Viewing file:  inventory.py (3.8 KB) -rw-r--r--
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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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