How to generate a random UUID which is reproducible (with a seed) in Python

Question

The uuid4() function of Python's module uuid generates a random UUID, and seems to generate a different one every time:

In [1]: import uuid  In [2]: uuid.uuid4() Out[2]: UUID('f6c9ad6c-eea0-4049-a7c5-56253bc3e9c0')  In [3]: uuid.uuid4() Out[3]: UUID('2fc1b6f9-9052-4564-9be0-777e790af58f') 

I would like to be able to generate the same random UUID every time I run a script - that is, I'd like to seed the random generator in uuid4(). Is there a way to do this? (Or achieve this by some other means)?

What I've tried so far

I've to generate a UUID using the uuid.UUID() method with a random 128-bit integer (from a seeded instance of random.Random()) as input:

import uuid import random  rd = random.Random() rd.seed(0) uuid.UUID(rd.getrandbits(128)) 

However, UUID() seems not to accept this as input:

Traceback (most recent call last):   File "uuid_gen_seed.py", line 6, in <module>     uuid.UUID(rd.getrandbits(128))   File "/usr/lib/python2.7/uuid.py", line 133, in __init__     hex = hex.replace('urn:', '').replace('uuid:', '') AttributeError: 'long' object has no attribute 'replace' 

Any other suggestions?

Answer 1

Almost there:

uuid.UUID(int=rd.getrandbits(128)) 

This was determined with the help of help:

>>> help(uuid.UUID.__init__) Help on method __init__ in module uuid:  __init__(self, hex=None, bytes=None, bytes_le=None, fields=None, int=None, version=None) unbound uuid.UUID method     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'.