feat(ft-conf): provide global killswitch

apps/emqx_ft/src/emqx_ft.erl

@@ -198,8 +198,7 @@ on_file_command(PacketId, FileId, Msg, FileCommand) ->
     end.
 
 on_init(PacketId, Msg, Transfer, Meta) ->
-    ?SLOG(info, #{
-        msg => "on_init",
+    ?tp(info, "file_transfer_init", #{
         mqtt_msg => Msg,
         packet_id => PacketId,
         transfer => Transfer,
@@ -229,8 +228,7 @@ on_abort(_Msg, _FileId) ->
     ?RC_SUCCESS.
 
 on_segment(PacketId, Msg, Transfer, Offset, Checksum) ->
-    ?SLOG(info, #{
-        msg => "on_segment",
+    ?tp(info, "file_transfer_segment", #{
         mqtt_msg => Msg,
         packet_id => PacketId,
         transfer => Transfer,
@@ -255,8 +253,7 @@ on_segment(PacketId, Msg, Transfer, Offset, Checksum) ->
     end).
 
 on_fin(PacketId, Msg, Transfer, FinalSize, Checksum) ->
-    ?SLOG(info, #{
-        msg => "on_fin",
+    ?tp(info, "file_transfer_fin", #{
         mqtt_msg => Msg,
         packet_id => PacketId,
         transfer => Transfer,

apps/emqx_ft/src/emqx_ft_app.erl

@@ -22,11 +22,9 @@
 
 start(_StartType, _StartArgs) ->
     {ok, Sup} = emqx_ft_sup:start_link(),
-    ok = emqx_ft:hook(),
     ok = emqx_ft_conf:load(),
     {ok, Sup}.
 
 stop(_State) ->
     ok = emqx_ft_conf:unload(),
-    ok = emqx_ft:unhook(),
     ok.

apps/emqx_ft/src/emqx_ft_conf.erl

@@ -23,6 +23,7 @@
 -include_lib("emqx/include/logger.hrl").
 
 %% Accessors
+-export([enabled/0]).
 -export([storage/0]).
 -export([gc_interval/1]).
 -export([segments_ttl/1]).
@@ -49,6 +50,10 @@
 %% Accessors
 %%--------------------------------------------------------------------
 
+-spec enabled() -> boolean().
+enabled() ->
+    emqx_config:get([file_transfer, enable], false).
+
 -spec storage() -> _Storage.
 storage() ->
     emqx_config:get([file_transfer, storage], undefined).
@@ -83,7 +88,7 @@ store_segment_timeout() ->
 
 -spec load() -> ok.
 load() ->
-    ok = emqx_ft_storage:on_config_update(undefined, storage()),
+    ok = on_config_update(#{}, emqx_config:get([file_transfer], #{})),
     emqx_conf:add_handler([file_transfer], ?MODULE).
 
 -spec unload() -> ok.
@@ -107,7 +112,26 @@ pre_config_update(_, Req, _Config) ->
     emqx_config:app_envs()
 ) ->
     ok | {ok, Result :: any()} | {error, Reason :: term()}.
-post_config_update(_Path, _Req, NewConfig, OldConfig, _AppEnvs) ->
-    OldStorageConfig = maps:get(storage, OldConfig, undefined),
-    NewStorageConfig = maps:get(storage, NewConfig, undefined),
-    emqx_ft_storage:on_config_update(OldStorageConfig, NewStorageConfig).
+post_config_update([file_transfer | _], _Req, NewConfig, OldConfig, _AppEnvs) ->
+    on_config_update(OldConfig, NewConfig).
+
+on_config_update(OldConfig, NewConfig) ->
+    lists:foreach(
+        fun(ConfKey) ->
+            on_config_update(
+                ConfKey,
+                maps:get(ConfKey, OldConfig, undefined),
+                maps:get(ConfKey, NewConfig, undefined)
+            )
+        end,
+        [storage, enable]
+    ).
+
+on_config_update(_, Config, Config) ->
+    ok;
+on_config_update(storage, OldConfig, NewConfig) ->
+    ok = emqx_ft_storage:on_config_update(OldConfig, NewConfig);
+on_config_update(enable, _, true) ->
+    ok = emqx_ft:hook();
+on_config_update(enable, _, false) ->
+    ok = emqx_ft:unhook().

apps/emqx_ft/src/emqx_ft_schema.erl

@@ -55,6 +55,15 @@ roots() -> [file_transfer].
 
 fields(file_transfer) ->
     [
+        {enable,
+            mk(
+                boolean(),
+                #{
+                    desc => ?DESC("enable"),
+                    required => false,
+                    default => false
+                }
+            )},
         {init_timeout,
             mk(
                 emqx_schema:duration_ms(),
@@ -87,22 +96,19 @@ fields(file_transfer) ->
                 hoconsc:union(
                     fun
                         (all_union_members) ->
-                            [
-                                % NOTE: by default storage is disabled
-                                undefined,
-                                ref(local_storage)
-                            ];
+                            [ref(local_storage)];
                         ({value, #{<<"type">> := <<"local">>}}) ->
                             [ref(local_storage)];
                         ({value, #{<<"type">> := _}}) ->
                             throw(#{field_name => type, expected => "local"});
-                        (_) ->
-                            [undefined]
+                        ({value, _}) ->
+                            [ref(local_storage)]
                     end
                 ),
                 #{
                     required => false,
-                    desc => ?DESC("storage")
+                    desc => ?DESC("storage"),
+                    default => #{<<"type">> => <<"local">>}
                 }
             )}
     ];

apps/emqx_ft/test/emqx_ft_SUITE.erl

@@ -63,6 +63,7 @@ set_special_configs(Config) ->
                 % NOTE
                 % Inhibit local fs GC to simulate it isn't fast enough to collect
                 % complete transfers.
+                enable => true,
                 storage => emqx_utils_maps:deep_merge(
                     Storage,
                     #{segments => #{gc => #{interval => 0}}}

apps/emqx_ft/test/emqx_ft_api_SUITE.erl

@@ -30,7 +30,7 @@ all() -> emqx_common_test_helpers:all(?MODULE).
 
 init_per_suite(Config) ->
     ok = emqx_mgmt_api_test_util:init_suite(
-        [emqx_conf, emqx_ft], set_special_configs(Config)
+        [emqx_conf, emqx_ft], emqx_ft_test_helpers:env_handler(Config)
     ),
     {ok, _} = emqx:update_config([rpc, port_discovery], manual),
     Config.
@@ -38,16 +38,6 @@ end_per_suite(_Config) ->
     ok = emqx_mgmt_api_test_util:end_suite([emqx_ft, emqx_conf]),
     ok.
 
-set_special_configs(Config) ->
-    fun
-        (emqx_ft) ->
-            emqx_ft_test_helpers:load_config(#{
-                storage => emqx_ft_test_helpers:local_storage(Config)
-            });
-        (_) ->
-            ok
-    end.
-
 init_per_testcase(Case, Config) ->
     [{tc, Case} | Config].
 end_per_testcase(_Case, _Config) ->

apps/emqx_ft/test/emqx_ft_conf_SUITE.erl

@@ -26,22 +26,21 @@
 all() -> emqx_common_test_helpers:all(?MODULE).
 
 init_per_suite(Config) ->
-    _ = emqx_config:save_schema_mod_and_names(emqx_ft_schema),
-    ok = emqx_common_test_helpers:start_apps(
-        [emqx_conf, emqx_ft], emqx_ft_test_helpers:env_handler(Config)
-    ),
-    {ok, _} = emqx:update_config([rpc, port_discovery], manual),
     Config.
 
 end_per_suite(_Config) ->
-    ok = emqx_common_test_helpers:stop_apps([emqx_ft, emqx_conf]),
     ok.
 
 init_per_testcase(_Case, Config) ->
+    % NOTE: running each testcase with clean config
+    _ = emqx_config:save_schema_mod_and_names(emqx_ft_schema),
+    ok = emqx_common_test_helpers:start_apps([emqx_conf, emqx_ft], fun(_) -> ok end),
+    {ok, _} = emqx:update_config([rpc, port_discovery], manual),
     Config.
 
 end_per_testcase(_Case, _Config) ->
-    ok.
+    ok = emqx_common_test_helpers:stop_apps([emqx_ft, emqx_conf]),
+    ok = emqx_config:erase(file_transfer).
 
 %%--------------------------------------------------------------------
 %% Tests
@@ -61,6 +60,7 @@ t_update_config(_Config) ->
         emqx_conf:update(
             [file_transfer],
             #{
+                <<"enable">> => true,
                 <<"storage">> => #{
                     <<"type">> => <<"local">>,
                     <<"segments">> => #{
@@ -87,10 +87,14 @@ t_update_config(_Config) ->
         emqx_ft_conf:gc_interval(emqx_ft_conf:storage())
     ).
 
-t_remove_restore_config(Config) ->
+t_disable_restore_config(Config) ->
     ?assertMatch(
         {ok, _},
-        emqx_conf:update([file_transfer, storage], #{<<"type">> => <<"local">>}, #{})
+        emqx_conf:update(
+            [file_transfer],
+            #{<<"enable">> => true, <<"storage">> => #{<<"type">> => <<"local">>}},
+            #{}
+        )
     ),
     ?assertEqual(
         60 * 60 * 1000,
@@ -98,24 +102,29 @@ t_remove_restore_config(Config) ->
     ),
     % Verify that transfers work
     ok = emqx_ft_test_helpers:upload_file(gen_clientid(), <<"f1">>, "f1", <<?MODULE_STRING>>),
+    % Verify that clearing storage settings reverts config to defaults
     ?assertMatch(
         {ok, _},
-        emqx_conf:remove([file_transfer, storage], #{})
+        emqx_conf:update(
+            [file_transfer],
+            #{<<"enable">> => false, <<"storage">> => undefined},
+            #{}
+        )
     ),
     ?assertEqual(
-        undefined,
-        emqx_ft_conf:storage()
+        false,
+        emqx_ft_conf:enabled()
     ),
-    ?assertEqual(
-        undefined,
-        emqx_ft_conf:gc_interval(emqx_ft_conf:storage())
+    ?assertMatch(
+        #{type := local, exporter := #{type := local}},
+        emqx_ft_conf:storage()
     ),
     ClientId = gen_clientid(),
     Client = emqx_ft_test_helpers:start_client(ClientId),
     % Verify that transfers fail cleanly when storage is disabled
     ?check_trace(
         ?assertMatch(
-            {ok, #{reason_code_name := unspecified_error}},
+            {ok, #{reason_code_name := no_matching_subscribers}},
             emqtt:publish(
                 Client,
                 <<"$file/f2/init">>,
@@ -124,23 +133,24 @@ t_remove_restore_config(Config) ->
             )
         ),
         fun(Trace) ->
-            ?assertMatch(
-                [#{transfer := {ClientId, <<"f2">>}, reason := {error, disabled}}],
-                ?of_kind("store_filemeta_failed", Trace)
-            )
+            ?assertMatch([], ?of_kind("file_transfer_init", Trace))
         end
     ),
+    ok = emqtt:stop(Client),
     % Restore local storage backend
     Root = iolist_to_binary(emqx_ft_test_helpers:root(Config, node(), [segments])),
     ?assertMatch(
         {ok, _},
         emqx_conf:update(
-            [file_transfer, storage],
+            [file_transfer],
             #{
-                <<"type">> => <<"local">>,
-                <<"segments">> => #{
-                    <<"root">> => Root,
-                    <<"gc">> => #{<<"interval">> => <<"1s">>}
+                <<"enable">> => true,
+                <<"storage">> => #{
+                    <<"type">> => <<"local">>,
+                    <<"segments">> => #{
+                        <<"root">> => Root,
+                        <<"gc">> => #{<<"interval">> => <<"1s">>}
+                    }
                 }
             },
             #{}
@@ -167,5 +177,62 @@ t_remove_restore_config(Config) ->
     % Verify that transfers work again
     ok = emqx_ft_test_helpers:upload_file(gen_clientid(), <<"f1">>, "f1", <<?MODULE_STRING>>).
 
+t_switch_exporter(_Config) ->
+    ?assertMatch(
+        {ok, _},
+        emqx_conf:update(
+            [file_transfer],
+            #{<<"enable">> => true},
+            #{}
+        )
+    ),
+    ?assertMatch(
+        #{type := local, exporter := #{type := local}},
+        emqx_ft_conf:storage()
+    ),
+    % Verify that switching to a different exporter works
+    ?assertMatch(
+        {ok, _},
+        emqx_conf:update(
+            [file_transfer, storage, exporter],
+            #{
+                <<"type">> => <<"s3">>,
+                <<"bucket">> => <<"emqx">>,
+                <<"host">> => <<"https://localhost">>,
+                <<"port">> => 9000,
+                <<"transport_options">> => #{
+                    <<"ipv6_probe">> => false
+                }
+            },
+            #{}
+        )
+    ),
+    ?assertMatch(
+        #{type := local, exporter := #{type := s3}},
+        emqx_ft_conf:storage()
+    ),
+    % Verify that switching back to local exporter works
+    ?assertMatch(
+        {ok, _},
+        emqx_conf:remove(
+            [file_transfer, storage, exporter],
+            #{}
+        )
+    ),
+    ?assertMatch(
+        {ok, _},
+        emqx_conf:update(
+            [file_transfer, storage, exporter],
+            #{<<"type">> => <<"local">>},
+            #{}
+        )
+    ),
+    ?assertMatch(
+        #{type := local, exporter := #{type := local}},
+        emqx_ft_conf:storage()
+    ),
+    % Verify that transfers work
+    ok = emqx_ft_test_helpers:upload_file(gen_clientid(), <<"f1">>, "f1", <<?MODULE_STRING>>).
+
 gen_clientid() ->
     emqx_base62:encode(emqx_guid:gen()).

apps/emqx_ft/test/emqx_ft_storage_fs_SUITE.erl

@@ -35,22 +35,12 @@ groups() ->
     ].
 
 init_per_suite(Config) ->
-    ok = emqx_common_test_helpers:start_apps([emqx_ft], set_special_configs(Config)),
+    ok = emqx_common_test_helpers:start_apps([emqx_ft], emqx_ft_test_helpers:env_handler(Config)),
     Config.
 end_per_suite(_Config) ->
     ok = emqx_common_test_helpers:stop_apps([emqx_ft]),
     ok.
 
-set_special_configs(Config) ->
-    fun
-        (emqx_ft) ->
-            emqx_ft_test_helpers:load_config(#{
-                storage => emqx_ft_test_helpers:local_storage(Config)
-            });
-        (_) ->
-            ok
-    end.
-
 init_per_testcase(Case, Config) ->
     [{tc, Case} | Config].
 end_per_testcase(_Case, _Config) ->

apps/emqx_ft/test/emqx_ft_test_helpers.erl

@@ -41,7 +41,7 @@ stop_additional_node(Node) ->
 env_handler(Config) ->
     fun
         (emqx_ft) ->
-            load_config(#{storage => local_storage(Config)});
+            load_config(#{enable => true, storage => local_storage(Config)});
         (_) ->
             ok
     end.

rel/i18n/emqx_ft_schema.hocon

@@ -1,5 +1,11 @@
 emqx_ft_schema {
 
+enable.desc:
+"""Enable the File Transfer feature.<br/>
+Enabling File Transfer implies reserving special MQTT topics in order to serve the protocol.<br/>
+This toggle does not have an effect neither on the availability of the File Transfer REST API, nor
+on storage-dependent background activities (e.g. garbage collection)."""
+
 init_timeout.desc:
 """Timeout for initializing the file transfer.<br/>
 After reaching the timeout, `init` message will be acked with an error"""