python-compute/node_agent/utils/xml.py
2023-08-31 20:37:41 +03:00

146 lines
5.3 KiB
Python

from lxml.builder import E
from lxml.etree import Element, QName, SubElement, fromstring, tostring
class Constructor:
"""
The XML constructor. This class builds XML configs for libvirt.
"""
def gen_domain_xml(self, name: str, title: str, desc: str, memory: int,
vcpus: int, domain_type: str, machine: str, arch: str,
boot_order: tuple, cpu: str, mac: str) -> str:
"""
Return basic libvirt domain configuration.
"""
domain = E.domain(
E.name(name),
E.title(title),
E.description(desc),
E.metadata(),
E.memory(str(memory), unit='MB'),
E.currentMemory(str(memory), unit='MB'),
E.vcpu(str(vcpus), placement='static'),
type='kvm'
)
os = E.os(E.type(domain_type, machine=machine, arch=arch))
for dev in boot_order:
os.append(E.boot(dev=dev))
domain.append(os)
domain.append(E.features(E.acpi(), E.apic()))
domain.append(fromstring(cpu))
domain.append(E.on_poweroff('destroy'))
domain.append(E.on_reboot('restart'))
domain.append(E.on_crash('restart'))
domain.append(E.pm(
E('suspend-to-mem', enabled='no'),
E('suspend-to-disk', enabled='no'))
)
devices = E.devices()
devices.append(E.emulator('/usr/bin/qemu-system-x86_64'))
devices.append(E.interface(
E.source(network='default'),
E.mac(address=mac),
type='network')
)
devices.append(E.graphics(type='vnc', port='-1', autoport='yes'))
devices.append(E.input(type='tablet', bus='usb'))
devices.append(E.channel(
E.source(mode='bind'),
E.target(type='virtio', name='org.qemu.guest_agent.0'),
E.address(type='virtio-serial', controller='0', bus='0', port='1'),
type='unix')
)
devices.append(E.console(
E.target(type='serial', port='0'),
type='pty')
)
devices.append(E.video(
E.model(type='vga', vram='16384', heads='1', primary='yes'))
)
domain.append(devices)
return tostring(domain, encoding='unicode', pretty_print=True).strip()
def gen_volume_xml(self, dev: str, mode: str, path: str) -> str:
"""
Todo: No hardcode
https://libvirt.org/formatdomain.html#hard-drives-floppy-disks-cdroms
"""
volume = E.disk(type='file', device='disk')
volume.append(
E.driver(
name='qemu',
type='qcow2',
cache='writethrough'))
volume.append(E.source(file=path))
volume.append(E.target(dev=dev, bus='virtio'))
if mode.lower() == 'ro':
volume.append(E.readonly())
return tostring(volume, encoding='unicode', pretty_print=True).strip()
def construct_xml(self,
tag: dict,
namespace: str | None = None,
nsprefix: str | None = None,
root: Element = None) -> Element:
"""
Shortly this recursive function transforms dictonary to XML.
Return etree.Element built from dict with following structure::
{
'name': 'device', # tag name
'text': '', # optional key
'values': { # optional key, must be a dict of key-value pairs
'type': 'disk'
},
children: [] # optional key, must be a list of dicts
}
Child elements must have the same structure. Infinite `children` nesting
is allowed.
"""
use_ns = False
if isinstance(namespace, str) and isinstance(nsprefix, str):
use_ns = True
# Create element
if root is None:
if use_ns:
element = Element(QName(namespace, tag['name']),
nsmap={nsprefix: namespace})
else:
element = Element(tag['name'])
else:
if use_ns:
element = SubElement(root, QName(namespace, tag['name']))
else:
element = SubElement(root, tag['name'])
# Fill up element with content
if 'text' in tag.keys():
element.text = tag['text']
if 'values' in tag.keys():
for key in tag['values'].keys():
element.set(str(key), str(tag['values'][key]))
if 'children' in tag.keys():
for child in tag['children']:
element.append(
self.construct_xml(child,
namespace=namespace,
nsprefix=nsprefix,
root=element))
return element
def add_meta(self, xml: Element, data: dict,
namespace: str, nsprefix: str) -> None:
"""
Add metadata to domain. See:
https://libvirt.org/formatdomain.html#general-metadata
"""
metadata = metadata_old = xml.xpath('/domain/metadata')[0]
metadata.append(
self.construct_xml(
data,
namespace=namespace,
nsprefix=nsprefix,
))
xml.replace(metadata_old, metadata)