virt-tool.py

#! /usr/bin/python
#
# * install libvirt network and domain (guest) from xml file
# * uninstall libvirt network and domain (guest) by name
#
# Copyright (C) 2009 Satoru SATOH <satoru.satoh at gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#

import libxml2
import libvirt
import logging
import optparse
import os
import re
import shutil
import subprocess
import sys
import tempfile


VMM_URI = 'qemu:///system'
VMM_IMAGES_DIR = '/var/lib/libvirt/images'

(_NOT_DEFINED, _DEFINED, _ACTIVE) = (0, 1, 2)
(CMD_INSTALL, CMD_UNINSTALL) = (0, 1)
(_TYPE_UNKNOWN, _TYPE_DOMAIN, _TYPE_NETWORK) = (-1, 0, 1)


class ParseError(Exception): pass
class ActiveTargetError(Exception): pass
class DefinedTargetError(Exception): pass



def __xml_type(xml):
    """@throw IOError, libxml2.parserError, etc.
    """
    return libxml2.parseFile(xml).children.name  # root element's name; domain, network


def __name_by_xml(xml):
    """Get domain or network name from given xml file.

    @throw IOError, libxml2.parserError, etc.
    """
    xpath = '/%s/name' % __xml_type(xml)
    try:
        return libxml2.parseFile(xml).xpathEval(xpath)[0].content
    except IndexError:
        raise ParseError("Xpath expression '%s' does not match" % xpath)


def __network_name_by_xml(network_xml):
    """Extract network name from given network xml file.

    @see http://libvirt.org/formatnetwork.html
    """
    try:
        name = libxml2.parseFile(network_xml).xpathEval('/network/name')[0].content
    except IOError:
        logging.error("Could not open '%s'" % network_xml)
        sys.exit(1)
    except IndexError:
        logging.error("Parse failed: '%s'" % network_xml)
        sys.exit(1)

    logging.debug("Network Name = '%s'" % name)
    return name


def __domain_name_by_xml(domain_xml):
    """Extract domain (guest) name from given domain xml file.

    @see http://libvirt.org/formatdomain.html
    """
    name = ''
    try:
        name = libxml2.parseFile(domain_xml).xpathEval('/domain/name')[0].content
    except IOError:
        logging.error("Could not open '%s'" % network_xml)
        sys.exit(1)
    except IndexError:
        logging.error("Parse failed: '%s'" % network_xml)
        sys.exit(1)

    logging.debug("Domain Name = '%s'" % name)
    return name


def __network_status(conn, network_name):
    """Query the status of the network.
    """
    if network_name in conn.listNetworks():
        logging.debug("The network '%s' is active." % network_name)
        ret = _ACTIVE
    elif network_name in conn.listDefinedNetworks():
        logging.debug("The network '%s' is defined but inactive." % network_name)
        ret = _DEFINED
    else:
        logging.debug("The network '%s' is not defined." % network_name)
        ret = _NOT_DEFINED

    return ret


def __domain_status(conn, name):
    """Query the status of the domain.
    """
    try:
        if conn.lookupByName(name).name() == name:
            logging.debug("The domain '%s' is active." % name)
            return _ACTIVE

    except libvirt.libvirtError:  # It indicates the domain is not found.
        pass
    
    if name in conn.listDefinedDomains():
        logging.debug("The domain '%s' is defined but inactive." % name)
        ret = _DEFINED
    else:
        logging.debug("The domain '%s' is not defined." % name)
        ret = _NOT_DEFINED

    return ret


def __copy_image(path, newpath):
    assert os.path.realpath(path) != os.path.realpath(newpath), \
        "src = '%s', dst = '%s'" % (path, newpath)

    logging.info("Copying %s to %s" % (path, newpath))
    shutil.copy2(path, newpath)


def __base_image_path(image):
    """Get the path of base (backing) file for given image (path).

    NOTE: $image should be QCow2 file, I guess.
    """
    pipe = subprocess.Popen(['qemu-img', 'info', image], stdout=subprocess.PIPE)
    (output, errors) = pipe.communicate()

    # ex. backing file: test-base.qcow2 (actual path: /.../test-base.qcow2)
    try:
        return re.match(r'^backing file: \S+ \(actual path: ([^\)]+)\)',
            output.splitlines()[-1]).groups()[0]
    except:
        return ''


def __uninstall(uri, name, force, backup, type=_TYPE_NETWORK):
    """Uninstall the given target; domain or network.
    """
    conn = libvirt.open(uri)

    if type == _TYPE_NETWORK:
        stat_check_f = __network_status
        find_by_name_f = conn.networkLookupByName
    else:
        stat_check_f = __domain_status
        find_by_name_f = conn.lookupByName

    stat = stat_check_f(conn, name)

    if stat == _NOT_DEFINED:
        logging.warn("Target '%s' is not defined. Nothing to do..." % name)
        return False

    target = find_by_name_f(name)

    if backup is not None:
        out = open(backup, 'w')
        print >> out, target.XMLDesc(0)

    if stat == _ACTIVE:
        if force:
            logging.debug("Try destroying and uninstalling '%s'..." % name)
            target.destroy()  # FIXME: It should take some time to finish.
            target.undefine()
            logging.debug("... Done")
        else:
            raise ActiveTargetError("Target '%s' is active." % name)

    elif stat == _DEFINED:
        logging.debug("Try uninstalling '%s'..." % name)
        target.undefine()
        logging.debug("... Done")

    stat = stat_check_f(conn, name)
    conn.close()

    return stat == _NOT_DEFINED


def __install(uri, xml, force, autostart, type=_TYPE_NETWORK):
    """Install the target (domain or network) defined in given XML file.
    """
    name = __name_by_xml(xml)
    conn = libvirt.open(uri)

    if type == _TYPE_NETWORK:
        stat_check_f = __network_status
        uninstall_f = uninstall_network
        define_f = conn.networkDefineXML

        # It will be called after connection object is deleted once and
        # recreated so that new connection object must be passed.
        find_by_name_f = lambda conn, name: conn.networkLookupByName(name)
    else:
        stat_check_f = __domain_status
        uninstall_f = uninstall_domain
        define_f = conn.defineXML

        # Likewise
        find_by_name_f = lambda conn, name: conn.lookupByName(name)

    if force:
        uninstall_f(uri, name, force)

    content = open(xml).read()
    define_f(content)

    # FIXME: Reopen connection. It seems that to re-connect is needed to apply
    # the changes above.
    conn.close()
    conn = libvirt.open(uri)

    target = find_by_name_f(conn, name)

    if autostart:
        logging.debug("Making the target '%s' to be autostarted later." % name)
        target.setAutostart(True)

    logging.debug("Starts the target '%s' just created." % name)
    target.create()

    stat = stat_check_f(conn, name)
    conn.close()

    return stat == _ACTIVE


def __install_2(uri, xml, force, autostart):
    """It does basically samething as above although it will detect the target
    type contrary to the avove.
    """
    type = __xml_type(xml)
    name = __name_by_xml(xml)
    conn = libvirt.open(uri)

    if type == 'network':
        stat_check_f = __network_status
        uninstall_f = uninstall_network
        define_f = conn.networkDefineXML

        # It will be called after connection object is deleted once and
        # recreated so that new connection object must be passed.
        find_by_name_f = lambda conn, name: conn.networkLookupByName(name)

    elif type == 'domain':
        stat_check_f = __domain_status
        uninstall_f = uninstall_domain
        define_f = conn.defineXML

        # Likewise
        find_by_name_f = lambda conn, name: conn.lookupByName(name)

    else:
        raise RuntimeError("XML type '%s' is unknown. Aborting..." % type)

    if force:
        uninstall_f(uri, name, force)

    content = open(xml).read()
    define_f(content)

    # FIXME: Reopen connection. It seems that to re-connect is needed to apply
    # the changes above.
    conn.close()
    conn = libvirt.open(uri)

    target = find_by_name_f(conn, name)

    if autostart:
        logging.debug("Making the target '%s' to be autostarted later." % name)
        target.setAutostart(True)

    logging.debug("Starts the target '%s' just created." % name)
    target.create()

    stat = stat_check_f(conn, name)
    conn.close()

    return stat == _ACTIVE


# actions:
def confirm(action):
    ans = raw_input('Do you really want to %s [yes/No] >' % action)
    if ans.lower() == 'yes':
        return

    logging.info("Aborting...")
    sys.exit(0)


def do_network_check(uri, name, **kwargs):
    """Check the status of the given network.
    """
    conn = libvirt.openReadOnly(uri)
    stat = __network_status(conn, name)
    conn.close()

    return stat


def install_images(xml, search_path=None):
    """Search images defined in $xml from $search_path and install these into
    the appropriate locations.

    $search_path will be set to dirname($xml) if $search_path is not given.
    """
    image_paths = [x.content for x in \
        libxml2.parseFile(xml).xpathEval(
            '/domain/devices/disk[@type="file" and @device="disk"]/source/@file'
        )
        if x and getattr(x, 'content', False)
    ]

    # Search images in the dir
    #  a. where $xml exists if search_path is None 
    #  b. search_path if search_path is NOT None
    if search_path is None:
        search_path = os.path.dirname(xml)

    copy_pairs = [
        (os.path.join(search_path, os.path.basename(p)), p) \
            for p in image_paths
    ]

    # Search base images also (only for QCow2?)
    # FIXME: Current implementation expects image and corresponding base image
    # are in same dir.
    for (src, dst) in copy_pairs:
        base_image_src = __base_image_path(src)

        if base_image_src:
            base_image_dst = os.path.join(
                os.path.dirname(dst), os.path.basename(base_image_src)
            )

            copy_pairs.append((base_image_src, base_image_dst))

    #pprint.pprint(copy_pairs)
    #sys.exit(0)

    for src, dst in copy_pairs:
        __copy_image(src, dst)


def relocate_images(xml, newxml, destdir=VMM_IMAGES_DIR):
    doc = libxml2.parseFile(xml)
    images = doc.xpathEval('/domain/devices/disk[@type="file" and @device="disk"]/source')
    fileattr = 'file'

    for image_elem in images:
        filepath = image_elem.prop(fileattr)
        filename = os.path(filename)
        newpath = os.path.join(destdir, filename)

        logging.debug("Try copying image...: %s -> %s" % (filepath, newpath))
        __copy_image(filepath, newpath)

        logging.debug("Rewrite image's path in the domain configuration")
        image_elem.setProp(fileattr, newpath)

    logging.info("Wrote new domain configuration: %s" % newxml)
    out = open(newxml, 'w')
    out.write(doc.serialize())
    out.close()

    del doc


def uninstall_domain(uri, name, force, backup=None):
    """Uninstall the given domain (guest).
    """
    return __uninstall(uri, name, force, backup, _TYPE_DOMAIN)


def uninstall_network(uri, name, force, backup=None):
    """Uninstall the given network.
    """
    return __uninstall(uri, name, force, backup, _TYPE_NETWORK)


def install_domain(uri, xml, force=False, autostart=True, search_path=None):
    """Install the domain defined in given XML file.

        * Domain images are copied into path
        * Image path in definitions 
    """
    install_images(xml, search_path)
    return __install(uri, xml, force, autostart, _TYPE_DOMAIN)


def install_network(uri, xml, force=False, autostart=True):
    """Install the network defined in given XML file.
    """
    return __install(uri, xml, force, autostart, _TYPE_NETWORK)


def option_parser(parser=None):
    if parser is None:
        parser = optparse.OptionParser('%prog COMMAND [OPTION ...] [ARGS...]')

    parser.add_option('--uri', dest='uri', action="store",
        type="string", help='Connection URI', default=VMM_URI)
    parser.add_option('-v', '--verbose', dest='verbose', action="store_true",
        default=False, help='verbose mode')
    parser.add_option('-q', '--quiet', dest='quiet', action="store_true",
        default=False, help='quiet mode')

    return parser


def usage(prog=sys.argv[0]):
    print >> sys.stderr, "Usage: %s COMMAND [OPTION ...] ARGS..." % prog


def help_extras():
    print >> sys.stderr, """
Command:
  net-install, net-uninstall    install / uninstall network.
  dom-install, dom-uninstall    install / uninstall domain (guest).
"""


def dom_uninstall_option_parser():
    parser = optparse.OptionParser('%prog [OPTION ...] dom-uninstall DOMAIN_NAME')
    option_parser(parser)

    parser.add_option('-f', '--force', dest='force', action="store_true",
        default=False, help='Uninstall the domain even if it\'s active.')
    parser.add_option('--backup', dest='backup', action="store", default=None,
        type="string", help='Backup domain configuration to the file.')

    return parser


def dom_install_option_parser():
    parser = optparse.OptionParser('%prog [OPTION ...] dom-install DOMAIN_XML')
    option_parser(parser)

    parser.add_option('-f', '--force', dest='force', action="store_true",
        default=False, help='Install the domain even if it exists.')
    parser.add_option('-a', '--autostart', dest='autostart', action="store_true",
        default=False, help='Make the domain autostarted after installed')
    parser.add_option('--search-path', dest='search_path', action="store",
        default=None, type="string",
        help='Specify the path (dir) to search the domain disk images. [Default: dir contains the domain configuration]')

    return parser


def net_uninstall_option_parser():
    parser = optparse.OptionParser('%prog [OPTION ...] net-uninstall NETWORK_NAME')
    option_parser(parser)

    parser.add_option('-f', '--force', dest='force', action="store_true",
        default=False, help='Uninstall the network even if it\'s active.')
    parser.add_option('--backup', dest='backup', action="store", default=None,
        type="string", help='Backup network configuration to the file.')

    return parser


def net_install_option_parser():
    parser = optparse.OptionParser('%prog [OPTION ...] net-install NETWORK_XML')
    option_parser(parser)

    parser.add_option('-f', '--force', dest='force', action="store_true",
        default=False, help='Re-install the network even if it exists.')
    parser.add_option('-a', '--autostart', dest='autostart', action="store_true",
        default=False, help='Make the network autostarted after installed')

    return parser


def main():
    loglevel = logging.INFO

    if len(sys.argv) < 2:
        usage()
        sys.exit(1)

    cmd = sys.argv[1]

    if cmd.startswith('net-i'):
        cmd = 'net-install'
    elif cmd.startswith('net-u'):
        cmd = 'net-uninstall'
    elif cmd.startswith('dom-i'):
        cmd = 'dom-install'
    elif cmd.startswith('dom-u'):
        cmd = 'dom-uninstall'
    else:
        usage()
        help_extras()
        sys.exit(1)

    # FIXME: Hack.
    parser_f = globals().get('%s_option_parser' % cmd.replace('-','_'))
    parser = parser_f()

    (options, args) = parser.parse_args(sys.argv[2:])

    if options.verbose:
        loglevel = logging.DEBUG

    if options.quiet:
        loglevel = logging.WARN

    # logging.basicConfig() in python older than 2.4 cannot handle kwargs,
    # then exception 'TypeError' will be thrown.
    try:
        logging.basicConfig(level=loglevel)

    except TypeError:
        # To keep backward compatibility. See above comment also.
        logging.getLogger().setLevel(loglevel)

    if cmd == 'net-install':
        if len(args) < 1:
            parser.print_help()
            sys.exit(1)

        xml = args[0]
        ret = install_network(options.uri, xml, options.force, options.autostart)

    elif cmd == 'net-uninstall':
        if len(args) < 1:
            parser.print_help()
            sys.exit(1)

        name = args[0]

        if not options.force:
            confirm('uninstall the network %s' % name)

        ret = uninstall_network(options.uri, name, options.force, options.backup)

    elif cmd == 'dom-install':
        if len(args) < 1:
            parser.print_help()
            sys.exit(1)

        xml = args[0]
        ret = install_domain(options.uri, xml, options.force, \
            options.autostart, options.search_path)

    elif cmd == 'dom-uninstall':
        if len(args) < 1:
            parser.print_help()
            sys.exit(1)

        name = args[0]

        if not options.force:
            confirm('uninstall the domain %s' % name)

        ret = uninstall_domain(options.uri, name, options.force, options.backup)

    sys.exit(ret)


if __name__ == '__main__':
    main()

# vim:sw=4:ts=4:et:ft=python: