Exemplo n.º 1
0
Arquivo: ros.py Projeto: bopopescu/ros
class ROS(AbstractTask):
    '''
        Extends AbstractTask as a Finite State Machine (FSM) basis of a Robot 
        Operating System (ROS) or behaviour-based system (BBS), including 
        spawning the various tasks and an Arbitrator as separate threads, 
        inter-communicating over a common message queue.
    
        This establishes a RESTful flask service, a message queue, an Arbitrator 
        and a Controller. 
    
        The message queue receives Event-containing messages, which are passed 
        on to the Arbitrator, whose job it is to determine the highest priority 
        action to execute for that task cycle.

        Example usage:

            try:
                _ros = ROS()
                _ros.start()
            except Exception:
                _ros.close()
    '''

    # ..........................................................................
    def __init__(self):
        '''
            This initialises the ROS and calls the YAML configurer.
        '''
        self._queue = MessageQueue(Level.INFO)
        self._mutex = threading.Lock()
        super().__init__("os", self._queue, None, None, self._mutex)
        self._log.info('initialising...')
        self._active = False
        self._closing = False
        self._disable_leds = False
        self._switch = None
        self._motors = None
        self._arbitrator = None
        self._controller = None
        # read YAML configuration
        _loader = ConfigLoader(Level.INFO)
        filename = 'config.yaml'
        self._config = _loader.configure(filename)
        # import available features
        self._features = []
        _configurer = Configurer(self, Level.INFO)
        _configurer.scan()
        self._log.info('initialised.')

#   def configure(self):
#       '''
#           Read and return configuration from the YAML file.
#       '''
#       filename = 'config.yaml'
#       self._log.info('reading from yaml configuration file {}...'.format(filename))
#       _config = yaml.safe_load(open(filename, 'r'))
#       for key, value in _config.items():
#           self._log.debug('config key: {}; value: {}'.format(key, str(value)))
#       self._log.info('configuration read.')
#       return _config

# ..........................................................................

    def get_message_queue(self):
        return self._queue

    # ..........................................................................
    def get_controller(self):
        return self._controller

    # ..........................................................................
    def get_configuration(self):
        return self._config

    # ..........................................................................
    def get_property(self, section, property_name):
        '''
            Return the value of the named property of the application
            configuration, provided its section and property name.
        '''
        return self._config[section].get(property_name)

    # ..........................................................................
    def set_property(self, section, property_name, property_value):
        '''
            Set the value of the named property of the application
            configuration, provided its section, property name and value.
        '''
        self._log.info(
            Fore.GREEN +
            'set config on section \'{}\' for property key: \'{}\' to value: {}.'
            .format(section, property_name, property_value))
        if section == 'ros':
            self._config[section].update(property_name=property_value)
        else:
            _ros = self._config['ros']
            _ros[section].update(property_name=property_value)

    # ..........................................................................
    def _set_pi_leds(self, enable):
        '''
            Enables or disables the Raspberry Pi's board LEDs.
        '''
        sudo_name = self.get_property('pi', 'sudo_name')
        led_0_path = self._config['pi'].get('led_0_path')
        led_1_path = self._config['pi'].get('led_1_path')
        if enable:
            self._log.info('re-enabling LEDs...')
            os.system('echo 1 | {} tee {}'.format(sudo_name, led_0_path))
            os.system('echo 1 | {} tee {}'.format(sudo_name, led_1_path))
        else:
            self._log.debug('disabling LEDs...')
            os.system('echo 0 | {} tee {}'.format(sudo_name, led_0_path))
            os.system('echo 0 | {} tee {}'.format(sudo_name, led_1_path))

    # ..........................................................................
    def add_feature(self, feature):
        '''
            Add the feature to the list of features. Features must have 
            an enable() method.
        '''
        self._features.append(feature)
        self._log.info('added feature {}.'.format(feature.name()))

    # ..........................................................................
    def _callback_shutdown(self):
        __enable_self_shutdown = self._config['ros'].get(
            'enable_self_shutdown')
        if _enable_self_shutdown:
            self._log.critical('callback: shutting down os...')
            if self._arbitrator:
                self._arbitrator.disable()
            self.close()
        else:
            self._log.critical('self-shutdown disabled.')

    # ..........................................................................
    def run(self):
        '''
            This first disables the Pi's status LEDs, establishes the
            message queue arbitrator, the controller, enables the set
            of features, then starts the main OS loop.
        '''
        super(AbstractTask, self).run()
        loop_count = 0

        self._disable_leds = self._config['pi'].get('disable_leds')
        if self._disable_leds:
            # disable Pi LEDs since they may be distracting
            self._set_pi_leds(False)

        self._log.info('enabling features...')
        for feature in self._features:
            self._log.info('enabling feature {}...'.format(feature.name()))
            feature.enable()

        __enable_player = self._config['ros'].get('enable_player')
        if __enable_player:
            self._log.info('configuring sound player...')
            self._player = Player(Level.INFO)
        else:
            self._player = None

        vl53l1x_available = True  # self.get_property('features', 'vl53l1x')
        self._log.critical('vl53l1x_available? {}'.format(vl53l1x_available))
        ultraborg_available = True  # self.get_property('features', 'ultraborg')
        self._log.critical(
            'ultraborg available? {}'.format(ultraborg_available))
        if vl53l1x_available and ultraborg_available:
            self._log.critical('starting scanner tool...')
            self._lidar = Lidar(self._config, self._player, Level.INFO)
            self._lidar.enable()
        else:
            self._log.critical(
                'scanner tool does not have necessary dependencies.')

        # wait to stabilise features?

        # configure the Controller and Arbitrator
        self._log.info('configuring controller...')
        self._controller = Controller(Level.INFO, self._config, self._switch,
                                      self._infrareds, self._motors,
                                      self._rgbmatrix, self._lidar,
                                      self._callback_shutdown)

        self._log.info('configuring arbitrator...')
        self._arbitrator = Arbitrator(_level, self._queue, self._controller,
                                      self._mutex)

        flask_enabled = self._config['flask'].get('enabled')
        if flask_enabled:
            self._log.info('starting flask web server...')
            self.configure_web_server()
        else:
            self._log.info(
                'not starting flask web server (suppressed from command line).'
            )

        self._log.warning('Press Ctrl-C to exit.')

        wait_for_button_press = self._config['ros'].get(
            'wait_for_button_press')
        self._controller.set_standby(wait_for_button_press)

        # begin main loop ..............................

        #       self._log.info('starting battery check thread...')
        #       self._battery_check.enable()

        self._log.info('starting button thread...')
        self._button.start()

        #       self._log.info('enabling bno055 sensor...')
        #       self._bno055.enable()

        self._log.info('enabling bumpers...')
        self._bumpers.enable()

        #       self._log.info('starting info thread...')
        #       self._info.start()

        #       self._log.info('starting blinky thread...')
        #       self._rgbmatrix.enable(DisplayType.RANDOM)

        # enable arbitrator tasks (normal functioning of robot)

        main_loop_delay_ms = self._config['ros'].get('main_loop_delay_ms')
        self._log.info(
            'begin main os loop with {:d}ms delay.'.format(main_loop_delay_ms))
        _loop_delay_sec = main_loop_delay_ms / 1000
        self._arbitrator.start()
        while self._arbitrator.is_alive():
            #           The sensors and the flask service sends messages to the message queue,
            #           which forwards those messages on to the arbitrator, which chooses the
            #           highest priority message to send on to the controller. So the timing
            #           of this loop is inconsequential; it exists solely as a keep-alive.
            time.sleep(_loop_delay_sec)
            # end application loop .........................

        if not self._closing:
            self._log.warning('closing following loop...')
            self.close()
        # end main ...................................

    # ..........................................................................
    def configure_web_server(self):
        '''
            Start flask web server.
        '''
        try:
            self._mutex.acquire()
            self._log.info('starting web service...')
            self._flask_wrapper = FlaskWrapperService(self._queue,
                                                      self._controller)
            self._flask_wrapper.start()
        except KeyboardInterrupt:
            self._log.error('caught Ctrl-C interrupt.')
        finally:
            self._mutex.release()
            time.sleep(1)
            self._log.info(Fore.BLUE + 'web service started.' +
                           Style.RESET_ALL)

    # ..........................................................................
    def emergency_stop(self):
        '''
            Stop immediately, something has hit the top feelers.
        '''
        self._motors.stop()
        self._log.info(Fore.RED + Style.BRIGHT +
                       'emergency stop: contact on upper feelers.')

    # ..........................................................................
    def send_message(self, message):
        '''
            Send the Message into the MessageQueue.
        '''
        self._queue.add(message)

    # ..........................................................................
    def enable(self):
        super(AbstractTask, self).enable()

    # ..........................................................................
    def disable(self):
        super(AbstractTask, self).disable()

    # ..........................................................................
    def close(self):
        '''
            This sets the ROS back to normal following a session.
        '''
        if self._closing:
            # this also gets called by the arbitrator so we ignore that
            self._log.info('already closing.')
            return
        else:
            self._active = False
            self._closing = True
            self._log.info(Style.BRIGHT + 'closing...')
            self._flask_wrapper.close()
            if self._arbitrator:
                self._arbitrator.disable()
            super().close()
            #           self._arbitrator.join(timeout=1.0)

            # close features
            for feature in self._features:
                self._log.info('closing feature {}...'.format(feature.name()))
                feature.close()
            self._log.info('finished closing features.')

            if self._motors:
                self._motors.close()

#           self._info.close()
#           self._rgbmatrix.close()
            if self._switch:
                self._switch.close()
#           super(AbstractTask, self).close()
            if self._arbitrator:
                self._arbitrator.close()

            if self._disable_leds:
                # restore LEDs
                self._set_pi_leds(True)

#           GPIO.cleanup()
#           self._log.info('joining main thread...')
#           self.join(timeout=0.5)
            self._log.info('os closed.')
            sys.stderr = DevNull()
            sys.exit(0)
Exemplo n.º 2
0
class ROS(AbstractTask):
    '''
        Extends AbstractTask as a Finite State Machine (FSM) basis of a Robot 
        Operating System (ROS) or behaviour-based system (BBS), including 
        spawning the various tasks and an Arbitrator as separate threads, 
        inter-communicating over a common message queue.
    
        This establishes a message queue, an Arbitrator and a Controller, as
        well as an optional RESTful flask-based web service.
    
        The message queue receives Event-containing messages, which are passed 
        on to the Arbitrator, whose job it is to determine the highest priority 
        action to execute for that task cycle.

        Example usage:

            try:
                _ros = ROS()
                _ros.start()
            except Exception:
                _ros.close()

      
        There is also a rosd linux daemon, which can be used to start, enable
        and disable ros (actually via its Arbitrator).
    '''

    # ..........................................................................
    def __init__(self):
        '''
            This initialises the ROS and calls the YAML configurer.
        '''
        self._queue = MessageQueue(Level.INFO)
        self._mutex = threading.Lock()
        super().__init__("ros", self._queue, None, None, self._mutex)
        self._log.info('initialising...')
        self._active = False
        self._closing = False
        self._disable_leds = False
        #       self._switch        = None
        self._motors = None
        self._arbitrator = None
        self._controller = None
        self._gamepad = None
        self._features = []
        #       self._flask_wrapper = None
        # read YAML configuration
        _loader = ConfigLoader(Level.INFO)
        filename = 'config.yaml'
        self._config = _loader.configure(filename)
        self._gamepad_enabled = self._config['ros'].get('gamepad').get(
            'enabled')
        self._log.info('initialised.')
        self._configure()

    # ..........................................................................
    def _configure(self):
        '''
            Configures ROS based on both KR01 standard hardware as well as
            optional features, the latter based on devices showing up (by 
            address) on the I²C bus. Optional devices are only enabled at
            startup time via registration of their feature availability.
        '''
        scanner = I2CScanner(Level.WARN)
        self._addresses = scanner.getAddresses()
        hexAddresses = scanner.getHexAddresses()
        self._addrDict = dict(
            list(map(lambda x, y: (x, y), self._addresses, hexAddresses)))
        for i in range(len(self._addresses)):
            self._log.debug(
                Fore.BLACK + Style.DIM +
                'found device at address: {}'.format(hexAddresses[i]) +
                Style.RESET_ALL)

        self._log.info('configure default features...')
        # standard devices ...........................................
        self._log.info('configuring integrated front sensors...')
        self._ifs = IntegratedFrontSensor(self._config, self._queue,
                                          Level.INFO)
        self._log.info('configure ht0740 switch...')
        self._switch = Switch(Level.INFO)
        # since we're using the HT0740 Switch, turn it on to enable sensors that rely upon its power
        #       self._switch.enable()
        self._switch.on()
        self._log.info('configuring button...')
        self._button = Button(self._config, self.get_message_queue(),
                              self._mutex)

        self._log.info('configure battery check...')
        _battery_check = BatteryCheck(self._config, self.get_message_queue(),
                                      Level.INFO)
        self.add_feature(_battery_check)

        self._log.info('configure CPU temperature check...')
        _temperature_check = Temperature(self._config, self._queue, Level.INFO)
        self.add_feature(_temperature_check)

        ultraborg_available = (0x36 in self._addresses)
        if ultraborg_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            '-- UltraBorg available at 0x36.' +
                            Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            '-- no UltraBorg available at 0x36.' +
                            Style.RESET_ALL)
        self._set_feature_available('ultraborg', ultraborg_available)

        thunderborg_available = (0x15 in self._addresses)
        if thunderborg_available:  # then configure motors
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            '-- ThunderBorg available at 0x15' +
                            Style.RESET_ALL)
            _motor_configurer = MotorConfigurer(self, self._config, Level.INFO)
            self._motors = _motor_configurer.configure()
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            '-- no ThunderBorg available at 0x15.' +
                            Style.RESET_ALL)
        self._set_feature_available('thunderborg', thunderborg_available)

        # optional devices ...........................................
        # the 5x5 RGB Matrix is at 0x74 for port, 0x77 for starboard
        rgbmatrix5x5_stbd_available = (0x74 in self._addresses)
        if rgbmatrix5x5_stbd_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            '-- RGB Matrix available at 0x74.' +
                            Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            '-- no RGB Matrix available at 0x74.' +
                            Style.RESET_ALL)
        self._set_feature_available('rgbmatrix5x5_stbd',
                                    rgbmatrix5x5_stbd_available)
        rgbmatrix5x5_port_available = (0x77 in self._addresses)
        if rgbmatrix5x5_port_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            '-- RGB Matrix available at 0x77.' +
                            Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            '-- no RGB Matrix available at 0x77.' +
                            Style.RESET_ALL)
        self._set_feature_available('rgbmatrix5x5_port',
                                    rgbmatrix5x5_port_available)

        if rgbmatrix5x5_stbd_available or rgbmatrix5x5_port_available:
            self._log.info('configure rgbmatrix...')
            self._rgbmatrix = RgbMatrix(Level.INFO)
            self.add_feature(self._rgbmatrix)  # FIXME this is added twice

        # ............................................
        # the 11x7 LED matrix is at 0x75 for starboard, 0x77 for port. The latter
        # conflicts with the RGB LED matrix, so both cannot be used simultaneously.
        matrix11x7_stbd_available = (0x75 in self._addresses)
        if matrix11x7_stbd_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            '-- 11x7 Matrix LEDs available at 0x75.' +
                            Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            '-- no 11x7 Matrix LEDs available at 0x75.' +
                            Style.RESET_ALL)
        self._set_feature_available('matrix11x7_stbd',
                                    matrix11x7_stbd_available)

        # device availability ........................................

        bno055_available = (0x28 in self._addresses)
        if bno055_available:
            self._log.info('configuring BNO055 9DoF sensor...')
            self._bno055 = BNO055(self._config, self.get_message_queue(),
                                  Level.INFO)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            'no BNO055 orientation sensor available at 0x28.' +
                            Style.RESET_ALL)
        self._set_feature_available('bno055', bno055_available)

        # NOTE: the default address for the ICM20948 is 0x68, but this conflicts with the PiJuice
        icm20948_available = (0x69 in self._addresses)
        if icm20948_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            'ICM20948 available at 0x69.' + Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            'no ICM20948 available at 0x69.' + Style.RESET_ALL)
        self._set_feature_available('icm20948', icm20948_available)

        lsm303d_available = (0x1D in self._addresses)
        if lsm303d_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            'LSM303D available at 0x1D.' + Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            'no LSM303D available at 0x1D.' + Style.RESET_ALL)
        self._set_feature_available('lsm303d', lsm303d_available)

        vl53l1x_available = (0x29 in self._addresses)
        if vl53l1x_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            'VL53L1X available at 0x29.' + Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            'no VL53L1X available at 0x29.' + Style.RESET_ALL)
        self._set_feature_available('vl53l1x', vl53l1x_available)

        as7262_available = (0x49 in self._addresses)
        if as7262_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            '-- AS7262 Spectrometer available at 0x49.' +
                            Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            '-- no AS7262 Spectrometer available at 0x49.' +
                            Style.RESET_ALL)
        self._set_feature_available('as7262', as7262_available)

        pijuice_available = (0x68 in self._addresses)
        if pijuice_available:
            self._log.debug(Fore.CYAN + Style.BRIGHT +
                            'PiJuice hat available at 0x68.' + Style.RESET_ALL)
        else:
            self._log.debug(Fore.RED + Style.BRIGHT +
                            'no PiJuice hat available at 0x68.' +
                            Style.RESET_ALL)
        self._set_feature_available('pijuice', pijuice_available)

        self._log.info('configured.')

    # ..........................................................................
    def summation():
        '''
            Displays unaccounted I2C addresses. This is currently non-functional,
            as we don't remove a device from the list when its address is found.
        '''
        self._log.info(Fore.YELLOW + '-- unaccounted for self._addresses:')
        for i in range(len(self._addresses)):
            hexAddr = self._addrDict.get(self._addresses[i])
            self._log.info(Fore.YELLOW + Style.BRIGHT +
                           '-- address: {}'.format(hexAddr) + Style.RESET_ALL)

    # ..........................................................................
    def _set_feature_available(self, name, value):
        '''
            Sets a feature's availability to the boolean value.
        '''
        self._log.debug(Fore.BLUE + Style.BRIGHT +
                        '-- set feature available. name: \'{}\' value: \'{}\'.'
                        .format(name, value))
        self.set_property('features', name, value)

    # ..........................................................................
    def get_message_queue(self):
        return self._queue

    # ..........................................................................
    def get_controller(self):
        return self._controller

    # ..........................................................................
    def get_configuration(self):
        return self._config

    # ..........................................................................
    def get_property(self, section, property_name):
        '''
            Return the value of the named property of the application
            configuration, provided its section and property name.
        '''
        return self._config[section].get(property_name)

    # ..........................................................................
    def set_property(self, section, property_name, property_value):
        '''
            Set the value of the named property of the application
            configuration, provided its section, property name and value.
        '''
        self._log.debug(
            Fore.GREEN +
            'set config on section \'{}\' for property key: \'{}\' to value: {}.'
            .format(section, property_name, property_value))
        if section == 'ros':
            self._config[section].update(property_name=property_value)
        else:
            _ros = self._config['ros']
            _ros[section].update(property_name=property_value)

    # ..........................................................................
    def _set_pi_leds(self, enable):
        '''
            Enables or disables the Raspberry Pi's board LEDs.
        '''
        sudo_name = self.get_property('pi', 'sudo_name')
        led_0_path = self._config['pi'].get('led_0_path')
        led_1_path = self._config['pi'].get('led_1_path')
        if enable:
            self._log.info('re-enabling LEDs...')
            os.system('echo 1 | {} tee {}'.format(sudo_name, led_0_path))
            os.system('echo 1 | {} tee {}'.format(sudo_name, led_1_path))
        else:
            self._log.debug('disabling LEDs...')
            os.system('echo 0 | {} tee {}'.format(sudo_name, led_0_path))
            os.system('echo 0 | {} tee {}'.format(sudo_name, led_1_path))

    # ..........................................................................
    def _connect_gamepad(self):
        if not self._gamepad_enabled:
            self._log.info('gamepad disabled.')
            return
        if self._gamepad is None:
            self._log.info('creating gamepad...')
            try:
                self._gamepad = Gamepad(self._config, self._queue, Level.INFO)
            except GamepadConnectException as e:
                self._log.error('unable to connect to gamepad: {}'.format(e))
                self._gamepad = None
                self._gamepad_enabled = False
                self._log.info('gamepad unavailable.')
                return
        if self._gamepad is not None:
            self._log.info('enabling gamepad...')
            self._gamepad.enable()
            _count = 0
            while not self._gamepad.has_connection():
                _count += 1
                if _count == 1:
                    self._log.info('connecting to gamepad...')
                else:
                    self._log.info(
                        'gamepad not connected; re-trying... [{:d}]'.format(
                            _count))
                self._gamepad.connect()
                time.sleep(0.5)
                if self._gamepad.has_connection() or _count > 5:
                    break

    # ..........................................................................
    def has_connected_gamepad(self):
        return self._gamepad is not None and self._gamepad.has_connection()

    # ..........................................................................
    def get_arbitrator(self):
        return self._arbitrator

    # ..........................................................................
    def add_feature(self, feature):
        '''
            Add the feature to the list of features. Features must have 
            an enable() method.
        '''
        self._features.append(feature)
        self._log.info('added feature {}.'.format(feature.name()))

    # ..........................................................................
    def _callback_shutdown(self):
        _enable_self_shutdown = self._config['ros'].get('enable_self_shutdown')
        if _enable_self_shutdown:
            self._log.critical('callback: shutting down os...')
            self.close()
            sys.exit(0)
        else:
            self._log.critical('self-shutdown disabled.')

    # ..........................................................................
    def run(self):
        '''
            This first disables the Pi's status LEDs, establishes the
            message queue arbitrator, the controller, enables the set
            of features, then starts the main OS loop.
        '''
        super(AbstractTask, self).run()
        loop_count = 0
        # display banner!
        _banner = '\n' \
                  'ros\n' \
                  'ros                         █▒▒▒▒▒▒▒     █▒▒▒▒▒▒     █▒▒▒▒▒▒    █▒▒  \n' \
                + 'ros                         █▒▒   █▒▒   █▒▒   █▒▒   █▒▒         █▒▒  \n' \
                + 'ros                         █▒▒▒▒▒▒     █▒▒   █▒▒    █▒▒▒▒▒▒    █▒▒  \n' \
                + 'ros                         █▒▒  █▒▒    █▒▒   █▒▒         █▒▒        \n' \
                + 'ros                         █▒▒   █▒▒    █▒▒▒▒▒▒     █▒▒▒▒▒▒    █▒▒  \n' \
                + 'ros\n'
        self._log.info(_banner)

        self._disable_leds = self._config['pi'].get('disable_leds')
        if self._disable_leds:
            # disable Pi LEDs since they may be distracting
            self._set_pi_leds(False)

        self._log.info('enabling features...')
        for feature in self._features:
            self._log.info('enabling feature {}...'.format(feature.name()))
            feature.enable()

#       __enable_player = self._config['ros'].get('enable_player')
#       if __enable_player:
#           self._log.info('configuring sound player...')
#           self._player = Player(Level.INFO)
#       else:
#           self._player = None

#       i2c_slave_address = config['ros'].get('i2c_master').get('device_id') # i2c hex address of I2C slave device

        vl53l1x_available = True  # self.get_property('features', 'vl53l1x')
        ultraborg_available = True  # self.get_property('features', 'ultraborg')
        if vl53l1x_available and ultraborg_available:
            self._log.critical('starting scanner tool...')
            self._lidar = Lidar(self._config, Level.INFO)
            self._lidar.enable()
        else:
            self._log.critical(
                'lidar scanner tool does not have necessary dependencies.')

        # wait to stabilise features?

        # configure the Controller and Arbitrator
        self._log.info('configuring controller...')
        self._controller = Controller(self._config, self._ifs, self._motors,
                                      self._callback_shutdown, Level.INFO)

        self._log.info('configuring arbitrator...')
        self._arbitrator = Arbitrator(self._config, self._queue,
                                      self._controller, Level.WARN)

        _flask_enabled = self._config['flask'].get('enabled')
        if _flask_enabled:
            self._log.info('starting flask web server...')
            self.configure_web_server()
        else:
            self._log.info(
                'not starting flask web server (suppressed from command line).'
            )

        # bluetooth gamepad controller
        if self._gamepad_enabled:
            self._connect_gamepad()

        self._log.warning('Press Ctrl-C to exit.')

        _wait_for_button_press = self._config['ros'].get(
            'wait_for_button_press')
        self._controller.set_standby(_wait_for_button_press)

        # begin main loop ..............................

        self._log.info('starting button thread...')
        self._button.start()

        #       self._log.info('enabling bno055 sensor...')
        #       self._bno055.enable()

        #       self._bumpers.enable()

        self._indicator = Indicator(Level.INFO)
        # add indicator as message consumer
        self._queue.add_consumer(self._indicator)

        self._log.info(Fore.MAGENTA + 'enabling integrated front sensor...')
        self._ifs.enable()
        #       self._log.info('starting info thread...')
        #       self._info.start()

        #       self._log.info('starting blinky thread...')
        #       self._rgbmatrix.enable(DisplayType.RANDOM)

        # enable arbitrator tasks (normal functioning of robot)

        main_loop_delay_ms = self._config['ros'].get('main_loop_delay_ms')
        self._log.info(
            'begin main os loop with {:d}ms delay.'.format(main_loop_delay_ms))
        _loop_delay_sec = main_loop_delay_ms / 1000
        _main_loop_count = 0
        self._arbitrator.start()
        self._active = True
        while self._active:
            #           The sensors and the flask service sends messages to the message queue,
            #           which forwards those messages on to the arbitrator, which chooses the
            #           highest priority message to send on to the controller. So the timing
            #           of this loop is inconsequential; it exists solely as a keep-alive.
            _main_loop_count += 1
            self._log.debug(Fore.BLACK + Style.DIM +
                            '[{:d}] main loop...'.format(_main_loop_count))
            time.sleep(_loop_delay_sec)
            # end application loop .........................

        if not self._closing:
            self._log.warning('closing following loop...')
            self.close()
        # end main ...................................

    # ..........................................................................
    def configure_web_server(self):
        '''
            Start flask web server.
        '''
        try:
            self._mutex.acquire()
            self._log.info('starting web service...')
            self._flask_wrapper = FlaskWrapperService(self._queue,
                                                      self._controller)
            self._flask_wrapper.start()
        except KeyboardInterrupt:
            self._log.error('caught Ctrl-C interrupt.')
        finally:
            self._mutex.release()
            time.sleep(1)
            self._log.info(Fore.BLUE + 'web service started.' +
                           Style.RESET_ALL)

    # ..........................................................................
    def emergency_stop(self):
        '''
            Stop immediately, something has hit the top feelers.
        '''
        self._motors.stop()
        self._log.info(Fore.RED + Style.BRIGHT +
                       'emergency stop: contact on upper feelers.')

    # ..........................................................................
    def send_message(self, message):
        '''
            Send the Message into the MessageQueue.
        '''
        self._queue.add(message)

    # ..........................................................................
    def enable(self):
        super(AbstractTask, self).enable()

    # ..........................................................................
    def disable(self):
        super(AbstractTask, self).disable()

    # ..........................................................................
    def close(self):
        '''
            This sets the ROS back to normal following a session.
        '''
        if self._closing:
            # this also gets called by the arbitrator so we ignore that
            self._log.info('already closing.')
            return
        else:
            self._active = False
            self._closing = True
            self._log.info(Style.BRIGHT + 'closing...')

            if self._gamepad:
                self._gamepad.close()
            if self._motors:
                self._motors.close()
            if self._ifs:
                self._ifs.close()

            # close features
            for feature in self._features:
                self._log.info('closing feature {}...'.format(feature.name()))
                feature.close()
            self._log.info('finished closing features.')

            if self._arbitrator:
                self._arbitrator.disable()
                self._arbitrator.close()
#               self._arbitrator.join(timeout=1.0)
            if self._controller:
                self._controller.disable()

#           if self._flask_wrapper is not None:
#               self._flask_wrapper.close()

            super().close()

            #           self._info.close()
            #           self._rgbmatrix.close()
            #           if self._switch:
            #               self._switch.close()
            #           super(AbstractTask, self).close()

            if self._disable_leds:
                # restore LEDs
                self._set_pi_leds(True)

#           GPIO.cleanup()
#           self._log.info('joining main thread...')
#           self.join(timeout=0.5)
            self._log.info('os closed.')
            sys.stderr = DevNull()
            sys.exit(0)