Jug Documentation and Tutorial
Here is a one minute example. Save the following to a file called
primes.py:
from jug import TaskGenerator
from time import sleep
@TaskGenerator
def is_prime(n):
sleep(1.)
for j in range(2,n-1):
if (n % j) == 0:
return False
return True
primes100 = map(is_prime, list(range(2,101)))
Of course, this is only for didactical purposes, normally you would use
a better method. Similarly, the sleep function is so that it does not
run too fast.
Now type jug status primes.py to get:
Task name Waiting Ready Finished Running
------------------------------------------------------------------------
primes.is_prime 0 99 0 0
........................................................................
Total: 0 99 0 0
This tells you that you have 99 tasks called primes.is_prime ready to
run. So run jug execute primes.py &. You can even run multiple
instances in the background (if you have multiple cores, for example).
After starting 4 instances and waiting a few seconds, you can check the
status again (with jug status primes.py):
Task name Waiting Ready Finished Running
------------------------------------------------------------------------
primes.is_prime 0 63 32 4
........................................................................
Total: 0 63 32 4
Now you have 32 tasks finished, 4 running, and 63 still ready.
Eventually, they will all finish and you can inspect the results with
jug shell primes.py. This will give you an ipython shell. The
[primes100]{.title-ref} variable is available, but it is an ugly list of
[jug.Task]{.title-ref} objects. To get the actual value, you call the
[value]{.title-ref} function:
In [1]: primes100 = value(primes100)
In [2]: primes100[:10]
Out[2]: [True, True, False, True, False, True, False, False, False, True]
The current version is Jug 2.6.0 (released September 20, 2026), mostly a correctness and robustness release. Two changes to task hashing mean that some cached results will be recomputed after upgrading: the pickle protocol is now pinned to 4 (so hashes are stable across Python versions, a one-time break for users on Python 3.14 or 3.15), and lambdas are hashed by their constants, names, closure, and default arguments rather than by their bytecode alone. See the ChangeLog for the other fixes and the full history.
Jug is available on PyPI and conda-forge:
pip install jug
# or
conda install -c conda-forge jug
Copyright (c) 2018–2026. Luis Pedro Coelho and other group members. All rights reserved.