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Move python example programs into python/examples/ subdirectory

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Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrange
2013-11-22 15:55:39 +00:00
parent 70b8c9a2a3
commit 34aa32ba8a
10 changed files with 1139 additions and 0 deletions
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examples/Makefile.am Normal file
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## Copyright (C) 2005-2013 Red Hat, Inc.
##
## This library is free software; you can redistribute it and/or
## modify it under the terms of the GNU Lesser General Public
## License as published by the Free Software Foundation; either
## version 2.1 of the License, or (at your option) any later version.
##
## This library 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
## Lesser General Public License for more details.
##
## You should have received a copy of the GNU Lesser General Public
## License along with this library. If not, see
## <http://www.gnu.org/licenses/>.
EXTRA_DIST= \
README \
consolecallback.py \
topology.py \
dominfo.py domrestore.py domsave.py domstart.py esxlist.py

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Some simple examples on how to use the Python API for libvirt
The examples are:
dominfo.py - print information about a running domU based on the results of
virDomainGetInfo and virDomainGetXMLDesc
domstart.py - create a domU from an XML description if the domU isn't
running yet
domsave.py - save all running domU's into a directory
domrestore.py - restore domU's from their saved files in a directory
esxlist.py - list active domains of an VMware ESX host and print some info.
also demonstrates how to use the libvirt.openAuth() method
The XML files in this directory are examples of the XML format that libvirt
expects, and will have to be adapted for your setup. They are only needed
for domstart.py
Some additional notes for the esxlist.py example:
You may see remote errors complaining about missing certificates:
Cannot access CA certificate '/usr/local/etc/pki/CA/cacert.pem': No such file
or directory
This is expected, libvirt tries to find network and storage drivers for ESX,
but those are not implemented yet (November 2009). While searching for this
drivers, libvirt may try to start a local libvirtd instance, but fails because
of the missing certificates. It'll warn about that:
Failed to find the network: Is the daemon running?
This is also expected and can be ignored.

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#!/usr/bin/env python
# consolecallback - provide a persistent console that survives guest reboots
import sys, os, logging, libvirt, tty, termios, atexit
def reset_term():
termios.tcsetattr(0, termios.TCSADRAIN, attrs)
def error_handler(unused, error):
# The console stream errors on VM shutdown; we don't care
if (error[0] == libvirt.VIR_ERR_RPC and
error[1] == libvirt.VIR_FROM_STREAMS):
return
logging.warn(error)
class Console(object):
def __init__(self, uri, uuid):
self.uri = uri
self.uuid = uuid
self.connection = libvirt.open(uri)
self.domain = self.connection.lookupByUUIDString(uuid)
self.state = self.domain.state(0)
self.connection.domainEventRegister(lifecycle_callback, self)
self.stream = None
self.run_console = True
logging.info("%s initial state %d, reason %d",
self.uuid, self.state[0], self.state[1])
def check_console(console):
if (console.state[0] == libvirt.VIR_DOMAIN_RUNNING or
console.state[0] == libvirt.VIR_DOMAIN_PAUSED):
if console.stream is None:
console.stream = console.connection.newStream(libvirt.VIR_STREAM_NONBLOCK)
console.domain.openConsole(None, console.stream, 0)
console.stream.eventAddCallback(libvirt.VIR_STREAM_EVENT_READABLE, stream_callback, console)
else:
if console.stream:
console.stream.eventRemoveCallback()
console.stream = None
return console.run_console
def stdin_callback(watch, fd, events, console):
readbuf = os.read(fd, 1024)
if readbuf.startswith(""):
console.run_console = False
return
if console.stream:
console.stream.send(readbuf)
def stream_callback(stream, events, console):
try:
received_data = console.stream.recv(1024)
except:
return
os.write(0, received_data)
def lifecycle_callback (connection, domain, event, detail, console):
console.state = console.domain.state(0)
logging.info("%s transitioned to state %d, reason %d",
console.uuid, console.state[0], console.state[1])
# main
if len(sys.argv) != 3:
print "Usage:", sys.argv[0], "URI UUID"
print "for example:", sys.argv[0], "'qemu:///system' '32ad945f-7e78-c33a-e96d-39f25e025d81'"
sys.exit(1)
uri = sys.argv[1]
uuid = sys.argv[2]
print "Escape character is ^]"
logging.basicConfig(filename='msg.log', level=logging.DEBUG)
logging.info("URI: %s", uri)
logging.info("UUID: %s", uuid)
libvirt.virEventRegisterDefaultImpl()
libvirt.registerErrorHandler(error_handler, None)
atexit.register(reset_term)
attrs = termios.tcgetattr(0)
tty.setraw(0)
console = Console(uri, uuid)
console.stdin_watch = libvirt.virEventAddHandle(0, libvirt.VIR_EVENT_HANDLE_READABLE, stdin_callback, console)
while check_console(console):
libvirt.virEventRunDefaultImpl()

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#!/usr/bin/env python
# dominfo - print some information about a domain
import libvirt
import sys
import os
import libxml2
import pdb
def usage():
print 'Usage: %s DOMAIN' % sys.argv[0]
print ' Print information about the domain DOMAIN'
def print_section(title):
print "\n%s" % title
print "=" * 60
def print_entry(key, value):
print "%-10s %-10s" % (key, value)
def print_xml(key, ctx, path):
res = ctx.xpathEval(path)
if res is None or len(res) == 0:
value="Unknown"
else:
value = res[0].content
print_entry(key, value)
return value
if len(sys.argv) != 2:
usage()
sys.exit(2)
name = sys.argv[1]
# Connect to libvirt
conn = libvirt.openReadOnly(None)
if conn is None:
print 'Failed to open connection to the hypervisor'
sys.exit(1)
try:
dom = conn.lookupByName(name)
# Annoyiingly, libvirt prints its own error message here
except libvirt.libvirtError:
print "Domain %s is not running" % name
sys.exit(0)
info = dom.info()
print_section("Domain info")
print_entry("State:", info[0])
print_entry("MaxMem:", info[1])
print_entry("UsedMem:", info[2])
print_entry("VCPUs:", info[3])
# Read some info from the XML desc
xmldesc = dom.XMLDesc(0)
doc = libxml2.parseDoc(xmldesc)
ctx = doc.xpathNewContext()
print_section("Kernel")
print_xml("Type:", ctx, "/domain/os/type")
print_xml("Kernel:", ctx, "/domain/os/kernel")
print_xml("initrd:", ctx, "/domain/os/initrd")
print_xml("cmdline:", ctx, "/domain/os/cmdline")
print_section("Devices")
devs = ctx.xpathEval("/domain/devices/*")
for d in devs:
ctx.setContextNode(d)
#pdb.set_trace()
type = print_xml("Type:", ctx, "@type")
if type == "file":
print_xml("Source:", ctx, "source/@file")
print_xml("Target:", ctx, "target/@dev")
elif type == "block":
print_xml("Source:", ctx, "source/@dev")
print_xml("Target:", ctx, "target/@dev")
elif type == "bridge":
print_xml("Source:", ctx, "source/@bridge")
print_xml("MAC Addr:", ctx, "mac/@address")

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#!/usr/bin/env python
# domstart - make sure a given domU is running, if not start it
import libvirt
import sys
import os
import libxml2
import pdb
def usage():
print 'Usage: %s DIR' % sys.argv[0]
print ' Restore all the domains contained in DIR'
print ' It is assumed that all files in DIR are'
print ' images of domU\'s previously created with save'
if len(sys.argv) != 2:
usage()
sys.exit(2)
dir = sys.argv[1]
imgs = os.listdir(dir)
conn = libvirt.open(None)
if conn is None:
print 'Failed to open connection to the hypervisor'
sys.exit(1)
for img in imgs:
file = os.path.join(dir, img)
print "Restoring %s ... " % img,
sys.stdout.flush()
ret = conn.restore(file)
if ret == 0:
print "done"
else:
print "error %d" % ret

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#!/usr/bin/env python
# domstart - make sure a given domU is running, if not start it
import libvirt
import sys
import os
import libxml2
import pdb
def usage():
print 'Usage: %s DIR' % sys.argv[0]
print ' Save all currently running domU\'s into DIR'
print ' DIR must exist and be writable by this process'
if len(sys.argv) != 2:
usage()
sys.exit(2)
dir = sys.argv[1]
conn = libvirt.open(None)
if conn is None:
print 'Failed to open connection to the hypervisor'
sys.exit(1)
doms = conn.listDomainsID()
for id in doms:
if id == 0:
continue
dom = conn.lookupByID(id)
print "Saving %s[%d] ... " % (dom.name(), id),
sys.stdout.flush()
path = os.path.join(dir, dom.name())
ret = dom.save(path)
if ret == 0:
print "done"
else:
print "error %d" % ret
#pdb.set_trace()

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#!/usr/bin/env python
# domstart - make sure a given domU is running, if not start it
import libvirt
import sys
import os
import libxml2
import pdb
# Parse the XML description of domU from FNAME
# and return a tuple (name, xmldesc) where NAME
# is the name of the domain, and xmldesc is the contetn of FNAME
def read_domain(fname):
fp = open(fname, "r")
xmldesc = fp.read()
fp.close()
doc = libxml2.parseDoc(xmldesc)
name = doc.xpathNewContext().xpathEval("/domain/name")[0].content
return (name, xmldesc)
def usage():
print 'Usage: %s domain.xml' % sys.argv[0]
print ' Check that the domain described by DOMAIN.XML is running'
print ' If the domain is not running, create it'
print ' DOMAIN.XML must be a XML description of the domain'
print ' in libvirt\'s XML format'
if len(sys.argv) != 2:
usage()
sys.exit(2)
(name, xmldesc) = read_domain(sys.argv[1])
conn = libvirt.open(None)
if conn is None:
print 'Failed to open connection to the hypervisor'
sys.exit(1)
try:
dom = conn.lookupByName(name)
except libvirt.libvirtError:
print "Starting domain %s ... " % name,
sys.stdout.flush()
dom = conn.createLinux(xmldesc, 0)
if dom is None:
print "failed"
sys.exit(1)
else:
print "done"

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#!/usr/bin/env python
# esxlist - list active domains of an ESX host and print some info.
# also demonstrates how to use the libvirt.openAuth() method
import libvirt
import sys
import os
import libxml2
import getpass
def usage():
print "Usage: %s HOSTNAME" % sys.argv[0]
print " List active domains of HOSTNAME and print some info"
# This is the callback method passed to libvirt.openAuth() (see below).
#
# The credentials argument is a list of credentials that libvirt (actually
# the ESX driver) would like to request. An element of this list is itself a
# list containing 5 items (4 inputs, 1 output):
# - the credential type, e.g. libvirt.VIR_CRED_AUTHNAME
# - a prompt to be displayed to the user
# - a challenge, the ESX driver sets this to the hostname to allow automatic
# distinction between requests for ESX and vCenter credentials
# - a default result for the request
# - a place to store the actual result for the request
#
# The user_data argument is the user data item of the auth argument (see below)
# passed to libvirt.openAuth().
def request_credentials(credentials, user_data):
for credential in credentials:
if credential[0] == libvirt.VIR_CRED_AUTHNAME:
# prompt the user to input a authname. display the provided message
credential[4] = raw_input(credential[1] + ": ")
# if the user just hits enter raw_input() returns an empty string.
# in this case return the default result through the last item of
# the list
if len(credential[4]) == 0:
credential[4] = credential[3]
elif credential[0] == libvirt.VIR_CRED_NOECHOPROMPT:
# use the getpass module to prompt the user to input a password.
# display the provided message and return the result through the
# last item of the list
credential[4] = getpass.getpass(credential[1] + ": ")
else:
return -1
return 0
def print_section(title):
print "\n%s" % title
print "=" * 60
def print_entry(key, value):
print "%-10s %-10s" % (key, value)
def print_xml(key, ctx, path):
res = ctx.xpathEval(path)
if res is None or len(res) == 0:
value = "Unknown"
else:
value = res[0].content
print_entry(key, value)
return value
if len(sys.argv) != 2:
usage()
sys.exit(2)
hostname = sys.argv[1]
# Connect to libvirt
uri = "esx://%s/?no_verify=1" % hostname
# The auth argument is a list that contains 3 items:
# - a list of supported credential types
# - a callable that takes 2 arguments
# - user data that will be passed to the callable as second argument
#
# In this example the supported credential types are VIR_CRED_AUTHNAME and
# VIR_CRED_NOECHOPROMPT, the callable is the unbound method request_credentials
# (see above) and the user data is None.
#
# libvirt (actually the ESX driver) will call the callable to request
# credentials in order to log into the ESX host. The callable would also be
# called if the connection URI would reference a vCenter to request credentials
# in order to log into the vCenter
auth = [[libvirt.VIR_CRED_AUTHNAME, libvirt.VIR_CRED_NOECHOPROMPT],
request_credentials, None]
conn = libvirt.openAuth(uri, auth, 0)
if conn is None:
print "Failed to open connection to %s" % hostname
sys.exit(1)
state_names = { libvirt.VIR_DOMAIN_RUNNING : "running",
libvirt.VIR_DOMAIN_BLOCKED : "idle",
libvirt.VIR_DOMAIN_PAUSED : "paused",
libvirt.VIR_DOMAIN_SHUTDOWN : "in shutdown",
libvirt.VIR_DOMAIN_SHUTOFF : "shut off",
libvirt.VIR_DOMAIN_CRASHED : "crashed",
libvirt.VIR_DOMAIN_NOSTATE : "no state" }
for id in conn.listDomainsID():
domain = conn.lookupByID(id)
info = domain.info()
print_section("Domain " + domain.name())
print_entry("ID:", id)
print_entry("UUID:", domain.UUIDString())
print_entry("State:", state_names[info[0]])
print_entry("MaxMem:", info[1])
print_entry("UsedMem:", info[2])
print_entry("VCPUs:", info[3])
# Read some info from the XML desc
print_section("Devices of " + domain.name())
xmldesc = domain.XMLDesc(0)
doc = libxml2.parseDoc(xmldesc)
ctx = doc.xpathNewContext()
devs = ctx.xpathEval("/domain/devices/*")
first = True
for d in devs:
ctx.setContextNode(d)
if not first:
print "------------------------------------------------------------"
else:
first = False
print_entry("Device", d.name)
type = print_xml("Type:", ctx, "@type")
if type == "file":
print_xml("Source:", ctx, "source/@file")
print_xml("Target:", ctx, "target/@dev")
elif type == "block":
print_xml("Source:", ctx, "source/@dev")
print_xml("Target:", ctx, "target/@dev")
elif type == "bridge":
print_xml("Source:", ctx, "source/@bridge")
print_xml("MAC Addr:", ctx, "mac/@address")

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#!/usr/bin/python -u
#
#
#
#################################################################################
# Start off by implementing a general purpose event loop for anyones use
#################################################################################
import sys
import getopt
import os
import libvirt
import select
import errno
import time
import threading
# For the sake of demonstration, this example program includes
# an implementation of a pure python event loop. Most applications
# would be better off just using the default libvirt event loop
# APIs, instead of implementing this in python. The exception is
# where an application wants to integrate with an existing 3rd
# party event loop impl
#
# Change this to 'False' to make the demo use the native
# libvirt event loop impl
use_pure_python_event_loop = True
do_debug = False
def debug(msg):
global do_debug
if do_debug:
print msg
#
# This general purpose event loop will support waiting for file handle
# I/O and errors events, as well as scheduling repeatable timers with
# a fixed interval.
#
# It is a pure python implementation based around the poll() API
#
class virEventLoopPure:
# This class contains the data we need to track for a
# single file handle
class virEventLoopPureHandle:
def __init__(self, handle, fd, events, cb, opaque):
self.handle = handle
self.fd = fd
self.events = events
self.cb = cb
self.opaque = opaque
def get_id(self):
return self.handle
def get_fd(self):
return self.fd
def get_events(self):
return self.events
def set_events(self, events):
self.events = events
def dispatch(self, events):
self.cb(self.handle,
self.fd,
events,
self.opaque)
# This class contains the data we need to track for a
# single periodic timer
class virEventLoopPureTimer:
def __init__(self, timer, interval, cb, opaque):
self.timer = timer
self.interval = interval
self.cb = cb
self.opaque = opaque
self.lastfired = 0
def get_id(self):
return self.timer
def get_interval(self):
return self.interval
def set_interval(self, interval):
self.interval = interval
def get_last_fired(self):
return self.lastfired
def set_last_fired(self, now):
self.lastfired = now
def dispatch(self):
self.cb(self.timer,
self.opaque)
def __init__(self):
self.poll = select.poll()
self.pipetrick = os.pipe()
self.pendingWakeup = False
self.runningPoll = False
self.nextHandleID = 1
self.nextTimerID = 1
self.handles = []
self.timers = []
self.quit = False
# The event loop can be used from multiple threads at once.
# Specifically while the main thread is sleeping in poll()
# waiting for events to occur, another thread may come along
# and add/update/remove a file handle, or timer. When this
# happens we need to interrupt the poll() sleep in the other
# thread, so that it'll see the file handle / timer changes.
#
# Using OS level signals for this is very unreliable and
# hard to implement correctly. Thus we use the real classic
# "self pipe" trick. A anonymous pipe, with one end registered
# with the event loop for input events. When we need to force
# the main thread out of a poll() sleep, we simple write a
# single byte of data to the other end of the pipe.
debug("Self pipe watch %d write %d" %(self.pipetrick[0], self.pipetrick[1]))
self.poll.register(self.pipetrick[0], select.POLLIN)
# Calculate when the next timeout is due to occur, returning
# the absolute timestamp for the next timeout, or 0 if there is
# no timeout due
def next_timeout(self):
next = 0
for t in self.timers:
last = t.get_last_fired()
interval = t.get_interval()
if interval < 0:
continue
if next == 0 or (last + interval) < next:
next = last + interval
return next
# Lookup a virEventLoopPureHandle object based on file descriptor
def get_handle_by_fd(self, fd):
for h in self.handles:
if h.get_fd() == fd:
return h
return None
# Lookup a virEventLoopPureHandle object based on its event loop ID
def get_handle_by_id(self, handleID):
for h in self.handles:
if h.get_id() == handleID:
return h
return None
# This is the heart of the event loop, performing one single
# iteration. It asks when the next timeout is due, and then
# calcuates the maximum amount of time it is able to sleep
# for in poll() pending file handle events.
#
# It then goes into the poll() sleep.
#
# When poll() returns, there will zero or more file handle
# events which need to be dispatched to registered callbacks
# It may also be time to fire some periodic timers.
#
# Due to the coarse granularity of schedular timeslices, if
# we ask for a sleep of 500ms in order to satisfy a timer, we
# may return up to 1 schedular timeslice early. So even though
# our sleep timeout was reached, the registered timer may not
# technically be at its expiry point. This leads to us going
# back around the loop with a crazy 5ms sleep. So when checking
# if timeouts are due, we allow a margin of 20ms, to avoid
# these pointless repeated tiny sleeps.
def run_once(self):
sleep = -1
self.runningPoll = True
try:
next = self.next_timeout()
debug("Next timeout due at %d" % next)
if next > 0:
now = int(time.time() * 1000)
if now >= next:
sleep = 0
else:
sleep = (next - now) / 1000.0
debug("Poll with a sleep of %d" % sleep)
events = self.poll.poll(sleep)
# Dispatch any file handle events that occurred
for (fd, revents) in events:
# See if the events was from the self-pipe
# telling us to wakup. if so, then discard
# the data just continue
if fd == self.pipetrick[0]:
self.pendingWakeup = False
data = os.read(fd, 1)
continue
h = self.get_handle_by_fd(fd)
if h:
debug("Dispatch fd %d handle %d events %d" % (fd, h.get_id(), revents))
h.dispatch(self.events_from_poll(revents))
now = int(time.time() * 1000)
for t in self.timers:
interval = t.get_interval()
if interval < 0:
continue
want = t.get_last_fired() + interval
# Deduct 20ms, since scheduler timeslice
# means we could be ever so slightly early
if now >= (want-20):
debug("Dispatch timer %d now %s want %s" % (t.get_id(), str(now), str(want)))
t.set_last_fired(now)
t.dispatch()
except (os.error, select.error), e:
if e.args[0] != errno.EINTR:
raise
finally:
self.runningPoll = False
# Actually the event loop forever
def run_loop(self):
self.quit = False
while not self.quit:
self.run_once()
def interrupt(self):
if self.runningPoll and not self.pendingWakeup:
self.pendingWakeup = True
os.write(self.pipetrick[1], 'c')
# Registers a new file handle 'fd', monitoring for 'events' (libvirt
# event constants), firing the callback cb() when an event occurs.
# Returns a unique integer identier for this handle, that should be
# used to later update/remove it
def add_handle(self, fd, events, cb, opaque):
handleID = self.nextHandleID + 1
self.nextHandleID = self.nextHandleID + 1
h = self.virEventLoopPureHandle(handleID, fd, events, cb, opaque)
self.handles.append(h)
self.poll.register(fd, self.events_to_poll(events))
self.interrupt()
debug("Add handle %d fd %d events %d" % (handleID, fd, events))
return handleID
# Registers a new timer with periodic expiry at 'interval' ms,
# firing cb() each time the timer expires. If 'interval' is -1,
# then the timer is registered, but not enabled
# Returns a unique integer identier for this handle, that should be
# used to later update/remove it
def add_timer(self, interval, cb, opaque):
timerID = self.nextTimerID + 1
self.nextTimerID = self.nextTimerID + 1
h = self.virEventLoopPureTimer(timerID, interval, cb, opaque)
self.timers.append(h)
self.interrupt()
debug("Add timer %d interval %d" % (timerID, interval))
return timerID
# Change the set of events to be monitored on the file handle
def update_handle(self, handleID, events):
h = self.get_handle_by_id(handleID)
if h:
h.set_events(events)
self.poll.unregister(h.get_fd())
self.poll.register(h.get_fd(), self.events_to_poll(events))
self.interrupt()
debug("Update handle %d fd %d events %d" % (handleID, h.get_fd(), events))
# Change the periodic frequency of the timer
def update_timer(self, timerID, interval):
for h in self.timers:
if h.get_id() == timerID:
h.set_interval(interval)
self.interrupt()
debug("Update timer %d interval %d" % (timerID, interval))
break
# Stop monitoring for events on the file handle
def remove_handle(self, handleID):
handles = []
for h in self.handles:
if h.get_id() == handleID:
self.poll.unregister(h.get_fd())
debug("Remove handle %d fd %d" % (handleID, h.get_fd()))
else:
handles.append(h)
self.handles = handles
self.interrupt()
# Stop firing the periodic timer
def remove_timer(self, timerID):
timers = []
for h in self.timers:
if h.get_id() != timerID:
timers.append(h)
debug("Remove timer %d" % timerID)
self.timers = timers
self.interrupt()
# Convert from libvirt event constants, to poll() events constants
def events_to_poll(self, events):
ret = 0
if events & libvirt.VIR_EVENT_HANDLE_READABLE:
ret |= select.POLLIN
if events & libvirt.VIR_EVENT_HANDLE_WRITABLE:
ret |= select.POLLOUT
if events & libvirt.VIR_EVENT_HANDLE_ERROR:
ret |= select.POLLERR
if events & libvirt.VIR_EVENT_HANDLE_HANGUP:
ret |= select.POLLHUP
return ret
# Convert from poll() event constants, to libvirt events constants
def events_from_poll(self, events):
ret = 0
if events & select.POLLIN:
ret |= libvirt.VIR_EVENT_HANDLE_READABLE
if events & select.POLLOUT:
ret |= libvirt.VIR_EVENT_HANDLE_WRITABLE
if events & select.POLLNVAL:
ret |= libvirt.VIR_EVENT_HANDLE_ERROR
if events & select.POLLERR:
ret |= libvirt.VIR_EVENT_HANDLE_ERROR
if events & select.POLLHUP:
ret |= libvirt.VIR_EVENT_HANDLE_HANGUP
return ret
###########################################################################
# Now glue an instance of the general event loop into libvirt's event loop
###########################################################################
# This single global instance of the event loop wil be used for
# monitoring libvirt events
eventLoop = virEventLoopPure()
# This keeps track of what thread is running the event loop,
# (if it is run in a background thread)
eventLoopThread = None
# These next set of 6 methods are the glue between the official
# libvirt events API, and our particular impl of the event loop
#
# There is no reason why the 'virEventLoopPure' has to be used.
# An application could easily may these 6 glue methods hook into
# another event loop such as GLib's, or something like the python
# Twisted event framework.
def virEventAddHandleImpl(fd, events, cb, opaque):
global eventLoop
return eventLoop.add_handle(fd, events, cb, opaque)
def virEventUpdateHandleImpl(handleID, events):
global eventLoop
return eventLoop.update_handle(handleID, events)
def virEventRemoveHandleImpl(handleID):
global eventLoop
return eventLoop.remove_handle(handleID)
def virEventAddTimerImpl(interval, cb, opaque):
global eventLoop
return eventLoop.add_timer(interval, cb, opaque)
def virEventUpdateTimerImpl(timerID, interval):
global eventLoop
return eventLoop.update_timer(timerID, interval)
def virEventRemoveTimerImpl(timerID):
global eventLoop
return eventLoop.remove_timer(timerID)
# This tells libvirt what event loop implementation it
# should use
def virEventLoopPureRegister():
libvirt.virEventRegisterImpl(virEventAddHandleImpl,
virEventUpdateHandleImpl,
virEventRemoveHandleImpl,
virEventAddTimerImpl,
virEventUpdateTimerImpl,
virEventRemoveTimerImpl)
# Directly run the event loop in the current thread
def virEventLoopPureRun():
global eventLoop
eventLoop.run_loop()
def virEventLoopNativeRun():
while True:
libvirt.virEventRunDefaultImpl()
# Spawn a background thread to run the event loop
def virEventLoopPureStart():
global eventLoopThread
virEventLoopPureRegister()
eventLoopThread = threading.Thread(target=virEventLoopPureRun, name="libvirtEventLoop")
eventLoopThread.setDaemon(True)
eventLoopThread.start()
def virEventLoopNativeStart():
global eventLoopThread
libvirt.virEventRegisterDefaultImpl()
eventLoopThread = threading.Thread(target=virEventLoopNativeRun, name="libvirtEventLoop")
eventLoopThread.setDaemon(True)
eventLoopThread.start()
##########################################################################
# Everything that now follows is a simple demo of domain lifecycle events
##########################################################################
def eventToString(event):
eventStrings = ( "Defined",
"Undefined",
"Started",
"Suspended",
"Resumed",
"Stopped",
"Shutdown",
"PMSuspended",
"Crashed" )
return eventStrings[event]
def detailToString(event, detail):
eventStrings = (
( "Added", "Updated" ),
( "Removed", ),
( "Booted", "Migrated", "Restored", "Snapshot", "Wakeup" ),
( "Paused", "Migrated", "IOError", "Watchdog", "Restored", "Snapshot", "API error" ),
( "Unpaused", "Migrated", "Snapshot" ),
( "Shutdown", "Destroyed", "Crashed", "Migrated", "Saved", "Failed", "Snapshot"),
( "Finished", ),
( "Memory", "Disk" ),
( "Panicked", )
)
return eventStrings[event][detail]
def myDomainEventCallback1 (conn, dom, event, detail, opaque):
print "myDomainEventCallback1 EVENT: Domain %s(%s) %s %s" % (dom.name(), dom.ID(),
eventToString(event),
detailToString(event, detail))
def myDomainEventCallback2 (conn, dom, event, detail, opaque):
print "myDomainEventCallback2 EVENT: Domain %s(%s) %s %s" % (dom.name(), dom.ID(),
eventToString(event),
detailToString(event, detail))
def myDomainEventRebootCallback(conn, dom, opaque):
print "myDomainEventRebootCallback: Domain %s(%s)" % (dom.name(), dom.ID())
def myDomainEventRTCChangeCallback(conn, dom, utcoffset, opaque):
print "myDomainEventRTCChangeCallback: Domain %s(%s) %d" % (dom.name(), dom.ID(), utcoffset)
def myDomainEventWatchdogCallback(conn, dom, action, opaque):
print "myDomainEventWatchdogCallback: Domain %s(%s) %d" % (dom.name(), dom.ID(), action)
def myDomainEventIOErrorCallback(conn, dom, srcpath, devalias, action, opaque):
print "myDomainEventIOErrorCallback: Domain %s(%s) %s %s %d" % (dom.name(), dom.ID(), srcpath, devalias, action)
def myDomainEventGraphicsCallback(conn, dom, phase, localAddr, remoteAddr, authScheme, subject, opaque):
print "myDomainEventGraphicsCallback: Domain %s(%s) %d %s" % (dom.name(), dom.ID(), phase, authScheme)
def myDomainEventDiskChangeCallback(conn, dom, oldSrcPath, newSrcPath, devAlias, reason, opaque):
print "myDomainEventDiskChangeCallback: Domain %s(%s) disk change oldSrcPath: %s newSrcPath: %s devAlias: %s reason: %s" % (
dom.name(), dom.ID(), oldSrcPath, newSrcPath, devAlias, reason)
def myDomainEventTrayChangeCallback(conn, dom, devAlias, reason, opaque):
print "myDomainEventTrayChangeCallback: Domain %s(%s) tray change devAlias: %s reason: %s" % (
dom.name(), dom.ID(), devAlias, reason)
def myDomainEventPMWakeupCallback(conn, dom, reason, opaque):
print "myDomainEventPMWakeupCallback: Domain %s(%s) system pmwakeup" % (
dom.name(), dom.ID())
def myDomainEventPMSuspendCallback(conn, dom, reason, opaque):
print "myDomainEventPMSuspendCallback: Domain %s(%s) system pmsuspend" % (
dom.name(), dom.ID())
def myDomainEventBalloonChangeCallback(conn, dom, actual, opaque):
print "myDomainEventBalloonChangeCallback: Domain %s(%s) %d" % (dom.name(), dom.ID(), actual)
def myDomainEventPMSuspendDiskCallback(conn, dom, reason, opaque):
print "myDomainEventPMSuspendDiskCallback: Domain %s(%s) system pmsuspend_disk" % (
dom.name(), dom.ID())
def myDomainEventDeviceRemovedCallback(conn, dom, dev, opaque):
print "myDomainEventDeviceRemovedCallback: Domain %s(%s) device removed: %s" % (
dom.name(), dom.ID(), dev)
run = True
def myConnectionCloseCallback(conn, reason, opaque):
reasonStrings = (
"Error", "End-of-file", "Keepalive", "Client",
)
print "myConnectionCloseCallback: %s: %s" % (conn.getURI(), reasonStrings[reason])
run = False
def usage(out=sys.stderr):
print >>out, "usage: "+os.path.basename(sys.argv[0])+" [-hdl] [uri]"
print >>out, " uri will default to qemu:///system"
print >>out, " --help, -h Print this help message"
print >>out, " --debug, -d Print debug output"
print >>out, " --loop, -l Toggle event-loop-implementation"
def main():
try:
opts, args = getopt.getopt(sys.argv[1:], "hdl", ["help", "debug", "loop"])
except getopt.GetoptError, err:
# print help information and exit:
print str(err) # will print something like "option -a not recognized"
usage()
sys.exit(2)
for o, a in opts:
if o in ("-h", "--help"):
usage(sys.stdout)
sys.exit()
if o in ("-d", "--debug"):
global do_debug
do_debug = True
if o in ("-l", "--loop"):
global use_pure_python_event_loop
use_pure_python_event_loop ^= True
if len(args) >= 1:
uri = args[0]
else:
uri = "qemu:///system"
print "Using uri:" + uri
# Run a background thread with the event loop
if use_pure_python_event_loop:
virEventLoopPureStart()
else:
virEventLoopNativeStart()
vc = libvirt.openReadOnly(uri)
# Close connection on exit (to test cleanup paths)
old_exitfunc = getattr(sys, 'exitfunc', None)
def exit():
print "Closing " + str(vc)
vc.close()
if (old_exitfunc): old_exitfunc()
sys.exitfunc = exit
vc.registerCloseCallback(myConnectionCloseCallback, None)
#Add 2 callbacks to prove this works with more than just one
vc.domainEventRegister(myDomainEventCallback1,None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_LIFECYCLE, myDomainEventCallback2, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_REBOOT, myDomainEventRebootCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_RTC_CHANGE, myDomainEventRTCChangeCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_IO_ERROR, myDomainEventIOErrorCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_WATCHDOG, myDomainEventWatchdogCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_GRAPHICS, myDomainEventGraphicsCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_DISK_CHANGE, myDomainEventDiskChangeCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_TRAY_CHANGE, myDomainEventTrayChangeCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_PMWAKEUP, myDomainEventPMWakeupCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_PMSUSPEND, myDomainEventPMSuspendCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_BALLOON_CHANGE, myDomainEventBalloonChangeCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_PMSUSPEND_DISK, myDomainEventPMSuspendDiskCallback, None)
vc.domainEventRegisterAny(None, libvirt.VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED, myDomainEventDeviceRemovedCallback, None)
vc.setKeepAlive(5, 3)
# The rest of your app would go here normally, but for sake
# of demo we'll just go to sleep. The other option is to
# run the event loop in your main thread if your app is
# totally event based.
while run:
time.sleep(1)
if __name__ == "__main__":
main()

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examples/topology.py Executable file
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#!/usr/bin/env python
# Parse topology information from the capabilities XML and use
# them to calculate host topology
#
# Authors:
# Amador Pahim <apahim@redhat.com>
# Peter Krempa <pkrempa@redhat.com>
import libvirt
import sys
from xml.dom import minidom
try:
conn = libvirt.openReadOnly(None)
except libvirt.libvirtError:
print 'Failed to connect to the hypervisor'
sys.exit(1)
try:
capsXML = conn.getCapabilities()
except libvirt.libvirtError:
print 'Failed to request capabilities'
sys.exit(1)
caps = minidom.parseString(capsXML)
host = caps.getElementsByTagName('host')[0]
cells = host.getElementsByTagName('cells')[0]
total_cpus = cells.getElementsByTagName('cpu').length
socketIds = []
siblingsIds = []
socketIds = [ proc.getAttribute('socket_id')
for proc in cells.getElementsByTagName('cpu')
if proc.getAttribute('socket_id') not in socketIds ]
siblingsIds = [ proc.getAttribute('siblings')
for proc in cells.getElementsByTagName('cpu')
if proc.getAttribute('siblings') not in siblingsIds ]
print "Host topology"
print "NUMA nodes:", cells.getAttribute('num')
print " Sockets:", len(set(socketIds))
print " Cores:", len(set(siblingsIds))
print " Threads:", total_cpus