Python utility to maximize the root partition of a vm image for cloud-init

resize_part

#! /opt/pyparted/bin/python

import parted
import os
import sys
import dbus

def ask_udisk2(mountpath):
    bus = dbus.SystemBus()
    udisks2obj = bus.get_object('org.freedesktop.UDisks2', '/org/freedesktop/UDisks2')
    udisks2om = dbus.Interface(udisks2obj, 'org.freedesktop.DBus.ObjectManager')
    udisks2 = udisks2om.GetManagedObjects()
    def find_mounted_partition(mountpath, objects):
        for k in objects.keys():
            try:
                if 'org.freedesktop.UDisks2.Filesystem' in [str(x) for x in objects[k].keys()]:
                    for mountpoint_b in objects[k]['org.freedesktop.UDisks2.Filesystem']['MountPoints']:
                        mountpoint = ''.join([chr(x) for x in mountpoint_b if x])
                        if mountpoint == mountpath:
                            return k
            except:
                pass
    def find_partition_device(partition, objects):
        table = objects[partition]['org.freedesktop.UDisks2.Partition']['Table']
        blockdev = objects[table]['org.freedesktop.UDisks2.Block']['Device']
        return ''.join([chr(x) for x in blockdev if x])
    return find_partition_device(find_mounted_partition(mountpath,udisks2),udisks2)


def main():
    device = parted.getDevice(ask_udisk2('/'))
    disk = parted.Disk(device)
    constraint = parted.Constraint(device=disk.device)
    try:
        disk.maximizePartition(disk.partitions[1], constraint)
        disk.commit()
    except Exception as i:
        if 'reboot' in str(i):
            return 2
        print("Partition resize failed, {}".format(i))
        return 1
    print("Partition resized.")
    return 0

if __name__ == "__main__":
    sys.exit(main())

Copied the constraint usage from anaconda. Seems to have fixed the constraint error.