fix(bridge-s3): validate aggreg key template before adding a channel

apps/emqx_bridge_s3/src/emqx_bridge_s3_connector.erl

@@ -162,8 +162,13 @@ 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}}}.
+        {ok, State#{channels => Channels#{ChannelId => ChannelState}}}
+    catch
+        throw:Reason ->
+            {error, Reason}
+    end.
 
 -spec on_remove_channel(_InstanceId :: resource_id(), state(), channel_id()) ->
     {ok, state()}.
@@ -221,9 +226,10 @@ start_channel(State, #{
         max_records => MaxRecords,
         work_dir => work_dir(Type, Name)
     },
+    Template = ensure_ok(emqx_bridge_s3_upload:mk_key_template(Parameters)),
     DeliveryOpts = #{
         bucket => Bucket,
-        key => emqx_bridge_s3_upload:mk_key_template(Parameters),
+        key => Template,
         container => Container,
         upload_options => emqx_bridge_s3_upload:mk_upload_options(Parameters),
         callback_module => ?MODULE,
@@ -247,6 +253,11 @@ 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

@@ -248,17 +248,35 @@ convert_action(Conf = #{<<"parameters">> := Params, <<"resource_opts">> := Resou
 
 %% Interpreting options
 
--spec mk_key_template(_Parameters :: map()) -> emqx_template:str().
+-spec mk_key_template(_Parameters :: map()) ->
+    {ok, emqx_template:str()} | {error, _Reason}.
 mk_key_template(#{key := Key}) ->
     Template = emqx_template:parse(Key),
-    {_, BindingErrors} = emqx_template:render(Template, #{}),
+    case validate_bindings(emqx_template:placeholders(Template)) of
-    {UsedBindings, _} = lists:unzip(BindingErrors),
+        UsedBindings when is_list(UsedBindings) ->
             SuffixTemplate = mk_suffix_template(UsedBindings),
             case emqx_template:is_const(SuffixTemplate) of
                 true ->
-            Template;
+                    {ok, Template};
                 false ->
-            Template ++ SuffixTemplate
+                    {ok, Template ++ SuffixTemplate}
+            end;
+        Error = {error, _} ->
+            Error
+    end.
+
+validate_bindings(Bindings) ->
+    Formats = ["rfc3339", "rfc3339utc", "unix"],
+    AllowedBindings = lists:append([
+        ["action", "node", "sequence"],
+        ["datetime." ++ F || F <- Formats],
+        ["datetime_until." ++ F || F <- Formats]
+    ]),
+    case Bindings -- AllowedBindings of
+        [] ->
+            Bindings;
+        Disallowed ->
+            {error, {invalid_key_template, {disallowed_placeholders, Disallowed}}}
     end.
 
 mk_suffix_template(UsedBindings) ->