virt-manager/virtManager/libvirtobject.py

385 lines
13 KiB
Python

#
# Copyright (C) 2010, 2013 Red Hat, Inc.
# Copyright (C) 2010 Cole Robinson <crobinso@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301 USA.
#
from gi.repository import GObject
import logging
from .baseclass import vmmGObject
class vmmLibvirtObject(vmmGObject):
__gsignals__ = {
"state-changed": (GObject.SignalFlags.RUN_FIRST, None, []),
"started": (GObject.SignalFlags.RUN_FIRST, None, []),
"stopped": (GObject.SignalFlags.RUN_FIRST, None, []),
}
_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._initial_status_update = False
self.__status = self._STATUS_ACTIVE
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
self._name = None
self.get_name()
self._refresh_status()
@staticmethod
def log_redefine_xml_diff(obj, origxml, newxml):
objname = "<%s name=%s>" % (obj.__class__.__name__, obj.get_name())
if origxml == newxml:
logging.debug("Redefine requested for %s, but XML didn't change!",
objname)
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", objname, 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 _cleanup(self):
pass
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):
oldname = self.get_xmlobj().name
self._invalidate_xml()
xmlobj = self._get_xmlobj_to_define()
if xmlobj.name == newname:
return
logging.debug("Changing %s name from %s to %s",
self.__class__, oldname, newname)
origxml = xmlobj.get_xml_config()
xmlobj.name = newname
newxml = xmlobj.get_xml_config()
try:
self._key = newname
self.conn.rename_object(self, origxml, newxml, oldname, newname)
except:
self._key = oldname
raise
finally:
self._invalidate_xml()
self.emit("state-changed")
#############################################################
# 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()
###################
# 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_from_event_loop(self):
"""
Updates VM status, because we received a status event from libvirt's
event implementations. That's the only time this should be used.
"""
return self._refresh_status(skip_if_have_events=False)
def _refresh_status(self, skip_if_have_events=True, newstatus=None):
"""
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 skip_if_have_events: If this object is served by libvirt
events, we want this to be a no-op for most usages, like
from tick(), so don't do anything.
:param newstatus: Used by vmmDomain as a small optimization to
avoid polling info() twice
"""
if (self._using_events() and
skip_if_have_events and
self._initial_status_update):
return
try:
status = newstatus
if newstatus is None:
status = self._get_backend_status()
if status == self.__status:
return
self.__status = status
# This will send state-change for us
self.refresh_xml(forcesignal=True)
except Exception, 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 polling status for %s: %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)
finally:
self._initial_status_update = 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 refresh_xml(self, forcesignal=False):
"""
Force an xml update. Signal 'state-changed' if domain xml has
changed since last refresh
:param forcesignal: Send state-changed unconditionally
"""
origxml = None
if self._xmlobj:
origxml = self._xmlobj.get_xml_config()
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 forcesignal or 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.refresh_xml()
return self._xmlobj
@property
def xmlobj(self):
return self.get_xmlobj()
def redefine_cached(self):
"""
Redefine the _xmlobj_to_define cache.
Used by places like details.py and addhardware.py to queue a bunch
of XML changes via vmmDomain functions, but only call 'define'
once.
"""
if not self._xmlobj_to_define:
logging.debug("No cached XML to define, skipping.")
return
try:
self._redefine_object(self._xmlobj_to_define)
except:
# If something fails here, we need to drop the cached object,
# since some edits like addhardware.py may not be idempotent
self._invalidate_xml()
raise
#########################
# 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._is_xml_valid = False
self._xmlobj_to_define = None
self._name = None
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 _get_xmlobj_to_define(self):
"""
Return the XML object that should be used to queue up new XML changes.
This is what is flushed with redefine_cached.
Most subclasses shouldn't touch this, but vmmDomainVirtinst needs to.
"""
if not self._xmlobj_to_define:
self._xmlobj_to_define = self._make_xmlobj_to_define()
return self._xmlobj_to_define
def _redefine_object(self, xmlobj, origxml=None):
"""
Redefine the passed object. This is called by redefine_cached and
shouldn't be called directly.
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_config()
newxml = xmlobj.get_xml_config()
self.log_redefine_xml_diff(self, origxml, newxml)
if origxml != newxml:
self._define(newxml)
if not self._using_events():
# Make sure we have latest XML
self.refresh_xml(forcesignal=True)