refactor(emqx_sup): move global gc to emqx_machine app

apps/emqx/src/emqx_app.erl

@@ -24,6 +24,7 @@
         , get_description/0
         , get_release/0
         , set_init_config_load_done/0
+        , set_override_conf_file/1
         ]).
 
 -include("emqx.hrl").
@@ -70,6 +71,13 @@ stop(_State) -> ok.
 set_init_config_load_done() ->
     application:set_env(emqx, init_config_load_done, true).
 
+%% @doc This API is mostly for testing.
+%% The override config file is typically located in the 'data' dir when
+%% it is a emqx release, but emqx app should not have to konw where the
+%% 'data' dir is located.
+set_override_conf_file(File) ->
+    application:set_env(emqx, override_conf_file, File).
+
 maybe_load_config() ->
     case application:get_env(emqx, init_config_load_done, false) of
         true ->

apps/emqx/src/emqx_config.erl

@@ -260,7 +260,7 @@ load_hocon_file(FileName, LoadType) ->
     end.
 
 emqx_override_conf_name() ->
-    filename:join([?MODULE:get([node, data_dir]), "emqx_override.conf"]).
+    application:get_env(emqx, override_conf_file, "emqx_override.conf").
 
 bin(Bin) when is_binary(Bin) -> Bin;
 bin(Atom) when is_atom(Atom) -> atom_to_binary(Atom, utf8).

apps/emqx/src/emqx_kernel_sup.erl

@@ -29,7 +29,6 @@ init([]) ->
     {ok, {{one_for_one, 10, 100},
            %% always start emqx_config_handler first to load the emqx.conf to emqx_config
           [ child_spec(emqx_config_handler, worker)
-          , child_spec(emqx_global_gc, worker)
           , child_spec(emqx_pool_sup, supervisor)
           , child_spec(emqx_hooks, worker)
           , child_spec(emqx_stats, worker)

apps/emqx/src/emqx_sup.erl

@@ -67,7 +67,7 @@ init([]) ->
     BrokerSup = child_spec(emqx_broker_sup, supervisor),
     CMSup = child_spec(emqx_cm_sup, supervisor),
     SysSup = child_spec(emqx_sys_sup, supervisor),
-    Childs = [KernelSup] ++
+    Children = [KernelSup] ++
                [RouterSup || emqx_boot:is_enabled(router)] ++
                [BrokerSup || emqx_boot:is_enabled(broker)] ++
                [CMSup || emqx_boot:is_enabled(broker)] ++
@@ -76,7 +76,7 @@ init([]) ->
                  intensity => 0,
                  period => 1
                 },
-    {ok, {SupFlags, Childs}}.
+    {ok, {SupFlags, Children}}.
 
 %%--------------------------------------------------------------------
 %% Internal functions

apps/emqx_machine/src/emqx_machine_app.erl

@@ -32,13 +32,15 @@ start(_Type, _Args) ->
 
     ok = load_config_files(),
 
+    {ok, RootSupPid} = emqx_machine_sup:start_link(),
+
     {ok, _} = application:ensure_all_started(emqx),
 
     _ = emqx_plugins:load(),
     _ = start_modules(),
 
     ok = print_vsn(),
-    emqx_machine_sup:start_link().
+    {ok, RootSupPid}.
 
 prep_stop(_State) ->
     application:stop(emqx).

apps/emqx_machine/src/emqx_machine_schema.erl

@@ -128,10 +128,8 @@ fields("node") ->
                                        sensitive => true,
                                        override_env => "EMQX_NODE_COOKIE"
                                       })}
-    , {"data_dir", t(string(), undefined, undefined)}
+    , {"data_dir", hoconsc:t(string(), #{nullable => false})}
-    , {"config_files", t(list(string()), "emqx.config_files",
+    , {"config_files", t(list(string()), "emqx.config_files", undefined)}
-        [ filename:join([os:getenv("RUNNER_ETC_DIR"), "emqx.conf"])
-        ])}
     , {"global_gc_interval", t(emqx_schema:duration(), undefined, "15m")}
     , {"crash_dump_dir", t(file(), "vm_args.-env ERL_CRASH_DUMP", undefined)}
     , {"dist_net_ticktime", t(emqx_schema:duration(), "vm_args.-kernel net_ticktime", "2m")}
@@ -230,6 +228,7 @@ translation("kernel") ->
     , {"logger", fun tr_logger/1}];
 translation("emqx") ->
     [ {"config_files", fun tr_config_files/1}
+    , {"override_conf_file", fun tr_override_conf_fie/1}
     ].
 
 tr_config_files(Conf) ->
@@ -245,6 +244,12 @@ tr_config_files(Conf) ->
             end
     end.
 
+tr_override_conf_fie(Conf) ->
+    DataDir = conf_get("node.data_dir", Conf),
+    %% assert, this config is not nullable
+    [_ | _] = DataDir,
+    filename:join([DataDir, "emqx_override.conf"]).
+
 tr_cluster__discovery(Conf) ->
     Strategy = conf_get("cluster.discovery_strategy", Conf),
     {Strategy, filter(options(Strategy, Conf))}.

apps/emqx_machine/src/emqx_machine_sup.erl

@@ -27,8 +27,28 @@ start_link() ->
     supervisor:start_link({local, ?MODULE}, ?MODULE, []).
 
 init([]) ->
+    GlobalGC = child_worker(emqx_global_gc, []),
+    Children = [GlobalGC],
     SupFlags = #{strategy => one_for_all,
-                 intensity => 0,
+                 intensity => 100,
-                 period => 1
+                 period => 10
                 },
-    {ok, {SupFlags, []}}.
+    {ok, {SupFlags, Children}}.
+
+% child_supervisor(Mod) ->
+%     #{id => Mod,
+%       start => {Mod, start_link, []},
+%       restart => permanent,
+%       shutdown => infinity,
+%       type => supervisor,
+%       modules => [Mod]
+%      }.
+
+child_worker(M, Args) ->
+    #{id       => M,
+      start    => {M, start_link, Args},
+      restart  => permanent,
+      shutdown => 5000,
+      type     => worker,
+      modules  => [M]
+     }.