From 62eeb4b8e8290f5e9869fe987fdb9c2d872f26ee Mon Sep 17 00:00:00 2001
From: Thales Macedo Garitezi <thalesmg@gmail.com>
Date: Tue, 18 Oct 2022 09:32:35 -0300
Subject: [PATCH] feat(resource): reset metrics when stopping a resource

---
 .../emqx_resource/src/emqx_resource_manager.erl |  5 ++++-
 apps/emqx_resource/test/emqx_resource_SUITE.erl | 17 ++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/apps/emqx_resource/src/emqx_resource_manager.erl b/apps/emqx_resource/src/emqx_resource_manager.erl
index c8d5e4194..10c501865 100644
--- a/apps/emqx_resource/src/emqx_resource_manager.erl
+++ b/apps/emqx_resource/src/emqx_resource_manager.erl
@@ -507,13 +507,16 @@ start_resource(Data, From) ->
 
 stop_resource(#data{state = undefined, id = ResId} = _Data) ->
     _ = maybe_clear_alarm(ResId),
+    ok = emqx_metrics_worker:reset_metrics(?RES_METRICS, ResId),
     ok;
 stop_resource(Data) ->
     %% We don't care the return value of the Mod:on_stop/2.
     %% The callback mod should make sure the resource is stopped after on_stop/2
     %% is returned.
+    ResId = Data#data.id,
     _ = emqx_resource:call_stop(Data#data.manager_id, Data#data.mod, Data#data.state),
-    _ = maybe_clear_alarm(Data#data.id),
+    _ = maybe_clear_alarm(ResId),
+    ok = emqx_metrics_worker:reset_metrics(?RES_METRICS, ResId),
     ok.
 
 make_test_id() ->
diff --git a/apps/emqx_resource/test/emqx_resource_SUITE.erl b/apps/emqx_resource/test/emqx_resource_SUITE.erl
index 672e01896..107ca2a93 100644
--- a/apps/emqx_resource/test/emqx_resource_SUITE.erl
+++ b/apps/emqx_resource/test/emqx_resource_SUITE.erl
@@ -502,6 +502,10 @@ t_stop_start(_) ->
         #{<<"name">> => <<"test_resource">>}
     ),
 
+    %% add some metrics to test their persistence
+    emqx_resource_metrics:batching_change(?ID, 5),
+    ?assertEqual(5, emqx_resource_metrics:batching_get(?ID)),
+
     {ok, _} = emqx_resource:check_and_recreate(
         ?ID,
         ?TEST_RESOURCE,
@@ -513,6 +517,9 @@ t_stop_start(_) ->
 
     ?assert(is_process_alive(Pid0)),
 
+    %% metrics are reset when recreating
+    ?assertEqual(0, emqx_resource_metrics:batching_get(?ID)),
+
     ok = emqx_resource:stop(?ID),
 
     ?assertNot(is_process_alive(Pid0)),
@@ -527,7 +534,15 @@ t_stop_start(_) ->
 
     {ok, #{pid := Pid1}} = emqx_resource:query(?ID, get_state),
 
-    ?assert(is_process_alive(Pid1)).
+    ?assert(is_process_alive(Pid1)),
+
+    %% now stop while resetting the metrics
+    emqx_resource_metrics:batching_change(?ID, 5),
+    ?assertEqual(5, emqx_resource_metrics:batching_get(?ID)),
+    ok = emqx_resource:stop(?ID),
+    ?assertEqual(0, emqx_resource_metrics:batching_get(?ID)),
+
+    ok.
 
 t_stop_start_local(_) ->
     {error, _} = emqx_resource:check_and_create_local(