refactor(emqx_plugin): Decorate RPCs

apps/emqx_plugin_libs/src/emqx_plugin_libs_metrics.erl

@@ -55,7 +55,7 @@
 -define(SAMPLING, 1).
 -endif.
 
--export_type([metrics/0]).
+-export_type([metrics/0, handler_name/0, metric_id/0]).
 
 -type rate() :: #{
     current => float(),

apps/emqx_plugin_libs/src/proto/emqx_plugin_libs_proto_v1.erl

@@ -0,0 +1,36 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2022 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_plugin_libs_proto_v1).
+
+-behaviour(emqx_bpapi).
+
+-export([ introduced_in/0
+
+        , get_metrics/3
+        ]).
+
+-include_lib("emqx/include/bpapi.hrl").
+
+introduced_in() ->
+    "5.0.0".
+
+-spec get_metrics( node()
+                 , emqx_plugin_libs_metrics:handler_name()
+                 , emqx_plugin_libs_metrics:metric_id()
+                 ) -> emqx_plugin_libs_metrics:metrics() | {badrpc, _}.
+get_metrics(Node, HandlerName, MetricId) ->
+    rpc:call(Node, emqx_plugin_libs_metrics, get_metrics, [HandlerName, MetricId]).

apps/emqx_rule_engine/src/emqx_rule_engine_api.erl

@@ -322,7 +322,7 @@ get_rule_metrics(Id) ->
          , node => Node
          }
     end,
-    [Format(Node, rpc:call(Node, emqx_plugin_libs_metrics, get_metrics, [rule_metrics, Id]))
+    [Format(Node, emqx_plugin_libs_proto_v1:get_metrics(Node, rule_metrics, Id))
      || Node <- mria_mnesia:running_nodes()].
 
 aggregate_metrics(AllMetrics) ->
@@ -350,4 +350,3 @@ filter_out_request_body(Conf) ->
     ExtraConfs = [<<"id">>, <<"status">>, <<"node_status">>, <<"node_metrics">>,
         <<"metrics">>, <<"node">>],
     maps:without(ExtraConfs, Conf).
-