Bin Log issues

[stephendade]

The "bin file" logging will sometimes give a "Bad logging" error message in ArduPilot.

Typically happens after first arm then disarm, as mavlink-router sees no log messages for 5 seconds
and assumes a lost link. Then it tries to restart logging and triggers a stop (MAV_REMOTE_LOG_DATA_BLOCK_STOP) in the process. ArduPilot
then interprets this as a logging backend failure for <0.5sec during the logging restart.

ArduPilot: ./libraries/AP_Logger/AP_logger_MAVLink.cpp:

AP_Logger_MAVLink::handle_ack
    if(seqno == MAV_REMOTE_LOG_DATA_BLOCK_STOP) {
        Debug("Received stop-logging packet");
        stop_logging();
        return;
    }

void AP_Logger_MAVLink::stop_logging()
{
    if (_sending_to_client) {
        _sending_to_client = false;
        _last_response_time = AP_HAL::millis();
    }
}

bool AP_Logger_MAVLink::logging_failed() const
{
    return !_sending_to_client;
}

mavlink-router: ./src/binlog.cpp:

void BinLog::_send_stop()
{
    mavlink_message_t msg;

    mavlink_msg_remote_log_block_status_pack(LOG_ENDPOINT_SYSTEM_ID,
                                             MAV_COMP_ID_ALL,
                                             &msg,
                                             _target_system_id,
                                             MAV_COMP_ID_ALL,
                                             MAV_REMOTE_LOG_DATA_BLOCK_STOP,
                                             1);
    _send_msg(&msg, _target_system_id);
}

./src/logendpoint.cpp:

bool LogEndpoint::_alive_timeout()
{
    if (_timeout_write_total == _stat.write.total) {
        log_warning("No Log messages received in %u seconds restarting Log...", ALIVE_TIMEOUT);
        stop();
        start();
    }

    _timeout_write_total = _stat.write.total;
    return true;
}

References:
https://mavlink.io/en/messages/ardupilotmega.html#MAV_REMOTE_LOG_DATA_BLOCK_STATUSES
mavlink-router/mavlink-router#318
ArduPilot/ardupilot#19660