fix issue #561 - websocket client's process may leak when no mqtt packets received

src/emqttd_http.erl

@@ -52,13 +52,14 @@ handle_request('POST', "/mqtt/publish", Req) ->
 %%--------------------------------------------------------------------
 %% MQTT Over WebSocket
 %%--------------------------------------------------------------------
+
 handle_request('GET', "/mqtt", Req) ->
     lager:info("WebSocket Connection from: ~s", [Req:get(peer)]),
     Upgrade = Req:get_header_value("Upgrade"),
     Proto   = Req:get_header_value("Sec-WebSocket-Protocol"),
     case {is_websocket(Upgrade), Proto} of
         {true, "mqtt" ++ _Vsn} ->
-            emqttd_ws_client:start_link(Req);
+            emqttd_ws:handle_request(Req);
         {false, _} ->
             lager:error("Not WebSocket: Upgrade = ~s", [Upgrade]),
             Req:respond({400, [], <<"Bad Request">>});
@@ -144,7 +145,6 @@ authorized(Req) ->
 user_passwd(BasicAuth) ->
     list_to_tuple(binary:split(base64:decode(BasicAuth), <<":">>)). 
 
-
 int(S) -> list_to_integer(S).
 
 bool("0") -> false;

src/emqttd_parser.erl

@@ -36,8 +36,7 @@ new(Opts) ->
     fun(Bin) -> parse(Bin, {none, limit(Opts)}) end.
 
 limit(Opts) ->
-    #mqtt_packet_limit{max_packet_size = 
+    #mqtt_packet_limit{max_packet_size = proplists:get_value(max_packet_size, Opts, ?MAX_LEN)}.
-                        proplists:get_value(max_packet_size, Opts, ?MAX_LEN)}.
 
 %% @doc Parse MQTT Packet
 -spec(parse(binary(), {none, [option()]} | fun())

src/emqttd_ws.erl

@@ -0,0 +1,75 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2012-2016 Feng Lee <feng@emqtt.io>.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqttd_ws).
+
+-export([handle_request/1, ws_loop/3]).
+
+%% WebSocket Loop State
+-record(wsocket_state, {peer, client_pid, packet_opts, parser_fun}).
+
+-define(LOG(Level, Peer, Format, Args),
+        lager:Level("WsClient(~s): " ++ Format, [Peer | Args])).
+
+%%--------------------------------------------------------------------
+%% Handle WebSocket Request
+%%--------------------------------------------------------------------
+
+%% @doc Handle WebSocket Request.
+handle_request(Req) ->
+    Peer = Req:get(peer),
+    PktOpts = emqttd:env(mqtt, packet),
+    ParserFun = emqttd_parser:new(PktOpts),
+    {ReentryWs, ReplyChannel} = upgrade(Req),
+    {ok, ClientPid} = emqttd_ws_client_sup:start_client(self(), Req, ReplyChannel),
+    ReentryWs(#wsocket_state{peer = Peer, client_pid = ClientPid,
+                             packet_opts = PktOpts, parser_fun = ParserFun}).
+
+%% @doc Upgrade WebSocket.
+%% @private
+upgrade(Req) ->
+    mochiweb_websocket:upgrade_connection(Req, fun ?MODULE:ws_loop/3).
+
+%%--------------------------------------------------------------------
+%% Receive Loop
+%%--------------------------------------------------------------------
+
+%% @doc WebSocket frame receive loop.
+ws_loop(<<>>, State, _ReplyChannel) ->
+    State;
+ws_loop([<<>>], State, _ReplyChannel) ->
+    State;
+ws_loop(Data, State = #wsocket_state{peer = Peer, client_pid = ClientPid,
+                                     parser_fun = ParserFun}, ReplyChannel) ->
+    ?LOG(debug, Peer, "RECV ~p", [Data]),
+    case catch ParserFun(iolist_to_binary(Data)) of
+        {more, NewParser} ->
+            State#wsocket_state{parser_fun = NewParser};
+        {ok, Packet, Rest} ->
+            gen_server:cast(ClientPid, {received, Packet}),
+            ws_loop(Rest, reset_parser(State), ReplyChannel);
+        {error, Error} ->
+            ?LOG(error, Peer, "Frame error: ~p", [Error]),
+            exit({shutdown, Error});
+        {'EXIT', Reason} ->
+            ?LOG(error, Peer, "Frame error: ~p", [Reason]),
+            ?LOG(error, Peer, "Error data: ~p", [Data]),
+            exit({shutdown, parser_error})
+    end.
+
+reset_parser(State = #wsocket_state{packet_opts = PktOpts}) ->
+    State#wsocket_state{parser_fun = emqttd_parser:new(PktOpts)}.
+

src/emqttd_ws_client.erl

@@ -16,42 +16,31 @@
 
 -module(emqttd_ws_client).
 
+-behaviour(gen_server).
+
 -include("emqttd.hrl").
 
 -include("emqttd_protocol.hrl").
 
 %% API Exports
--export([start_link/1, ws_loop/3, session/1, info/1, kick/1]).
+-export([start_link/4, session/1, info/1, kick/1]).
 
 %% SUB/UNSUB Asynchronously
 -export([subscribe/2, unsubscribe/2]).
 
--behaviour(gen_server).
-
 %% gen_server Function Exports
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
          terminate/2, code_change/3]).
 
-%% WebSocket Loop State
--record(wsocket_state, {request, client_pid, packet_opts, parser_fun}).
-
 %% WebSocket Client State
--record(wsclient_state, {ws_pid, request, proto_state, keepalive}).
+-record(wsclient_state, {ws_pid, peer, connection, proto_state, keepalive}).
 
--define(WSLOG(Level, Format, Args, Req),
+-define(WSLOG(Level, Peer, Format, Args),
-              lager:Level("WsClient(~s): " ++ Format, [Req:get(peer) | Args])).
+              lager:Level("WsClient(~s): " ++ Format, [Peer | Args])).
 
-%% @doc Start WebSocket client.
+%% @doc Start WebSocket Client.
-start_link(Req) ->
+start_link(MqttEnv, WsPid, Req, ReplyChannel) ->
-    PktOpts = emqttd:env(mqtt, packet),
+    gen_server:start_link(?MODULE, [MqttEnv, WsPid, Req, ReplyChannel], []).
-    ParserFun = emqttd_parser:new(PktOpts),
-    {ReentryWs, ReplyChannel} = upgrade(Req),
-    Params = [self(), Req, ReplyChannel, PktOpts],
-    {ok, ClientPid} = gen_server:start_link(?MODULE, Params, []),
-    ReentryWs(#wsocket_state{request     = Req,
-                             client_pid  = ClientPid,
-                             packet_opts = PktOpts,
-                             parser_fun  = ParserFun}).
 
 session(CPid) ->
     gen_server:call(CPid, session, infinity).
@@ -68,66 +57,40 @@ subscribe(CPid, TopicTable) ->
 unsubscribe(CPid, Topics) ->
     gen_server:cast(CPid, {unsubscribe, Topics}).
 
-%% @private
-%% @doc Upgrade WebSocket.
-upgrade(Req) ->
-    mochiweb_websocket:upgrade_connection(Req, fun ?MODULE:ws_loop/3).
-
-%% @doc WebSocket frame receive loop.
-ws_loop(<<>>, State, _ReplyChannel) ->
-    State;
-ws_loop([<<>>], State, _ReplyChannel) ->
-    State;
-ws_loop(Data, State = #wsocket_state{request    = Req,
-                                     client_pid = ClientPid,
-                                     parser_fun = ParserFun}, ReplyChannel) ->
-    ?WSLOG(debug, "RECV ~p", [Data], Req),
-    case catch ParserFun(iolist_to_binary(Data)) of
-        {more, NewParser} ->
-            State#wsocket_state{parser_fun = NewParser};
-        {ok, Packet, Rest} ->
-            gen_server:cast(ClientPid, {received, Packet}),
-            ws_loop(Rest, reset_parser(State), ReplyChannel);
-        {error, Error} ->
-            ?WSLOG(error, "Frame error: ~p", [Error], Req),
-            exit({shutdown, Error});
-        {'EXIT', Reason} ->
-            ?WSLOG(error, "Frame error: ~p", [Reason], Req),
-            ?WSLOG(error, "Error data: ~p", [Data], Req),
-            exit({shutdown, parser_error})
-    end.
-
-reset_parser(State = #wsocket_state{packet_opts = PktOpts}) ->
-    State#wsocket_state{parser_fun = emqttd_parser:new(PktOpts)}.
-
 %%--------------------------------------------------------------------
-%% gen_server callbacks
+%% gen_server Callbacks
 %%--------------------------------------------------------------------
 
-init([WsPid, Req, ReplyChannel, PktOpts]) ->
+init([MqttEnv, WsPid, Req, ReplyChannel]) ->
-    %%issue#413: trap_exit is unnecessary
+    true = link(WsPid),
-    %%process_flag(trap_exit, true),
     {ok, Peername} = Req:get(peername),
+    Headers = mochiweb_headers:to_list(
+                mochiweb_request:get(headers, Req)),
+    PktOpts = proplists:get_value(packet, MqttEnv),
     SendFun = fun(Payload) -> ReplyChannel({binary, Payload}) end,
-    Headers = mochiweb_request:get(headers, Req),
-    HeadersList = mochiweb_headers:to_list(Headers),
     ProtoState = emqttd_protocol:init(Peername, SendFun,
-                                      [{ws_initial_headers, HeadersList} | PktOpts]),
+                                      [{ws_initial_headers, Headers} | PktOpts]),
-    {ok, #wsclient_state{ws_pid = WsPid, request = Req, proto_state = ProtoState}}.
+    {ok, #wsclient_state{ws_pid = WsPid, peer = Req:get(peer),
+                         connection = Req:get(connection),
+                         proto_state = ProtoState}, idle_timeout(MqttEnv)}.
+
+idle_timeout(MqttEnv) ->
+    ClientOpts = proplists:get_value(client, MqttEnv),
+    timer:seconds(proplists:get_value(idle_timeout, ClientOpts, 10)).
 
 handle_call(session, _From, State = #wsclient_state{proto_state = ProtoState}) ->
     {reply, emqttd_protocol:session(ProtoState), State};
 
-handle_call(info, _From, State = #wsclient_state{request     = Req,
+handle_call(info, _From, State = #wsclient_state{peer = Peer,
                                                  proto_state = ProtoState}) ->
     ProtoInfo = emqttd_protocol:info(ProtoState),
-    {reply, [{websocket, true}, {peer, Req:get(peer)}| ProtoInfo], State};
+    {reply, [{websocket, true}, {peer, Peer}| ProtoInfo], State};
 
 handle_call(kick, _From, State) ->
     {stop, {shutdown, kick}, ok, State};
 
-handle_call(Req, _From, State = #wsclient_state{request = HttpReq}) ->
+handle_call(Req, _From, State = #wsclient_state{peer = Peer}) ->
-    ?WSLOG(critical, "Unexpected request: ~p", [Req], HttpReq),
+    ?WSLOG(critical, Peer, "Unexpected request: ~p", [Req]),
     {reply, {error, unsupported_request}, State}.
 
 handle_cast({subscribe, TopicTable}, State) ->
@@ -140,13 +103,12 @@ handle_cast({unsubscribe, Topics}, State) ->
                    emqttd_session:unsubscribe(SessPid, Topics)
                  end, State);
 
-handle_cast({received, Packet}, State = #wsclient_state{request     = Req,
+handle_cast({received, Packet}, State = #wsclient_state{peer = Peer, proto_state = ProtoState}) ->
-                                                        proto_state = ProtoState}) ->
     case emqttd_protocol:received(Packet, ProtoState) of
         {ok, ProtoState1} ->
             noreply(State#wsclient_state{proto_state = ProtoState1});
         {error, Error} ->
-            ?WSLOG(error, "Protocol error - ~p", [Error], Req),
+            ?WSLOG(error, Peer, "Protocol error - ~p", [Error]),
             shutdown(Error, State);
         {error, Error, ProtoState1} ->
             shutdown(Error, State#wsclient_state{proto_state = ProtoState1});
@@ -154,9 +116,12 @@ handle_cast({received, Packet}, State = #wsclient_state{request     = Req,
             stop(Reason, State#wsclient_state{proto_state = ProtoState1})
     end;
 
-handle_cast(Msg, State = #wsclient_state{request = Req}) ->
+handle_cast(Msg, State = #wsclient_state{peer = Peer}) ->
-    ?WSLOG(critical, "Unexpected msg: ~p", [Msg], Req),
+    ?WSLOG(critical, Peer, "Unexpected msg: ~p", [Msg]),
-    {noreply, State}.
+    noreply(State).
+
+handle_info(timeout, State) ->
+    shutdown(idle_timeout, State);
 
 handle_info({suback, PacketId, GrantedQos}, State) ->
     with_proto_state(fun(ProtoState) ->
@@ -174,13 +139,12 @@ handle_info({redeliver, {?PUBREL, PacketId}}, State) ->
                        emqttd_protocol:redeliver({?PUBREL, PacketId}, ProtoState)
                      end, State);
 
-handle_info({shutdown, conflict, {ClientId, NewPid}}, State = #wsclient_state{request = Req}) ->
+handle_info({shutdown, conflict, {ClientId, NewPid}}, State = #wsclient_state{peer = Peer}) ->
-    ?WSLOG(warning, "clientid '~s' conflict with ~p", [ClientId, NewPid], Req),
+    ?WSLOG(warning, Peer, "clientid '~s' conflict with ~p", [ClientId, NewPid]),
     shutdown(conflict, State);
 
-handle_info({keepalive, start, Interval}, State = #wsclient_state{request = Req}) ->
+handle_info({keepalive, start, Interval}, State = #wsclient_state{peer = Peer, connection = Conn}) ->
-    ?WSLOG(debug, "Keepalive at the interval of ~p", [Interval], Req),
+    ?WSLOG(debug, Peer, "Keepalive at the interval of ~p", [Interval]),
-    Conn = Req:get(connection),
     StatFun = fun() ->
         case Conn:getstat([recv_oct]) of
             {ok, [{recv_oct, RecvOct}]} -> {ok, RecvOct};
@@ -190,25 +154,21 @@ handle_info({keepalive, start, Interval}, State = #wsclient_state{request = Req}
     KeepAlive = emqttd_keepalive:start(StatFun, Interval, {keepalive, check}),
     noreply(State#wsclient_state{keepalive = KeepAlive});
 
-handle_info({keepalive, check}, State = #wsclient_state{request   = Req,
+handle_info({keepalive, check}, State = #wsclient_state{peer      = Peer,
                                                         keepalive = KeepAlive}) ->
     case emqttd_keepalive:check(KeepAlive) of
         {ok, KeepAlive1} ->
             noreply(State#wsclient_state{keepalive = KeepAlive1});
         {error, timeout} ->
-            ?WSLOG(debug, "Keepalive Timeout!", [], Req),
+            ?WSLOG(debug, Peer, "Keepalive Timeout!", []),
             shutdown(keepalive_timeout, State);
         {error, Error} ->
-            ?WSLOG(warning, "Keepalive error - ~p", [Error], Req),
+            ?WSLOG(warning, Peer, "Keepalive error - ~p", [Error]),
             shutdown(keepalive_error, State)
     end;
 
-%%issue#413: removed the trap_exit flag
+handle_info(Info, State = #wsclient_state{peer = Peer}) ->
-%%handle_info({'EXIT', WsPid, Reason}, State = #wsclient_state{ws_pid = WsPid}) ->
+    ?WSLOG(critical, Peer, "Unexpected Info: ~p", [Info]),
-%%    stop(Reason, State);
-
-handle_info(Info, State = #wsclient_state{request = Req}) ->
-    ?WSLOG(critical, "Unexpected Info: ~p", [Info], Req),
     noreply(State).
 
 terminate(Reason, #wsclient_state{proto_state = ProtoState, keepalive = KeepAlive}) ->