Merge pull request #11423 from lafirest/chore/limiter_utils

fix(limiter): simplify the code of the limiter

apps/emqx/src/emqx_limiter/src/emqx_htb_limiter.erl

@@ -139,7 +139,7 @@ make_local_limiter(Cfg, Bucket) ->
         tokens => emqx_limiter_server:get_initial_val(Cfg),
         lasttime => ?NOW,
         bucket => Bucket,
-        capacity => emqx_limiter_schema:calc_capacity(Cfg)
+        capacity => emqx_limiter_utils:calc_capacity(Cfg)
     }.
 
 %%@doc create a limiter server's reference

apps/emqx/src/emqx_limiter/src/emqx_limiter_correction.erl

@@ -1,36 +0,0 @@
-%%--------------------------------------------------------------------
-%% Copyright (c) 2019-2023 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_limiter_correction).
-
-%% API
--export([add/2]).
-
--type correction_value() :: #{
-    correction := emqx_limiter_decimal:zero_or_float(),
-    any() => any()
-}.
-
--export_type([correction_value/0]).
-
-%%--------------------------------------------------------------------
-%%% API
-%%--------------------------------------------------------------------
--spec add(number(), correction_value()) -> {integer(), correction_value()}.
-add(Inc, #{correction := Correction} = Data) ->
-    FixedInc = Inc + Correction,
-    IntInc = erlang:floor(FixedInc),
-    {IntInc, Data#{correction := FixedInc - IntInc}}.

apps/emqx/src/emqx_limiter/src/emqx_limiter_decimal.erl

@@ -24,13 +24,19 @@
     sub/2,
     mul/2,
     put_to_counter/3,
-    floor_div/2
+    floor_div/2,
+    precisely_add/2
 ]).
--export_type([decimal/0, zero_or_float/0]).
+-export_type([decimal/0, zero_or_float/0, correction_value/0]).
 
 -type decimal() :: infinity | number().
 -type zero_or_float() :: 0 | float().
 
+-type correction_value() :: #{
+    correction := emqx_limiter_decimal:zero_or_float(),
+    any() => any()
+}.
+
 %%--------------------------------------------------------------------
 %%% API
 %%--------------------------------------------------------------------
@@ -43,6 +49,12 @@ add(A, B) when
 add(A, B) ->
     A + B.
 
+-spec precisely_add(number(), correction_value()) -> {integer(), correction_value()}.
+precisely_add(Inc, #{correction := Correction} = Data) ->
+    FixedInc = Inc + Correction,
+    IntInc = erlang:floor(FixedInc),
+    {IntInc, Data#{correction := FixedInc - IntInc}}.
+
 -spec sub(decimal(), decimal()) -> decimal().
 sub(A, B) when
     A =:= infinity orelse

apps/emqx/src/emqx_limiter/src/emqx_limiter_manager.erl

@@ -131,7 +131,7 @@ delete_root(Type) ->
     delete_bucket(?ROOT_ID, Type).
 
 post_config_update([limiter], _Config, NewConf, _OldConf, _AppEnvs) ->
-    Conf = emqx_limiter_schema:convert_node_opts(NewConf),
+    Conf = emqx_limiter_utils:convert_node_opts(NewConf),
     _ = [on_post_config_update(Type, Cfg) || {Type, Cfg} <- maps:to_list(Conf)],
     ok.
 

apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl

@@ -33,14 +33,7 @@
     desc/1,
     types/0,
     short_paths/0,
-    calc_capacity/1,
+    short_paths_fields/1
-    extract_with_type/2,
-    default_client_config/0,
-    default_bucket_config/0,
-    short_paths_fields/1,
-    get_listener_opts/1,
-    get_node_opts/1,
-    convert_node_opts/1
 ]).
 
 -define(KILOBYTE, 1024).
@@ -263,80 +256,6 @@ types() ->
 short_paths() ->
     [max_conn_rate, messages_rate, bytes_rate].
 
-calc_capacity(#{rate := infinity}) ->
-    infinity;
-calc_capacity(#{rate := Rate, burst := Burst}) ->
-    erlang:floor(1000 * Rate / default_period()) + Burst.
-
-extract_with_type(_Type, undefined) ->
-    undefined;
-extract_with_type(Type, #{client := ClientCfg} = BucketCfg) ->
-    BucketVal = maps:find(Type, BucketCfg),
-    ClientVal = maps:find(Type, ClientCfg),
-    merge_client_bucket(Type, ClientVal, BucketVal);
-extract_with_type(Type, BucketCfg) ->
-    BucketVal = maps:find(Type, BucketCfg),
-    merge_client_bucket(Type, undefined, BucketVal).
-
-%% Since the client configuration can be absent and be a undefined value,
-%% but we must need some basic settings to control the behaviour of the limiter,
-%% so here add this helper function to generate a default setting.
-%% This is a temporary workaround until we found a better way to simplify.
-default_client_config() ->
-    #{
-        rate => infinity,
-        initial => 0,
-        low_watermark => 0,
-        burst => 0,
-        divisible => true,
-        max_retry_time => timer:hours(1),
-        failure_strategy => force
-    }.
-
-default_bucket_config() ->
-    #{
-        rate => infinity,
-        burst => 0,
-        initial => 0
-    }.
-
-get_listener_opts(Conf) ->
-    Limiter = maps:get(limiter, Conf, undefined),
-    ShortPaths = maps:with(short_paths(), Conf),
-    get_listener_opts(Limiter, ShortPaths).
-
-get_node_opts(Type) ->
-    Opts = emqx:get_config([limiter, Type], default_bucket_config()),
-    case type_to_short_path_name(Type) of
-        undefined ->
-            Opts;
-        Name ->
-            case emqx:get_config([limiter, Name], undefined) of
-                undefined ->
-                    Opts;
-                Rate ->
-                    Opts#{rate := Rate}
-            end
-    end.
-
-convert_node_opts(Conf) ->
-    DefBucket = default_bucket_config(),
-    ShorPaths = short_paths(),
-    Fun = fun
-        %% The `client` in the node options was deprecated
-        (client, _Value, Acc) ->
-            Acc;
-        (Name, Value, Acc) ->
-            case lists:member(Name, ShorPaths) of
-                true ->
-                    Type = short_path_name_to_type(Name),
-                    Acc#{Type => DefBucket#{rate => Value}};
-                _ ->
-                    Acc#{Name => Value}
-            end
-    end,
-    maps:fold(Fun, #{}, Conf).
-
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------
@@ -538,51 +457,3 @@ alias_of_type(bytes) ->
     [bytes_in];
 alias_of_type(_) ->
     [].
-
-merge_client_bucket(Type, {ok, ClientVal}, {ok, BucketVal}) ->
-    #{Type => BucketVal, client => #{Type => ClientVal}};
-merge_client_bucket(Type, {ok, ClientVal}, _) ->
-    #{client => #{Type => ClientVal}};
-merge_client_bucket(Type, _, {ok, BucketVal}) ->
-    #{Type => BucketVal};
-merge_client_bucket(_, _, _) ->
-    undefined.
-
-short_path_name_to_type(max_conn_rate) ->
-    connection;
-short_path_name_to_type(messages_rate) ->
-    messages;
-short_path_name_to_type(bytes_rate) ->
-    bytes.
-
-type_to_short_path_name(connection) ->
-    max_conn_rate;
-type_to_short_path_name(messages) ->
-    messages_rate;
-type_to_short_path_name(bytes) ->
-    bytes_rate;
-type_to_short_path_name(_) ->
-    undefined.
-
-get_listener_opts(Limiter, ShortPaths) when map_size(ShortPaths) =:= 0 ->
-    Limiter;
-get_listener_opts(undefined, ShortPaths) ->
-    convert_listener_short_paths(ShortPaths);
-get_listener_opts(Limiter, ShortPaths) ->
-    Shorts = convert_listener_short_paths(ShortPaths),
-    emqx_utils_maps:deep_merge(Limiter, Shorts).
-
-convert_listener_short_paths(ShortPaths) ->
-    DefBucket = default_bucket_config(),
-    DefClient = default_client_config(),
-    Fun = fun(Name, Rate, Acc) ->
-        Type = short_path_name_to_type(Name),
-        case Name of
-            max_conn_rate ->
-                Acc#{Type => DefBucket#{rate => Rate}};
-            _ ->
-                Client = maps:get(client, Acc, #{}),
-                Acc#{client => Client#{Type => DefClient#{rate => Rate}}}
-        end
-    end,
-    maps:fold(Fun, #{}, ShortPaths).

apps/emqx/src/emqx_limiter/src/emqx_limiter_server.erl

@@ -383,7 +383,7 @@ longitudinal(
 
     case lists:min([ShouldAlloc, Flow, Capacity]) of
         Available when Available > 0 ->
-            {Inc, Bucket2} = emqx_limiter_correction:add(Available, Bucket),
+            {Inc, Bucket2} = emqx_limiter_decimal:precisely_add(Available, Bucket),
             counters:add(Counter, Index, Inc),
 
             {Available, Buckets#{Name := Bucket2#{obtained := Obtained + Available}}};
@@ -419,7 +419,7 @@ maybe_adjust_root_tokens(#{root := #{rate := Rate} = Root, counter := Counter} =
             State;
         _ ->
             Available = erlang:min(Rate - Token, InFlow),
-            {Inc, Root2} = emqx_limiter_correction:add(Available, Root),
+            {Inc, Root2} = emqx_limiter_decimal:precisely_add(Available, Root),
             counters:add(Counter, ?ROOT_COUNTER_IDX, Inc),
             State#{root := Root2}
     end.
@@ -473,7 +473,7 @@ dispatch_burst_to_buckets([Bucket | T], InFlow, Alloced, Buckets) ->
         index := Index,
         obtained := Obtained
     } = Bucket,
-    {Inc, Bucket2} = emqx_limiter_correction:add(InFlow, Bucket),
+    {Inc, Bucket2} = emqx_limiter_decimal:precisely_add(InFlow, Bucket),
 
     counters:add(Counter, Index, Inc),
 
@@ -484,7 +484,7 @@ dispatch_burst_to_buckets([], _, Alloced, Buckets) ->
 
 -spec init_tree(emqx_limiter_schema:limiter_type()) -> state().
 init_tree(Type) when is_atom(Type) ->
-    Cfg = emqx_limiter_schema:get_node_opts(Type),
+    Cfg = emqx_limiter_utils:get_node_opts(Type),
     init_tree(Type, Cfg).
 
 init_tree(Type, #{rate := Rate} = Cfg) ->
@@ -515,7 +515,7 @@ do_add_bucket(Id, #{rate := Rate} = Cfg, #{buckets := Buckets} = State) ->
         undefined ->
             make_bucket(Id, Cfg, State);
         Bucket ->
-            Bucket2 = Bucket#{rate := Rate, capacity := emqx_limiter_schema:calc_capacity(Cfg)},
+            Bucket2 = Bucket#{rate := Rate, capacity := emqx_limiter_utils:calc_capacity(Cfg)},
             State#{buckets := Buckets#{Id := Bucket2}}
     end.
 
@@ -536,7 +536,7 @@ make_bucket(
         rate => Rate,
         obtained => Initial,
         correction => 0,
-        capacity => emqx_limiter_schema:calc_capacity(Cfg),
+        capacity => emqx_limiter_utils:calc_capacity(Cfg),
         counter => Counter,
         index => NewIndex
     },
@@ -601,7 +601,7 @@ create_limiter_without_client(Id, Type, BucketCfg) ->
         false ->
             {ok, emqx_htb_limiter:make_infinity_limiter()};
         {ok, Bucket, RefCfg} ->
-            ClientCfg = emqx_limiter_schema:default_client_config(),
+            ClientCfg = emqx_limiter_utils:default_client_config(),
             create_limiter_with_ref(Bucket, ClientCfg, RefCfg);
         Error ->
             Error
@@ -627,7 +627,7 @@ find_referenced_bucket(Id, Type, #{rate := Rate} = Cfg) when Rate =/= infinity -
     end;
 %% this is a node-level reference
 find_referenced_bucket(_Id, Type, _) ->
-    case emqx_limiter_schema:get_node_opts(Type) of
+    case emqx_limiter_utils:get_node_opts(Type) of
         #{rate := infinity} ->
             false;
         NodeCfg ->

apps/emqx/src/emqx_limiter/src/emqx_limiter_server_sup.erl

@@ -86,7 +86,7 @@ init([]) ->
 %%  Internal functions
 %%--==================================================================
 make_child(Type) ->
-    Cfg = emqx_limiter_schema:get_node_opts(Type),
+    Cfg = emqx_limiter_utils:get_node_opts(Type),
     make_child(Type, Cfg).
 
 make_child(Type, Cfg) ->

apps/emqx/src/emqx_limiter/src/emqx_limiter_utils.erl

@@ -0,0 +1,158 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2021-2023 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_limiter_utils).
+
+-export([
+    calc_capacity/1,
+    extract_with_type/2,
+    get_listener_opts/1,
+    get_node_opts/1,
+    convert_node_opts/1,
+    default_client_config/0,
+    default_bucket_config/0
+]).
+
+-import(emqx_limiter_schema, [default_period/0, short_paths/0]).
+
+%%--------------------------------------------------------------------
+%% Configuration-related runtime code
+%%--------------------------------------------------------------------
+
+calc_capacity(#{rate := infinity}) ->
+    infinity;
+calc_capacity(#{rate := Rate, burst := Burst}) ->
+    erlang:floor(1000 * Rate / default_period()) + Burst.
+
+%% @doc extract data of a type from the nested config
+extract_with_type(_Type, undefined) ->
+    undefined;
+extract_with_type(Type, #{client := ClientCfg} = BucketCfg) ->
+    BucketVal = maps:find(Type, BucketCfg),
+    ClientVal = maps:find(Type, ClientCfg),
+    merge_client_bucket(Type, ClientVal, BucketVal);
+extract_with_type(Type, BucketCfg) ->
+    BucketVal = maps:find(Type, BucketCfg),
+    merge_client_bucket(Type, undefined, BucketVal).
+
+%% @doc get the limiter configuration from the listener setting
+%% and compatible with the old version limiter schema
+get_listener_opts(Conf) ->
+    Limiter = maps:get(limiter, Conf, undefined),
+    ShortPaths = maps:with(short_paths(), Conf),
+    get_listener_opts(Limiter, ShortPaths).
+
+get_listener_opts(Limiter, ShortPaths) when map_size(ShortPaths) =:= 0 ->
+    Limiter;
+get_listener_opts(undefined, ShortPaths) ->
+    convert_listener_short_paths(ShortPaths);
+get_listener_opts(Limiter, ShortPaths) ->
+    Shorts = convert_listener_short_paths(ShortPaths),
+    emqx_utils_maps:deep_merge(Limiter, Shorts).
+
+convert_listener_short_paths(ShortPaths) ->
+    DefBucket = default_bucket_config(),
+    DefClient = default_client_config(),
+    Fun = fun(Name, Rate, Acc) ->
+        Type = short_path_name_to_type(Name),
+        case Name of
+            max_conn_rate ->
+                Acc#{Type => DefBucket#{rate => Rate}};
+            _ ->
+                Client = maps:get(client, Acc, #{}),
+                Acc#{client => Client#{Type => DefClient#{rate => Rate}}}
+        end
+    end,
+    maps:fold(Fun, #{}, ShortPaths).
+
+%% @doc get the node-level limiter configuration and compatible with the old version limiter schema
+get_node_opts(Type) ->
+    Opts = emqx:get_config([limiter, Type], default_bucket_config()),
+    case type_to_short_path_name(Type) of
+        undefined ->
+            Opts;
+        Name ->
+            case emqx:get_config([limiter, Name], undefined) of
+                undefined ->
+                    Opts;
+                Rate ->
+                    Opts#{rate := Rate}
+            end
+    end.
+
+convert_node_opts(Conf) ->
+    DefBucket = default_bucket_config(),
+    ShorPaths = short_paths(),
+    Fun = fun
+        %% The `client` in the node options was deprecated
+        (client, _Value, Acc) ->
+            Acc;
+        (Name, Value, Acc) ->
+            case lists:member(Name, ShorPaths) of
+                true ->
+                    Type = short_path_name_to_type(Name),
+                    Acc#{Type => DefBucket#{rate => Value}};
+                _ ->
+                    Acc#{Name => Value}
+            end
+    end,
+    maps:fold(Fun, #{}, Conf).
+
+merge_client_bucket(Type, {ok, ClientVal}, {ok, BucketVal}) ->
+    #{Type => BucketVal, client => #{Type => ClientVal}};
+merge_client_bucket(Type, {ok, ClientVal}, _) ->
+    #{client => #{Type => ClientVal}};
+merge_client_bucket(Type, _, {ok, BucketVal}) ->
+    #{Type => BucketVal};
+merge_client_bucket(_, _, _) ->
+    undefined.
+
+short_path_name_to_type(max_conn_rate) ->
+    connection;
+short_path_name_to_type(messages_rate) ->
+    messages;
+short_path_name_to_type(bytes_rate) ->
+    bytes.
+
+type_to_short_path_name(connection) ->
+    max_conn_rate;
+type_to_short_path_name(messages) ->
+    messages_rate;
+type_to_short_path_name(bytes) ->
+    bytes_rate;
+type_to_short_path_name(_) ->
+    undefined.
+
+%% Since the client configuration can be absent and be a undefined value,
+%% but we must need some basic settings to control the behaviour of the limiter,
+%% so here add this helper function to generate a default setting.
+%% This is a temporary workaround until we found a better way to simplify.
+default_client_config() ->
+    #{
+        rate => infinity,
+        initial => 0,
+        low_watermark => 0,
+        burst => 0,
+        divisible => true,
+        max_retry_time => timer:hours(1),
+        failure_strategy => force
+    }.
+
+default_bucket_config() ->
+    #{
+        rate => infinity,
+        burst => 0,
+        initial => 0
+    }.

apps/emqx/src/emqx_listeners.erl

@@ -587,7 +587,7 @@ esockd_opts(ListenerId, Type, Opts0) ->
     Opts1 = maps:with([acceptors, max_connections, proxy_protocol, proxy_protocol_timeout], Opts0),
     Limiter = limiter(Opts0),
     Opts2 =
-        case emqx_limiter_schema:extract_with_type(connection, Limiter) of
+        case emqx_limiter_utils:extract_with_type(connection, Limiter) of
             undefined ->
                 Opts1;
             BucketCfg ->
@@ -732,7 +732,7 @@ zone(Opts) ->
     maps:get(zone, Opts, undefined).
 
 limiter(Opts) ->
-    emqx_limiter_schema:get_listener_opts(Opts).
+    emqx_limiter_utils:get_listener_opts(Opts).
 
 add_limiter_bucket(_Id, undefined) ->
     ok;

apps/emqx/test/emqx_ratelimiter_SUITE.erl

@@ -589,11 +589,11 @@ t_extract_with_type(_) ->
         (Type, Cfg) ->
             IsOnly(Type, Cfg)
     end,
-    ?assertEqual(undefined, emqx_limiter_schema:extract_with_type(messages, undefined)),
+    ?assertEqual(undefined, emqx_limiter_utils:extract_with_type(messages, undefined)),
     ?assert(
         Checker(
             messages,
-            emqx_limiter_schema:extract_with_type(messages, #{
+            emqx_limiter_utils:extract_with_type(messages, #{
                 messages => #{rate => 1}, bytes => #{rate => 1}
             })
         )
@@ -601,7 +601,7 @@ t_extract_with_type(_) ->
     ?assert(
         Checker(
             messages,
-            emqx_limiter_schema:extract_with_type(messages, #{
+            emqx_limiter_utils:extract_with_type(messages, #{
                 messages => #{rate => 1},
                 bytes => #{rate => 1},
                 client => #{messages => #{rate => 2}}
@@ -611,7 +611,7 @@ t_extract_with_type(_) ->
     ?assert(
         Checker(
             messages,
-            emqx_limiter_schema:extract_with_type(messages, #{
+            emqx_limiter_utils:extract_with_type(messages, #{
                 client => #{messages => #{rate => 2}, bytes => #{rate => 1}}
             })
         )
@@ -622,7 +622,7 @@ t_add_bucket(_) ->
         #{buckets := Buckets} = sys:get_state(emqx_limiter_server:whereis(bytes)),
         ?assertEqual(Size, maps:size(Buckets), Buckets)
     end,
-    DefBucket = emqx_limiter_schema:default_bucket_config(),
+    DefBucket = emqx_limiter_utils:default_bucket_config(),
     ?assertEqual(ok, emqx_limiter_server:add_bucket(?FUNCTION_NAME, bytes, undefined)),
     Checker(0),
     ?assertEqual(ok, emqx_limiter_server:add_bucket(?FUNCTION_NAME, bytes, DefBucket)),
@@ -765,7 +765,7 @@ t_esockd_htb_consume(_) ->
 t_node_short_paths(_) ->
     CfgStr = <<"limiter {max_conn_rate = \"1000\", messages_rate = \"100\", bytes_rate = \"10\"}">>,
     ok = emqx_common_test_helpers:load_config(emqx_limiter_schema, CfgStr),
-    Accessor = fun emqx_limiter_schema:get_node_opts/1,
+    Accessor = fun emqx_limiter_utils:get_node_opts/1,
     ?assertMatch(#{rate := 100.0}, Accessor(connection)),
     ?assertMatch(#{rate := 10.0}, Accessor(messages)),
     ?assertMatch(#{rate := 1.0}, Accessor(bytes)),
@@ -776,7 +776,7 @@ t_compatibility_for_node_short_paths(_) ->
     CfgStr =
         <<"limiter {max_conn_rate = \"1000\", connection.rate = \"500\", bytes.rate = \"200\"}">>,
     ok = emqx_common_test_helpers:load_config(emqx_limiter_schema, CfgStr),
-    Accessor = fun emqx_limiter_schema:get_node_opts/1,
+    Accessor = fun emqx_limiter_utils:get_node_opts/1,
     ?assertMatch(#{rate := 100.0}, Accessor(connection)),
     ?assertMatch(#{rate := 20.0}, Accessor(bytes)).
 
@@ -796,7 +796,7 @@ t_listener_short_paths(_) ->
             },
             connection := #{rate := 100.0}
         },
-        emqx_limiter_schema:get_listener_opts(ListenerOpt)
+        emqx_limiter_utils:get_listener_opts(ListenerOpt)
     ).
 
 t_compatibility_for_listener_short_paths(_) ->
@@ -809,7 +809,7 @@ t_compatibility_for_listener_short_paths(_) ->
         #{
             connection := #{rate := 100.0}
         },
-        emqx_limiter_schema:get_listener_opts(ListenerOpt)
+        emqx_limiter_utils:get_listener_opts(ListenerOpt)
     ).
 
 t_no_limiter_for_listener(_) ->
@@ -818,7 +818,7 @@ t_no_limiter_for_listener(_) ->
     ListenerOpt = emqx:get_config([listeners, tcp, default]),
     ?assertEqual(
         undefined,
-        emqx_limiter_schema:get_listener_opts(ListenerOpt)
+        emqx_limiter_utils:get_listener_opts(ListenerOpt)
     ).
 
 %%--------------------------------------------------------------------
@@ -1135,5 +1135,5 @@ parse_schema(ConfigString) ->
     ).
 
 default_client_config() ->
-    Conf = emqx_limiter_schema:default_client_config(),
+    Conf = emqx_limiter_utils:default_client_config(),
     Conf#{divisible := false, max_retry_time := timer:seconds(10)}.