fix: run the 'message.acked' hook when ACK received from CoAP devices

apps/emqx_coap/src/emqx_coap.app.src

@@ -1,6 +1,6 @@
 {application, emqx_coap,
  [{description, "EMQ X CoAP Gateway"},
-  {vsn, "4.3.1"}, % strict semver, bump manually!
+  {vsn, "4.3.2"}, % strict semver, bump manually!
   {modules, []},
   {registered, []},
   {applications, [kernel,stdlib,gen_coap]},

apps/emqx_coap/src/emqx_coap.appup.src

@@ -1,9 +1,15 @@
 %% -*-: erlang -*-
 {VSN,
-  [{"4.3.0",[
-    {load_module, emqx_coap_mqtt_adapter, brutal_purge, soft_purge, []}]},
+  [{<<"4\\.3\\.[0-1]">>,[
+    {load_module, emqx_coap_mqtt_adapter, brutal_purge, soft_purge, []},
+    {load_module, emqx_coap_pubsub_resource, brutal_purge, soft_purge, []},
+    {load_module, emqx_coap_resource, brutal_purge, soft_purge, []}
+   ]},
    {<<".*">>, []}],
-  [{"4.3.0",[
-    {load_module, emqx_coap_mqtt_adapter, brutal_purge, soft_purge, []}]},
+  [{<<"4\\.3\\.[0-1]">>,[
+    {load_module, emqx_coap_mqtt_adapter, brutal_purge, soft_purge, []},
+    {load_module, emqx_coap_pubsub_resource, brutal_purge, soft_purge, []},
+    {load_module, emqx_coap_resource, brutal_purge, soft_purge, []}
+   ]},
    {<<".*">>, []}]
 }.

apps/emqx_coap/src/emqx_coap_mqtt_adapter.erl

@@ -31,6 +31,9 @@
 -export([ subscribe/2
         , unsubscribe/2
         , publish/3
+        , received_puback/2
+        , message_payload/1
+        , message_topic/1
         ]).
 
 -export([ client_pid/4
@@ -95,6 +98,15 @@ unsubscribe(Pid, Topic) ->
 publish(Pid, Topic, Payload) ->
     gen_server:call(Pid, {publish, Topic, Payload}).
 
+received_puback(Pid, Msg) ->
+    gen_server:cast(Pid, {received_puback, Msg}).
+
+message_payload(#message{payload = Payload}) ->
+    Payload.
+
+message_topic(#message{topic = Topic}) ->
+    Topic.
+
 %% For emqx_management plugin
 call(Pid, Msg) ->
     call(Pid, Msg, infinity).
@@ -172,13 +184,19 @@ handle_call(Request, _From, State) ->
     ?LOG(error, "adapter unexpected call ~p", [Request]),
     {reply, ignored, State, hibernate}.
 
+handle_cast({received_puback, Msg}, State) ->
+    %% NOTE: the counter named 'messages.acked', but the hook named 'message.acked'!
+    ok = emqx_metrics:inc('messages.acked'),
+    _ = emqx_hooks:run('message.acked', [conninfo(State), Msg]),
+    {noreply, State, hibernate};
+
 handle_cast(Msg, State) ->
     ?LOG(error, "broker_api unexpected cast ~p", [Msg]),
     {noreply, State, hibernate}.
 
-handle_info({deliver, _Topic, #message{topic = Topic, payload = Payload}},
+handle_info({deliver, _Topic, #message{} = Msg},
             State = #state{sub_topics = Subscribers}) ->
-    deliver([{Topic, Payload}], Subscribers),
+    deliver([Msg], Subscribers),
     {noreply, State, hibernate};
 
 handle_info(check_alive, State = #state{sub_topics = []}) ->
@@ -271,27 +289,25 @@ packet_to_message(Topic, Payload,
 %% Deliver
 
 deliver([], _) -> ok;
-deliver([Pub | More], Subscribers) ->
-    ok = do_deliver(Pub, Subscribers),
+deliver([Msg | More], Subscribers) ->
+    ok = do_deliver(Msg, Subscribers),
     deliver(More, Subscribers).
 
-do_deliver({Topic, Payload}, Subscribers) ->
+do_deliver(Msg, Subscribers) ->
     %% handle PUBLISH packet from broker
-    ?LOG(debug, "deliver message from broker Topic=~p, Payload=~p", [Topic, Payload]),
-    deliver_to_coap(Topic, Payload, Subscribers),
+    ?LOG(debug, "deliver message from broker, msg: ~p", [Msg]),
+    deliver_to_coap(Msg, Subscribers),
     ok.
 
-deliver_to_coap(_TopicName, _Payload, []) ->
+deliver_to_coap(_Msg, []) ->
     ok;
-deliver_to_coap(TopicName, Payload, [{TopicFilter, {IsWild, CoapPid}} | T]) ->
+deliver_to_coap(#message{topic = TopicName} = Msg, [{TopicFilter, {IsWild, CoapPid}} | T]) ->
     Matched =   case IsWild of
                     true  -> emqx_topic:match(TopicName, TopicFilter);
                     false -> TopicName =:= TopicFilter
                 end,
-    %?LOG(debug, "deliver_to_coap Matched=~p, CoapPid=~p, TopicName=~p, Payload=~p, T=~p",
-    %     [Matched, CoapPid, TopicName, Payload, T]),
-    Matched andalso (CoapPid ! {dispatch, TopicName, Payload}),
-    deliver_to_coap(TopicName, Payload, T).
+    Matched andalso (CoapPid ! {dispatch, Msg}),
+    deliver_to_coap(Msg, T).
 
 %%--------------------------------------------------------------------
 %% Helper funcs
@@ -328,12 +344,13 @@ chann_info(State) ->
       will_msg => undefined
      }.
 
-conninfo(#state{peername = Peername,
+conninfo(#state{peername = {PeerHost, _} = Peername,
                 clientid = ClientId,
                 connected_at = ConnectedAt}) ->
     #{socktype => udp,
       sockname => {{127, 0, 0, 1}, 5683},
       peername => Peername,
+      peerhost => PeerHost,
       peercert => nossl,        %% TODO: dtls
       conn_mod => ?MODULE,
       proto_name => <<"CoAP">>,

apps/emqx_coap/src/emqx_coap_pubsub_resource.erl

@@ -138,16 +138,32 @@ coap_unobserve({state, ChId, Prefix, TopicPath}) ->
     ok.
 
 handle_info({dispatch, Topic, Payload}, State) ->
+    %% This clause should never be matched any more. We keep it here to handle
+    %% the old format messages during the release upgrade.
+    %% In this case the second function clause of `coap_ack/2` will be called,
+    %% and the ACKs is discarded.
     ?LOG(debug, "dispatch Topic=~p, Payload=~p", [Topic, Payload]),
     {ok, Ret} = emqx_coap_pubsub_topics:reset_topic_info(Topic, Payload),
     ?LOG(debug, "Updated publish info of topic=~p, the Ret is ~p", [Topic, Ret]),
     {notify, [], #coap_content{format = <<"application/octet-stream">>, payload = Payload}, State};
+handle_info({dispatch, Msg}, State) ->
+    Payload = emqx_coap_mqtt_adapter:message_payload(Msg),
+    Topic = emqx_coap_mqtt_adapter:message_topic(Msg),
+    {ok, Ret} = emqx_coap_pubsub_topics:reset_topic_info(Topic, Payload),
+    ?LOG(debug, "Updated publish info of topic=~p, the Ret is ~p", [Topic, Ret]),
+    {notify, {pub, Msg}, #coap_content{format = <<"application/octet-stream">>, payload = Payload}, State};
 handle_info(Message, State) ->
     ?LOG(error, "Unknown Message ~p", [Message]),
     {noreply, State}.
 
-coap_ack(_Ref, State) -> {ok, State}.
-
+coap_ack({pub, Msg}, State) ->
+    ?LOG(debug, "received coap ack for publish msg: ~p", [Msg]),
+    Pid = get(mqtt_client_pid),
+    emqx_coap_mqtt_adapter:received_puback(Pid, Msg),
+    {ok, State};
+coap_ack(_Ref, State) ->
+    ?LOG(debug, "received coap ack: ~p", [_Ref]),
+    {ok, State}.
 
 %%--------------------------------------------------------------------
 %% Internal Functions

apps/emqx_coap/src/emqx_coap_resource.erl

@@ -104,12 +104,26 @@ coap_unobserve({state, ChId, Prefix, Topic}) ->
     ok.
 
 handle_info({dispatch, Topic, Payload}, State) ->
+    %% This clause should never be matched any more. We keep it here to handle
+    %% the old format messages during the release upgrade.
+    %% In this case the second function clause of `coap_ack/2` will be called,
+    %% and the ACKs is discarded.
     ?LOG(debug, "dispatch Topic=~p, Payload=~p", [Topic, Payload]),
     {notify, [], #coap_content{format = <<"application/octet-stream">>, payload = Payload}, State};
+handle_info({dispatch, Msg}, State) ->
+    Payload = emqx_coap_mqtt_adapter:message_payload(Msg),
+    {notify, {pub, Msg}, #coap_content{format = <<"application/octet-stream">>, payload = Payload}, State};
 handle_info(Message, State) ->
     emqx_coap_mqtt_adapter:handle_info(Message, State).
 
-coap_ack(_Ref, State) -> {ok, State}.
+coap_ack({pub, Msg}, State) ->
+    ?LOG(debug, "received coap ack for publish msg: ~p", [Msg]),
+    Pid = get(mqtt_client_pid),
+    emqx_coap_mqtt_adapter:received_puback(Pid, Msg),
+    {ok, State};
+coap_ack(_Ref, State) ->
+    ?LOG(debug, "received coap ack: ~p", [_Ref]),
+    {ok, State}.
 
 get_auth(Query) ->
     get_auth(Query, #coap_mqtt_auth{}).

apps/emqx_coap/test/emqx_coap_SUITE.erl

@@ -91,7 +91,7 @@ t_observe(_Config) ->
     Topic = <<"abc">>, TopicStr = binary_to_list(Topic),
     Payload = <<"123">>,
     Uri = "coap://127.0.0.1/mqtt/"++TopicStr++"?c=client1&u=tom&p=secret",
-    {ok, Pid, N, Code, Content} = er_coap_observer:observe(Uri), 
+    {ok, Pid, N, Code, Content} = er_coap_observer:observe(Uri),
     ?LOGT("observer Pid=~p, N=~p, Code=~p, Content=~p", [Pid, N, Code, Content]),
 
     [SubPid] = emqx:subscribers(Topic),
@@ -195,12 +195,16 @@ t_one_clientid_sub_2_topics(_Config) ->
     [SubPid] = emqx:subscribers(Topic2),
     ?assert(is_pid(SubPid)),
 
+    CntrAcked1 = emqx_metrics:val('messages.acked'),
     emqx:publish(emqx_message:make(Topic1, Payload1)),
 
     Notif1 = receive_notification(),
     ?LOGT("observer 1 get Notif=~p", [Notif1]),
     {coap_notify, _, _, {ok,content}, #coap_content{payload = PayloadRecv1}} = Notif1,
     ?assertEqual(Payload1, PayloadRecv1),
+    timer:sleep(100),
+    CntrAcked2 = emqx_metrics:val('messages.acked'),
+    ?assertEqual(CntrAcked2, CntrAcked1 + 1),
 
     emqx:publish(emqx_message:make(Topic2, Payload2)),
 
@@ -208,6 +212,9 @@ t_one_clientid_sub_2_topics(_Config) ->
     ?LOGT("observer 2 get Notif=~p", [Notif2]),
     {coap_notify, _, _, {ok,content}, #coap_content{payload = PayloadRecv2}} = Notif2,
     ?assertEqual(Payload2, PayloadRecv2),
+    timer:sleep(100),
+    CntrAcked3 = emqx_metrics:val('messages.acked'),
+    ?assertEqual(CntrAcked3, CntrAcked2 + 1),
 
     er_coap_observer:stop(Pid1),
     er_coap_observer:stop(Pid2).

changes/v4.3.22-en.md

@@ -2,6 +2,11 @@
 
 ## Enhancements
 
+- We now trigger the `'message.acked'` hook after the CoAP gateway sends a message to the device and receives the ACK from the device [#9264](https://github.com/emqx/emqx/pull/9264).
+  With this change, the CoAP gateway can be combined with the offline message caching function (in the
+  emqx enterprise), so that CoAP devices are able to read the missed messages from the database when
+  it is online again.
+
 - Support to use placeholders like `${var}` in the HTTP `Headers` of rule-engine's Webhook actions [#9239](https://github.com/emqx/emqx/pull/9239).
 
 - Asynchronously refresh the resources and rules during emqx boot-up [#9199](https://github.com/emqx/emqx/pull/9199).

changes/v4.3.22-zh.md

@@ -2,6 +2,9 @@
 
 ## 增强
 
+- 当 CoAP 网关给设备投递消息并收到设备发来的确认之后，回调 `'message.acked'` 钩子 [#9264](https://github.com/emqx/emqx/pull/9264)。
+  有了这个改动，CoAP 网关可以配合 EMQX (企业版)的离线消息缓存功能，让 CoAP 设备重新上线之后，从数据库读取其离线状态下错过的消息。
+
 - 支持在规则引擎的 Webhook 动作的 HTTP Headers 里使用 `${var}` 格式的占位符 [#9239](https://github.com/emqx/emqx/pull/9239)。
 
 - 在 emqx 启动时，异步地刷新资源和规则 [#9199](https://github.com/emqx/emqx/pull/9199)。