refactor: move metrics logic to separate module

apps/emqx_cluster_link/src/emqx_cluster_link.erl

@@ -26,29 +26,11 @@
     on_message_publish/1
 ]).
 
-%% metrics API
--export([
-    maybe_create_metrics/1,
-    drop_metrics/1,
-
-    get_metrics/1,
-    routes_inc/2
-]).
-
 -include("emqx_cluster_link.hrl").
 -include_lib("emqx/include/emqx.hrl").
 -include_lib("emqx/include/emqx_hooks.hrl").
 -include_lib("emqx/include/logger.hrl").
 
-%%--------------------------------------------------------------------
-%% Type definitions
-%%--------------------------------------------------------------------
-
--define(METRICS, [
-    ?route_metric
-]).
--define(RATE_METRICS, []).
-
 %%--------------------------------------------------------------------
 %% emqx_external_broker API
 %%--------------------------------------------------------------------
@@ -150,32 +132,6 @@ put_hook() ->
 delete_hook() ->
     emqx_hooks:del('message.publish', {?MODULE, on_message_publish, []}).
 
-%%--------------------------------------------------------------------
-%% metrics API
-%%--------------------------------------------------------------------
-
-get_metrics(ClusterName) ->
-    Nodes = emqx:running_nodes(),
-    Timeout = 15_000,
-    Results = emqx_metrics_proto_v2:get_metrics(Nodes, ?METRIC_NAME, ClusterName, Timeout),
-    sequence_multicall_results(Nodes, Results).
-
-maybe_create_metrics(ClusterName) ->
-    case emqx_metrics_worker:has_metrics(?METRIC_NAME, ClusterName) of
-        true ->
-            ok = emqx_metrics_worker:reset_metrics(?METRIC_NAME, ClusterName);
-        false ->
-            ok = emqx_metrics_worker:create_metrics(
-                ?METRIC_NAME, ClusterName, ?METRICS, ?RATE_METRICS
-            )
-    end.
-
-drop_metrics(ClusterName) ->
-    ok = emqx_metrics_worker:clear_metrics(?METRIC_NAME, ClusterName).
-
-routes_inc(ClusterName, Val) ->
-    catch emqx_metrics_worker:inc(?METRIC_NAME, ClusterName, ?route_metric, Val).
-
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------
@@ -297,16 +253,3 @@ maybe_filter_incomming_msg(#message{topic = T} = Msg, ClusterName) ->
         true -> with_sender_name(Msg, ClusterName);
         false -> []
     end.
-
--spec sequence_multicall_results([node()], emqx_rpc:erpc_multicall(term())) ->
-    {ok, [{node(), term()}]} | {error, [term()]}.
-sequence_multicall_results(Nodes, Results) ->
-    case lists:partition(fun is_ok/1, lists:zip(Nodes, Results)) of
-        {OkResults, []} ->
-            {ok, [{Node, Res} || {Node, {ok, Res}} <- OkResults]};
-        {_OkResults, BadResults} ->
-            {error, BadResults}
-    end.
-
-is_ok({_Node, {ok, _}}) -> true;
-is_ok(_) -> false.

apps/emqx_cluster_link/src/emqx_cluster_link_api.erl

@@ -227,7 +227,7 @@ handle_lookup(Name, Link) ->
     ?OK(add_status(Name, Link)).
 
 handle_metrics(Name) ->
-    case emqx_cluster_link:get_metrics(Name) of
+    case emqx_cluster_link_metrics:get_metrics(Name) of
         {error, BadResults} ->
             ?SLOG(warning, #{
                 msg => "cluster_link_api_metrics_bad_erpc_results",

apps/emqx_cluster_link/src/emqx_cluster_link_app.erl

@@ -59,7 +59,7 @@ remove_msg_fwd_resources(LinksConf) ->
 create_metrics(LinksConf) ->
     lists:foreach(
         fun(#{name := ClusterName}) ->
-            ok = emqx_cluster_link:maybe_create_metrics(ClusterName)
+            ok = emqx_cluster_link_metrics:maybe_create_metrics(ClusterName)
         end,
         LinksConf
     ).

apps/emqx_cluster_link/src/emqx_cluster_link_config.erl

@@ -280,7 +280,7 @@ add_links(LinksConf) ->
 add_link(#{name := ClusterName, enable := true} = LinkConf) ->
     {ok, _Pid} = emqx_cluster_link_sup:ensure_actor(LinkConf),
     {ok, _} = emqx_cluster_link_mqtt:ensure_msg_fwd_resource(LinkConf),
-    ok = emqx_cluster_link:maybe_create_metrics(ClusterName),
+    ok = emqx_cluster_link_metrics:maybe_create_metrics(ClusterName),
     ok;
 add_link(_DisabledLinkConf) ->
     ok.
@@ -291,7 +291,7 @@ remove_links(LinksConf) ->
 remove_link(Name) ->
     _ = emqx_cluster_link_mqtt:remove_msg_fwd_resource(Name),
     _ = ensure_actor_stopped(Name),
-    emqx_cluster_link:drop_metrics(Name).
+    emqx_cluster_link_metrics:drop_metrics(Name).
 
 update_links(LinksConf) ->
     [update_link(Link) || Link <- LinksConf].

apps/emqx_cluster_link/src/emqx_cluster_link_extrouter.erl

@@ -282,7 +282,7 @@ apply_operation(ActorID, Entry, MCounter, OpName, Lane) ->
     case MCounter band Marker of
         0 when OpName =:= add ->
             Res = mria:dirty_update_counter(?EXTROUTE_TAB, Entry, Marker),
-            _ = emqx_cluster_link:routes_inc(ClusterName, 1),
+            _ = emqx_cluster_link_metrics:routes_inc(ClusterName, 1),
             ?tp("cluster_link_extrouter_route_added", #{}),
             Res;
         Marker when OpName =:= add ->
@@ -293,7 +293,7 @@ apply_operation(ActorID, Entry, MCounter, OpName, Lane) ->
                 0 ->
                     Record = #extroute{entry = Entry, mcounter = 0},
                     ok = mria:dirty_delete_object(?EXTROUTE_TAB, Record),
-                    _ = emqx_cluster_link:routes_inc(ClusterName, -1),
+                    _ = emqx_cluster_link_metrics:routes_inc(ClusterName, -1),
                     ?tp("cluster_link_extrouter_route_deleted", #{}),
                     0;
                 C ->

apps/emqx_cluster_link/src/emqx_cluster_link_metrics.erl

@@ -0,0 +1,67 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2024 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%--------------------------------------------------------------------
+-module(emqx_cluster_link_metrics).
+
+-include("emqx_cluster_link.hrl").
+
+%% API
+-export([
+    maybe_create_metrics/1,
+    drop_metrics/1,
+
+    get_metrics/1,
+    routes_inc/2
+]).
+
+%%--------------------------------------------------------------------
+%% Type definitions
+%%--------------------------------------------------------------------
+
+-define(METRICS, [
+    ?route_metric
+]).
+-define(RATE_METRICS, []).
+
+%%--------------------------------------------------------------------
+%% metrics API
+%%--------------------------------------------------------------------
+
+get_metrics(ClusterName) ->
+    Nodes = emqx:running_nodes(),
+    Timeout = 15_000,
+    Results = emqx_metrics_proto_v2:get_metrics(Nodes, ?METRIC_NAME, ClusterName, Timeout),
+    sequence_multicall_results(Nodes, Results).
+
+maybe_create_metrics(ClusterName) ->
+    case emqx_metrics_worker:has_metrics(?METRIC_NAME, ClusterName) of
+        true ->
+            ok = emqx_metrics_worker:reset_metrics(?METRIC_NAME, ClusterName);
+        false ->
+            ok = emqx_metrics_worker:create_metrics(
+                ?METRIC_NAME, ClusterName, ?METRICS, ?RATE_METRICS
+            )
+    end.
+
+drop_metrics(ClusterName) ->
+    ok = emqx_metrics_worker:clear_metrics(?METRIC_NAME, ClusterName).
+
+routes_inc(ClusterName, Val) ->
+    catch emqx_metrics_worker:inc(?METRIC_NAME, ClusterName, ?route_metric, Val).
+
+%%--------------------------------------------------------------------
+%% Internal functions
+%%--------------------------------------------------------------------
+
+-spec sequence_multicall_results([node()], emqx_rpc:erpc_multicall(term())) ->
+    {ok, [{node(), term()}]} | {error, [term()]}.
+sequence_multicall_results(Nodes, Results) ->
+    case lists:partition(fun is_ok/1, lists:zip(Nodes, Results)) of
+        {OkResults, []} ->
+            {ok, [{Node, Res} || {Node, {ok, Res}} <- OkResults]};
+        {_OkResults, BadResults} ->
+            {error, BadResults}
+    end.
+
+is_ok({_Node, {ok, _}}) -> true;
+is_ok(_) -> false.