refactor(emqx_exhook): Decorate RPCs

apps/emqx/src/emqx_rpc.erl

@@ -25,6 +25,8 @@
         , cast/5
         , multicall/4
         , multicall/5
+
+        , unwrap_erpc/1
         ]).
 
 -export_type([ badrpc/0
@@ -106,3 +108,15 @@ filter_result(Delivery) ->
 
 max_client_num() ->
     emqx:get_config([rpc, tcp_client_num], ?DefaultClientNum).
+
+-spec unwrap_erpc(emqx_rpc:erpc(A)) -> A | {error, _Err}.
+unwrap_erpc({ok, A}) ->
+    A;
+unwrap_erpc({throw, A}) ->
+    {error, A};
+unwrap_erpc({error, {exception, Err, _Stack}}) ->
+    {error, Err};
+unwrap_erpc({error, {exit, Err}}) ->
+    {error, Err};
+unwrap_erpc({error, {erpc, Err}}) ->
+    {error, Err}.

apps/emqx/test/emqx_bpapi_static_checks.erl

@@ -51,7 +51,7 @@
 %% List of known functions also known to do RPC:
 -define(RPC_FUNCTIONS, "emqx_cluster_rpc:multicall/3, emqx_cluster_rpc:multicall/5").
 %% List of functions in the RPC backend modules that we can ignore:
--define(IGNORED_RPC_CALLS, "gen_rpc:nodes/0").
+-define(IGNORED_RPC_CALLS, "gen_rpc:nodes/0, emqx_rpc:unwrap_erpc/1").
 %% List of business-layer functions that are exempt from the checks:
 -define(EXEMPTIONS, "emqx_mgmt_api:do_query/6"  % Reason: legacy code. A fun and a QC query are
                                                 % passed in the args, it's futile to try to statically
@@ -213,7 +213,7 @@ prepare(#{reldir := RelDir, plt := PLT}) ->
 
 find_remote_calls(_Opts) ->
     Query = "XC | (A - [" ?IGNORED_APPS "]:App - [" ?IGNORED_MODULES "]:Mod - [" ?EXEMPTIONS "])
-               || (([" ?RPC_MODULES "] : Mod + [" ?RPC_FUNCTIONS "]) - " ?IGNORED_RPC_CALLS ")",
+               || (([" ?RPC_MODULES "] : Mod + [" ?RPC_FUNCTIONS "]) - [" ?IGNORED_RPC_CALLS "])",
     {ok, Calls} = xref:q(?XREF, Query),
     ?INFO("Calls to RPC modules ~p", [Calls]),
     {Callers, _Callees} = lists:unzip(Calls),

apps/emqx_exhook/src/emqx_exhook_api.erl

@@ -32,9 +32,6 @@
 -define(BAD_REQUEST, 'BAD_REQUEST').
 -define(BAD_RPC, 'BAD_RPC').
 
--type rpc_result() :: {error, any()}
-                    | any().
-
 -dialyzer([{nowarn_function, [ fill_cluster_server_info/5
                              , nodes_server_info/5
                              , fill_server_hooks_info/4
@@ -285,7 +282,7 @@ get_nodes_server_info(Name) ->
 %% GET /exhooks
 %%--------------------------------------------------------------------
 nodes_all_server_info(ConfL) ->
-    AllInfos = call_cluster(emqx_exhook_mgr, all_servers_info, []),
+    AllInfos = call_cluster(fun(Nodes) -> emqx_exhook_proto_v1:all_servers_info(Nodes) end),
     Default = emqx_exhook_metrics:new_metrics_info(),
     node_all_server_info(ConfL, AllInfos, Default, []).
 
@@ -324,7 +321,7 @@ fill_cluster_server_info([], StatusL, MetricsL, ServerName, _) ->
 %% GET /exhooks/{name}
 %%--------------------------------------------------------------------
 nodes_server_info(Name) ->
-    InfoL = call_cluster(emqx_exhook_mgr, server_info, [Name]),
+    InfoL = call_cluster(fun(Nodes) -> emqx_exhook_proto_v1:server_info(Nodes, Name) end),
     Default = emqx_exhook_metrics:new_metrics_info(),
     nodes_server_info(InfoL, Name, Default, [], []).
 
@@ -359,7 +356,7 @@ get_nodes_server_hooks_info(Name) ->
     case emqx_exhook_mgr:hooks(Name) of
         [] -> [];
         Hooks ->
-            AllInfos = call_cluster(emqx_exhook_mgr, server_hooks_metrics, [Name]),
+            AllInfos = call_cluster(fun(Nodes) -> emqx_exhook_proto_v1:server_hooks_metrics(Nodes, Name) end),
             Default = emqx_exhook_metrics:new_metrics_info(),
             get_nodes_server_hooks_info(Hooks, AllInfos, Default, [])
     end.
@@ -387,16 +384,10 @@ fill_server_hooks_info([], _Name, _Default, MetricsL) ->
 %%--------------------------------------------------------------------
 %% cluster call
 %%--------------------------------------------------------------------
-call_cluster(Module, Fun, Args) ->
-    Nodes = mria_mnesia:running_nodes(),
-    [{Node, rpc_call(Node, Module, Fun, Args)} || Node <- Nodes].
-
--spec rpc_call(node(), atom(), atom(), list()) -> rpc_result().
-rpc_call(Node, Module, Fun, Args) when Node =:= node() ->
-    erlang:apply(Module, Fun, Args);
 
-rpc_call(Node, Module, Fun, Args) ->
-    case rpc:call(Node, Module, Fun, Args) of
-        {badrpc, Reason} -> {error, Reason};
-        Res -> Res
-    end.
+-spec call_cluster(fun(([node()]) -> emqx_rpc:erpc_multicall(A))) ->
+          [{node(), A | {error, _Err}}].
+call_cluster(Fun) ->
+    Nodes = mria_mnesia:running_nodes(),
+    Ret = Fun(Nodes),
+    lists:zip(Nodes, lists:map(fun emqx_rpc:unwrap_erpc/1, Ret)).

apps/emqx_exhook/src/proto/emqx_exhook_proto_v1.erl

@@ -0,0 +1,46 @@
+%%--------------------------------------------------------------------
+%% 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_exhook_proto_v1).
+
+-behaviour(emqx_bpapi).
+
+-export([ introduced_in/0
+
+        , all_servers_info/1
+        , server_info/2
+        , server_hooks_metrics/2
+        ]).
+
+-include_lib("emqx/include/bpapi.hrl").
+
+introduced_in() ->
+    "5.0.0".
+
+-spec all_servers_info([node()]) ->
+          emqx_rpc:erpc_multicall(map()).
+all_servers_info(Nodes) ->
+    erpc:multicall(Nodes, emqx_exhook_mgr, all_servers_info, []).
+
+-spec server_info([node()], emqx_exhook_mgr:server_name()) ->
+          emqx_rpc:erpc_multicall(map()).
+server_info(Nodes, Name) ->
+    erpc:multicall(Nodes, emqx_exhook_mgr, server_info, [Name]).
+
+-spec server_hooks_metrics([node()], emqx_exhook_mgr:server_name()) ->
+          emqx_rpc:erpc_multicall(emqx_exhook_metrics:hooks_metrics()).
+server_hooks_metrics(Nodes, Name) ->
+    erpc:multicall(Nodes, emqx_exhook_mgr, server_hooks_metrics, [Name]).