fix(license): license file is not taking effect after importing backup files

apps/emqx_license/src/emqx_license.app.src

@@ -1,6 +1,6 @@
 {application, emqx_license, [
     {description, "EMQX License"},
-    {vsn, "5.0.16"},
+    {vsn, "5.0.17"},
     {modules, []},
     {registered, [emqx_license_sup]},
     {applications, [kernel, stdlib, emqx_ctl]},

apps/emqx_license/src/emqx_license.erl

@@ -10,6 +10,7 @@
 -include_lib("typerefl/include/types.hrl").
 
 -behaviour(emqx_config_handler).
+-behaviour(emqx_config_backup).
 
 -export([
     pre_config_update/3,
@@ -26,6 +27,8 @@
     update_setting/1
 ]).
 
+-export([import_config/1]).
+
 -define(CONF_KEY_PATH, [license]).
 
 %% Give the license app the highest priority.
@@ -58,21 +61,20 @@ unload() ->
 -spec update_key(binary() | string()) ->
     {ok, emqx_config:update_result()} | {error, emqx_config:update_error()}.
 update_key(Value) when is_binary(Value); is_list(Value) ->
-    Result = emqx_conf:update(
-        ?CONF_KEY_PATH,
-        {key, Value},
-        #{rawconf_with_defaults => true, override_to => cluster}
-    ),
+    Result = exec_config_update({key, Value}),
     handle_config_update_result(Result).
 
 update_setting(Setting) when is_map(Setting) ->
-    Result = emqx_conf:update(
-        ?CONF_KEY_PATH,
-        {setting, Setting},
-        #{rawconf_with_defaults => true, override_to => cluster}
-    ),
+    Result = exec_config_update({setting, Setting}),
     handle_config_update_result(Result).
 
+exec_config_update(Param) ->
+    emqx_conf:update(
+        ?CONF_KEY_PATH,
+        Param,
+        #{rawconf_with_defaults => true, override_to => cluster}
+    ).
+
 %%------------------------------------------------------------------------------
 %% emqx_hooks
 %%------------------------------------------------------------------------------
@@ -106,6 +108,17 @@ check(_ConnInfo, AckProps) ->
             {stop, {error, ?RC_QUOTA_EXCEEDED}}
     end.
 
+import_config(#{<<"license">> := Config}) ->
+    OldConf = emqx:get_config(?CONF_KEY_PATH),
+    case exec_config_update(Config) of
+        {ok, #{config := NewConf}} ->
+            Changed = maps:get(changed, emqx_utils_maps:diff_maps(NewConf, OldConf)),
+            Changed1 = lists:map(fun(Key) -> [license, Key] end, maps:keys(Changed)),
+            {ok, #{root_key => license, changed => Changed1}};
+        Error ->
+            {error, #{root_key => license, reason => Error}}
+    end.
+
 %%------------------------------------------------------------------------------
 %% emqx_config_handler callbacks
 %%------------------------------------------------------------------------------

apps/emqx_license/test/emqx_license_SUITE.erl

@@ -149,6 +149,36 @@ t_check_not_loaded(_Config) ->
         emqx_license:check(#{}, #{})
     ).
 
+t_import_config(_Config) ->
+    %% Import to default license
+    ?assertMatch(
+        {ok, #{root_key := license, changed := _}},
+        emqx_license:import_config(#{<<"license">> => #{<<"key">> => <<"default">>}})
+    ),
+    ?assertEqual(default, emqx:get_config([license, key])),
+    ?assertMatch({ok, #{max_connections := 10}}, emqx_license_checker:limits()),
+
+    %% Import to a new license
+    EncodedLicense = emqx_license_test_lib:make_license(#{max_connections => "100"}),
+    ?assertMatch(
+        {ok, #{root_key := license, changed := _}},
+        emqx_license:import_config(
+            #{
+                <<"license">> =>
+                    #{
+                        <<"key">> => EncodedLicense,
+                        <<"connection_low_watermark">> => <<"20%">>,
+                        <<"connection_high_watermark">> => <<"50%">>
+                    }
+            }
+        )
+    ),
+    ?assertMatch({ok, #{max_connections := 100}}, emqx_license_checker:limits()),
+    ?assertMatch(
+        #{connection_low_watermark := 0.2, connection_high_watermark := 0.5},
+        emqx:get_config([license])
+    ).
+
 %%------------------------------------------------------------------------------
 %% Helpers
 %%------------------------------------------------------------------------------