增加带容量限制的缓冲队列，避免内存耗尽

apps/iot/src/endpoint/iot_zd_endpoint.erl

@@ -22,13 +22,16 @@
 %% 消息重发间隔
 -define(RETRY_INTERVAL, 5000).
 
+%% 最大数据缓冲量
+-define(MAX_QUEUE_SIZE, 5_000_000).
+
 -record(state, {
     mqtt_opts = [],
     postman_pid :: undefined | pid(),
     logger_pid :: pid(),
 
     %% 数据缓存队列
-    queue = queue:new(),
+    iot_queue,
 
     %% 定时器
     timer_ref :: undefined | reference(),
@@ -78,7 +81,7 @@ init([]) ->
     %% 启动日志记录器
     {ok, LoggerPid} = iot_logger:start_link("north_data"),
 
-    {ok, disconnected, #state{mqtt_opts = Opts, queue = queue:new(), postman_pid = undefined, logger_pid = LoggerPid}}.
+    {ok, disconnected, #state{mqtt_opts = Opts, iot_queue = iot_queue:new(?MAX_QUEUE_SIZE), postman_pid = undefined, logger_pid = LoggerPid}}.
 
 %% @private
 %% @doc This function is called by a gen_statem when it needs to find out
@@ -92,7 +95,12 @@ callback_mode() ->
 %% functions is called when gen_statem receives and event from
 %% call/2, cast/2, or as a normal process message.
 
-handle_event(cast, {forward, LocationCode, DynamicLocationCode, Fields, Timestamp}, StateName, State = #state{is_busy = IsBusy, queue = Q}) ->
+handle_event(cast, {forward, LocationCode, DynamicLocationCode, Fields, Timestamp}, StateName, State = #state{is_busy = IsBusy, iot_queue = Q}) ->
+    case iot_queue:is_full(Q) of
+        true ->
+            lager:debug("[iot_zd_endpoint] queue is full discard data: ~p", [{LocationCode, DynamicLocationCode, Fields, Timestamp}]),
+            {keep_state, State};
+        false ->
             case format_data(LocationCode, DynamicLocationCode, Fields, Timestamp) of
                 {ok, Body} ->
                     %% 避免不必要的内部消息
@@ -100,9 +108,10 @@ handle_event(cast, {forward, LocationCode, DynamicLocationCode, Fields, Timestam
                                   true  -> [{next_event, info, fetch_next}];
                                   false -> []
                               end,
-            {keep_state, State#state{queue = queue:in(Body, Q)}, Actions};
+                    {keep_state, State#state{iot_queue = iot_queue:in(Body, Q)}, Actions};
                 error ->
                     {keep_state, State}
+            end
     end;
 
 %% 触发读取下一条数据
@@ -111,14 +120,14 @@ handle_event(info, fetch_next, disconnected, State) ->
     {keep_state, State};
 handle_event(info, fetch_next, connected, State = #state{is_busy = true}) ->
     {keep_state, State};
-handle_event(info, fetch_next, connected, State = #state{postman_pid = PostmanPid, queue = Q}) ->
-    case queue:out(Q) of
+handle_event(info, fetch_next, connected, State = #state{postman_pid = PostmanPid, iot_queue = Q}) ->
+    case iot_queue:out(Q) of
         {{value, Body}, Q1} ->
             lager:debug("[iot_zd_endpoint] fetch_next success, north data is: ~p", [Body]),
             PostmanPid ! {post, self(), Body},
             TimerRef = erlang:start_timer(?RETRY_INTERVAL, self(), {repost_ticker, Body}),
 
-            {keep_state, State#state{queue = Q1, timer_ref = TimerRef, is_busy = true}};
+            {keep_state, State#state{iot_queue = Q1, timer_ref = TimerRef, is_busy = true}};
         {empty, _} ->
             {keep_state, State}
     end;
@@ -161,10 +170,10 @@ handle_event(info, {timeout, _, create_postman}, disconnected, State = #state{mq
     end;
 
 %% 获取当前统计信息
-handle_event({call, From}, get_stat, StateName, State = #state{acc_num = AccNum, queue = Q}) ->
+handle_event({call, From}, get_stat, StateName, State = #state{acc_num = AccNum, iot_queue = Q}) ->
     Stat = #{
         <<"acc_num">> => AccNum,
-        <<"queue_num">> => queue:len(Q),
+        <<"queue_num">> => iot_queue:len(Q),
         <<"state_name">> => atom_to_binary(StateName)
     },
     {keep_state, State, [{reply, From, Stat}]};

apps/iot/src/struct/iot_queue.erl

@@ -10,7 +10,7 @@
 -author("anlicheng").
 
 %% API
--export([new/1, in/2, out/1]).
+-export([new/1, in/2, out/1, is_full/1, len/1]).
 
 -record(iot_queue, {
     capacity = 1024,
@@ -26,6 +26,14 @@ new(Capacity) when is_integer(Capacity) ->
         queue = queue:new()
     }.
 
+-spec is_full(Iot_queue :: #iot_queue{}) -> boolean().
+is_full(#iot_queue{capacity = Capacity, len = Len}) ->
+    Len >= Capacity.
+
+-spec len(Iot_queue :: #iot_queue{}) -> integer().
+len(#iot_queue{len = Len}) ->
+    Len.
+
 -spec in(Item :: any(), TQ :: #iot_queue{}) -> NQ :: #iot_queue{}.
 in(_Item, TQ = #iot_queue{capacity = Capacity, len = Len}) when Len >= Capacity ->
     TQ;