topic_suffix, binary()} |
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{topic_prefix, binary()} |
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{ping_down_interval, pos_integer()}.
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-export_type([option/0]).
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%%%=============================================================================
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%%% API
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%%%=============================================================================
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%%------------------------------------------------------------------------------
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%% @doc
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%% Start a bridge.
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%%
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%% @end
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%%------------------------------------------------------------------------------
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-spec start_link(atom(), binary(), [option()]) -> {ok, pid()} | ignore | {error, term()}.
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start_link(Node, SubTopic, Options) ->
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gen_server:start_link(?MODULE, [Node, SubTopic, Options], []).
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%%%=============================================================================
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%%% gen_server callbacks
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%%%=============================================================================
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init([Node, SubTopic, Options]) ->
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process_flag(trap_exit, true),
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case net_kernel:connect_node(Node) of
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true ->
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true = erlang:monitor_node(Node, true),
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State = parse_opts(Options, #state{node = Node, subtopic = SubTopic}),
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emqttd_pubsub:subscribe({SubTopic, ?QOS_0}),
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{ok, State};
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false ->
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{stop, {cannot_connect, Node}}
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end.
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parse_opts([], State) ->
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State;
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parse_opts([{qos, Qos} | Opts], State) ->
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parse_opts(Opts, State#state{qos = Qos});
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parse_opts([{topic_suffix, Suffix} | Opts], State) ->
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parse_opts(Opts, State#state{topic_suffix= Suffix});
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parse_opts([{topic_prefix, Prefix} | Opts], State) ->
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parse_opts(Opts, State#state{topic_prefix = Prefix});
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parse_opts([{max_queue_len, Len} | Opts], State) ->
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parse_opts(Opts, State#state{max_queue_len = Len});
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parse_opts([{ping_down_interval, Interval} | Opts], State) ->
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parse_opts(Opts, State#state{ping_down_interval = Interval*1000}).
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handle_call(_Request, _From, State) ->
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{reply, ok, State}.
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handle_cast(_Msg, State) ->
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{noreply, State}.
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handle_info({dispatch, {_From, Msg}}, State = #state{node = Node, status = down}) ->
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lager:warning("Bridge Dropped Msg for ~p Down:~n~p", [Node, Msg]),
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{noreply, State};
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handle_info({dispatch, {_From, Msg}}, State = #state{node = Node, status = up}) ->
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rpc:cast(Node, emqttd_router, route, [transform(Msg, State)]),
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{noreply, State};
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handle_info({nodedown, Node}, State = #state{node = Node, ping_down_interval = Interval}) ->
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lager:warning("Bridge Node Down: ~p", [Node]),
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erlang:send_after(Interval, self(), ping_down_node),
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{noreply, State#state{status = down}};
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handle_info({nodeup, Node}, State = #state{node = Node}) ->
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%% TODO: Really fast??
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case emqttd:is_running(Node) of
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true ->
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lager:warning("Bridge Node Up: ~p", [Node]),
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{noreply, State#state{status = up}};
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false ->
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self() ! {nodedown, Node},
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{noreply, State#state{status = down}}
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end;
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handle_info(ping_down_node, State = #state{node = Node, ping_down_interval = Interval}) ->
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Self = self(),
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spawn_link(fun() ->
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case net_kernel:connect_node(Node) of
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true -> %%TODO: this is not right... fixme later
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Self ! {nodeup, Node};
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false ->
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erlang:send_after(Interval, Self, ping_down_node)
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end
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end),
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{noreply, State};
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handle_info({'EXIT', _Pid, normal}, State) ->
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{noreply, State};
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handle_info(Info, State) ->
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lager:error("Unexpected Info: ~p", [Info]),
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{noreply, State}.
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terminate(_Reason, _State) ->
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ok.
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code_change(_OldVsn, State, _Extra) ->
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{ok, State}.
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%%%=============================================================================
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%%% Internal functions
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%%%=============================================================================
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%TODO: qos is not right...
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transform(Msg = #mqtt_message{topic = Topic}, #state{qos = Qos,
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topic_prefix = Prefix,
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topic_suffix = Suffix}) ->
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Msg1 =
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if
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Qos =:= undefined -> Msg;
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true -> Msg#mqtt_message{qos = Qos}
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end,
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Msg1#mqtt_message{topic = <<Prefix/binary, Topic/binary, Suffix/binary>>}.
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