How to create a random UUID that reproduces (with seed) in Python

Question

The uuid4 () function of the Python uuid module generates a random UUID and seems to generate each time each 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 the script - that is, I would like to seed a random generator in uuid4() . Is there any way to do this? (Or achieve this in other ways)?

What I tried so far

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

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

However, UUID() does not seem 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 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'. 

Answer 2

Faker makes it easy

 >>> from faker import Faker >>> f1 = Faker() >>> f1.seed(4321) >>> print(f1.uuid4()) cc733c92-6853-15f6-0e49-bec741188ebb >>> print(f1.uuid4()) a41f020c-2d4d-333f-f1d3-979f1043fae0 >>> f1.seed(4321) >>> print(f1.uuid4()) cc733c92-6853-15f6-0e49-bec741188ebb 

Answer 3

Based on alex's solution, the following will provide the correct UUID4:

 random.seed(123210912) a = "%32x" % random.getrandbits(128) rd = a[:12] + '4' + a[13:16] + 'a' + a[17:] uuid4 = uuid.UUID(rd) 

Answer 4

This is based on the solution used here :

 import hashlib import uuid m = hashlib.md5() m.update(seed.encode('utf-8')) new_uuid = uuid.UUID(m.hexdigest()) 

Answer 5

I'm going to add this here if someone needs a monkey patch in a seeded UUID. My code uses uuid.uuid4() but for testing I needed consistent UUIDs. The following code, as I did it:

 import uuid import random # ------------------------------------------- # Remove this block to generate different # UUIDs everytime you run this code. # This block should be right below the uuid # import. rd = random.Random() rd.seed(0) uuid.uuid4 = lambda: uuid.UUID(int=rd.getrandbits(128)) # ------------------------------------------- # Then normal code: print(uuid.uuid4().hex) print(uuid.uuid4().hex) print(uuid.uuid4().hex) print(uuid.uuid4().hex)