feat(telemetry): count advanced mqtt feature usage

Originally, we wanted to just check if certain features were enabled.
Now, we want to count certain usage metrics for them.

apps/emqx_auto_subscribe/src/emqx_auto_subscribe.erl

@@ -33,6 +33,9 @@
 %% hook callback
 -export([on_client_connected/3]).
 
+%% exported for `emqx_telemetry'
+-export([get_basic_usage_info/0]).
+
 load() ->
     ok = emqx_conf:add_handler([auto_subscribe, topics], ?MODULE),
     update_hook().
@@ -67,6 +70,15 @@ on_client_connected(ClientInfo, ConnInfo, {TopicHandler, Options}) ->
 on_client_connected(_, _, _) ->
     ok.
 
+%%--------------------------------------------------------------------
+%% Telemetry
+%%--------------------------------------------------------------------
+
+-spec get_basic_usage_info() -> #{auto_subscribe_count => non_neg_integer()}.
+get_basic_usage_info() ->
+    AutoSubscribe = emqx_conf:get([auto_subscribe, topics], []),
+    #{auto_subscribe_count => length(AutoSubscribe)}.
+
 %%--------------------------------------------------------------------
 %% internal
 

apps/emqx_auto_subscribe/test/emqx_auto_subscribe_SUITE.erl

@@ -41,7 +41,7 @@
 -define(CLIENT_USERNAME, <<"auto_sub_u">>).
 
 all() ->
-    [t_auto_subscribe, t_update].
+    emqx_common_test_helpers:all(?MODULE).
 
 init_per_suite(Config) ->
     mria:start(),
@@ -99,6 +99,18 @@ init_per_suite(Config) ->
     ),
     Config.
 
+init_per_testcase(t_get_basic_usage_info, Config) ->
+    {ok, _} = emqx_auto_subscribe:update([]),
+    Config;
+init_per_testcase(_TestCase, Config) ->
+    Config.
+
+end_per_testcase(t_get_basic_usage_info, _Config) ->
+    {ok, _} = emqx_auto_subscribe:update([]),
+    ok;
+end_per_testcase(_TestCase, _Config) ->
+    ok.
+
 set_special_configs(emqx_dashboard) ->
     emqx_dashboard_api_test_helpers:set_default_config(),
     ok;
@@ -150,6 +162,21 @@ t_update(_) ->
     ?assertEqual(1, erlang:length(GETResponseMap)),
     ok.
 
+t_get_basic_usage_info(_Config) ->
+    ?assertEqual(#{auto_subscribe_count => 0}, emqx_auto_subscribe:get_basic_usage_info()),
+    AutoSubscribeTopics =
+        lists:map(
+            fun(N) ->
+                Num = integer_to_binary(N),
+                Topic = <<"auto/", Num/binary>>,
+                #{<<"topic">> => Topic}
+            end,
+            lists:seq(1, 3)
+        ),
+    {ok, _} = emqx_auto_subscribe:update(AutoSubscribeTopics),
+    ?assertEqual(#{auto_subscribe_count => 3}, emqx_auto_subscribe:get_basic_usage_info()),
+    ok.
+
 check_subs(Count) ->
     Subs = ets:tab2list(emqx_suboption),
     ct:pal("--->  ~p ~p ~n", [Subs, Count]),

apps/emqx_modules/src/emqx_delayed.erl

@@ -61,6 +61,9 @@
 
 -export([format_delayed/1]).
 
+%% exported for `emqx_telemetry'
+-export([get_basic_usage_info/0]).
+
 -record(delayed_message, {key, delayed, msg}).
 -type delayed_message() :: #delayed_message{}.
 -type with_id_return() :: ok | {error, not_found}.
@@ -314,6 +317,19 @@ terminate(_Reason, #{stats_timer := StatsTimer} = State) ->
 code_change(_Vsn, State, _Extra) ->
     {ok, State}.
 
+%%--------------------------------------------------------------------
+%% Telemetry
+%%--------------------------------------------------------------------
+
+-spec get_basic_usage_info() -> #{delayed_message_count => non_neg_integer()}.
+get_basic_usage_info() ->
+    DelayedCount =
+        case ets:info(?TAB, size) of
+            undefined -> 0;
+            Num -> Num
+        end,
+    #{delayed_message_count => DelayedCount}.
+
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------

apps/emqx_modules/src/emqx_modules.erl

@@ -1,37 +0,0 @@
-%%--------------------------------------------------------------------
-%% Copyright (c) 2022 EMQ Technologies Co., Ltd. All Rights Reserved.
-%%
-%% Licensed under the Apache License, Version 2.0 (the "License");
-%% you may not use this file except in compliance with the License.
-%% You may obtain a copy of the License at
-%%
-%%     http://www.apache.org/licenses/LICENSE-2.0
-%%
-%% Unless required by applicable law or agreed to in writing, software
-%% distributed under the License is distributed on an "AS IS" BASIS,
-%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%% See the License for the specific language governing permissions and
-%% limitations under the License.
-%%--------------------------------------------------------------------
-
--module(emqx_modules).
-
--export([
-    get_advanced_mqtt_features_in_use/0,
-    set_advanced_mqtt_features_in_use/1
-]).
-
--type advanced_mqtt_feature() :: delayed | topic_rewrite | retained | auto_subscribe.
--type advanced_mqtt_features_in_use() :: #{advanced_mqtt_feature() => boolean()}.
-
-%%--------------------------------------------------------------------
-%% API
-%%--------------------------------------------------------------------
-
--spec get_advanced_mqtt_features_in_use() -> advanced_mqtt_features_in_use().
-get_advanced_mqtt_features_in_use() ->
-    application:get_env(?MODULE, advanced_mqtt_features_in_use, #{}).
-
--spec set_advanced_mqtt_features_in_use(advanced_mqtt_features_in_use()) -> ok.
-set_advanced_mqtt_features_in_use(Features) ->
-    application:set_env(?MODULE, advanced_mqtt_features_in_use, Features).

apps/emqx_modules/src/emqx_modules_app.erl

@@ -33,19 +33,7 @@ stop(_State) ->
     ok.
 
 maybe_enable_modules() ->
-    DelayedEnabled = emqx_conf:get([delayed, enable], true),
-    RewriteEnabled = length(emqx_conf:get([rewrite], [])) > 0,
-    RetainerEnabled = emqx_conf:get([retainer, enable], false),
-    AutoSubscribeEnabled = length(emqx_conf:get([auto_subscribe, topics], [])) > 0,
-    emqx_modules:set_advanced_mqtt_features_in_use(
-        #{
-            delayed => DelayedEnabled,
-            topic_rewrite => RewriteEnabled,
-            retained => RetainerEnabled,
-            auto_subscribe => AutoSubscribeEnabled
-        }
-    ),
-    DelayedEnabled andalso emqx_delayed:enable(),
+    emqx_conf:get([delayed, enable], true) andalso emqx_delayed:enable(),
     emqx_modules_conf:is_telemetry_enabled() andalso emqx_telemetry:enable(),
     emqx_conf:get([observer_cli, enable], true) andalso emqx_observer_cli:enable(),
     emqx_conf_cli:load(),

apps/emqx_modules/src/emqx_rewrite.erl

@@ -45,6 +45,9 @@
     post_config_update/5
 ]).
 
+%% exported for `emqx_telemetry'
+-export([get_basic_usage_info/0]).
+
 %%--------------------------------------------------------------------
 %% Load/Unload
 %%--------------------------------------------------------------------
@@ -98,6 +101,15 @@ rewrite_unsubscribe(_ClientInfo, _Properties, TopicFilters, Rules) ->
 rewrite_publish(Message = #message{topic = Topic}, Rules) ->
     {ok, Message#message{topic = match_and_rewrite(Topic, Rules)}}.
 
+%%--------------------------------------------------------------------
+%% Telemetry
+%%--------------------------------------------------------------------
+
+-spec get_basic_usage_info() -> #{topic_rewrite_rule_count => non_neg_integer()}.
+get_basic_usage_info() ->
+    RewriteRules = list(),
+    #{topic_rewrite_rule_count => length(RewriteRules)}.
+
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------

apps/emqx_modules/src/emqx_telemetry.erl

@@ -447,8 +447,16 @@ update_mqtt_rates(State) ->
     {#{}, State}.
 
 advanced_mqtt_features() ->
-    AdvancedFeatures = emqx_modules:get_advanced_mqtt_features_in_use(),
-    maps:map(fun(_K, V) -> bool2int(V) end, AdvancedFeatures).
+    #{retained_messages := RetainedMessages} = emqx_retainer:get_basic_usage_info(),
+    #{topic_rewrite_rule_count := RewriteRules} = emqx_rewrite:get_basic_usage_info(),
+    #{delayed_message_count := DelayedCount} = emqx_delayed:get_basic_usage_info(),
+    #{auto_subscribe_count := AutoSubscribe} = emqx_auto_subscribe:get_basic_usage_info(),
+    #{
+        topic_rewrite => RewriteRules,
+        delayed => DelayedCount,
+        retained => RetainedMessages,
+        auto_subscribe => AutoSubscribe
+    }.
 
 get_authn_authz_info() ->
     try
@@ -521,9 +529,6 @@ bin(A) when is_atom(A) ->
 bin(B) when is_binary(B) ->
     B.
 
-bool2int(true) -> 1;
-bool2int(false) -> 0.
-
 ensure_uuids() ->
     Txn = fun() ->
         NodeUUID =

apps/emqx_modules/test/emqx_delayed_SUITE.erl

@@ -49,6 +49,7 @@ init_per_testcase(_Case, Config) ->
     Config.
 
 end_per_testcase(_Case, _Config) ->
+    {atomic, ok} = mria:clear_table(emqx_delayed),
     ok = emqx_delayed:disable().
 
 %%--------------------------------------------------------------------
@@ -178,3 +179,16 @@ t_unknown_messages(_) ->
         ignored,
         gen_server:call(OldPid, unknown)
     ).
+
+t_get_basic_usage_info(_Config) ->
+    ?assertEqual(#{delayed_message_count => 0}, emqx_delayed:get_basic_usage_info()),
+    lists:foreach(
+        fun(N) ->
+            Num = integer_to_binary(N),
+            Message = emqx_message:make(<<"$delayed/", Num/binary, "/delayed">>, <<"payload">>),
+            {stop, _} = emqx_delayed:on_message_publish(Message)
+        end,
+        lists:seq(1, 4)
+    ),
+    ?assertEqual(#{delayed_message_count => 4}, emqx_delayed:get_basic_usage_info()),
+    ok.

apps/emqx_modules/test/emqx_rewrite_SUITE.erl

@@ -55,6 +55,18 @@ init_per_suite(Config) ->
 end_per_suite(_Config) ->
     emqx_common_test_helpers:stop_apps([emqx_conf, emqx_modules]).
 
+init_per_testcase(t_get_basic_usage_info, Config) ->
+    ok = emqx_rewrite:update([]),
+    Config;
+init_per_testcase(_TestCase, Config) ->
+    Config.
+
+end_per_testcase(t_get_basic_usage_info, _Config) ->
+    ok = emqx_rewrite:update([]),
+    ok;
+end_per_testcase(_TestCase, _Config) ->
+    ok.
+
 t_subscribe_rewrite(_Config) ->
     {ok, Conn} = init(),
     SubOrigTopics = [<<"y/a/z/b">>, <<"y/def">>],
@@ -200,6 +212,27 @@ t_update_re_failed(_Config) ->
     ),
     ok.
 
+t_get_basic_usage_info(_Config) ->
+    ?assertEqual(#{topic_rewrite_rule_count => 0}, emqx_rewrite:get_basic_usage_info()),
+    RewriteTopics =
+        lists:map(
+            fun(N) ->
+                Num = integer_to_binary(N),
+                DestTopic = <<"rewrite/dest/", Num/binary>>,
+                SourceTopic = <<"rewrite/source/", Num/binary>>,
+                #{
+                    <<"source_topic">> => SourceTopic,
+                    <<"dest_topic">> => DestTopic,
+                    <<"action">> => all,
+                    <<"re">> => DestTopic
+                }
+            end,
+            lists:seq(1, 2)
+        ),
+    ok = emqx_rewrite:update(RewriteTopics),
+    ?assertEqual(#{topic_rewrite_rule_count => 2}, emqx_rewrite:get_basic_usage_info()),
+    ok.
+
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------

apps/emqx_modules/test/emqx_telemetry_SUITE.erl

@@ -91,14 +91,14 @@ init_per_testcase(t_get_telemetry, Config) ->
     {ok, _} = application:ensure_all_started(emqx_gateway),
     Config;
 init_per_testcase(t_advanced_mqtt_features, Config) ->
-    OldValues = emqx_modules:get_advanced_mqtt_features_in_use(),
-    emqx_modules:set_advanced_mqtt_features_in_use(#{
-        delayed => false,
-        topic_rewrite => false,
-        retained => false,
-        auto_subscribe => false
-    }),
-    [{old_values, OldValues} | Config];
+    {ok, _} = emqx_cluster_rpc:start_link(node(), emqx_cluster_rpc, 1000),
+    {ok, Retainer} = emqx_retainer:start_link(),
+    {atomic, ok} = mria:clear_table(emqx_delayed),
+    mock_advanced_mqtt_features(),
+    [
+        {retainer, Retainer}
+        | Config
+    ];
 init_per_testcase(t_authn_authz_info, Config) ->
     mock_httpc(),
     {ok, _} = emqx_cluster_rpc:start_link(node(), emqx_cluster_rpc, 1000),
@@ -160,8 +160,14 @@ end_per_testcase(t_get_telemetry, _Config) ->
     application:stop(emqx_gateway),
     ok;
 end_per_testcase(t_advanced_mqtt_features, Config) ->
-    OldValues = ?config(old_values, Config),
-    emqx_modules:set_advanced_mqtt_features_in_use(OldValues);
+    Retainer = ?config(retainer, Config),
+    process_flag(trap_exit, true),
+    ok = emqx_retainer:clean(),
+    exit(Retainer, kill),
+    {ok, _} = emqx_auto_subscribe:update([]),
+    ok = emqx_rewrite:update([]),
+    {atomic, ok} = mria:clear_table(emqx_delayed),
+    ok;
 end_per_testcase(t_authn_authz_info, _Config) ->
     meck:unload([httpc]),
     emqx_authz:update({delete, postgresql}, #{}),
@@ -322,28 +328,13 @@ t_advanced_mqtt_features(_) ->
     AdvFeats = get_value(advanced_mqtt_features, TelemetryData),
     ?assertEqual(
         #{
-            retained => 0,
-            topic_rewrite => 0,
-            auto_subscribe => 0,
-            delayed => 0
+            retained => 5,
+            topic_rewrite => 2,
+            auto_subscribe => 3,
+            delayed => 4
         },
         AdvFeats
     ),
-    lists:foreach(
-        fun(TelemetryKey) ->
-            EnabledFeats = emqx_modules:get_advanced_mqtt_features_in_use(),
-            emqx_modules:set_advanced_mqtt_features_in_use(EnabledFeats#{TelemetryKey => true}),
-            {ok, Data} = emqx_telemetry:get_telemetry(),
-            #{TelemetryKey := Value} = get_value(advanced_mqtt_features, Data),
-            ?assertEqual(1, Value, #{key => TelemetryKey})
-        end,
-        [
-            retained,
-            topic_rewrite,
-            auto_subscribe,
-            delayed
-        ]
-    ),
     ok.
 
 t_authn_authz_info(_) ->
@@ -514,6 +505,56 @@ mock_httpc() ->
         TestPID ! {request, Method, URL, Headers, Body}
     end).
 
+mock_advanced_mqtt_features() ->
+    Context = undefined,
+    lists:foreach(
+        fun(N) ->
+            Num = integer_to_binary(N),
+            Message = emqx_message:make(<<"retained/", Num/binary>>, <<"payload">>),
+            ok = emqx_retainer:store_retained(Context, Message)
+        end,
+        lists:seq(1, 5)
+    ),
+
+    lists:foreach(
+        fun(N) ->
+            Num = integer_to_binary(N),
+            Message = emqx_message:make(<<"$delayed/", Num/binary, "/delayed">>, <<"payload">>),
+            {stop, _} = emqx_delayed:on_message_publish(Message)
+        end,
+        lists:seq(1, 4)
+    ),
+
+    AutoSubscribeTopics =
+        lists:map(
+            fun(N) ->
+                Num = integer_to_binary(N),
+                Topic = <<"auto/", Num/binary>>,
+                #{<<"topic">> => Topic}
+            end,
+            lists:seq(1, 3)
+        ),
+    {ok, _} = emqx_auto_subscribe:update(AutoSubscribeTopics),
+
+    RewriteTopics =
+        lists:map(
+            fun(N) ->
+                Num = integer_to_binary(N),
+                DestTopic = <<"rewrite/dest/", Num/binary>>,
+                SourceTopic = <<"rewrite/source/", Num/binary>>,
+                #{
+                    <<"source_topic">> => SourceTopic,
+                    <<"dest_topic">> => DestTopic,
+                    <<"action">> => all,
+                    <<"re">> => DestTopic
+                }
+            end,
+            lists:seq(1, 2)
+        ),
+    ok = emqx_rewrite:update(RewriteTopics),
+
+    ok.
+
 create_authn(ChainName, built_in_database) ->
     emqx_authentication:initialize_authentication(
         ChainName,

apps/emqx_retainer/src/emqx_retainer.erl

@@ -54,6 +54,9 @@
     code_change/3
 ]).
 
+%% exported for `emqx_telemetry'
+-export([get_basic_usage_info/0]).
+
 -type state() :: #{
     enable := boolean(),
     context_id := non_neg_integer(),
@@ -161,6 +164,20 @@ call(Req) ->
 stats_fun() ->
     gen_server:cast(?MODULE, ?FUNCTION_NAME).
 
+%%--------------------------------------------------------------------
+%% APIs
+%%--------------------------------------------------------------------
+
+-spec get_basic_usage_info() -> #{retained_messages => non_neg_integer()}.
+get_basic_usage_info() ->
+    try
+        RetainedMessages = gen_server:call(?MODULE, retained_count),
+        #{retained_messages => RetainedMessages}
+    catch
+        _:_ ->
+            #{retained_messages => 0}
+    end.
+
 %%--------------------------------------------------------------------
 %% gen_server callbacks
 %%--------------------------------------------------------------------
@@ -191,6 +208,10 @@ handle_call({page_read, Topic, Page, Limit}, _, #{context := Context} = State) -
     Mod = get_backend_module(),
     Result = Mod:page_read(Context, Topic, Page, Limit),
     {reply, Result, State};
+handle_call(retained_count, _From, State = #{context := Context}) ->
+    Mod = get_backend_module(),
+    RetainedCount = Mod:size(Context),
+    {reply, RetainedCount, State};
 handle_call(Req, _From, State) ->
     ?SLOG(error, #{msg => "unexpected_call", call => Req}),
     {reply, ignored, State}.

apps/emqx_retainer/test/emqx_retainer_SUITE.erl

@@ -103,6 +103,14 @@ end_per_group(_Group, Config) ->
     emqx_retainer_mnesia:populate_index_meta(),
     Config.
 
+init_per_testcase(t_get_basic_usage_info, Config) ->
+    mnesia:clear_table(?TAB_INDEX),
+    mnesia:clear_table(?TAB_MESSAGE),
+    emqx_retainer_mnesia:populate_index_meta(),
+    Config;
+init_per_testcase(_TestCase, Config) ->
+    Config.
+
 load_base_conf() ->
     ok = emqx_common_test_helpers:load_config(emqx_retainer_schema, ?BASE_CONF).
 
@@ -602,6 +610,20 @@ t_reindex(_) ->
         end
     ).
 
+t_get_basic_usage_info(_Config) ->
+    ?assertEqual(#{retained_messages => 0}, emqx_retainer:get_basic_usage_info()),
+    Context = undefined,
+    lists:foreach(
+        fun(N) ->
+            Num = integer_to_binary(N),
+            Message = emqx_message:make(<<"retained/", Num/binary>>, <<"payload">>),
+            ok = emqx_retainer:store_retained(Context, Message)
+        end,
+        lists:seq(1, 5)
+    ),
+    ?assertEqual(#{retained_messages => 5}, emqx_retainer:get_basic_usage_info()),
+    ok.
+
 %%--------------------------------------------------------------------
 %% Helper functions
 %%--------------------------------------------------------------------