new session

apps/emqtt/src/emqtt.app.src

@@ -1,7 +1,7 @@
 {application, emqtt,
  [
   {description, "Erlang MQTT Common Library"},
-  {vsn, "0.8.3"},
+  {vsn, git},
   {modules, []},
   {registered, []},
   {applications, [

apps/emqttd/src/emqttd.app.src

@@ -1,7 +1,7 @@
 {application, emqttd,
  [
   {description, "Erlang MQTT Broker"},
-  {vsn, "0.8.3"},
+  {vsn, git},
   {modules, []},
   {registered, []},
   {applications, [kernel,

apps/emqttd/src/emqttd_mqueue.erl

@@ -0,0 +1,15 @@
+
+-module(emqttd_mqueue).
+
+-export([init/1, in/1]).
+
+-record(queue_state, {
+        max_queued_messages = 1000
+}).
+
+init(Opts) ->
+    {ok, #queue_state{}}.
+
+in(Msg, Q = #queue_state{}) ->
+    Q.
+

apps/emqttd/src/emqttd_pubsub.erl

@@ -24,6 +24,7 @@
 %%%
 %%% @end
 %%%-----------------------------------------------------------------------------
+
 -module(emqttd_pubsub).
 
 -author("Feng Lee <feng@emqtt.io>").
@@ -217,6 +218,7 @@ match(Topic) when is_binary(Topic) ->
 init([Id, _Opts]) ->
     process_flag(min_heap_size, 1024*1024),
     gproc_pool:connect_worker(pubsub, {?MODULE, Id}),
+    %%TODO: gb_trees to replace maps?
     {ok, #state{id = Id, submap = maps:new()}}.
 
 handle_call({subscribe, SubPid, Topics}, _From, State) ->
@@ -384,9 +386,24 @@ add_topic(TopicR = #mqtt_topic{topic = Topic}) ->
             end
     end.
 
-add_subscriber({TopicR, Subscriber}) when is_record(TopicR, mqtt_topic) ->
+%% Fix issue #53 - Remove Overlapping Subscriptions
+add_subscriber({TopicR, Subscriber = #mqtt_subscriber{topic = Topic, qos = Qos, pid = SubPid}})
+                when is_record(TopicR, mqtt_topic) ->
     case add_topic(TopicR) of
         ok ->
+            OverlapSubs = [Sub || Sub = #mqtt_subscriber{topic = SubTopic, qos = SubQos}
+                                    <- mnesia:index_read(subscriber, SubPid, #mqtt_subscriber.pid),
+                                        SubTopic =:= Topic, SubQos =/= Qos],
+
+            %% remove overlapping subscribers
+            if
+                length(OverlapSubs) =:= 0 -> ok;
+                true ->
+                    lager:warning("Remove overlapping subscribers: ~p", [OverlapSubs]),
+                    [mnesia:delete_object(subscriber, OverlapSub, write) || OverlapSub <- OverlapSubs]
+            end,
+
+            %% insert subscriber
             mnesia:write(subscriber, Subscriber, write);
         Error -> 
             Error

apps/emqttd/src/emqttd_session.erl

@@ -43,6 +43,7 @@
          unsubscribe/2,
          destroy/2]).
 
+%% This api looks strange... :(
 -export([store/2]).
 
 %% Start gen_server
@@ -52,19 +53,53 @@
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
          terminate/2, code_change/3]).
 
--record(session_state, { 
-        clientid   :: binary(),
+-record(session_state, {
+        %% ClientId: Identifier of Session
+        clientid    :: binary(),
+
+        %% Client Pid linked with session
         client_pid  :: pid(),
-		message_id  = 1,
-        submap      :: map(),
-        inflight_messages,
-        queued_messages,
-        msg_queue, %% do not receive rel
-        awaiting_ack :: map(),
-        awaiting_rel :: map(),
+
+        %% Last message id of the session
+		message_id = 1,
+        
+        %% Client’s subscriptions.
+        subscriptions :: list(),
+
+        %% Inflight window size
+        inflight_window = 40,
+
+        %% Inflight qos1, qos2 messages sent to the client but unacked, QoS 1 and QoS 2 messages which have been sent to the Client, but have not been completely acknowledged.
+        %% Client <- Broker
+        inflight_queue :: list(),
+
+        %% Inflight qos2 messages received from client and waiting for pubrel. QoS 2 messages which have been received from the Client, but have not been completely acknowledged.
+        %% Client -> Broker
+        awaiting_queue :: list(),
+
+        %% All qos1, qos2 messages published to when client is disconnected. QoS 1 and QoS 2 messages pending transmission to the Client.
+        %% Optionally, QoS 0 messages pending transmission to the Client.
+        pending_queue  :: emqttd_mqueue:mqueue(),
+
+        %% Awaiting timers for ack, rel and comp.
+        awaiting_ack  :: map(),
+
+        awaiting_rel  :: map(),
+
         awaiting_comp :: map(),
-        expires,
-        expire_timer}).
+
+        %% Retries to resend the unacked messages
+        max_unack_retries = 3,
+
+        %% 4, 8, 16 seconds if 3 retries:)
+        unack_retry_after = 4,
+
+        %% session expired
+        sess_expired_after = 48,
+
+        sess_expired_timer,
+        
+        timestamp}).
 
 -type session() :: #session_state{} | pid().
 
@@ -235,11 +270,13 @@ store(SessState = #session_state{message_id = MsgId, awaiting_ack = Awaiting},
     {Message1, next_msg_id(SessState#session_state{awaiting_ack = Awaiting1})}.
 
 initial_state(ClientId) ->
-    #session_state{clientid     = ClientId,
-                   submap        = #{}, 
-                   awaiting_ack  = #{},
-                   awaiting_rel  = #{},
-                   awaiting_comp = #{}}.
+    #session_state{clientid       = ClientId,
+                   subscriptions  = [],
+                   inflight_queue = [],
+                   awaiting_queue = [],
+                   awaiting_ack   = #{},
+                   awaiting_rel   = #{},
+                   awaiting_comp  = #{}}.
 
 initial_state(ClientId, ClientPid) ->
     State = initial_state(ClientId),
@@ -258,16 +295,36 @@ start_link(ClientId, ClientPid) ->
 
 init([ClientId, ClientPid]) ->
     process_flag(trap_exit, true),
-    %%TODO: Is this OK? or should monitor...
     true = link(ClientPid),
-    SessOpts = emqttd:env(mqtt, session),
     State = initial_state(ClientId, ClientPid),
-    Expires = proplists:get_value(expires, SessOpts, 1) * 3600,
-    MsgQueue = emqttd_queue:new(proplists:get_value(max_queue, SessOpts, 1000), 
-                               proplists:get_value(store_qos0, SessOpts, false)),
-    {ok, State#session_state{expires = Expires,
-                             msg_queue = MsgQueue}, hibernate}.
+    MQueue = emqttd_mqueue:new(ClientId, emqttd:env(mqtt, queue)),
+    State1 = State#session_state{pending_queue = MQueue,
+                                 timestamp = os:timestamp()},
+    {ok, init(emqttd:env(mqtt, session), State1), hibernate}.
 
+init([], State) ->
+    State;
+
+%% Session expired after hours
+init([{expired_after, Hours} | Opts], State) ->
+    init(Opts, State#session_state{sess_expired_after = Hours * 3600 * 1000});
+    
+%% Max number of QoS 1 and 2 messages that can be “inflight” at one time.
+init([{max_inflight_messages, MaxInflight} | Opts], State) ->
+    init(Opts, State#session_state{inflight_window = MaxInflight});
+
+%% Max retries for unacknolege Qos1/2 messages
+init([{max_unack_retries, Retries} | Opts], State) ->
+    init(Opts, State#session_state{max_unack_retries = Retries});
+
+%% Retry after 4, 8, 16 seconds
+init([{unack_retry_after, Secs} | Opts], State) ->
+    init(Opts, State#session_state{unack_retry_after = Secs * 1000});
+
+init([Opt | Opts], State) ->
+    lager:error("Bad Session Option: ~p", [Opt]),
+    init(Opts, State).
+    
 handle_call({subscribe, Topics}, _From, State) ->
     {ok, NewState, GrantedQos} = subscribe(State, Topics),
     {reply, {ok, GrantedQos}, NewState};

apps/zenmq/README

@@ -0,0 +1,14 @@
+## Overview
+
+ZenMQ is a general architecture of a distributed messaging queue written in Erlang.
+
+## Responsibilties
+
+* Topic Trie Tree
+* Message Route
+* Queue Management
+* Broker Cluster
+* Distributed Broker
+
+**Notice that this is an experimental design**
+

apps/zenmq/src/zenmq.app.src

@@ -0,0 +1,12 @@
+{application, zenmq,
+ [
+  {description, ""},
+  {vsn, "1"},
+  {registered, []},
+  {applications, [
+                  kernel,
+                  stdlib
+                 ]},
+  {mod, { zenmq_app, []}},
+  {env, []}
+ ]}.

apps/zenmq/src/zenmq.erl

@@ -0,0 +1,2 @@
+-module(zenmq).
+

apps/zenmq/src/zenmq_app.erl

@@ -0,0 +1,16 @@
+-module(zenmq_app).
+
+-behaviour(application).
+
+%% Application callbacks
+-export([start/2, stop/1]).
+
+%% ===================================================================
+%% Application callbacks
+%% ===================================================================
+
+start(_StartType, _StartArgs) ->
+    zenmq_sup:start_link().
+
+stop(_State) ->
+    ok.

apps/zenmq/src/zenmq_sup.erl

@@ -0,0 +1,27 @@
+-module(zenmq_sup).
+
+-behaviour(supervisor).
+
+%% API
+-export([start_link/0]).
+
+%% Supervisor callbacks
+-export([init/1]).
+
+%% Helper macro for declaring children of supervisor
+-define(CHILD(I, Type), {I, {I, start_link, []}, permanent, 5000, Type, [I]}).
+
+%% ===================================================================
+%% API functions
+%% ===================================================================
+
+start_link() ->
+    supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+%% ===================================================================
+%% Supervisor callbacks
+%% ===================================================================
+
+init([]) ->
+    {ok, { {one_for_one, 5, 10}, []} }.
+

rel/files/emqttd.config

@@ -93,8 +93,8 @@
             {max_inflight_messages, 20},
             %% Max retries for unacknolege Qos1/2 messages
             {max_unack_retries, 3},
-            %% Retry after 10 seconds
-            {unack_retry_after, 10}
+            %% Retry after 2, 4,8 seconds
+            {unack_retry_after, 2}
         ]},
         {queue, [
             %% Max messages queued when client is disconnected, or inflight messsages is overload

rel/reltool.config

@@ -4,7 +4,7 @@
        {lib_dirs, ["../apps", "../deps", "../plugins"]},
        {erts, [{mod_cond, derived}, {app_file, strip}]},
        {app_file, strip},
-       {rel, "emqttd", "0.8.3",
+       {rel, "emqttd", git,
         [
          kernel,
          stdlib,