From c7c7b597c56f99c30cf8473d180ad01503a0b65b Mon Sep 17 00:00:00 2001
From: Feng Lee <ery.lee@gmail.com>
Date: Sun, 8 Mar 2015 13:38:59 +0800
Subject: [PATCH] getstats

---
 apps/emqtt/src/emqtt_cm.erl | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/apps/emqtt/src/emqtt_cm.erl b/apps/emqtt/src/emqtt_cm.erl
index 64cd451f4..d4089eebd 100644
--- a/apps/emqtt/src/emqtt_cm.erl
+++ b/apps/emqtt/src/emqtt_cm.erl
@@ -29,7 +29,7 @@
 
 -define(SERVER, ?MODULE).
 
--define(TAB, emqtt_client).
+-define(TABLE, emqtt_client).
 
 %% ------------------------------------------------------------------
 %% API Function Exports
@@ -39,6 +39,8 @@
 
 -export([lookup/1, register/2, unregister/2]).
 
+-export([getstats/0]).
+
 %% ------------------------------------------------------------------
 %% gen_server Function Exports
 %% ------------------------------------------------------------------
@@ -50,6 +52,8 @@
          terminate/2,
 		 code_change/3]).
 
+-record(state, {max = 0}).
+
 %% ------------------------------------------------------------------
 %% API Function Definitions
 %% ------------------------------------------------------------------
@@ -80,17 +84,20 @@ register(ClientId, Pid) when is_binary(ClientId), is_pid(Pid) ->
 unregister(ClientId, Pid) when is_binary(ClientId), is_pid(Pid) ->
 	gen_server:cast(?SERVER, {unregister, ClientId, Pid}).
 
+getstats(?SERVER) ->
+    gen_server:call(?SERVER, getstats).
+
 %% ------------------------------------------------------------------
 %% gen_server Function Definitions
 %% ------------------------------------------------------------------
 
 init([]) ->
 	%on one node
-	ets:new(?TAB, [set, named_table, protected]),
+	ets:new(?TABLE, [set, named_table, protected]),
     {ok, none}.
 
 handle_call({register, ClientId, Pid}, _From, State) ->
-	case ets:lookup(?TAB, ClientId) of
+	case ets:lookup(?TABLE, ClientId) of
         [{_, Pid, _}] ->
 			lager:error("clientId '~s' has been registered with ~p", [ClientId, Pid]),
             ignore;
@@ -103,14 +110,18 @@ handle_call({register, ClientId, Pid}, _From, State) ->
 	end,
 	{reply, ok, State};
 
+handle_call(getstats, _From, State = #state{max = Max}) ->
+    Stats = [{total, ets:info(?TABLE, size)}, {max, Max}],
+    {reply, Stats, State};
+
 handle_call(_Request, _From, State) ->
     {reply, ok, State}.
 
 handle_cast({unregister, ClientId, Pid}, State) ->
-	case ets:lookup(?TAB, ClientId) of
+	case ets:lookup(?TABLE, ClientId) of
 	[{_, Pid, MRef}] ->
 		erlang:demonitor(MRef),
-		ets:delete(?TAB, ClientId);
+		ets:delete(?TABLE, ClientId);
 	[_] -> 
 		ignore;
 	[] ->
@@ -122,7 +133,7 @@ handle_cast(_Msg, State) ->
     {noreply, State}.
 
 handle_info({'DOWN', MRef, process, DownPid, _Reason}, State) ->
-	ets:match_delete(emqtt_client, {{'_', DownPid, MRef}}),
+	ets:match_delete(?TABLE, {{'_', DownPid, MRef}}),
     {noreply, State};
 
 handle_info(_Info, State) ->
@@ -135,5 +146,5 @@ code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
 
 insert(ClientId, Pid) ->
-    ets:insert(emqtt_client, {ClientId, Pid, erlang:monitor(process, Pid)}).
+    ets:insert(?TABLE, {ClientId, Pid, erlang:monitor(process, Pid)}).