feat(exhook): expose process pool_size for grpc client

apps/emqx_exhook/etc/emqx_exhook.conf

@@ -24,6 +24,11 @@
 ## Value: false | Duration
 #exhook.auto_reconnect = 60s
 
+## The process pool size for gRPC client
+##
+## Default: Equals cpu cores
+## Value: Integer
+#exhook.pool_size = 16
 
 ##--------------------------------------------------------------------
 ## The Hook callback servers

apps/emqx_exhook/priv/emqx_exhook.schema

@@ -26,6 +26,10 @@
   end
 end}.
 
+{mapping, "exhook.pool_size", "emqx_exhook.pool_size", [
+  {datatype, integer}
+]}.
+
 {mapping, "exhook.server.$name.url", "emqx_exhook.servers", [
   {datatype, string}
 ]}.

apps/emqx_exhook/src/emqx_exhook_mngr.erl

@@ -36,6 +36,8 @@
         , server/1
         , put_request_failed_action/1
         , get_request_failed_action/0
+        , put_pool_size/1
+        , get_pool_size/0
         ]).
 
 %% gen_server callbacks
@@ -117,6 +119,9 @@ init([Servers, AutoReconnect, ReqOpts0]) ->
     put_request_failed_action(
       maps:get(request_failed_action, ReqOpts0, deny)
      ),
+    put_pool_size(
+      maps:get(pool_size, ReqOpts0, erlang:system_info(schedulers))
+     ),
 
     %% Load the hook servers
     ReqOpts = maps:without([request_failed_action], ReqOpts0),
@@ -286,6 +291,12 @@ put_request_failed_action(Val) ->
 get_request_failed_action() ->
     persistent_term:get({?APP, request_failed_action}).
 
+put_pool_size(Val) ->
+    persistent_term:put({?APP, pool_size}, Val).
+
+get_pool_size() ->
+    persistent_term:get({?APP, pool_size}).
+
 save(Name, ServerState) ->
     Saved = persistent_term:get(?APP, []),
     persistent_term:put(?APP, lists:reverse([Name | Saved])),

apps/emqx_exhook/src/emqx_exhook_server.erl

@@ -131,7 +131,8 @@ channel_opts(Opts) ->
                              transport_opts => SslOpts}};
                      _ -> #{}
                  end,
-    {SvrAddr, ClientOpts}.
+    NClientOpts = ClientOpts#{pool_size => emqx_exhook_mngr:get_pool_size()},
+    {SvrAddr, NClientOpts}.
 
 format_http_uri(Scheme, Host0, Port) ->
     Host = case is_tuple(Host0) of

apps/emqx_exhook/src/emqx_exhook_sup.erl

@@ -54,7 +54,8 @@ auto_reconnect() ->
 
 request_options() ->
     #{timeout => env(request_timeout, 5000),
-      request_failed_action => env(request_failed_action, deny)
+      request_failed_action => env(request_failed_action, deny),
+      pool_size => env(pool_size, erlang:system_info(schedulers))
      }.
 
 env(Key, Def) ->
@@ -67,7 +68,7 @@ env(Key, Def) ->
 -spec start_grpc_client_channel(
         string(),
         uri_string:uri_string(),
-        grpc_client:options()) -> {ok, pid()} | {error, term()}.
+        grpc_client_sup:options()) -> {ok, pid()} | {error, term()}.
 start_grpc_client_channel(Name, SvrAddr, Options) ->
     grpc_client_sup:create_channel_pool(Name, SvrAddr, Options).