chore(rule_engine): reset metrics when disabling a rule

https://emqx.atlassian.net/browse/EMQX-8502

When a bridge is disabled, its metrics are reset.  With this change,
we make rule actions behave like that: disabling a rule will reset its
metrics.

apps/emqx_rule_engine/src/emqx_rule_engine.app.src

@@ -2,7 +2,7 @@
 {application, emqx_rule_engine, [
     {description, "EMQX Rule Engine"},
     % strict semver, bump manually!
-    {vsn, "5.0.6"},
+    {vsn, "5.0.7"},
     {modules, []},
     {registered, [emqx_rule_engine_sup, emqx_rule_engine]},
     {applications, [kernel, stdlib, rulesql, getopt]},

apps/emqx_rule_engine/src/emqx_rule_engine.erl

@@ -268,7 +268,7 @@ load_hooks_for_rule(#{from := Topics}) ->
 maybe_add_metrics_for_rule(Id) ->
     case emqx_metrics_worker:has_metrics(rule_metrics, Id) of
         true ->
-            ok;
+            ok = reset_metrics_for_rule(Id);
         false ->
             ok = emqx_metrics_worker:create_metrics(rule_metrics, Id, ?METRICS, ?RATE_METRICS)
     end.

apps/emqx_rule_engine/test/emqx_rule_engine_api_SUITE.erl

@@ -189,6 +189,38 @@ t_list_rule_api(_Config) ->
     ?assertEqual(maps:get(data, Result1), maps:get(data, Result6)),
     ok.
 
+t_reset_metrics_on_disable(_Config) ->
+    Params = #{
+        <<"description">> => <<"A simple rule">>,
+        <<"enable">> => true,
+        <<"actions">> => [#{<<"function">> => <<"console">>}],
+        <<"sql">> => <<"SELECT * from \"t/1\"">>,
+        <<"name">> => atom_to_binary(?FUNCTION_NAME)
+    },
+    {201, #{id := RuleId}} = emqx_rule_engine_api:'/rules'(post, #{body => Params}),
+
+    %% generate some fake metrics
+    emqx_metrics_worker:inc(rule_metrics, RuleId, 'matched', 10),
+    emqx_metrics_worker:inc(rule_metrics, RuleId, 'passed', 10),
+    {200, #{metrics := Metrics0}} = emqx_rule_engine_api:'/rules/:id/metrics'(
+        get,
+        #{bindings => #{id => RuleId}}
+    ),
+    ?assertMatch(#{passed := 10, matched := 10}, Metrics0),
+
+    %% disable the rule; metrics should be reset
+    {200, _Rule2} = emqx_rule_engine_api:'/rules/:id'(put, #{
+        bindings => #{id => RuleId},
+        body => Params#{<<"enable">> := false}
+    }),
+
+    {200, #{metrics := Metrics1}} = emqx_rule_engine_api:'/rules/:id/metrics'(
+        get,
+        #{bindings => #{id => RuleId}}
+    ),
+    ?assertMatch(#{passed := 0, matched := 0}, Metrics1),
+    ok.
+
 test_rule_params() ->
     #{
         body => #{

changes/v5.0.14-en.md

@@ -9,6 +9,8 @@
 
 - Obfuscated sensitive data in the response when querying `bridges` information by API [#9593](https://github.com/emqx/emqx/pull/9593/).
 
+- Made rule engine behavior more consistent with bridge behavior regarding metrics: if a rule engine is disabled, its metrics are now reset []().
+
 ## Bug Fixes
 
 - Fix an issue where testing the GCP PubSub could leak memory, and an issue where its JWT token would fail to refresh a second time. [#9641](https://github.com/emqx/emqx/pull/9641)

changes/v5.0.14-zh.md

@@ -9,6 +9,8 @@
 
 - 通过 API 查询 `bridges` 信息时将混淆响应中的敏感数据 [#9593](https://github.com/emqx/emqx/pull/9593/)。
 
+- 使得规则引擎的行为与桥梁的指标行为更加一致：如果一个规则引擎被禁用，其指标现在会被重置 []()。
+
 ## 修复
 
 - 修复了测试GCP PubSub可能泄露内存的问题，以及其JWT令牌第二次刷新失败的问题。 [#9640](https://github.com/emqx/emqx/pull/9640)