#!/usr/bin/python3
# Check if all libvirt domains are prepared for TRIM/fstrim
# (for use on qcow2 images or thin provisioned volumes)

from __future__ import division, print_function

from distutils.version import LooseVersion
from lxml import objectify
import libvirt
import re
import sys


conn = libvirt.openReadOnly('qemu:///system')
if not conn:
    print('Failed to open connection to the hypervisor!')
    sys.exit(1)

if not hasattr(conn, "listAllDomains"):
    print('connection does not have listAllDomains(), is python-libvirt too old?')
    sys.exit(1)

for domain in conn.listAllDomains():
    print('== {}'.format(domain.name()))

    xml = domain.XMLDesc()
    tree = objectify.fromstring(xml)

    # machine type version should be >= 2.1 if i440fx
    machine = tree.os.type.get('machine')
    matches = re.match('^pc-(?:i440fx-)?([0-9.]*)', machine)
    if matches:
        i440_version = matches.group(1)
        if LooseVersion(i440_version) < LooseVersion('2.1'):
            print('machine type (version) should be at least pc-i440fx-2.1')
        # Might want to check "qemu-system-x86_64 -M help" for supported
        # machines.

    # no disks, no need to check
    if not hasattr(tree.devices, 'disk'):
        print('(has no disks)')
        continue

    # every disk should be scsi + discard=unmap
    for disk in tree.devices.disk:
        if disk.get('device') != 'disk':
            continue

        disk_desc = disk.target.get('dev')

        if disk.target.get('bus') != 'scsi':
            print('{} target should be scsi'.format(disk_desc))
        if disk.driver.get('discard') != 'unmap':
            print('{} driver should have discard=unmap'.format(disk_desc))

    # every scsi controller should be model='virtio-scsi'
    for controller in tree.devices.controller:
        if controller.get('type') != 'scsi':
            continue

        if controller.get('model') != 'virtio-scsi':
            print('scsi controller should be a virtio model')