r"""UUID objects (universally unique identifiers) according to RFC 4122.
This module provides immutable UUID objects (class UUID) and the functions
uuid1(), uuid3(), uuid4(), uuid5() for generating version 1, 3, 4, and 5
UUIDs as specified in RFC 4122.
If all you want is a unique ID, you should probably call uuid1() or uuid4().
Note that uuid1() may compromise privacy since it creates a UUID containing
the computer's network address. uuid4() creates a random UUID.
# make a UUID based on the host ID and current time
>>> uuid.uuid1() # doctest: +SKIP
UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')
# make a UUID using an MD5 hash of a namespace UUID and a name
>>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')
>>> uuid.uuid4() # doctest: +SKIP
UUID('16fd2706-8baf-433b-82eb-8c7fada847da')
# make a UUID using a SHA-1 hash of a namespace UUID and a name
>>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')
# make a UUID from a string of hex digits (braces and hyphens ignored)
>>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}')
# convert a UUID to a string of hex digits in standard form
'00010203-0405-0607-0809-0a0b0c0d0e0f'
# get the raw 16 bytes of the UUID
b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f'
# make a UUID from a 16-byte string
>>> uuid.UUID(bytes=x.bytes)
UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')
__author__ = 'Ka-Ping Yee <ping@zesty.ca>'
# The recognized platforms - known behaviors
if sys.platform in ('win32', 'darwin'):
_platform_system = platform.system()
_AIX = _platform_system == 'AIX'
_LINUX = _platform_system == 'Linux'
_MAC_OMITS_LEADING_ZEROES = False
_MAC_OMITS_LEADING_ZEROES = True
RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [
'reserved for NCS compatibility', 'specified in RFC 4122',
'reserved for Microsoft compatibility', 'reserved for future definition']
int_ = int # The built-in int type
bytes_ = bytes # The built-in bytes type
"""Instances of the UUID class represent UUIDs as specified in RFC 4122.
UUID objects are immutable, hashable, and usable as dictionary keys.
Converting a UUID to a string with str() yields something in the form
'12345678-1234-1234-1234-123456789abc'. The UUID constructor accepts
five possible forms: a similar string of hexadecimal digits, or a tuple
of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and
48-bit values respectively) as an argument named 'fields', or a string
of 16 bytes (with all the integer fields in big-endian order) as an
argument named 'bytes', or a string of 16 bytes (with the first three
fields in little-endian order) as an argument named 'bytes_le', or a
single 128-bit integer as an argument named 'int'.
UUIDs have these read-only attributes:
bytes the UUID as a 16-byte string (containing the six
integer fields in big-endian byte order)
bytes_le the UUID as a 16-byte string (with time_low, time_mid,
and time_hi_version in little-endian byte order)
fields a tuple of the six integer fields of the UUID,
which are also available as six individual attributes
and two derived attributes:
time_low the first 32 bits of the UUID
time_mid the next 16 bits of the UUID
time_hi_version the next 16 bits of the UUID
clock_seq_hi_variant the next 8 bits of the UUID
clock_seq_low the next 8 bits of the UUID
node the last 48 bits of the UUID
time the 60-bit timestamp
clock_seq the 14-bit sequence number
hex the UUID as a 32-character hexadecimal string
int the UUID as a 128-bit integer
urn the UUID as a URN as specified in RFC 4122
variant the UUID variant (one of the constants RESERVED_NCS,
RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE)
version the UUID version number (1 through 5, meaningful only
when the variant is RFC_4122)
is_safe An enum indicating whether the UUID has been generated in
a way that is safe for multiprocessing applications, via
uuid_generate_time_safe(3).
__slots__ = ('int', 'is_safe', '__weakref__')
def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None,
*, is_safe=SafeUUID.unknown):
r"""Create a UUID from either a string of 32 hexadecimal digits,
a string of 16 bytes as the 'bytes' argument, a string of 16 bytes
in little-endian order as the 'bytes_le' argument, a tuple of six
integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version,
8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as
the 'fields' argument, or a single 128-bit integer as the 'int'
argument. When a string of hex digits is given, curly braces,
hyphens, and a URN prefix are all optional. For example, these
expressions all yield the same UUID:
UUID('{12345678-1234-5678-1234-567812345678}')
UUID('12345678123456781234567812345678')
UUID('urn:uuid:12345678-1234-5678-1234-567812345678')
UUID(bytes='\x12\x34\x56\x78'*4)
UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' +
'\x12\x34\x56\x78\x12\x34\x56\x78')
UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678))
UUID(int=0x12345678123456781234567812345678)
Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must
be given. The 'version' argument is optional; if given, the resulting
UUID will have its variant and version set according to RFC 4122,
overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'.
is_safe is an enum exposed as an attribute on the instance. It
indicates whether the UUID has been generated in a way that is safe
for multiprocessing applications, via uuid_generate_time_safe(3).
if [hex, bytes, bytes_le, fields, int].count(None) != 4:
raise TypeError('one of the hex, bytes, bytes_le, fields, '
'or int arguments must be given')
hex = hex.replace('urn:', '').replace('uuid:', '')
hex = hex.strip('{}').replace('-', '')
raise ValueError('badly formed hexadecimal UUID string')
raise ValueError('bytes_le is not a 16-char string')
bytes = (bytes_le[4-1::-1] + bytes_le[6-1:4-1:-1] +
bytes_le[8-1:6-1:-1] + bytes_le[8:])
raise ValueError('bytes is not a 16-char string')
assert isinstance(bytes, bytes_), repr(bytes)
int = int_.from_bytes(bytes, byteorder='big')
raise ValueError('fields is not a 6-tuple')
(time_low, time_mid, time_hi_version,
clock_seq_hi_variant, clock_seq_low, node) = fields
if not 0 <= time_low < 1<<32:
raise ValueError('field 1 out of range (need a 32-bit value)')
if not 0 <= time_mid < 1<<16:
raise ValueError('field 2 out of range (need a 16-bit value)')
if not 0 <= time_hi_version < 1<<16:
raise ValueError('field 3 out of range (need a 16-bit value)')
if not 0 <= clock_seq_hi_variant < 1<<8:
raise ValueError('field 4 out of range (need an 8-bit value)')
if not 0 <= clock_seq_low < 1<<8:
raise ValueError('field 5 out of range (need an 8-bit value)')
if not 0 <= node < 1<<48:
raise ValueError('field 6 out of range (need a 48-bit value)')
clock_seq = (clock_seq_hi_variant << 8) | clock_seq_low
int = ((time_low << 96) | (time_mid << 80) |
(time_hi_version << 64) | (clock_seq << 48) | node)
if not 0 <= int < 1<<128:
raise ValueError('int is out of range (need a 128-bit value)')
if not 1 <= version <= 5:
raise ValueError('illegal version number')
# Set the variant to RFC 4122.
# Set the version number.
object.__setattr__(self, 'int', int)
object.__setattr__(self, 'is_safe', is_safe)
if self.is_safe != SafeUUID.unknown:
# is_safe is a SafeUUID instance. Return just its value, so that
# it can be un-pickled in older Python versions without SafeUUID.
d['is_safe'] = self.is_safe.value
def __setstate__(self, state):
object.__setattr__(self, 'int', state['int'])
# is_safe was added in 3.7; it is also omitted when it is "unknown"
object.__setattr__(self, 'is_safe',
SafeUUID(state['is_safe'])
if 'is_safe' in state else SafeUUID.unknown)
if isinstance(other, UUID):
return self.int == other.int
# Q. What's the value of being able to sort UUIDs?
# A. Use them as keys in a B-Tree or similar mapping.
if isinstance(other, UUID):
return self.int < other.int
if isinstance(other, UUID):
return self.int > other.int
if isinstance(other, UUID):
return self.int <= other.int
if isinstance(other, UUID):
return self.int >= other.int
return '%s(%r)' % (self.__class__.__name__, str(self))
def __setattr__(self, name, value):
raise TypeError('UUID objects are immutable')
return '%s-%s-%s-%s-%s' % (
hex[:8], hex[8:12], hex[12:16], hex[16:20], hex[20:])
return self.int.to_bytes(16, 'big')
return (bytes[4-1::-1] + bytes[6-1:4-1:-1] + bytes[8-1:6-1:-1] +
return (self.time_low, self.time_mid, self.time_hi_version,
self.clock_seq_hi_variant, self.clock_seq_low, self.node)
return (self.int >> 80) & 0xffff
def time_hi_version(self):
return (self.int >> 64) & 0xffff
def clock_seq_hi_variant(self):
return (self.int >> 56) & 0xff
return (self.int >> 48) & 0xff
return (((self.time_hi_version & 0x0fff) << 48) |
(self.time_mid << 32) | self.time_low)
return (((self.clock_seq_hi_variant & 0x3f) << 8) |
return self.int & 0xffffffffffff
return '%032x' % self.int
return 'urn:uuid:' + str(self)
if not self.int & (0x8000 << 48):
elif not self.int & (0x4000 << 48):
elif not self.int & (0x2000 << 48):
return RESERVED_MICROSOFT
# The version bits are only meaningful for RFC 4122 UUIDs.
if self.variant == RFC_4122:
return int((self.int >> 76) & 0xf)
def _get_command_stdout(command, *args):
import io, os, shutil, subprocess
path_dirs = os.environ.get('PATH', os.defpath).split(os.pathsep)
path_dirs.extend(['/sbin', '/usr/sbin'])
executable = shutil.which(command, path=os.pathsep.join(path_dirs))
# LC_ALL=C to ensure English output, stderr=DEVNULL to prevent output
# on stderr (Note: we don't have an example where the words we search
# for are actually localized, but in theory some system could do so.)
proc = subprocess.Popen((executable,) + args,
stderr=subprocess.DEVNULL,
stdout, stderr = proc.communicate()
return io.BytesIO(stdout)
except (OSError, subprocess.SubprocessError):
# For MAC (a.k.a. IEEE 802, or EUI-48) addresses, the second least significant
# bit of the first octet signifies whether the MAC address is universally (0)
# or locally (1) administered. Network cards from hardware manufacturers will
# always be universally administered to guarantee global uniqueness of the MAC
# address, but any particular machine may have other interfaces which are
# locally administered. An example of the latter is the bridge interface to
# the Touch Bar on MacBook Pros.
# This bit works out to be the 42nd bit counting from 1 being the least
# significant, or 1<<41. We'll prefer universally administered MAC addresses
# over locally administered ones since the former are globally unique, but
# we'll return the first of the latter found if that's all the machine has.
# See https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local
return not (mac & (1 << 41))
def _find_mac_near_keyword(command, args, keywords, get_word_index):
"""Searches a command's output for a MAC address near a keyword.
Each line of words in the output is case-insensitively searched for
any of the given keywords. Upon a match, get_word_index is invoked
to pick a word from the line, given the index of the match. For
example, lambda i: 0 would get the first word on the line, while
lambda i: i - 1 would get the word preceding the keyword.
stdout = _get_command_stdout(command, args)
words = line.lower().rstrip().split()
for i in range(len(words)):
word = words[get_word_index(i)]
mac = int(word.replace(_MAC_DELIM, b''), 16)
except (ValueError, IndexError):
# Virtual interfaces, such as those provided by
# VPNs, do not have a colon-delimited MAC address
# as expected, but a 16-byte HWAddr separated by
# dashes. These should be ignored in favor of a
first_local_mac = first_local_mac or mac
return first_local_mac or None
# Accept 'HH:HH:HH:HH:HH:HH' MAC address (ex: '52:54:00:9d:0e:67'),
# but reject IPv6 address (ex: 'fe80::5054:ff:fe9' or '123:2:3:4:5:6:7:8').
# Virtual interfaces, such as those provided by VPNs, do not have a
# colon-delimited MAC address as expected, but a 16-byte HWAddr separated
# by dashes. These should be ignored in favor of a real MAC address
parts = word.split(_MAC_DELIM)
if _MAC_OMITS_LEADING_ZEROES:
# (Only) on AIX the macaddr value given is not prefixed by 0, e.g.
# en0 1500 link#2 fa.bc.de.f7.62.4 110854824 0 160133733 0 0
# en0 1500 link#2 fa.bc.de.f7.62.04 110854824 0 160133733 0 0
if not all(1 <= len(part) <= 2 for part in parts):
hexstr = b''.join(part.rjust(2, b'0') for part in parts)
if not all(len(part) == 2 for part in parts):
def _find_mac_under_heading(command, args, heading):
"""Looks for a MAC address under a heading in a command's output.
The first line of words in the output is searched for the given
heading. Words at the same word index as the heading in subsequent
lines are then examined to see if they look like MAC addresses.
stdout = _get_command_stdout(command, args)
keywords = stdout.readline().rstrip().split()
column_index = keywords.index(heading)
words = line.rstrip().split()
word = words[column_index]
if first_local_mac is None:
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
