Merge pull request #7522 from thalesmg/telemetry-revamp-part5

feat: add basic rule engine and bridge usage info to telemetry

apps/emqx_bridge/src/emqx_bridge.erl

@@ -60,6 +60,9 @@
 -export([ config_key_path/0
         ]).
 
+%% exported for `emqx_telemetry'
+-export([get_basic_usage_info/0]).
+
 load_hook() ->
     Bridges = emqx:get_config([bridges], #{}),
     load_hook(Bridges).
@@ -244,7 +247,7 @@ update(Type, Name, {OldConf, Conf}) ->
     %% the `method` or `headers` of a HTTP bridge is changed, then the bridge can be updated
     %% without restarting the bridge.
     %%
-    case if_only_to_toggole_enable(OldConf, Conf) of
+    case if_only_to_toggle_enable(OldConf, Conf) of
         false ->
             ?SLOG(info, #{msg => "update bridge", type => Type, name => Name,
                 config => Conf}),
@@ -396,7 +399,7 @@ maybe_disable_bridge(Type, Name, Conf) ->
         true -> ok
     end.
 
-if_only_to_toggole_enable(OldConf, Conf) ->
+if_only_to_toggle_enable(OldConf, Conf) ->
     #{added := Added, removed := Removed, changed := Updated} =
         emqx_map_lib:diff_maps(OldConf, Conf),
     case {Added, Removed, Updated} of
@@ -407,6 +410,31 @@ if_only_to_toggole_enable(OldConf, Conf) ->
         {_, _, _} -> false
     end.
 
+-spec get_basic_usage_info() ->
+          #{ num_bridges => non_neg_integer()
+           , count_by_type =>
+                 #{ BridgeType => non_neg_integer()
+                  }
+           } when BridgeType :: atom().
+get_basic_usage_info() ->
+    lists:foldl(
+      fun(#{resource_data := #{config := #{enable := false}}}, Acc) ->
+              Acc;
+         (#{type := BridgeType}, Acc) ->
+              NumBridges = maps:get(num_bridges, Acc),
+              CountByType0 = maps:get(count_by_type, Acc),
+              CountByType = maps:update_with(
+                              binary_to_atom(BridgeType, utf8),
+                              fun(X) -> X + 1 end,
+                              1,
+                              CountByType0),
+              Acc#{ num_bridges => NumBridges + 1
+                  , count_by_type => CountByType
+                  }
+      end,
+      #{num_bridges => 0, count_by_type => #{}},
+      list()).
+
 bin(Bin) when is_binary(Bin) -> Bin;
 bin(Str) when is_list(Str) -> list_to_binary(Str);
 bin(Atom) when is_atom(Atom) -> atom_to_binary(Atom, utf8).

apps/emqx_bridge/src/emqx_bridge_monitor.erl

@@ -19,6 +19,8 @@
 
 -behaviour(gen_server).
 
+-include_lib("snabbkaffe/include/snabbkaffe.hrl").
+
 %% API functions
 -export([ start_link/0
         , ensure_all_started/1
@@ -67,6 +69,11 @@ code_change(_OldVsn, State, _Extra) ->
 load_bridges(Configs) ->
     lists:foreach(fun({Type, NamedConf}) ->
             lists:foreach(fun({Name, Conf}) ->
-                    emqx_bridge:create(Type, Name, Conf)
+                    _Res = emqx_bridge:create(Type, Name, Conf),
+                    ?tp(emqx_bridge_monitor_loaded_bridge,
+                        #{ type => Type
+                         , name => Name
+                         , res  => _Res
+                         })
                 end, maps:to_list(NamedConf))
         end, maps:to_list(Configs)).

apps/emqx_bridge/test/emqx_bridge_SUITE.erl

@@ -0,0 +1,112 @@
+%%--------------------------------------------------------------------
+%% 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_bridge_SUITE).
+
+-compile(nowarn_export_all).
+-compile(export_all).
+
+-include_lib("eunit/include/eunit.hrl").
+-include_lib("common_test/include/ct.hrl").
+-include_lib("snabbkaffe/include/snabbkaffe.hrl").
+
+all() ->
+     emqx_common_test_helpers:all(?MODULE).
+
+init_per_suite(Config) ->
+    %% to avoid inter-suite dependencies
+    application:stop(emqx_connector),
+    ok = emqx_common_test_helpers:start_apps([emqx, emqx_bridge]),
+    Config.
+
+end_per_suite(_Config) ->
+    emqx_common_test_helpers:stop_apps([emqx, emqx_bridge]).
+
+init_per_testcase(t_get_basic_usage_info_1, Config) ->
+    setup_fake_telemetry_data(),
+    Config;
+init_per_testcase(_TestCase, Config) ->
+    Config.
+
+end_per_testcase(t_get_basic_usage_info_1, _Config) ->
+    ok = emqx_bridge:remove(<<"http:basic_usage_info_http">>),
+    ok = emqx_bridge:remove(<<"http:basic_usage_info_http_disabled">>),
+    ok = emqx_bridge:remove(<<"mqtt:basic_usage_info_mqtt">>),
+    emqx_config:delete_override_conf_files(),
+    ok;
+end_per_testcase(_TestCase, _Config) ->
+    ok.
+
+t_get_basic_usage_info_0(_Config) ->
+    ?assertEqual(
+       #{ num_bridges => 0
+        , count_by_type => #{}
+        },
+       emqx_bridge:get_basic_usage_info()).
+
+t_get_basic_usage_info_1(_Config) ->
+    BasicUsageInfo = emqx_bridge:get_basic_usage_info(),
+    ?assertEqual(
+       #{ num_bridges => 2
+        , count_by_type => #{ http => 1
+                            , mqtt => 1
+                            }
+        },
+       BasicUsageInfo).
+
+setup_fake_telemetry_data() ->
+    ConnectorConf =
+        #{<<"connectors">> =>
+              #{<<"mqtt">> => #{<<"my_mqtt_connector">> => #{}}}},
+    MQTTConfig = #{ connector => <<"mqtt:my_mqtt_connector">>
+                  , enable => true
+                  , direction => ingress
+                  , remote_topic => <<"aws/#">>
+                  , remote_qos => 1
+                  },
+    HTTPConfig = #{ url => <<"http://localhost:9901/messages/${topic}">>
+                  , enable => true
+                  , direction => egress
+                  , local_topic => "emqx_http/#"
+                  , method => post
+                  , body => <<"${payload}">>
+                  , headers => #{}
+                  , request_timeout => "15s"
+                  },
+    Conf =
+        #{ <<"bridges">> =>
+               #{ <<"http">> =>
+                      #{ <<"basic_usage_info_http">> => HTTPConfig
+                       , <<"basic_usage_info_http_disabled">> =>
+                             HTTPConfig#{enable => false}
+                       }
+                , <<"mqtt">> =>
+                      #{ <<"basic_usage_info_mqtt">> => MQTTConfig
+                       }
+                }
+         },
+    ok = emqx_common_test_helpers:load_config(emqx_connector_schema, ConnectorConf),
+    ok = emqx_common_test_helpers:load_config(emqx_bridge_schema, Conf),
+
+    ok = snabbkaffe:start_trace(),
+    Predicate = fun(#{?snk_kind := K}) -> K =:= emqx_bridge_monitor_loaded_bridge end,
+    NEvents = 3,
+    BackInTime = 0,
+    Timeout = 1_000,
+    {ok, Sub} = snabbkaffe_collector:subscribe(Predicate, NEvents, Timeout, BackInTime),
+    ok = emqx_bridge:load(),
+    {ok, _} = snabbkaffe_collector:receive_events(Sub),
+    ok = snabbkaffe:stop(),
+    ok.

apps/emqx_exhook/test/emqx_exhook_metrics_SUITE.erl

@@ -59,7 +59,7 @@ init_per_suite(Cfg) ->
     emqx_common_test_helpers:start_apps([emqx_exhook]),
     Cfg.
 
-end_per_suite(Cfg) ->
+end_per_suite(_Cfg) ->
     meck:unload(emqx_exhook_demo_svr),
     meck:unload(emqx_exhook_mgr),
     emqx_exhook_demo_svr:stop(),

apps/emqx_modules/src/emqx_telemetry.erl

@@ -325,6 +325,10 @@ generate_uuid() ->
 get_telemetry(State0 = #state{uuid = UUID}) ->
     OSInfo = os_info(),
     {MQTTRTInsights, State} = mqtt_runtime_insights(State0),
+    #{
+        rule_engine := RuleEngineInfo,
+        bridge := BridgeInfo
+    } = get_rule_engine_and_bridge_info(),
     {State, [
         {emqx_version, bin(emqx_app:get_release())},
         {license, [{edition, <<"community">>}]},
@@ -343,7 +347,9 @@ get_telemetry(State0 = #state{uuid = UUID}) ->
         {mqtt_runtime_insights, MQTTRTInsights},
         {advanced_mqtt_features, advanced_mqtt_features()},
         {authn_authz, get_authn_authz_info()},
-        {gateway, get_gateway_info()}
+        {gateway, get_gateway_info()},
+        {rule_engine, RuleEngineInfo},
+        {bridge, BridgeInfo}
     ]}.
 
 report_telemetry(State0 = #state{url = URL}) ->
@@ -468,6 +474,37 @@ get_gateway_info() ->
             #{}
     end.
 
+get_rule_engine_and_bridge_info() ->
+    #{
+        num_rules := NumRules,
+        referenced_bridges := ReferencedBridges
+    } = emqx_rule_engine:get_basic_usage_info(),
+    #{
+        num_bridges := NumDataBridges,
+        count_by_type := BridgeTypeCount
+    } = emqx_bridge:get_basic_usage_info(),
+    BridgeInfo =
+        maps:fold(
+            fun(BridgeType, BridgeCount, Acc) ->
+                ReferencingRules = maps:get(BridgeType, ReferencedBridges, 0),
+                Acc#{
+                    BridgeType => #{
+                        num => BridgeCount,
+                        num_linked_by_rules => ReferencingRules
+                    }
+                }
+            end,
+            #{},
+            BridgeTypeCount
+        ),
+    #{
+        rule_engine => #{num_rules => NumRules},
+        bridge => #{
+            num_data_bridges => NumDataBridges,
+            data_bridge => BridgeInfo
+        }
+    }.
+
 bin(L) when is_list(L) ->
     list_to_binary(L);
 bin(A) when is_atom(A) ->

apps/emqx_modules/test/emqx_telemetry_SUITE.erl

@@ -115,6 +115,14 @@ init_per_testcase(t_send_after_enable, Config) ->
     ok = meck:expect(emqx_telemetry, official_version, fun(_) -> true end),
     mock_httpc(),
     Config;
+init_per_testcase(t_rule_engine_and_data_bridge_info, Config) ->
+    mock_httpc(),
+    {ok, _} = emqx_cluster_rpc:start_link(node(), emqx_cluster_rpc, 1000),
+    {ok, _} = application:ensure_all_started(emqx_rule_engine),
+    ok = application:start(emqx_bridge),
+    ok = emqx_bridge_SUITE:setup_fake_telemetry_data(),
+    ok = setup_fake_rule_engine_data(),
+    Config;
 init_per_testcase(_Testcase, Config) ->
     TestPID = self(),
     ok = meck:new(httpc, [non_strict, passthrough, no_history, no_link]),
@@ -149,6 +157,18 @@ end_per_testcase(t_enable, _Config) ->
     meck:unload([httpc, emqx_telemetry]);
 end_per_testcase(t_send_after_enable, _Config) ->
     meck:unload([httpc, emqx_telemetry]);
+end_per_testcase(t_rule_engine_and_data_bridge_info, _Config) ->
+    meck:unload(httpc),
+    lists:foreach(
+        fun(App) ->
+            ok = application:stop(App)
+        end,
+        [
+            emqx_bridge,
+            emqx_rule_engine
+        ]
+    ),
+    ok;
 end_per_testcase(_Testcase, _Config) ->
     meck:unload([httpc]),
     ok.
@@ -350,6 +370,27 @@ t_mqtt_runtime_insights(_) ->
     ?assertEqual(30_000, maps:get(num_topics, MQTTRTInsights2)),
     ok.
 
+t_rule_engine_and_data_bridge_info(_Config) ->
+    {ok, TelemetryData} = emqx_telemetry:get_telemetry(),
+    RuleInfo = get_value(rule_engine, TelemetryData),
+    BridgeInfo = get_value(bridge, TelemetryData),
+    ?assertEqual(
+        #{num_rules => 2},
+        RuleInfo
+    ),
+    ?assertEqual(
+        #{
+            data_bridge =>
+                #{
+                    http => #{num => 1, num_linked_by_rules => 3},
+                    mqtt => #{num => 1, num_linked_by_rules => 1}
+                },
+            num_data_bridges => 2
+        },
+        BridgeInfo
+    ),
+    ok.
+
 assert_approximate(Map, Key, Expected) ->
     Value = maps:get(Key, Map),
     ?assertEqual(Expected, float_to_list(Value, [{decimals, 2}])).
@@ -427,6 +468,35 @@ assert_gateway_listener_shape(ListenerData, GatewayType) ->
         #{gateway_type => GatewayType}
     ).
 
+setup_fake_rule_engine_data() ->
+    {ok, _} =
+        emqx_rule_engine:create_rule(
+            #{
+                id => <<"rule:t_get_basic_usage_info:1">>,
+                sql => <<"select 1 from topic">>,
+                outputs =>
+                    [
+                        #{function => <<"erlang:hibernate">>, args => #{}},
+                        #{function => console},
+                        <<"http:my_http_bridge">>,
+                        <<"http:my_http_bridge">>
+                    ]
+            }
+        ),
+    {ok, _} =
+        emqx_rule_engine:create_rule(
+            #{
+                id => <<"rule:t_get_basic_usage_info:2">>,
+                sql => <<"select 1 from topic">>,
+                outputs =>
+                    [
+                        <<"mqtt:my_mqtt_bridge">>,
+                        <<"http:my_http_bridge">>
+                    ]
+            }
+        ),
+    ok.
+
 set_special_configs(emqx_authz) ->
     {ok, _} = emqx:update_config([authorization, cache, enable], false),
     {ok, _} = emqx:update_config([authorization, no_match], deny),

apps/emqx_rule_engine/src/emqx_rule_engine.erl

@@ -58,6 +58,9 @@
         , clear_metrics_for_rule/1
         ]).
 
+%% exported for `emqx_telemetry'
+-export([get_basic_usage_info/0]).
+
 %% gen_server Callbacks
 -export([ init/1
         , handle_call/3
@@ -201,6 +204,56 @@ unload_hooks_for_rule(#{id := Id, from := Topics}) ->
         end
     end, Topics).
 
+%%------------------------------------------------------------------------------
+%% Telemetry helper functions
+%%------------------------------------------------------------------------------
+
+-spec get_basic_usage_info() -> #{ num_rules => non_neg_integer()
+                                 , referenced_bridges =>
+                                       #{ BridgeType => non_neg_integer()
+                                        }
+                                 }
+              when BridgeType :: atom().
+get_basic_usage_info() ->
+    try
+        Rules = get_rules(),
+        EnabledRules =
+            lists:filter(
+              fun(#{enable := Enabled}) -> Enabled end,
+              Rules),
+        NumRules = length(EnabledRules),
+        ReferencedBridges =
+            lists:foldl(
+              fun(#{outputs := Outputs}, Acc) ->
+                      BridgeIDs = lists:filter(fun is_binary/1, Outputs),
+                      tally_referenced_bridges(BridgeIDs, Acc)
+              end,
+              #{},
+              EnabledRules),
+        #{ num_rules => NumRules
+         , referenced_bridges => ReferencedBridges
+         }
+    catch
+        _:_ ->
+            #{ num_rules => 0
+             , referenced_bridges => #{}
+             }
+    end.
+
+
+tally_referenced_bridges(BridgeIDs, Acc0) ->
+    lists:foldl(
+     fun(BridgeID, Acc) ->
+             {BridgeType, _BridgeName} = emqx_bridge:parse_bridge_id(BridgeID),
+             maps:update_with(
+               BridgeType,
+               fun(X) -> X + 1 end,
+               1,
+               Acc)
+     end,
+     Acc0,
+     BridgeIDs).
+
 %%------------------------------------------------------------------------------
 %% gen_server callbacks
 %%------------------------------------------------------------------------------

apps/emqx_rule_engine/test/emqx_rule_engine_SUITE.erl

@@ -278,11 +278,14 @@ t_get_rules_for_topic_2(_Config) ->
              make_simple_rule(<<"rule-debug-2">>, <<"select * from \"simple/+\"">>, [<<"simple/+">>]),
              make_simple_rule(<<"rule-debug-3">>, <<"select * from \"simple/+/1\"">>, [<<"simple/+/1">>]),
              make_simple_rule(<<"rule-debug-4">>, <<"select * from \"simple/1\"">>, [<<"simple/1">>]),
-             make_simple_rule(<<"rule-debug-5">>, <<"select * from \"simple/2,simple/+,simple/3\"">>, [<<"simple/2">>,<<"simple/+">>, <<"simple/3">>]),
-             make_simple_rule(<<"rule-debug-6">>, <<"select * from \"simple/2,simple/3,simple/4\"">>, [<<"simple/2">>,<<"simple/3">>, <<"simple/4">>])
+             make_simple_rule(<<"rule-debug-5">>, <<"select * from \"simple/2,simple/+,simple/3\"">>,
+                              [<<"simple/2">>,<<"simple/+">>, <<"simple/3">>]),
+             make_simple_rule(<<"rule-debug-6">>, <<"select * from \"simple/2,simple/3,simple/4\"">>,
+                              [<<"simple/2">>,<<"simple/3">>, <<"simple/4">>])
              ]),
     ?assertEqual(Len0+4, length(emqx_rule_engine:get_rules_for_topic(<<"simple/1">>))),
-    ok = delete_rules_by_ids([<<"rule-debug-1">>, <<"rule-debug-2">>,<<"rule-debug-3">>, <<"rule-debug-4">>,<<"rule-debug-5">>, <<"rule-debug-6">>]),
+    ok = delete_rules_by_ids([<<"rule-debug-1">>, <<"rule-debug-2">>,<<"rule-debug-3">>,
+                              <<"rule-debug-4">>,<<"rule-debug-5">>, <<"rule-debug-6">>]),
     ok.
 
 t_get_rules_with_same_event(_Config) ->
@@ -298,14 +301,23 @@ t_get_rules_with_same_event(_Config) ->
     ok = insert_rules(
             [make_simple_rule(<<"r1">>, <<"select * from \"simple/#\"">>, [<<"simple/#">>]),
              make_simple_rule(<<"r2">>, <<"select * from \"abc/+\"">>, [<<"abc/+">>]),
-             make_simple_rule(<<"r3">>, <<"select * from \"$events/client_connected\"">>, [<<"$events/client_connected">>]),
-             make_simple_rule(<<"r4">>, <<"select * from \"$events/client_disconnected\"">>, [<<"$events/client_disconnected">>]),
-             make_simple_rule(<<"r5">>, <<"select * from \"$events/session_subscribed\"">>, [<<"$events/session_subscribed">>]),
-             make_simple_rule(<<"r6">>, <<"select * from \"$events/session_unsubscribed\"">>, [<<"$events/session_unsubscribed">>]),
-             make_simple_rule(<<"r7">>, <<"select * from \"$events/message_delivered\"">>, [<<"$events/message_delivered">>]),
-             make_simple_rule(<<"r8">>, <<"select * from \"$events/message_acked\"">>, [<<"$events/message_acked">>]),
-             make_simple_rule(<<"r9">>, <<"select * from \"$events/message_dropped\"">>, [<<"$events/message_dropped">>]),
-             make_simple_rule(<<"r10">>, <<"select * from \"t/1, $events/session_subscribed, $events/client_connected\"">>, [<<"t/1">>, <<"$events/session_subscribed">>, <<"$events/client_connected">>])
+             make_simple_rule(<<"r3">>, <<"select * from \"$events/client_connected\"">>,
+                              [<<"$events/client_connected">>]),
+             make_simple_rule(<<"r4">>, <<"select * from \"$events/client_disconnected\"">>,
+                              [<<"$events/client_disconnected">>]),
+             make_simple_rule(<<"r5">>, <<"select * from \"$events/session_subscribed\"">>,
+                              [<<"$events/session_subscribed">>]),
+             make_simple_rule(<<"r6">>, <<"select * from \"$events/session_unsubscribed\"">>,
+                              [<<"$events/session_unsubscribed">>]),
+             make_simple_rule(<<"r7">>, <<"select * from \"$events/message_delivered\"">>,
+                              [<<"$events/message_delivered">>]),
+             make_simple_rule(<<"r8">>, <<"select * from \"$events/message_acked\"">>,
+                              [<<"$events/message_acked">>]),
+             make_simple_rule(<<"r9">>, <<"select * from \"$events/message_dropped\"">>,
+                              [<<"$events/message_dropped">>]),
+             make_simple_rule(<<"r10">>, <<"select * from \"t/1, "
+                                           "$events/session_subscribed, $events/client_connected\"">>,
+                              [<<"t/1">>, <<"$events/session_subscribed">>, <<"$events/client_connected">>])
              ]),
     ?assertEqual(PubN + 3, length(emqx_rule_engine:get_rules_with_same_event(PubT))),
     ?assertEqual(2, length(emqx_rule_engine:get_rules_with_same_event(<<"$events/client_connected">>))),
@@ -315,7 +327,8 @@ t_get_rules_with_same_event(_Config) ->
     ?assertEqual(1, length(emqx_rule_engine:get_rules_with_same_event(<<"$events/message_delivered">>))),
     ?assertEqual(1, length(emqx_rule_engine:get_rules_with_same_event(<<"$events/message_acked">>))),
     ?assertEqual(1, length(emqx_rule_engine:get_rules_with_same_event(<<"$events/message_dropped">>))),
-    ok = delete_rules_by_ids([<<"r1">>, <<"r2">>,<<"r3">>, <<"r4">>,<<"r5">>, <<"r6">>, <<"r7">>, <<"r8">>, <<"r9">>, <<"r10">>]),
+    ok = delete_rules_by_ids([<<"r1">>, <<"r2">>,<<"r3">>, <<"r4">>,
+                              <<"r5">>, <<"r6">>, <<"r7">>, <<"r8">>, <<"r9">>, <<"r10">>]),
     ok.
 
 %%------------------------------------------------------------------------------
@@ -867,7 +880,8 @@ t_sqlparse_foreach_7(_Config) ->
           "incase is_not_null(info.cmd) "
           "from \"t/#\" "
           "where s.page = '2' ",
-    Payload  = <<"{\"sensors\": {\"page\": 2, \"collection\": {\"info\":[{\"name\":\"cmd1\", \"cmd\":\"1\"}, {\"cmd\":\"2\"}]} } }">>,
+    Payload  = <<"{\"sensors\": {\"page\": 2, \"collection\": "
+                 "{\"info\":[{\"name\":\"cmd1\", \"cmd\":\"1\"}, {\"cmd\":\"2\"}]} } }">>,
     ?assertMatch({ok,[#{<<"name">> := <<"cmd1">>, <<"msg_type">> := <<"1">>}, #{<<"msg_type">> := <<"2">>}]},
                  emqx_rule_sqltester:test(
                     #{sql => Sql,
@@ -893,7 +907,8 @@ t_sqlparse_foreach_8(_Config) ->
           "incase is_map(info) "
           "from \"t/#\" "
           "where s.page = '2' ",
-    Payload  = <<"{\"sensors\": {\"page\": 2, \"collection\": {\"info\":[\"haha\", {\"name\":\"cmd1\", \"cmd\":\"1\"}]} } }">>,
+    Payload  = <<"{\"sensors\": {\"page\": 2, \"collection\": "
+                 "{\"info\":[\"haha\", {\"name\":\"cmd1\", \"cmd\":\"1\"}]} } }">>,
     ?assertMatch({ok,[#{<<"name">> := <<"cmd1">>, <<"msg_type">> := <<"1">>}]},
                  emqx_rule_sqltester:test(
                     #{sql => Sql,
@@ -1365,6 +1380,47 @@ t_sqlparse_invalid_json(_Config) ->
                                <<"{\"sensors\": [{\"cmd\":\"1\"} {\"cmd\":}]}">>,
                            topic => <<"t/a">>}})).
 %%------------------------------------------------------------------------------
+%% Test cases for telemetry functions
+%%------------------------------------------------------------------------------
+
+t_get_basic_usage_info_0(_Config) ->
+    ?assertEqual(
+      #{ num_rules => 0
+       , referenced_bridges => #{}
+       },
+      emqx_rule_engine:get_basic_usage_info()),
+    ok.
+
+t_get_basic_usage_info_1(_Config) ->
+    {ok, _} =
+        emqx_rule_engine:create_rule(
+          #{id => <<"rule:t_get_basic_usage_info:1">>,
+            sql => <<"select 1 from topic">>,
+            outputs =>
+                [ #{function => <<"erlang:hibernate">>, args => #{}}
+                , #{function => console}
+                , <<"http:my_http_bridge">>
+                , <<"http:my_http_bridge">>
+                ]}),
+    {ok, _} =
+        emqx_rule_engine:create_rule(
+          #{id => <<"rule:t_get_basic_usage_info:2">>,
+            sql => <<"select 1 from topic">>,
+            outputs =>
+                [ <<"mqtt:my_mqtt_bridge">>
+                , <<"http:my_http_bridge">>
+                ]}),
+    ?assertEqual(
+      #{ num_rules => 2
+       , referenced_bridges =>
+             #{ mqtt => 1
+              , http => 3
+              }
+       },
+      emqx_rule_engine:get_basic_usage_info()),
+    ok.
+
+%%------------------------------------------------------------------------------
 %% Internal helpers
 %%------------------------------------------------------------------------------