feat(message_validation): add `ignore` failure action

apps/emqx_message_validation/src/emqx_message_validation.erl

@@ -383,6 +383,12 @@ run_validations(Validations, Message) ->
             case run_validation(Validation, Message) of
                 ok ->
                     {cont, Acc};
+                ignore ->
+                    trace_failure(Validation, "validation_failed", #{
+                        validation => Name,
+                        action => ignore
+                    }),
+                    {cont, Acc};
                 FailureAction ->
                     trace_failure(Validation, "validation_failed", #{
                         validation => Name,

apps/emqx_message_validation/src/emqx_message_validation_schema.erl

@@ -75,7 +75,7 @@ fields(validation) ->
             )},
         {failure_action,
             mk(
-                hoconsc:enum([drop, disconnect]),
+                hoconsc:enum([drop, disconnect, ignore]),
                 #{desc => ?DESC("failure_action"), required => true}
             )},
         {log_failure,

apps/emqx_message_validation/test/emqx_message_validation_http_api_SUITE.erl

@@ -573,9 +573,31 @@ t_log_failure_none(_Config) ->
     ),
     ok.
 
+t_action_ignore(_Config) ->
+    ?check_trace(
+        begin
+            Name1 = <<"foo">>,
+            AlwaysFailCheck = sql_check(<<"select * where false">>),
+            Validation1 = validation(
+                Name1,
+                [AlwaysFailCheck],
+                #{<<"failure_action">> => <<"ignore">>}
+            ),
 
+            {201, _} = insert(Validation1),
 
+            C = connect(<<"c1">>),
+            {ok, _, [_]} = emqtt:subscribe(C, <<"t/#">>),
 
+            ok = publish(C, <<"t/1">>, #{}),
+            ?assertReceive({publish, _}),
+            ok
+        end,
+        fun(Trace) ->
+            ?assertMatch([#{action := ignore}], ?of_kind(message_validation_failure, Trace)),
+            ok
+        end
+    ),
     ok.
 
 %% Check the `all_pass' strategy

rel/i18n/emqx_message_validation_schema.hocon

@@ -71,7 +71,8 @@ emqx_message_validation_schema {
   """How to proceed if the validation fails.
 
   <code>drop</code>: The offending message is simply dropped without further processing.
-  <code>disconnect</code>: The message is not published, and the publishing client is disconnected."""
+  <code>disconnect</code>: The message is not published, and the publishing client is disconnected.
+  <code>ignore</code>: Only the failure is logged and traced.  No other action is taken."""
   failure_action.label:
   """Failure action"""