def lookup_disk(serial):
"""
Search for a disk by its serial number using /dev/disk/by-id/
"""
# Get all volumes in /dev/disk/by-id/ containing the serial string. The
# string specified can be either in the short or long serial format
# hack, some serials have spaces, udev usually converts ' ' -> '_'
serial_udev = serial.replace(' ', '_')
LOG.info('Processing serial %s via udev to %s', serial, serial_udev)
disks = list(
filter(lambda x: serial_udev in x, os.listdir("/dev/disk/by-id/")))
if not disks or len(disks) < 1:
raise ValueError("no disk with serial '%s' found" % serial_udev)
# Sort by length and take the shortest path name, as the longer path names
# will be the partitions on the disk. Then use os.path.realpath to
# determine the path to the block device in /dev/
disks.sort(key=lambda x: len(x))
LOG.debug('lookup_disks found: %s', disks)
path = os.path.realpath("/dev/disk/by-id/%s" % disks[0])
# /dev/dm-X
if multipath.is_mpath_device(path):
info = udevadm_info(path)
path = os.path.join('/dev/mapper', info['DM_NAME'])
# /dev/sdX
elif multipath.is_mpath_member(path):
mp_name = multipath.find_mpath_id_by_path(path)
path = os.path.join('/dev/mapper', mp_name)
if not os.path.exists(path):
raise ValueError("path '%s' to block device for disk with serial '%s' \
does not exist" % (path, serial_udev))
LOG.debug('block.lookup_disk() returning path %s', path)
return path
def test_find_mpath_id_by_path(self):
"""find_mpath_id_by_path returns the mp_id if specified device is
member.
"""
mp_id = 'mpatha'
paths = ['device=bar multipath=mpatha', 'device=wark multipath=mpathb']
self.m_subp.return_value = ("\n".join(paths), "")
self.assertEqual(mp_id, multipath.find_mpath_id_by_path('/dev/bar'))
def test_find_mpath_id_by_path_returns_none_not_found(self):
"""find_mpath_id_by_path returns None if specified device is not a
member.
"""
mp_id = 'mpatha'
paths = [
'device=bar multipath=%s' % mp_id,
'device=wark multipath=%s' % mp_id
]
self.m_subp.return_value = ("\n".join(paths), "")
self.assertIsNone(multipath.find_mpath_id_by_path('/dev/xxx'))