virt-manager/virtManager/libvirtobject.py

391 lines
12 KiB
Python

# Copyright (C) 2010, 2013 Red Hat, Inc.
# Copyright (C) 2010 Cole Robinson <crobinso@redhat.com>
#
# This work is licensed under the GNU GPLv2 or later.
# See the COPYING file in the top-level directory.
import logging
from .baseclass import vmmGObject
class vmmLibvirtObject(vmmGObject):
__gsignals__ = {
"state-changed": (vmmGObject.RUN_FIRST, None, []),
"initialized": (vmmGObject.RUN_FIRST, None, [bool]),
}
_STATUS_ACTIVE = 1
_STATUS_INACTIVE = 2
def __init__(self, conn, backend, key, parseclass):
vmmGObject.__init__(self)
self._conn = conn
self._backend = backend
self._key = key
self._parseclass = parseclass
self.__initialized = False
self.__status = None
self._support_isactive = None
self._xmlobj = None
self._xmlobj_to_define = None
self._is_xml_valid = False
# These should be set by the child classes if necessary
self._inactive_xml_flags = 0
self._active_xml_flags = 0
# Cache object name. We may need to do this even
# before init_libvirt_state since it might be needed ahead of time.
self._name = None
self.get_name()
@staticmethod
def log_redefine_xml_diff(obj, origxml, newxml):
if origxml == newxml:
logging.debug("Redefine requested for %s, but XML didn't change!",
obj)
return
import difflib
diff = "".join(difflib.unified_diff(origxml.splitlines(1),
newxml.splitlines(1),
fromfile="Original XML",
tofile="New XML"))
logging.debug("Redefining %s with XML diff:\n%s", obj, diff)
@staticmethod
def lifecycle_action(fn):
"""
Decorator for object lifecycle actions like start, stop, delete.
Will make sure any necessary state is updated accordingly.
"""
def newfn(self, *args, **kwargs):
ret = fn(self, *args, **kwargs)
# If events are supported, this is a no-op, but the event loop
# will trigger force_status_update, which will refresh_xml as well.
#
# If events aren't supported, the priority tick will call
# self.tick(), which will call force_status_update
poll_param = self._conn_tick_poll_param() # pylint: disable=protected-access
tick_kwargs = {poll_param: True}
self.conn.schedule_priority_tick(**tick_kwargs)
return ret
return newfn
def __repr__(self):
try:
name = self.get_name()
except Exception:
name = ""
return "<%s name=%s id=%s>" % (
self.__class__.__name__, name, hex(id(self)))
def _cleanup(self):
self._backend = None
def _get_conn(self):
return self._conn
conn = property(_get_conn)
def get_backend(self):
return self._backend
def get_connkey(self):
return self._key
def change_name_backend(self, newbackend):
# Used for changing the backing object after a rename
self._backend = newbackend
def define_name(self, newname):
oldconnkey = self.get_connkey()
oldname = self.get_xmlobj().name
self.ensure_latest_xml()
xmlobj = self._make_xmlobj_to_define()
if xmlobj.name == newname:
return
logging.debug("Changing %s name from %s to %s",
self, oldname, newname)
origxml = xmlobj.get_xml()
xmlobj.name = newname
newxml = xmlobj.get_xml()
try:
self._key = newname
self.conn.rename_object(self, origxml, newxml, oldconnkey)
except Exception:
self._key = oldname
raise
finally:
self.__force_refresh_xml()
#############################################################
# Functions that should probably be overridden in sub class #
#############################################################
def _XMLDesc(self, flags):
raise NotImplementedError()
def class_name(self):
raise NotImplementedError()
def _conn_tick_poll_param(self):
# The parameter name for conn.tick() object polling. So
# for vmmDomain == "pollvm"
raise NotImplementedError()
def reports_stats(self):
return False
def _using_events(self):
return False
def _check_supports_isactive(self):
return False
def _get_backend_status(self):
raise NotImplementedError()
def _define(self, xml):
ignore = xml
return
def delete(self, force=True):
ignore = force
def get_name(self):
if self._name is None:
self._name = self._backend_get_name()
return self._name
def _backend_get_name(self):
return self._backend.name()
def tick(self, stats_update=True):
raise NotImplementedError()
def _init_libvirt_state(self):
raise NotImplementedError()
def init_libvirt_state(self):
"""
Function called by vmmConnection to populate initial state when
a new object appears.
"""
if self.__initialized:
return
initialize_failed = False
try:
self._init_libvirt_state()
except Exception:
logging.debug("Error initializing libvirt state for %s", self,
exc_info=True)
initialize_failed = True
self.__initialized = True
self.idle_emit("initialized", initialize_failed)
###################
# Status handling #
###################
def _get_status(self):
return self.__status
def is_active(self):
# vmmDomain overwrites this since it has more fine grained statuses
return self._get_status() == self._STATUS_ACTIVE
def run_status(self):
if self.is_active():
return _("Active")
return _("Inactive")
def _refresh_status(self, newstatus=None, cansignal=True):
"""
Grab the object status/active state from libvirt, and if the
status has changed, update the XML cache. Typically called from
object tick functions for manually updating the object state.
:param newstatus: Used by vmmDomain as a small optimization to
avoid polling info() twice
:param cansignal: If True, this function will signal state-changed
if required.
:returns: True if status changed, false otherwise
"""
if (self._using_events() and
self.__status is not None):
return False
if newstatus is None:
newstatus = self._get_backend_status()
status = newstatus
if status == self.__status:
return False
self.__status = status
self.ensure_latest_xml(nosignal=True)
if cansignal:
self.idle_emit("state-changed")
return True
def _backend_get_active(self):
if self._support_isactive is None:
self._support_isactive = self._check_supports_isactive()
if not self._support_isactive:
return self._STATUS_ACTIVE
return (bool(self._backend.isActive()) and
self._STATUS_ACTIVE or
self._STATUS_INACTIVE)
##################
# Public XML API #
##################
def recache_from_event_loop(self):
"""
Updates the VM status and XML, because we received an event from
libvirt's event implementations. That's the only time this should
be used.
We refresh status and XML because they are tied together in subtle
ways, like runtime XML changing when a VM is started.
"""
try:
self.__force_refresh_xml(nosignal=True)
# status = None forces a signal to be emitted
self.__status = None
self._refresh_status()
except Exception as e:
# If we hit an exception here, it's often that the object
# disappeared, so request the poll loop to be updated
logging.debug("Error refreshing %s from events: %s", self, e)
poll_param = self._conn_tick_poll_param()
if poll_param:
kwargs = {"force": True, poll_param: True}
logging.debug("Scheduling priority tick with: %s", kwargs)
self.conn.schedule_priority_tick(**kwargs)
def ensure_latest_xml(self, nosignal=False):
"""
Refresh XML if it isn't up to date, basically if we aren't using
events.
"""
if (self._using_events() and
self._xmlobj and
self._is_xml_valid):
return
self.__force_refresh_xml(nosignal=nosignal)
def __force_refresh_xml(self, nosignal=False):
"""
Force an xml update. Signal 'state-changed' if domain xml has
changed since last refresh
:param nosignal: If true, don't send state-changed. Used by
callers that are going to send it anyways.
"""
origxml = None
if self._xmlobj:
origxml = self._xmlobj.get_xml()
self._invalidate_xml()
active_xml = self._XMLDesc(self._active_xml_flags)
self._xmlobj = self._parseclass(self.conn.get_backend(),
parsexml=active_xml)
self._is_xml_valid = True
if not nosignal and origxml != active_xml:
self.idle_emit("state-changed")
def get_xmlobj(self, inactive=False, refresh_if_nec=True):
"""
Get object xml, return it wrapped in a virtinst object.
If cached xml is invalid, update.
:param inactive: Return persistent XML, not the running config.
No effect if domain is not running. Use this flag
if the XML will be used for redefining a guest
:param refresh_if_nec: Check if XML is out of date, and if so,
refresh it (default behavior). Skipping a refresh is
useful to prevent updating xml in the tick loop when
it's not that important (disk/net stats)
"""
if inactive:
# If inactive XML requested, always return a fresh object even if
# the current object is inactive XML (like when the domain is
# stopped). Callers that request inactive are basically expecting
# a new copy.
inactive_xml = self._XMLDesc(self._inactive_xml_flags)
return self._parseclass(self.conn.get_backend(),
parsexml=inactive_xml)
if (self._xmlobj is None or
(refresh_if_nec and not self._is_xml_valid)):
self.ensure_latest_xml()
return self._xmlobj
@property
def xmlobj(self):
return self.get_xmlobj()
#########################
# Internal XML routines #
#########################
def _invalidate_xml(self):
"""
Mark cached XML as invalid. Subclasses may extend this
to invalidate any specific caches of their own
"""
self._name = None
# While for events we do want to clear cached XML values like
# _name, the XML is never invalid.
self._is_xml_valid = self._using_events()
def _make_xmlobj_to_define(self):
"""
Build an xmlobj that should be used for defining new XML.
Most subclasses shouldn't touch this, but vmmDomainVirtinst needs to.
"""
return self.get_xmlobj(inactive=True)
def _redefine_xmlobj(self, xmlobj, origxml=None):
"""
Redefine the passed xmlobj, which should be generated with
self._make_xmlobj_to_define()
Most subclasses shouldn't touch this, but vmmDomainVirtinst needs to.
:param origxml: vmmDomainVirtinst uses that field to make sure
we detect the actual XML change and log it correctly.
"""
if not origxml:
origxml = self._make_xmlobj_to_define().get_xml()
newxml = xmlobj.get_xml()
self.log_redefine_xml_diff(self, origxml, newxml)
if origxml != newxml:
self._define(newxml)
if self._using_events():
return
# Make sure we have latest XML.
self.ensure_latest_xml(nosignal=True)
# We force a signal even if XML didn't change, so the details
# window is correctly refreshed.
self.idle_emit("state-changed")