Edit File: inventory.py
import pyudev import tuned.logs from tuned import consts __all__ = ["Inventory"] log = tuned.logs.get() class Inventory(object): """ Inventory object can handle information about available hardware devices. It also informs the plugins about related hardware events. """ def __init__(self, udev_context=None, udev_monitor_cls=None, monitor_observer_factory=None, buffer_size=None, set_receive_buffer_size=True): if udev_context is not None: self._udev_context = udev_context else: self._udev_context = pyudev.Context() if udev_monitor_cls is None: udev_monitor_cls = pyudev.Monitor self._udev_monitor = udev_monitor_cls.from_netlink(self._udev_context) if buffer_size is None: buffer_size = consts.CFG_DEF_UDEV_BUFFER_SIZE if (set_receive_buffer_size): try: self._udev_monitor.set_receive_buffer_size(buffer_size) except EnvironmentError: log.warn("cannot set udev monitor receive buffer size, we are probably running inside " + "container or with limited capabilites, TuneD functionality may be limited") if monitor_observer_factory is None: monitor_observer_factory = _MonitorObserverFactory() self._monitor_observer_factory = monitor_observer_factory self._monitor_observer = None self._subscriptions = {} def get_device(self, subsystem, sys_name): """Get a pyudev.Device object for the sys_name (e.g. 'sda').""" try: return pyudev.Devices.from_name(self._udev_context, subsystem, sys_name) # workaround for pyudev < 0.18 except AttributeError: return pyudev.Device.from_name(self._udev_context, subsystem, sys_name) def get_devices(self, subsystem): """Get list of devices on a given subsystem.""" return self._udev_context.list_devices(subsystem=subsystem) def _handle_udev_event(self, event, device): if not device.subsystem in self._subscriptions: return for (plugin, callback) in self._subscriptions[device.subsystem]: try: callback(event, device) except Exception as e: log.error("Exception occured in event handler of '%s'." % plugin) log.exception(e) def subscribe(self, plugin, subsystem, callback): """Register handler of device events on a given subsystem.""" log.debug("adding handler: %s (%s)" % (subsystem, plugin)) callback_data = (plugin, callback) if subsystem in self._subscriptions: self._subscriptions[subsystem].append(callback_data) else: self._subscriptions[subsystem] = [callback_data, ] self._udev_monitor.filter_by(subsystem) # After start(), HW events begin to get queued up self._udev_monitor.start() def start_processing_events(self): if self._monitor_observer is None: log.debug("starting monitor observer") self._monitor_observer = self._monitor_observer_factory.create(self._udev_monitor, self._handle_udev_event) self._monitor_observer.start() def stop_processing_events(self): if self._monitor_observer is not None: log.debug("stopping monitor observer") self._monitor_observer.stop() self._monitor_observer = None def _unsubscribe_subsystem(self, plugin, subsystem): for callback_data in self._subscriptions[subsystem]: (_plugin, callback) = callback_data if plugin == _plugin: log.debug("removing handler: %s (%s)" % (subsystem, plugin)) self._subscriptions[subsystem].remove(callback_data) def unsubscribe(self, plugin, subsystem=None): """Unregister handler registered with subscribe method.""" empty_subsystems = [] for _subsystem in self._subscriptions: if subsystem is None or _subsystem == subsystem: self._unsubscribe_subsystem(plugin, _subsystem) if len(self._subscriptions[_subsystem]) == 0: empty_subsystems.append(_subsystem) for _subsystem in empty_subsystems: del self._subscriptions[_subsystem] class _MonitorObserverFactory(object): def create(self, *args, **kwargs): return pyudev.MonitorObserver(*args, **kwargs)
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