From 5a43afd07f530f6a5a5f7f4c6dc8d89df6ac62f0 Mon Sep 17 00:00:00 2001
From: Feng Lee <ery.lee@gmail.com>
Date: Wed, 29 Apr 2015 16:23:26 +0800
Subject: [PATCH] start_tick, stop_tick

---
 apps/emqttd/src/emqttd_broker.erl  | 33 ++++++++++++++++++++++++------
 apps/emqttd/src/emqttd_metrics.erl |  5 ++---
 apps/emqttd/src/emqttd_stats.erl   |  7 +++----
 3 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/apps/emqttd/src/emqttd_broker.erl b/apps/emqttd/src/emqttd_broker.erl
index 811bef7e7..52ee832d0 100644
--- a/apps/emqttd/src/emqttd_broker.erl
+++ b/apps/emqttd/src/emqttd_broker.erl
@@ -45,6 +45,9 @@
 %% Broker API
 -export([env/1, version/0, uptime/0, datetime/0, sysdescr/0]).
 
+%% Tick API
+-export([start_tick/1, stop_tick/1]).
+
 %% gen_server Function Exports
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
          terminate/2, code_change/3]).
@@ -124,6 +127,27 @@ datetime() ->
         io_lib:format(
             "~4..0w-~2..0w-~2..0w ~2..0w:~2..0w:~2..0w", [Y, M, D, H, MM, S])).
 
+%%------------------------------------------------------------------------------
+%% @doc Start a tick timer
+%% @end
+%%------------------------------------------------------------------------------
+start_tick(Msg) ->
+    start_tick(timer:seconds(env(sys_interval)), Msg).
+
+start_tick(0, _Msg) ->
+    undefined;
+start_tick(Interval, Msg) when Interval > 0 ->
+    {ok, TRef} = timer:send_interval(Interval, Msg), TRef.
+
+%%------------------------------------------------------------------------------
+%% @doc Start tick timer
+%% @end
+%%------------------------------------------------------------------------------
+stop_tick(undefined) ->
+    ok;
+stop_tick(TRef) ->
+    timer:cancel(TRef).
+
 %%%=============================================================================
 %%% gen_server callbacks
 %%%=============================================================================
@@ -134,10 +158,7 @@ init([]) ->
     % Create $SYS Topics
     [ok = create_topic(Topic) || Topic <- ?SYSTOP_BROKERS],
     % Tick
-    SysInterval = env(sys_interval),
-    {ok, TRef} = timer:send_interval(timer:seconds(SysInterval), tick),
-    State = #state{started_at = os:timestamp(), sys_interval = SysInterval, tick_tref = TRef},
-    {ok, State, hibernate}.
+    {ok, #state{started_at = os:timestamp(), tick_tref = start_tick(tick)}, hibernate}.
 
 handle_call(uptime, _From, State) ->
     {reply, uptime(State), State};
@@ -158,8 +179,8 @@ handle_info(tick, State) ->
 handle_info(_Info, State) ->
     {noreply, State}.
 
-terminate(_Reason, _State) ->
-    ok.
+terminate(_Reason, #state{tick_tref = TRef}) ->
+    stop_tick(TRef).
 
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
diff --git a/apps/emqttd/src/emqttd_metrics.erl b/apps/emqttd/src/emqttd_metrics.erl
index 98d2ec81c..085d7c98f 100644
--- a/apps/emqttd/src/emqttd_metrics.erl
+++ b/apps/emqttd/src/emqttd_metrics.erl
@@ -165,8 +165,7 @@ init([]) ->
     % $SYS Topics for metrics
     [ok = create_topic(Topic) || {_, Topic} <- Metrics],
     % Tick to publish metrics
-    {ok, TRef} = timer:send_interval(timer:seconds(emqttd_broker:env(sys_interval)), tick),
-    {ok, #state{tick_tref = TRef}, hibernate}.
+    {ok, #state{tick_tref = emqttd_broker:start_tick(tick)}, hibernate}.
 
 handle_call(_Req, _From, State) ->
     {reply, error,  State}.
@@ -183,7 +182,7 @@ handle_info(_Info, State) ->
     {noreply, State}.
 
 terminate(_Reason, #state{tick_tref = TRef}) ->
-    timer:cancel(TRef), ok.
+    emqttd_broker:stop_tick(TRef).
 
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
diff --git a/apps/emqttd/src/emqttd_stats.erl b/apps/emqttd/src/emqttd_stats.erl
index 550d7aa89..e558c94ae 100644
--- a/apps/emqttd/src/emqttd_stats.erl
+++ b/apps/emqttd/src/emqttd_stats.erl
@@ -128,8 +128,7 @@ init([]) ->
     % Create $SYS Topics
     [ok = emqttd_pubsub:create(emqtt_topic:systop(Topic)) || Topic <- Topics],
     % Tick to publish stats
-    {ok, TRef} = timer:send_interval(timer:seconds(emqttd_broker:env(sys_interval)), tick),
-    {ok, #state{tick_tref = TRef}, hibernate}.
+    {ok, #state{tick_tref = emqttd_broker:start_tick(tick)}, hibernate}.
 
 handle_call(_Request, _From, State) ->
     {reply, error, State}.
@@ -137,6 +136,7 @@ handle_call(_Request, _From, State) ->
 handle_cast(_Msg, State) ->
     {noreply, State}.
 
+%% Interval Tick.
 handle_info(tick, State) ->
     [publish(Stat, Val) || {Stat, Val} <- ets:tab2list(?STATS_TAB)],
     {noreply, State, hibernate};
@@ -145,7 +145,7 @@ handle_info(_Info, State) ->
     {noreply, State}.
 
 terminate(_Reason, #state{tick_tref = TRef}) ->
-    timer:cancel(TRef), ok.
+    emqttd_broker:stop_tick(TRef).
 
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
@@ -157,4 +157,3 @@ publish(Stat, Val) ->
     emqttd_pubsub:publish(stats, #mqtt_message{topic   = emqtt_topic:systop(Stat),
                                                payload = emqttd_util:integer_to_binary(Val)}).
 
-