virt-manager/virtinst/connection.py

#
# Copyright 2013  Red Hat, Inc.
#
# 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.

import logging
import os
import re
import weakref

import libvirt

from virtinst import Guest
from virtinst import CapabilitiesParser
from virtinst import pollhelpers
from virtinst import support
from virtinst import util
from virtinst.cli import parse_optstr

_virtinst_uri_magic = "__virtinst_test__"


def _fakemkstemp(prefix, *args, **kwargs):
    ignore = args
    ignore = kwargs
    filename = os.path.join(".", prefix)
    return os.open(filename, os.O_RDWR | os.O_CREAT), filename


def _sanitize_xml(xml):
    import difflib

    orig = xml
    xml = re.sub("arch='.*'", "arch='i686'", xml)
    xml = re.sub("domain type='.*'", "domain type='test'", xml)
    xml = re.sub("machine type='.*'", "", xml)
    xml = re.sub(">exe<", ">hvm<", xml)

    logging.debug("virtinst test sanitizing diff\n:%s",
                  "\n".join(difflib.unified_diff(orig.split("\n"),
                                                 xml.split("\n"))))
    return xml


class _FetchObjWrapper(object):
    """
    Wrapper to make virDomain etc. objects have a similar XML API as
    virt-manager objects, so fetch_all* callers get similar results
    """
    def __init__(self, backend):
        self._backend = backend
        self._xml = None

    def get_xml(self, refresh_if_nec=True):
        if self._xml is None or refresh_if_nec:
            self._xml = self._backend.XMLDesc(0)
        return self._xml

    def get_backend(self):
        return self._backend


class VirtualConnection(object):
    """
    Wrapper for libvirt connection that provides various bits like
    - caching static data
    - lookup for API feature support
    - simplified API wrappers that handle new and old ways of doing things
    """
    def __init__(self, uri):
        self._initial_uri = uri or ""

        # virtinst unit test URI handling
        if self._initial_uri.startswith(_virtinst_uri_magic):
            uri = self._initial_uri.replace(_virtinst_uri_magic, "")
            ret = uri.split(",", 1)
            self._open_uri = ret[0]
            self._test_opts = parse_optstr(len(ret) > 1 and ret[1] or "")
            self._uri = self._virtinst_uri_make_fake()
        else:
            self._open_uri = self._initial_uri
            self._uri = self._initial_uri
            self._test_opts = {}

        self._libvirtconn = None
        self._urisplits = util.uri_split(self._uri)
        self._caps = None

        self._fake_libvirt_version = None
        self._fake_conn_version = None
        self._daemon_version = None
        self._conn_version = None

        self._support_cache = {}
        self._fetch_cache = {}

        # Setting this means we only do fetch_all* once and just carry
        # the result. For the virt-* CLI tools this ensures any revalidation
        # isn't hammering the connection over and over
        self.cache_object_fetch = False

        # These let virt-manager register a callback which provides its
        # own cached object lists, rather than doing fresh calls
        self.cb_fetch_all_guests = None
        self.cb_fetch_all_pools = None


    ##############
    # Properties #
    ##############

    # Proxy virConnect API calls
    def __getattr__(self, attr):
        if attr in self.__dict__:
            return self.__dict__[attr]
        libvirtconn = self.__dict__.get("_libvirtconn")
        return getattr(libvirtconn, attr)

    def _get_uri(self):
        return self._uri or self._open_uri
    uri = property(_get_uri)

    libvirtconn = property(lambda self: getattr(self, "_libvirtconn"))

    def _get_caps(self):
        if not self._caps:
            self._caps = CapabilitiesParser.Capabilities(
                                        self.libvirtconn.getCapabilities())
        return self._caps
    caps = property(_get_caps)


    ##############
    # Public API #
    ##############

    def close(self):
        self._libvirtconn = None
        self._uri = None
        self._fetch_cache = {}

    def invalidate_caps(self):
        self._caps = None

    def is_open(self):
        return bool(self._libvirtconn)

    def open(self, passwordcb):
        open_flags = 0
        valid_auth_options = [libvirt.VIR_CRED_AUTHNAME,
                              libvirt.VIR_CRED_PASSPHRASE]
        authcb = self._auth_cb
        authcb_data = passwordcb

        conn = libvirt.openAuth(self._open_uri,
                    [valid_auth_options, authcb,
                    (authcb_data, valid_auth_options)],
                    open_flags)

        self._fixup_virtinst_test_uri(conn)
        self._libvirtconn = conn

    def fetch_all_guests(self):
        # pylint: disable=E1102
        if self.cb_fetch_all_guests:
            return self.cb_fetch_all_guests()
        # pylint: enable=E1102

        key = "vms"
        if key in self._fetch_cache:
            return self._fetch_cache[key]

        ignore, ignore, ret = pollhelpers.fetch_vms(self, {},
                                                    lambda obj, ignore: obj)
        ret = [Guest(weakref.ref(self), parsexml=obj.XMLDesc(0))
               for obj in ret.values()]
        if self.cache_object_fetch:
            self._fetch_cache[key] = ret
        return ret

    def fetch_all_pools(self):
        # pylint: disable=E1102
        if self.cb_fetch_all_pools:
            return self.cb_fetch_all_pools()
        # pylint: enable=E1102

        key = "pools"
        if key in self._fetch_cache:
            return self._fetch_cache[key]

        ignore, ignore, ret = pollhelpers.fetch_pools(self, {},
                                                    lambda obj, ignore: obj)
        ret = [_FetchObjWrapper(obj) for obj in ret.values()]
        if self.cache_object_fetch:
            self._fetch_cache[key] = ret
        return ret


    #########################
    # Libvirt API overrides #
    #########################

    def getURI(self):
        return self._uri


    #########################
    # Public version checks #
    #########################

    def local_libvirt_version(self):
        if self._fake_libvirt_version is not None:
            return self._fake_libvirt_version
        # This handles caching for us
        return util.local_libvirt_version()

    def daemon_version(self):
        if self._fake_libvirt_version is not None:
            return self._fake_libvirt_version
        if not self.is_remote():
            return self.local_libvirt_version()

        if not self._daemon_version:
            if not self.check_conn_support(support.SUPPORT_CONN_LIBVERSION):
                self._daemon_version = 0
            else:
                self._daemon_version = self.libvirtconn.getLibVersion()
        return self._daemon_version

    def conn_version(self):
        if self._fake_conn_version is not None:
            return self._fake_conn_version

        if not self._conn_version:
            if not self.check_conn_support(support.SUPPORT_CONN_GETVERSION):
                self._conn_version = 0
            else:
                self._conn_version = self.libvirtconn.getVersion()
        return self._conn_version


    ###################
    # Public URI bits #
    ###################

    def is_remote(self):
        if (hasattr(self, "_virtinst__fake_conn_remote") or
            self._urisplits[2]):
            return True

    def get_uri_hostname(self):
        return self._urisplits[2] or "localhost"

    def get_uri_transport(self):
        scheme = self._urisplits[0]
        username = self._urisplits[1]
        offset = scheme.find("+")
        if offset != -1:
            return [scheme[offset + 1:], username]
        return [None, None]

    def get_uri_driver(self):
        scheme = self._urisplits[0]
        offset = scheme.find("+")
        if offset > 0:
            return scheme[:offset]
        return scheme

    def is_session_uri(self):
        return self._urisplits[3] == "/session"
    def is_qemu(self):
        return self._urisplits[0].startswith("qemu")
    def is_qemu_system(self):
        return (self.is_qemu() and self._urisplits[3] == "/system")
    def is_qemu_session(self):
        return (self.is_qemu() and self.is_session_uri())

    def is_test(self):
        return self._urisplits[0].startswith("test")
    def is_xen(self):
        return (self._urisplits[0].startswith("xen") or
                self._urisplits[0].startswith("libxl"))
    def is_lxc(self):
        return self._urisplits[0].startswith("lxc")
    def is_openvz(self):
        return self._urisplits[0].startswith("openvz")
    def is_container(self):
        return self.is_lxc() or self.is_openvz()


    #########################
    # Support check helpers #
    #########################

    for _supportname in [_supportname for _supportname in dir(support) if
                         _supportname.startswith("SUPPORT_")]:
        locals()[_supportname] = getattr(support, _supportname)

    def check_conn_support(self, feature):
        key = feature
        if key not in self._support_cache:
            self._support_cache[key] = support.check_support(self,
                                                             feature, self)
        return self._support_cache[key]
    def check_conn_hv_support(self, feature, hv):
        key = (feature, hv)
        if key not in self._support_cache:
            self._support_cache[key] = support.check_support(self, feature, hv)
        return self._support_cache[key]
    def check_domain_support(self, dom, feature):
        return support.check_support(self, feature, dom)
    def check_pool_support(self, pool, feature):
        return support.check_support(self, feature, pool)
    def check_nodedev_support(self, nodedev, feature):
        return support.check_support(self, feature, nodedev)
    def check_interface_support(self, iface, feature):
        return support.check_support(self, feature, iface)
    def check_stream_support(self, feature):
        return (self.check_conn_support(self.SUPPORT_CONN_STREAM) and
                support.check_support(self, feature, self))
    def check_net_support(self, net, feature):
        return support.check_support(self, feature, net)


    ###################
    # Private helpers #
    ###################

    def _auth_cb(self, creds, (passwordcb, passwordcreds)):
        for cred in creds:
            if cred[0] not in passwordcreds:
                raise RuntimeError("Unknown cred type '%s', expected only "
                                   "%s" % (cred[0], passwordcreds))
        return passwordcb(creds)

    def _virtinst_uri_make_fake(self):
        if "qemu" in self._test_opts:
            return "qemu+abc:///system"
        elif "xen" in self._test_opts:
            return "xen+abc:///"
        elif "lxc" in self._test_opts:
            return "lxc+abc:///"
        return self._open_uri

    def _fixup_virtinst_test_uri(self, conn):
        """
        This hack allows us to fake various drivers via passing a magic
        URI string to virt-*. Helps with testing
        """
        if not self._test_opts:
            return
        opts = self._test_opts.copy()

        # Need tmpfile names to be deterministic
        if "predictable" in opts:
            opts.pop("predictable")
            import tempfile
            tempfile.mkstemp = _fakemkstemp
            setattr(self, "_virtinst__fake_conn_predictable", True)

        # Fake remote status
        if "remote" in opts:
            opts.pop("remote")
            setattr(self, "_virtinst__fake_conn_remote", True)

        # Fake capabilities
        if "caps" in opts:
            capsxml = file(opts.pop("caps")).read()
            conn.getCapabilities = lambda: capsxml

        if ("qemu" in opts) or ("xen" in opts) or ("lxc" in opts):
            opts.pop("qemu", None)
            opts.pop("xen", None)
            opts.pop("lxc", None)

            self._fake_conn_version = 10000000000

            origcreate = conn.createLinux
            origdefine = conn.defineXML
            def newcreate(xml, flags):
                xml = _sanitize_xml(xml)
                return origcreate(xml, flags)
            def newdefine(xml):
                xml = _sanitize_xml(xml)
                return origdefine(xml)
            conn.createLinux = newcreate
            conn.defineXML = newdefine

        # These need to come after the HV setter, since that sets a default
        # conn version
        if "connver" in opts:
            self._fake_conn_version = int(opts.pop("connver"))
        if "libver" in opts:
            self._fake_libvirt_version = int(opts.pop("libver"))

        if opts:
            raise RuntimeError("Unhandled virtinst test uri options %s" % opts)

        setattr(self, "_virtinst__fake_conn", True)