feat(bridge-s3): make validation errors more readable

And also turn them into schema-level validations, instead of
bridge-level error conditions.

apps/emqx_bridge_s3/src/emqx_bridge_s3_connector.erl

@@ -162,13 +162,8 @@ on_get_status(_InstId, State = #{client_config := Config}) ->
 -spec on_add_channel(_InstanceId :: resource_id(), state(), channel_id(), channel_config()) ->
     {ok, state()} | {error, _Reason}.
 on_add_channel(_InstId, State = #{channels := Channels}, ChannelId, Config) ->
-    try
-        ChannelState = start_channel(State, Config),
-        {ok, State#{channels => Channels#{ChannelId => ChannelState}}}
-    catch
-        throw:Reason ->
-            {error, Reason}
-    end.
+    ChannelState = start_channel(State, Config),
+    {ok, State#{channels => Channels#{ChannelId => ChannelState}}}.
 
 -spec on_remove_channel(_InstanceId :: resource_id(), state(), channel_id()) ->
     {ok, state()}.
@@ -217,7 +212,8 @@ start_channel(State, #{
             max_records := MaxRecords
         },
         container := Container,
-        bucket := Bucket
+        bucket := Bucket,
+        key := Key
     }
 }) ->
     AggregId = {Type, Name},
@@ -226,7 +222,7 @@ start_channel(State, #{
         max_records => MaxRecords,
         work_dir => work_dir(Type, Name)
     },
-    Template = ensure_ok(emqx_bridge_s3_upload:mk_key_template(Parameters)),
+    Template = emqx_bridge_s3_upload:mk_key_template(Key),
     DeliveryOpts = #{
         bucket => Bucket,
         key => Template,
@@ -253,11 +249,6 @@ start_channel(State, #{
         on_stop => fun() -> ?AGGREG_SUP:delete_child(AggregId) end
     }.
 
-ensure_ok({ok, V}) ->
-    V;
-ensure_ok({error, Reason}) ->
-    throw(Reason).
-
 upload_options(Parameters) ->
     #{acl => maps:get(acl, Parameters, undefined)}.
 

apps/emqx_bridge_s3/src/emqx_bridge_s3_upload.erl

@@ -29,7 +29,10 @@
 ]).
 
 %% Internal exports
--export([convert_actions/2]).
+-export([
+    convert_actions/2,
+    validate_key_template/1
+]).
 
 -define(DEFAULT_AGGREG_BATCH_SIZE, 100).
 -define(DEFAULT_AGGREG_BATCH_TIME, <<"10ms">>).
@@ -137,7 +140,10 @@ fields(s3_aggregated_upload_parameters) ->
                 )}
         ],
         emqx_resource_schema:override(emqx_s3_schema:fields(s3_upload), [
-            {key, #{desc => ?DESC(s3_aggregated_upload_key)}}
+            {key, #{
+                desc => ?DESC(s3_aggregated_upload_key),
+                validator => fun ?MODULE:validate_key_template/1
+            }}
         ]),
         emqx_s3_schema:fields(s3_uploader)
     ]);
@@ -246,23 +252,13 @@ convert_action(Conf = #{<<"parameters">> := Params, <<"resource_opts">> := Resou
             Conf#{<<"resource_opts">> := NResourceOpts}
     end.
 
-%% Interpreting options
-
--spec mk_key_template(_Parameters :: map()) ->
-    {ok, emqx_template:str()} | {error, _Reason}.
-mk_key_template(#{key := Key}) ->
-    Template = emqx_template:parse(Key),
+validate_key_template(Conf) ->
+    Template = emqx_template:parse(Conf),
     case validate_bindings(emqx_template:placeholders(Template)) of
-        UsedBindings when is_list(UsedBindings) ->
-            SuffixTemplate = mk_suffix_template(UsedBindings),
-            case emqx_template:is_const(SuffixTemplate) of
-                true ->
-                    {ok, Template};
-                false ->
-                    {ok, Template ++ SuffixTemplate}
-            end;
-        Error = {error, _} ->
-            Error
+        Bindings when is_list(Bindings) ->
+            ok;
+        {error, {disallowed_placeholders, Disallowed}} ->
+            {error, emqx_utils:format("Template placeholders are disallowed: ~p", [Disallowed])}
     end.
 
 validate_bindings(Bindings) ->
@@ -276,7 +272,22 @@ validate_bindings(Bindings) ->
         [] ->
             Bindings;
         Disallowed ->
-            {error, {invalid_key_template, {disallowed_placeholders, Disallowed}}}
+            {error, {disallowed_placeholders, Disallowed}}
+    end.
+
+%% Interpreting options
+
+-spec mk_key_template(unicode:chardata()) ->
+    emqx_template:str().
+mk_key_template(Key) ->
+    Template = emqx_template:parse(Key),
+    UsedBindings = emqx_template:placeholders(Template),
+    SuffixTemplate = mk_suffix_template(UsedBindings),
+    case emqx_template:is_const(SuffixTemplate) of
+        true ->
+            Template;
+        false ->
+            Template ++ SuffixTemplate
     end.
 
 mk_suffix_template(UsedBindings) ->

apps/emqx_bridge_s3/test/emqx_bridge_s3_aggreg_upload_SUITE.erl

@@ -177,6 +177,27 @@ t_create_invalid_config(Config) ->
         )
     ).
 
+t_create_invalid_config_key_template(Config) ->
+    ?assertMatch(
+        {error,
+            {_Status, _, #{
+                <<"code">> := <<"BAD_REQUEST">>,
+                <<"message">> := #{
+                    <<"kind">> := <<"validation_error">>,
+                    <<"reason">> := <<"Template placeholders are disallowed:", _/bytes>>,
+                    <<"path">> := <<"root.parameters.key">>
+                }
+            }}},
+        emqx_bridge_v2_testlib:create_bridge_api(
+            Config,
+            _Overrides = #{
+                <<"parameters">> => #{
+                    <<"key">> => <<"${action}/${foo}:${bar.rfc3339}">>
+                }
+            }
+        )
+    ).
+
 t_update_invalid_config(Config) ->
     ?assertMatch({ok, _Bridge}, emqx_bridge_v2_testlib:create_bridge(Config)),
     ?assertMatch(

apps/emqx_utils/src/emqx_utils.erl

@@ -65,6 +65,7 @@
     flattermap/2,
     tcp_keepalive_opts/4,
     format/1,
+    format/2,
     call_first_defined/1,
     ntoa/1,
     foldl_while/3,
@@ -565,6 +566,9 @@ tcp_keepalive_opts(OS, _Idle, _Interval, _Probes) ->
 format(Term) ->
     iolist_to_binary(io_lib:format("~0p", [Term])).
 
+format(Fmt, Args) ->
+    unicode:characters_to_binary(io_lib:format(Fmt, Args)).
+
 -spec call_first_defined(list({module(), atom(), list()})) -> term() | no_return().
 call_first_defined([{Module, Function, Args} | Rest]) ->
     try