Add emqx_boot module

src/emqx_boot.erl

@@ -0,0 +1,29 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2019 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_boot).
+
+-export([is_enabled/1]).
+
+-define(BOOT_MODULES, [router, broker, listeners]).
+
+-spec(is_enabled(all|list(router|broker|listener)) -> boolean()).
+is_enabled(Mod) ->
+    (BootMods = boot_modules() =:= all) orelse lists:member(Mod, BootMods).
+
+boot_modules() ->
+    application:get_env(emqx, boot_modules, ?BOOT_MODULES).
+