From 378a2b7b9e54c7caca20b8dde5b81c7e775306b0 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Tue, 15 Jun 2021 18:47:43 +0800
Subject: [PATCH] feat(config): update config to the sub config handler

---
 apps/emqx/src/emqx_config.erl                 | 15 ++++++
 apps/emqx/src/emqx_config_handler.erl         | 51 ++++++++++++-------
 .../emqx_data_bridge/src/emqx_data_bridge.erl | 17 -------
 .../src/emqx_data_bridge_api.erl              | 13 ++++-
 .../src/emqx_data_bridge_sup.erl              |  7 ++-
 5 files changed, 66 insertions(+), 37 deletions(-)

diff --git a/apps/emqx/src/emqx_config.erl b/apps/emqx/src/emqx_config.erl
index 3dd0c3087..d05486328 100644
--- a/apps/emqx/src/emqx_config.erl
+++ b/apps/emqx/src/emqx_config.erl
@@ -20,7 +20,9 @@
 -export([ get/0
         , get/2
         , put/1
+        , put/2
         , deep_get/3
+        , deep_put/3
         ]).
 
 -spec get() -> term().
@@ -31,6 +33,7 @@ get() ->
 get(KeyPath, Default) ->
     deep_get(KeyPath, get(), Default).
 
+-spec deep_get([atom()], map(), term()) -> term().
 deep_get([], Map, _Default) ->
     Map;
 deep_get([Key | KeyPath], Map, Default) when is_map(Map) ->
@@ -41,5 +44,17 @@ deep_get([Key | KeyPath], Map, Default) when is_map(Map) ->
 deep_get([_Key | _KeyPath], _Map, Default) ->
     Default.
 
+-spec put(term()) -> ok.
 put(Config) ->
     persistent_term:put(?MODULE, Config).
+
+-spec put([atom()], term()) -> ok.
+put(KeyPath, Config) ->
+    put(deep_put(KeyPath, get(), Config)).
+
+-spec deep_put([atom()], map(), term()) -> ok.
+deep_put([], Map, Config) when is_map(Map) ->
+    Config;
+deep_put([Key | KeyPath], Map, Config) ->
+    SubMap = deep_put(KeyPath, maps:get(Key, Map, #{}), Config),
+    Map#{Key => SubMap}.
diff --git a/apps/emqx/src/emqx_config_handler.erl b/apps/emqx/src/emqx_config_handler.erl
index fd01b648f..792ede35b 100644
--- a/apps/emqx/src/emqx_config_handler.erl
+++ b/apps/emqx/src/emqx_config_handler.erl
@@ -21,13 +21,13 @@
 
 %% API functions
 -export([ start_link/0
-        , start_handler/2
+        , start_handler/3
         , update_config/2
+        , child_spec/2
         ]).
 
 %% emqx_config_handler callbacks
 -export([ handle_update_config/2
-        , config_key_path/0
         ]).
 
 %% gen_server callbacks
@@ -39,24 +39,35 @@
          code_change/3]).
 
 -type config() :: term().
--type config_map() :: #{atom() => config()}.
+-type config_map() :: #{atom() => config()} | [config_map()].
 -type handler_name() :: module().
 -type key_path() :: [atom()].
 
-%% the path of the config that maintained by the (sub) handler.
--callback config_key_path() -> key_path().
+-optional_callbacks([handle_update_config/2]).
 
 -callback handle_update_config(config(), config_map()) -> config_map().
 
--record(state, {handler_name :: handler_name(), parent :: handler_name()}).
+-record(state, {
+    handler_name :: handler_name(),
+    parent :: handler_name(),
+    key_path :: key_path()
+}).
 
 start_link() ->
-    start_handler(?MODULE, top).
+    start_handler(?MODULE, top, []).
 
--spec start_handler(handler_name(), handler_name()) ->
+-spec start_handler(handler_name(), handler_name(), key_path()) ->
     {ok, pid()} | {error, {already_started, pid()}} | {error, term()}.
-start_handler(HandlerName, Parent) ->
-    gen_server:start_link({local, HandlerName}, ?MODULE, {HandlerName, Parent}, []).
+start_handler(HandlerName, Parent, ConfKeyPath) ->
+    gen_server:start_link({local, HandlerName}, ?MODULE, {HandlerName, Parent, ConfKeyPath}, []).
+
+-spec child_spec(module(), key_path()) -> supervisor:child_spec().
+child_spec(Mod, KeyPath) ->
+    #{id => Mod,
+      start => {?MODULE, start_handler, [Mod, ?MODULE, KeyPath]},
+      restart => permanent,
+      type => worker,
+      modules => [?MODULE]}.
 
 -spec update_config(handler_name(), config()) -> ok.
 update_config(top, Config) ->
@@ -67,28 +78,29 @@ update_config(Handler, Config) ->
 
 %%============================================================================
 %% callbacks of emqx_config_handler (the top-level handler)
-config_key_path() -> [].
-
 handle_update_config(Config, undefined) ->
     handle_update_config(Config, #{});
 handle_update_config(Config, OldConfigMap) ->
     %% simply merge the config to the overall config
     maps:merge(OldConfigMap, Config).
 
-init({HandlerName, Parent}) ->
-    {ok, #state{handler_name = HandlerName, parent = Parent}}.
+init({HandlerName, Parent, ConfKeyPath}) ->
+    {ok, #state{handler_name = HandlerName, parent = Parent, key_path = ConfKeyPath}}.
 
 handle_call(_Request, _From, State) ->
     Reply = ok,
     {reply, Reply, State}.
 
 handle_cast({handle_update_config, Config}, #state{handler_name = HandlerName,
-        parent = Parent} = State) ->
+        parent = Parent, key_path = ConfKeyPath} = State) ->
     %% accumulate the config map of this config handler
-    OldConfigMap = emqx_config:get(HandlerName:config_key_path(), undefined),
-    AccConfig = HandlerName:handle_update_config(Config, OldConfigMap),
+    OldConfigMap = emqx_config:get(ConfKeyPath, undefined),
+    SubConfigMap = case erlang:function_exported(HandlerName, handle_update_config, 2) of
+        true -> HandlerName:handle_update_config(Config, OldConfigMap);
+        false -> wrap_sub_config(ConfKeyPath, Config)
+    end,
     %% then notify the parent handler
-    update_config(Parent, AccConfig),
+    update_config(Parent, SubConfigMap),
     {noreply, State};
 
 handle_cast(_Msg, State) ->
@@ -114,3 +126,6 @@ save_config_to_disk(ConfigMap) ->
 emqx_data_dir() ->
     %emqx_config:get([node, data_dir])
     "data".
+
+wrap_sub_config(ConfKeyPath, Config) ->
+    emqx_config:deep_put(ConfKeyPath, #{}, Config).
diff --git a/apps/emqx_data_bridge/src/emqx_data_bridge.erl b/apps/emqx_data_bridge/src/emqx_data_bridge.erl
index 3aa72b1da..2adc48111 100644
--- a/apps/emqx_data_bridge/src/emqx_data_bridge.erl
+++ b/apps/emqx_data_bridge/src/emqx_data_bridge.erl
@@ -15,12 +15,6 @@
 %%--------------------------------------------------------------------
 -module(emqx_data_bridge).
 
--behaviour(emqx_config_handler).
-
--export([ config_key_path/0
-        , handle_update_config/2
-        ]).
-
 -export([ load_bridges/0
         , resource_type/1
         , bridge_type/1
@@ -52,14 +46,3 @@ is_bridge(#{id := <<"bridge:", _/binary>>}) ->
     true;
 is_bridge(_Data) ->
     false.
-
-%%============================================================================
-
-config_key_path() -> [emqx_data_bridge, bridges].
-
-handle_update_config(_Config, _OldConfigMap) ->
-    [format_conf(Data) || Data <- emqx_data_bridge:list_bridges()].
-
-format_conf(#{resource_type := Type, id := Id, config := Conf}) ->
-    #{type => Type, name => emqx_data_bridge:resource_id_to_name(Id),
-      config => Conf}.
\ No newline at end of file
diff --git a/apps/emqx_data_bridge/src/emqx_data_bridge_api.erl b/apps/emqx_data_bridge/src/emqx_data_bridge_api.erl
index 1a27351eb..df07d7a5e 100644
--- a/apps/emqx_data_bridge/src/emqx_data_bridge_api.erl
+++ b/apps/emqx_data_bridge/src/emqx_data_bridge_api.erl
@@ -76,6 +76,7 @@ create_bridge(#{name := Name}, Params) ->
             emqx_data_bridge:name_to_resource_id(Name),
             emqx_data_bridge:resource_type(BridgeType), Config) of
         {ok, Data} ->
+            emqx_config_handler:update_config(emqx_data_bridge, get_all_configs()),
             {200, #{code => 0, data => format_api_reply(emqx_resource_api:format_data(Data))}};
         {error, already_created} ->
             {400, #{code => 102, message => <<"bridge already created: ", Name/binary>>}};
@@ -92,6 +93,7 @@ update_bridge(#{name := Name}, Params) ->
             emqx_data_bridge:name_to_resource_id(Name),
             emqx_data_bridge:resource_type(BridgeType), Config, []) of
         {ok, Data} ->
+            emqx_config_handler:update_config(emqx_data_bridge, get_all_configs()),
             {200, #{code => 0, data => format_api_reply(emqx_resource_api:format_data(Data))}};
         {error, not_found} ->
             {400, #{code => 102, message => <<"bridge not_found: ", Name/binary>>}};
@@ -103,7 +105,9 @@ update_bridge(#{name := Name}, Params) ->
 
 delete_bridge(#{name := Name}, _Params) ->
     case emqx_resource:remove(emqx_data_bridge:name_to_resource_id(Name)) of
-        ok -> {200, #{code => 0, data => #{}}};
+        ok ->
+            emqx_config_handler:update_config(emqx_data_bridge, get_all_configs()),
+            {200, #{code => 0, data => #{}}};
         {error, Reason} ->
             {500, #{code => 102, message => emqx_resource_api:stringnify(Reason)}}
     end.
@@ -112,3 +116,10 @@ format_api_reply(#{resource_type := Type, id := Id, config := Conf, status := St
     #{type => emqx_data_bridge:bridge_type(Type),
       name => emqx_data_bridge:resource_id_to_name(Id),
       config => Conf, status => Status}.
+
+format_conf(#{resource_type := Type, id := Id, config := Conf}) ->
+    #{type => Type, name => emqx_data_bridge:resource_id_to_name(Id),
+      config => Conf}.
+
+get_all_configs() ->
+    [format_conf(Data) || Data <- emqx_data_bridge:list_bridges()].
diff --git a/apps/emqx_data_bridge/src/emqx_data_bridge_sup.erl b/apps/emqx_data_bridge/src/emqx_data_bridge_sup.erl
index 516d9b5ab..20a447bf0 100644
--- a/apps/emqx_data_bridge/src/emqx_data_bridge_sup.erl
+++ b/apps/emqx_data_bridge/src/emqx_data_bridge_sup.erl
@@ -35,7 +35,12 @@ init([]) ->
           start => {emqx_data_bridge_monitor, start_link, []},
           restart => permanent,
           type => worker,
-          modules => [emqx_data_bridge_monitor]}],
+          modules => [emqx_data_bridge_monitor]},
+        emqx_config_handler:child_spec(emqx_data_bridge_config_handler, config_key_path())
+    ],
     {ok, {SupFlags, ChildSpecs}}.
 
 %% internal functions
+
+config_key_path() ->
+    [emqx_data_bridge, bridges].