choose_your_port.py

#!/usr/bin/env python3

import random
import hashlib


def memoize(func):
    """Decorator used to cache results of a function."""
    cache = dict()

    def memoized_func(*args):
        if args in cache:
            return cache[args]
        result = func(*args)
        cache[args] = result
        return result

    return memoized_func

@memoize
def choose_from(input_options, entropy):
    """
    Choose from a list in a random-like fashion, but be consistent

    input_options: tuple of options
    entropy: string used to 
    """

    prng = random.Random(hashlib.sha256(entropy.encode()).digest())
    #prng = random.Random(entropy)
    n = prng.randrange(0,len(input_options)) % len(input_options)
    return input_options[n]

def main():
    OPTIONS = (7001, 7002, 7003)
    for r in ROUTER_LIST:
        opt = choose_from(OPTIONS, r)
        print("{:>10} {}".format(opt, r))

ROUTER_LIST = [
    'rtsw.alba.net.internet2.edu',
    'rtsw.ashb.net.internet2.edu',
    'rtsw.atla.net.internet2.edu',
    'rtsw.bato.net.internet2.edu',
    'rtsw.bost.net.internet2.edu',
    'rtsw.char.net.internet2.edu',
    'rtsw.chic.net.internet2.edu',
    'rtsw.cinc.net.internet2.edu',
    'rtsw.clev.net.internet2.edu',
    'rtsw.dall.net.internet2.edu',
    'rtsw.dall3.net.internet2.edu',
    'rtsw.denv.net.internet2.edu',
    'rtsw.elpa.net.internet2.edu',
    'rtsw.eqch.net.internet2.edu',
    'rtsw.hart2.net.internet2.edu',
    'rtsw.houh.net.internet2.edu',
    'rtsw.hous.net.internet2.edu',
    'rtsw.indi.net.internet2.edu',
    'rtsw.jack.net.internet2.edu',
    'rtsw.jcsn.net.internet2.edu',
    'rtsw.kans.net.internet2.edu',
    'rtsw.lasv.net.internet2.edu',
    'rtsw.losa.net.internet2.edu',
    'rtsw.loui.net.internet2.edu',
    'rtsw.minn.net.internet2.edu',
    'rtsw.miss2.net.internet2.edu',
    'rtsw.newy2.net.internet2.edu',
    'rtsw.newy32aoa.net.internet2.edu',
    'rtsw.phil.net.internet2.edu',
    'rtsw.phoe.net.internet2.edu',
    'rtsw.pitt.net.internet2.edu',
    'rtsw.port.net.internet2.edu',
    'rtsw.rale.net.internet2.edu',
    'rtsw.reno.net.internet2.edu',
    'rtsw.salt.net.internet2.edu',
    'rtsw.sanj.net.internet2.edu',
    'rtsw.seat.net.internet2.edu',
    'rtsw.star.net.internet2.edu',
    'rtsw.sunn.net.internet2.edu',
    'rtsw.tucs.net.internet2.edu',
    'rtsw.tuls.net.internet2.edu',
    'rtsw.wash.net.internet2.edu',
    'rtsw.wash2.net.internet2.edu',
    'rtsw.wilc.net.internet2.edu',
    'rtsw2.ashb.net.internet2.edu',
    'rtsw2.sanj.net.internet2.edu',
    'rtsw3.eqch.net.internet2.edu',
]

if __name__ == "__main__":
    main()