feat(emqx_slow_subs): add dyanamic threshold

lib-ce/emqx_modules/src/emqx_mod_slow_subs.erl

@@ -37,6 +37,8 @@
 
 -spec(load(list()) -> ok).
 load(Env) ->
+    Threshold = proplists:get_value(threshold, Env),
+    _ = emqx_message_latency_stats:update_threshold(Threshold),
     emqx_mod_sup:start_child(?LIB, worker, [Env]),
     ok.
 

lib-ce/emqx_modules/test/emqx_slow_subs_SUITE.erl

@@ -88,7 +88,8 @@ t_log_and_pub(_) ->
     [Client ! stop || Client <- Clients],
     ok.
 base_conf() ->
-    [ {top_k_num, 5}
+    [ {threshold, 500}
+    , {top_k_num, 5}
     , {expire_interval, timer:seconds(3)}
     , {notice_interval, 1500}
     , {notice_qos, 0}

lib-ce/emqx_modules/test/emqx_slow_subs_api_SUITE.erl

@@ -57,7 +57,8 @@ end_per_testcase(_, Config) ->
     Config.
 
 base_conf() ->
-    [ {top_k_num, 5}
+    [ {threshold, 500}
+    , {top_k_num, 5}
     , {expire_interval, timer:seconds(60)}
     , {notice_interval, 0}
     , {notice_qos, 0}

priv/emqx.schema

@@ -1013,12 +1013,6 @@ end}.
   {datatype, integer}
 ]}.
 
-%% @doc Threshold for slow subscription statistics
-{mapping, "zone.$name.latency_stats_threshold", "emqx.zones", [
-  {default, "100ms"},
-  {datatype, {duration, ms}}
-]}.
-
 %% @doc Max Packets that Awaiting PUBREL, 0 means no limit
 {mapping, "zone.$name.max_awaiting_rel", "emqx.zones", [
   {default, 0},
@@ -2230,6 +2224,11 @@ end}.
   {datatype, string}
 ]}.
 
+{mapping, "module.slow_subs.threshold", "emqx.modules", [
+  {default, "500ms"},
+  {datatype, {duration, ms}}
+]}.
+
 {mapping, "module.slow_subs.expire_interval", "emqx.modules", [
   {default, "5m"},
   {datatype, {duration, ms}}

src/emqx_slow_subs/emqx_message_latency_stats.erl

@@ -17,17 +17,18 @@
 -module(emqx_message_latency_stats).
 
 %% API
--export([ new/1, new/2, update/3
+-export([ new/1, update/3, check_expire/4, latency/1]).
-        , check_expire/4, latency/1]).
+
+-export([get_threshold/0, update_threshold/1]).
 
 -define(NOW, erlang:system_time(millisecond)).
 -define(MINIMUM_INSERT_INTERVAL, 1000).
--define(MINIMUM_THRESHOLD, 100).
+-define(MINIMUM_THRESHOLD, 500).
+-define(THRESHOLD_KEY, {?MODULE, threshold}).
 
--opaque stats() :: #{ threshold := number()
+-opaque stats() :: #{ ema := emqx_moving_average:ema()
-                    , ema := emqx_moving_average:ema()
                     , last_update_time := timestamp()
-                    , last_access_time := timestamp()  %% timestamp of last access top-k
+                    , last_access_time := timestamp()  %% timestamp of last try to call hook
                     , last_insert_value := non_neg_integer()
                     }.
 
@@ -44,22 +45,19 @@
 %%--------------------------------------------------------------------
 %% API
 %%--------------------------------------------------------------------
--spec new(emqx_types:zone()) -> stats().
-new(Zone) ->
-    Samples = get_env(Zone, latency_samples, 1),
-    Threshold = get_env(Zone, latency_stats_threshold, ?MINIMUM_THRESHOLD),
-    new(Samples, Threshold).
 
--spec new(non_neg_integer(), number()) -> stats().
+-spec new(non_neg_integer() | emqx_types:zone()) -> stats().
-new(SamplesT, ThresholdT) ->
+new(SamplesT) when is_integer(SamplesT) ->
     Samples = erlang:max(1, SamplesT),
-    Threshold = erlang:max(?MINIMUM_THRESHOLD, ThresholdT),
     #{ ema => emqx_moving_average:new(exponential, #{period => Samples})
-     , threshold => Threshold
      , last_update_time => 0
      , last_access_time => 0
      , last_insert_value => 0
-     }.
+     };
+
+new(Zone) ->
+    Samples = get_env(Zone, latency_samples, 1),
+    new(Samples).
 
 -spec update(emqx_types:clientid(), number(), stats()) -> stats().
 update(ClientId, Val, #{ema := EMA} = Stats) ->
@@ -82,19 +80,28 @@ check_expire(ClientId, Now, _Interval, #{last_update_time := LUT} = S) ->
 latency(#{ema := #{average := Average}}) ->
     Average.
 
+-spec update_threshold(pos_integer()) -> pos_integer().
+update_threshold(Threshold) ->
+    Val = erlang:max(Threshold, ?MINIMUM_THRESHOLD),
+    persistent_term:put(?THRESHOLD_KEY, Val),
+    Val.
+
+get_threshold() ->
+    persistent_term:get(?THRESHOLD_KEY, ?MINIMUM_THRESHOLD).
+
 %%--------------------------------------------------------------------
 %%  Internal functions
 %%--------------------------------------------------------------------
 -spec call_hook(emqx_types:clientid(), timestamp(), latency_type(), timespan(), stats()) -> stats().
-call_hook(_, Now, _, _, #{last_access_time := LIT} = S)
+call_hook(_, _, _, Latency, S)
-  when LIT >= Now - ?MINIMUM_INSERT_INTERVAL ->
+  when Latency =< ?MINIMUM_THRESHOLD ->
-    S;
-
-call_hook(_, _, _, Latency, #{threshold := Threshold} = S)
-  when Latency =< Threshold ->
     S;
 
 call_hook(ClientId, Now, Type, Latency, #{last_insert_value := LIV} = Stats) ->
+    case get_threshold() >= Latency of
+        true ->
+            Stats#{last_access_time := Now};
+        _ ->
             ToInsert = erlang:floor(Latency),
             Arg = #{clientid => ClientId,
                     latency => ToInsert,
@@ -103,4 +110,5 @@ call_hook(ClientId, Now, Type, Latency, #{last_insert_value := LIV} = Stats) ->
                     update_time => Now},
             emqx:run_hook('message.slow_subs_stats', [Arg]),
             Stats#{last_insert_value := ToInsert,
-           last_access_time := Now}.
+                   last_access_time := Now}
+    end.