fix: set own app environment and expose convenient api

... for accessing advanced mqtt features in use.

apps/emqx_modules/src/emqx_modules.erl

@@ -0,0 +1,37 @@
+%%--------------------------------------------------------------------
+%% 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

@@ -38,7 +38,7 @@ maybe_enable_modules() ->
     RetainerEnabled = emqx_conf:get([retainer, enable], false),
     AutoSubscribeEnabled = length(emqx_conf:get([auto_subscribe, topics], [])) > 0,
     application:set_env(
-        emqx_telemetry,
+        emqx_modules,
         advanced_mqtt_features_in_use,
         #{
             delayed => DelayedEnabled,

apps/emqx_modules/src/emqx_telemetry.erl

@@ -449,7 +449,7 @@ update_mqtt_rates(State) ->
     {#{}, State}.
 
 advanced_mqtt_features() ->
-    AdvancedFeatures = application:get_env(emqx_telemetry, advanced_mqtt_features_in_use, #{}),
+    AdvancedFeatures = emqx_modules:get_advanced_mqtt_features_in_use(),
     maps:map(fun(_K, V) -> bool2int(V) end, AdvancedFeatures).
 
 bin(L) when is_list(L) ->

apps/emqx_modules/test/emqx_telemetry_SUITE.erl

@@ -67,17 +67,13 @@ init_per_testcase(t_get_telemetry, Config) ->
     ),
     Config;
 init_per_testcase(t_advanced_mqtt_features, Config) ->
-    OldValues = application:get_env(emqx_telemetry, advanced_mqtt_features_in_use, #{}),
-    application:set_env(
-        emqx_telemetry,
-        advanced_mqtt_features_in_use,
-        #{
-            delayed => false,
-            topic_rewrite => false,
-            retained => false,
-            auto_subscribe => false
-        }
-    ),
+    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];
 init_per_testcase(_Testcase, Config) ->
     TestPID = self(),
@@ -94,7 +90,7 @@ end_per_testcase(t_get_telemetry, _Config) ->
     ok;
 end_per_testcase(t_advanced_mqtt_features, Config) ->
     OldValues = ?config(old_values, Config),
-    application:set_env(emqx_telemetry, advanced_mqtt_features_in_use, OldValues);
+    emqx_modules:set_advanced_mqtt_features_in_use(OldValues);
 end_per_testcase(_Testcase, _Config) ->
     meck:unload([httpc]),
     ok.
@@ -172,12 +168,8 @@ t_advanced_mqtt_features(_) ->
     ),
     lists:foreach(
         fun(TelemetryKey) ->
-            {ok, EnabledFeats} = application:get_env(emqx_telemetry, advanced_mqtt_features_in_use),
-            application:set_env(
-                emqx_telemetry,
-                advanced_mqtt_features_in_use,
-                EnabledFeats#{TelemetryKey => true}
-            ),
+            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})