FirmwareStatusNotification::Installed from system interface gets dropped if sent before registered

[barsnick]

OCPP Version

OCPP2.0.1

Describe the bug

If the System module (or whatever implementation of the system interface) publishes its firmware_update_status right after reboot (in ready() of course), but the OCPP201 module has not yet registered with the CSMS, the FirmwareStatusNotification::Installed apparently gets dropped and never sent to the CSMS.

If the System module delays publishing this value, it properly propagates to the CSMS.

To Reproduce

Trigger a firmware update from the CSMS. Handle sending of FirmwareStatusNotification::Installed after reboot.

Anything else?

This is possibly an issue with the FirmwareStatusNotification being sent "async":

libocpp/lib/ocpp/v201/charge_point.cpp

Lines 303 to 304 in 21292cf

	ocpp::Call<FirmwareStatusNotificationRequest> call(req, this->message_queue->createMessageId());
	this->send_async<FirmwareStatusNotificationRequest>(call);

and the applied filtering in send_async():

libocpp/lib/ocpp/v201/charge_point.cpp

Lines 3716 to 3724 in 21292cf

	case MessageTransmissionPriority::SendImmediately:
	return this->message_queue->push_async(call);
	case MessageTransmissionPriority::SendAfterRegistrationStatusAccepted:
	case MessageTransmissionPriority::Discard:
	auto promise = std::promise<EnhancedMessage<MessageType>>();
	auto enhanced_message = EnhancedMessage<MessageType>();
	enhanced_message.offline = true;
	promise.set_value(enhanced_message);
	return promise.get_future();

affected by get_message_transmission_priority():

libocpp/include/ocpp/common/message_queue.hpp

Lines 99 to 103 in 21292cf

	if (is_transaction_related || queue_all_message) {
	return MessageTransmissionPriority::SendAfterRegistrationStatusAccepted;
	}
	return MessageTransmissionPriority::Discard;

Possibly, a FirmwareStatusNotification should be handled with a similar priority to a transaction related message.

[barsnick]

It turns out that our System module sends FirmwareStatusNotification::Installed in ready(), but before OCPP201's ready() has managed to subscribe to the topic. This is very ugly. The OCPP (1.6) module has solved this by subscribing in init().

That said, I still don't know whether the said filter is doing the right thing.