feat: refactor connectors on_stop function to avoid resources leaking

Supplement to https://github.com/emqx/emqx/pull/10895

apps/emqx_bridge_cassandra/src/emqx_bridge_cassandra_connector.erl

@@ -132,6 +132,7 @@ on_start(
                 []
         end,
     State = parse_prepare_cql(Config),
+    ok = emqx_resource:allocate_resource(InstId, pool_name, InstId),
     case emqx_resource_pool:start(InstId, ?MODULE, Options ++ SslOpts) of
         ok ->
             {ok, init_prepare(State#{pool_name => InstId, prepare_statement => #{}})};
@@ -143,12 +144,17 @@ on_start(
             {error, Reason}
     end.
 
-on_stop(InstId, #{pool_name := PoolName}) ->
+on_stop(InstId, _State) ->
     ?SLOG(info, #{
         msg => "stopping_cassandra_connector",
         connector => InstId
     }),
-    emqx_resource_pool:stop(PoolName).
+    case emqx_resource:get_allocated_resources(InstId) of
+        #{pool_name := PoolName} ->
+            emqx_resource_pool:stop(PoolName);
+        _ ->
+            ok
+    end.
 
 -type request() ::
     % emqx_bridge.erl

apps/emqx_bridge_clickhouse/src/emqx_bridge_clickhouse_connector.erl

@@ -158,6 +158,7 @@ on_start(
             templates => Templates,
             connect_timeout => ConnectTimeout
         },
+        ok = emqx_resource:allocate_resource(InstanceID, pool_name, InstanceID),
         case emqx_resource_pool:start(InstanceID, ?MODULE, Options) of
             ok ->
                 {ok, State};
@@ -274,12 +275,17 @@ connect(Options) ->
 
 -spec on_stop(resource_id(), resource_state()) -> term().
 
-on_stop(InstanceID, #{pool_name := PoolName}) ->
+on_stop(InstanceID, _State) ->
     ?SLOG(info, #{
         msg => "stopping clickouse connector",
         connector => InstanceID
     }),
-    emqx_resource_pool:stop(PoolName).
+    case emqx_resource:get_allocated_resources(InstanceID) of
+        #{pool_name := PoolName} ->
+            emqx_resource_pool:stop(PoolName);
+        _ ->
+            ok
+    end.
 
 %% -------------------------------------------------------------------
 %% on_get_status emqx_resouce callback and related functions

apps/emqx_bridge_dynamo/src/emqx_bridge_dynamo_connector.erl

@@ -104,6 +104,7 @@ on_start(
         table => Table,
         templates => Templates
     },
+    ok = emqx_resource:allocate_resource(InstanceId, pool_name, InstanceId),
     case emqx_resource_pool:start(InstanceId, ?MODULE, Options) of
         ok ->
             {ok, State};
@@ -111,12 +112,17 @@ on_start(
             Error
     end.
 
-on_stop(InstanceId, #{pool_name := PoolName}) ->
+on_stop(InstanceId, _State) ->
     ?SLOG(info, #{
         msg => "stopping_dynamo_connector",
         connector => InstanceId
     }),
-    emqx_resource_pool:stop(PoolName).
+    case emqx_resource:get_allocated_resources(InstanceId) of
+        #{pool_name := PoolName} ->
+            emqx_resource_pool:stop(PoolName);
+        _ ->
+            ok
+    end.
 
 on_query(InstanceId, Query, State) ->
     do_query(InstanceId, Query, State).

apps/emqx_bridge_opents/src/emqx_bridge_opents_connector.erl

@@ -78,6 +78,7 @@ on_start(
     State = #{pool_name => InstanceId, server => Server},
     case opentsdb_connectivity(Server) of
         ok ->
+            ok = emqx_resource:allocate_resource(InstanceId, pool_name, InstanceId),
             case emqx_resource_pool:start(InstanceId, ?MODULE, Options) of
                 ok ->
                     {ok, State};
@@ -89,12 +90,17 @@ on_start(
             Error
     end.
 
-on_stop(InstanceId, #{pool_name := PoolName} = _State) ->
+on_stop(InstanceId, _State) ->
     ?SLOG(info, #{
         msg => "stopping_opents_connector",
         connector => InstanceId
     }),
-    emqx_resource_pool:stop(PoolName).
+    case emqx_resource:get_allocated_resources(InstanceId) of
+        #{pool_name := PoolName} ->
+            emqx_resource_pool:stop(PoolName);
+        _ ->
+            ok
+    end.
 
 on_query(InstanceId, Request, State) ->
     on_batch_query(InstanceId, [Request], State).

apps/emqx_bridge_rabbitmq/src/emqx_bridge_rabbitmq_connector.erl

@@ -242,6 +242,7 @@ on_start(
             %% Already initialized
             ok
     end,
+    ok = emqx_resource:allocate_resource(InstanceID, pool_name, InstanceID),
     case emqx_resource_pool:start(InstanceID, ?MODULE, Options) of
         ok ->
             {ok, State};
@@ -267,6 +268,14 @@ on_stop(
         msg => "stopping RabbitMQ connector",
         connector => ResourceID
     }),
+    case emqx_resource:get_allocated_resources(InstanceId) of
+        #{pool_name := PoolName} ->
+            stop_clients_and_pool(PoolName);
+        _ ->
+            ok
+    end.
+
+stop_clients_and_pool(PoolName) ->
     Workers = [Worker || {_WorkerName, Worker} <- ecpool:workers(PoolName)],
     Clients = [
         begin

apps/emqx_bridge_sqlserver/src/emqx_bridge_sqlserver_connector.erl

@@ -215,6 +215,7 @@ on_start(
         sql_templates => parse_sql_template(Config),
         resource_opts => ResourceOpts
     },
+    ok = emqx_resource:allocate_resource(InstanceId, pool_name, PoolName),
     case emqx_resource_pool:start(PoolName, ?MODULE, Options) of
         ok ->
             {ok, State};
@@ -231,7 +232,12 @@ on_stop(ResourceId, _State) ->
         msg => "stopping_sqlserver_connector",
         connector => ResourceId
     }),
-    emqx_resource_pool:stop(ResourceId).
+    case emqx_resource:get_allocated_resources(InstanceId) of
+        #{pool_name := PoolName} ->
+            emqx_resource_pool:stop(PoolName);
+        _ ->
+            ok
+    end.
 
 -spec on_query(
     resource_id(),