fix(gw_jt808): subscriptions and channel stats

apps/emqx_gateway_jt808/src/emqx_jt808_channel.erl

@@ -85,6 +85,8 @@
 
 -define(INFO_KEYS, [ctx, conninfo, zone, clientid, clientinfo, session, conn_state, authcode]).
 
+-define(DN_TOPIC_SUBOPTS, #{rap => 0, nl => 0, qos => 0, rh => 0}).
+
 -define(RETX_INTERVAL, 8000).
 -define(RETX_MAX_TIME, 5).
 
@@ -122,8 +124,21 @@ info(conn_state, #channel{conn_state = ConnState}) ->
 info(authcode, #channel{authcode = AuthCode}) ->
     AuthCode.
 
-stats(_Channel) ->
-    [].
+-spec stats(channel()) -> emqx_types:stats().
+stats(#channel{inflight = Inflight, mqueue = Queue}) ->
+    %% XXX: A fake stats for managed by emqx_management
+    [
+        {subscriptions_cnt, 1},
+        {subscriptions_max, 1},
+        {inflight_cnt, emqx_inflight:size(Inflight)},
+        {inflight_max, emqx_inflight:max_size(Inflight)},
+        {mqueue_len, queue:len(Queue)},
+        {mqueue_max, 0},
+        {mqueue_dropped, 0},
+        {next_pkt_id, 0},
+        {awaiting_rel_cnt, 0},
+        {awaiting_rel_max, 0}
+    ].
 
 %%--------------------------------------------------------------------
 %% Init the Channel
@@ -422,6 +437,8 @@ handle_call(kick, _From, Channel) ->
     disconnect_and_shutdown(kicked, ok, Channel1);
 handle_call(discard, _From, Channel) ->
     disconnect_and_shutdown(discarded, ok, Channel);
+handle_call(subscriptions, _From, Channel = #channel{dn_topic = DnTopic}) ->
+    reply({ok, [{DnTopic, ?DN_TOPIC_SUBOPTS}]}, Channel);
 handle_call(Req, _From, Channel) ->
     log(error, #{msg => "unexpected_call", call => Req}, Channel),
     reply(ignored, Channel).
@@ -633,7 +650,9 @@ process_connect(
             ok = autosubcribe(NChannel),
             _ = start_keepalive(?DEFAULT_KEEPALIVE, NChannel),
             _ = run_hooks(Ctx, 'client.connack', [ConnInfo, connection_accepted, #{}]),
-            _ = emqx_gateway_ctx:insert_channel_info(Ctx, ClientId, info(NChannel), undefined),
+            _ = emqx_gateway_ctx:insert_channel_info(
+                Ctx, ClientId, info(NChannel), stats(NChannel)
+            ),
             authack({0, MsgSn, NChannel});
         {error, Reason} ->
             log(
@@ -941,9 +960,10 @@ autosubcribe(#channel{
             #{clientid := ClientId},
     dn_topic = Topic
 }) ->
-    SubOpts = #{rap => 0, nl => 0, qos => 0, rh => 0},
-    _ = emqx_broker:subscribe(Topic, ClientId, SubOpts),
-    ok = emqx_hooks:run('session.subscribed', [ClientInfo, Topic, SubOpts#{is_new => true}]).
+    _ = emqx_broker:subscribe(Topic, ClientId, ?DN_TOPIC_SUBOPTS),
+    ok = emqx_hooks:run('session.subscribed', [
+        ClientInfo, Topic, ?DN_TOPIC_SUBOPTS#{is_new => true}
+    ]).
 
 start_keepalive(Secs, _Channel) when Secs > 0 ->
     self() ! {keepalive, start, round(Secs) * 1000}.