fix(rule_engine): don't increment unknown counter on unrecoverable errors

Closes: EMQX-8786

apps/emqx_rule_engine/src/emqx_rule_runtime.erl

@@ -514,6 +514,8 @@ inc_action_metrics({error, {recoverable_error, _}}, RuleId) ->
     emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.failed.out_of_service');
 inc_action_metrics(?RESOURCE_ERROR_M(R, _), RuleId) when ?IS_RES_DOWN(R) ->
     emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.failed.out_of_service');
+inc_action_metrics({error, {unrecoverable_error, _}}, RuleId) ->
+    emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.failed');
 inc_action_metrics(R, RuleId) ->
     case is_ok_result(R) of
         false ->
@@ -523,9 +525,7 @@ inc_action_metrics(R, RuleId) ->
             emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.success')
     end.
 
-is_ok_result(ok) ->
-    true;
 is_ok_result(R) when is_tuple(R) ->
     ok == erlang:element(1, R);
-is_ok_result(ok) ->
+is_ok_result(_) ->
     false.

changes/ce/fix-10327.en.md

@@ -0,0 +1,4 @@
+Don't increment 'actions.failed.unknown' rule metrics counter upon receiving unrecoverable bridge errors.
+This counter is displayed on the dashboard's rule overview tab ('Action statistics' - 'Unknown'). 
+The fix is only applicable for synchronous bridges, as all rule actions for asynchronous bridges 
+are counted as successful (they increment 'actions.success' which is displayed as 'Action statistics' - 'Success').