fix(ft-api): fix swagger schema dump for ft schema

apps/emqx_dashboard/src/emqx_dashboard_swagger.erl

@@ -902,6 +902,8 @@ typename_to_spec("json_binary()", _Mod) ->
     #{type => string, example => <<"{\"a\": [1,true]}">>};
 typename_to_spec("port_number()", _Mod) ->
     range("1..65535");
+typename_to_spec("secret_access_key()", _Mod) ->
+    #{type => string, example => <<"TW8dPwmjpjJJuLW....">>};
 typename_to_spec(Name, Mod) ->
     try_convert_to_spec(Name, Mod, [
         fun try_remote_module_type/2,

apps/emqx_s3/src/emqx_s3_schema.erl

@@ -14,6 +14,9 @@
 -export([translate/1]).
 -export([translate/2]).
 
+-type secret_access_key() :: string() | function().
+-reflect_type([secret_access_key/0]).
+
 roots() ->
     [s3].
 
@@ -34,7 +37,7 @@ fields(s3) ->
             )},
         {secret_access_key,
             mk(
-                hoconsc:union([string(), function()]),
+                secret_access_key(),
                 #{
                     desc => ?DESC("secret_access_key"),
                     required => false,