fix: also alarm resource down when start resource failed

apps/emqx_resource/include/emqx_resource.hrl

@@ -33,7 +33,7 @@
 -type create_opts() :: #{
     health_check_interval => integer(),
     health_check_timeout => integer(),
-    waiting_connect_complete => integer(),
+    wait_for_resource_ready => integer(),
     auto_retry_interval => integer()
 }.
 -type after_query() ::

apps/emqx_resource/src/emqx_resource_manager.erl

@@ -267,13 +267,13 @@ handle_event({call, From}, restart, _State, Data) ->
     _ = stop_resource(Data),
     start_resource(Data, From);
 % Called when the resource is to be started
-handle_event({call, From}, start, _State, #data{status = disconnected} = Data) ->
+handle_event({call, From}, start, stopped, Data) ->
     start_resource(Data, From);
 handle_event({call, From}, start, _State, _Data) ->
     {keep_state_and_data, [{reply, From, ok}]};
 % Called when the resource is to be stopped
-handle_event({call, From}, stop, _State, #data{status = disconnected} = Data) ->
+handle_event({call, From}, stop, stopped, _Data) ->
-    {next_state, stopped, Data, [{reply, From, ok}]};
+    {keep_state_and_data, [{reply, From, ok}]};
 handle_event({call, From}, stop, _State, Data) ->
     Result = stop_resource(Data),
     UpdatedData = Data#data{status = disconnected},
@@ -281,21 +281,27 @@ handle_event({call, From}, stop, _State, Data) ->
 % Called when a resource is to be stopped and removed.
 handle_event({call, From}, {remove, ClearMetrics}, _State, Data) ->
     handle_remove_event(From, ClearMetrics, Data);
-% Called when the state of the resource is being looked up.
+% Called when the state-data of the resource is being looked up.
 handle_event({call, From}, lookup, _State, #data{group = Group} = Data) ->
     Reply = {ok, Group, data_record_to_external_map_with_metrics(Data)},
     {keep_state_and_data, [{reply, From, Reply}]};
-% Connecting state enter
+% Called when doing a manually health check.
-handle_event(internal, try_connect, connecting, Data) ->
+handle_event({call, From}, health_check, stopped, _Data) ->
-    start_resource(Data, undefined);
+    Actions = [{reply, From, {error, resource_is_stopped}}],
+    {keep_state_and_data, Actions};
+handle_event({call, From}, health_check, _State, Data) ->
+    handle_manually_health_check(From, Data);
+% State: CONNECTING
 handle_event(enter, _OldState, connecting, Data) ->
     ets:insert(?ETS_TABLE, {Data#data.id, Data#data.group, Data}),
     Actions = [{state_timeout, 0, health_check}],
-    {next_state, connecting, Data, Actions};
+    {keep_state_and_data, Actions};
-% Connecting state health_check timeouts.
+handle_event(internal, try_connect, connecting, Data) ->
+    start_resource(Data, undefined);
 handle_event(state_timeout, health_check, connecting, Data) ->
-    connecting_health_check(Data);
+    handle_connecting_health_check(Data);
-%% The connected state is entered after a successful start of the callback mod
+%% State: CONNECTED
+%% The connected state is entered after a successful on_start/2 of the callback mod
 %% and successful health_checks
 handle_event(enter, _OldState, connected, Data) ->
     ets:insert(?ETS_TABLE, {Data#data.id, Data#data.group, Data}),
@@ -303,22 +309,19 @@ handle_event(enter, _OldState, connected, Data) ->
     Actions = [{state_timeout, ?HEALTHCHECK_INTERVAL, health_check}],
     {next_state, connected, Data, Actions};
 handle_event(state_timeout, health_check, connected, Data) ->
-    perform_connected_health_check(Data);
+    handle_connected_health_check(Data);
+%% State: DISCONNECTED
 handle_event(enter, _OldState, disconnected, Data) ->
     ets:insert(?ETS_TABLE, {Data#data.id, Data#data.group, Data}),
     handle_disconnected_state_enter(Data);
 handle_event(state_timeout, auto_retry, disconnected, Data) ->
     start_resource(Data, undefined);
+%% State: STOPPED
+%% The stopped state is entered after the resource has been explicitly stopped
 handle_event(enter, _OldState, stopped, Data) ->
     UpdatedData = Data#data{status = disconnected},
     ets:insert(?ETS_TABLE, {Data#data.id, Data#data.group, UpdatedData}),
     {next_state, stopped, UpdatedData};
-% Resource has been explicitly stopped, so return that as the error reason.
-handle_event({call, From}, health_check, stopped, _Data) ->
-    Actions = [{reply, From, {error, resource_is_stopped}}],
-    {keep_state_and_data, Actions};
-handle_event({call, From}, health_check, _State, Data) ->
-    handle_health_check_request(From, Data);
 % Ignore all other events
 handle_event(EventType, EventData, State, Data) ->
     ?SLOG(
@@ -331,7 +334,7 @@ handle_event(EventType, EventData, State, Data) ->
             data => Data
         }
     ),
-    {next_state, State, Data}.
+    keep_state_and_data.
 
 %%------------------------------------------------------------------------------
 %% internal functions
@@ -364,6 +367,7 @@ start_resource(Data, From) ->
             Actions = maybe_reply([{state_timeout, 0, health_check}], From, ok),
             {next_state, connecting, UpdatedData, Actions};
         {error, Reason} = Err ->
+            _ = maybe_alarm(disconnected, Data#data.id),
             %% Keep track of the error reason why the connection did not work
             %% so that the Reason can be returned when the verification call is made.
             UpdatedData = Data#data{status = disconnected, error = Reason},
@@ -371,25 +375,29 @@ start_resource(Data, From) ->
             {next_state, disconnected, UpdatedData, Actions}
     end.
 
-stop_resource(#data{state = undefined} = _Data) ->
+stop_resource(#data{state = undefined, id = ResId} = _Data) ->
+    _ = maybe_clear_alarm(ResId),
     ok;
 stop_resource(Data) ->
-    Result = emqx_resource:call_stop(Data#data.id, Data#data.mod, Data#data.state),
+    %% 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.
+    _ = emqx_resource:call_stop(Data#data.id, Data#data.mod, Data#data.state),
     _ = maybe_clear_alarm(Data#data.id),
-    Result.
+    ok.
 
 proc_name(Id) ->
     Module = atom_to_binary(?MODULE),
     Connector = <<"_">>,
     binary_to_atom(<<Module/binary, Connector/binary, Id/binary>>).
 
-handle_health_check_request(From, Data) ->
+handle_manually_health_check(From, Data) ->
     with_health_check(Data, fun(Status, UpdatedData) ->
         Actions = [{reply, From, {ok, Status}}],
         {next_state, Status, UpdatedData, Actions}
     end).
 
-connecting_health_check(Data) ->
+handle_connecting_health_check(Data) ->
     with_health_check(
         Data,
         fun
@@ -403,7 +411,7 @@ connecting_health_check(Data) ->
         end
     ).
 
-perform_connected_health_check(Data) ->
+handle_connected_health_check(Data) ->
     with_health_check(
         Data,
         fun
@@ -420,18 +428,18 @@ with_health_check(Data, Func) ->
     ResId = Data#data.id,
     HCRes = emqx_resource:call_health_check(ResId, Data#data.mod, Data#data.state),
     {Status, NewState, Err} = parse_health_check_result(HCRes, Data#data.state),
-    _ = maybe_alarm_resource_down(Status, ResId),
+    _ = maybe_alarm(Status, ResId),
     UpdatedData = Data#data{
         state = NewState, status = Status, error = Err
     },
     ets:insert(?ETS_TABLE, {ResId, UpdatedData#data.group, UpdatedData}),
     Func(Status, UpdatedData).
 
-maybe_alarm_resource_down(connected, _ResId) ->
+maybe_alarm(connected, _ResId) ->
     ok;
-maybe_alarm_resource_down(_Status, <<?TEST_ID_PREFIX, _/binary>>) ->
+maybe_alarm(_Status, <<?TEST_ID_PREFIX, _/binary>>) ->
     ok;
-maybe_alarm_resource_down(_Status, ResId) ->
+maybe_alarm(_Status, ResId) ->
     emqx_alarm:activate(
         ResId,
         #{resource_id => ResId, reason => resource_down},