rf3k.py

#!/usr/bin/env python
#
# Ring Finder 3000: finds rings that break the builder

import os
import pickle
import random
import time
import traceback
from StringIO import StringIO
from swift.common.ring import RingBuilder


NDEVS = 257
REGIONS = [1, 2, 3, 4, 5]
ZONES = [101, 102, 103]
IPS = ["10.1.1.%d" % octet for octet in range(1, 255)]
DEVICES = ["sda%d" % (i + 1) for i in range(24)]
MIN_WEIGHT = 1000000
MAX_WEIGHT = 8000000


def is_bad(builder):
    try:
        builder.rebalance(seed=12345)  # that's the same combination I use
                                       # on my luggage
        return False
    except Exception:
        print traceback.format_exc()
        return True


def make_random_dev(dev_id):
    return {
        'id': dev_id,
        'region': random.choice(REGIONS),
        'zone': random.choice(ZONES),
        'ip': random.choice(IPS),
        'port': 6000,
        'device': random.choice(DEVICES),
        'weight': random.randrange(MIN_WEIGHT, MAX_WEIGHT) / 1000.0,
    }


def make_random_builder():
    # Make a builder with some stuff in it. Doesn't balance anything.
    rb = RingBuilder(12, 3, 1)
    dev_ids = range(NDEVS)
    for dev_id in dev_ids:
        rb.add_dev(make_random_dev(dev_id))
    rb.rebalance()

    # got a bunch of devs; just randomly assign them wherever. weights? nah.
    # dispersion? screw it. just make something up and see if it fails.
    for p2d in rb._replica2part2dev:
        for i in range(len(p2d)):
            p2d[i] = random.randrange(0, NDEVS)

    return rb


def go_once():
    buf = StringIO()
    rb = make_random_builder()

    # hokey save; builder wants to be saved to a file path, but I'd rather
    # just buffer in memory until I know that things are bad
    pickle.dump(rb.to_dict(), buf, protocol=2)
    buf.seek(0)

    try:
        rb.pretend_min_part_hours_passed()
        rb.rebalance()

        # now mutate some stuff, just for giggles
        rb.remove_dev(2)
        rb.remove_dev(4)
        rb.remove_dev(100)
        rb.remove_dev(193)
        rb.remove_dev(88)

        rb.set_dev_weight(111, 0.0)
        rb.set_dev_weight(222, 0.0)

        rb.set_dev_weight(133, rb.devs[133]['weight'] * 2.71828)
        rb.set_dev_weight(134, rb.devs[133]['weight'] * 3.14159)
        rb.set_dev_weight(135, 0.1)

        rb.add_dev(make_random_dev(NDEVS))
        rb.add_dev(make_random_dev(NDEVS + 1))
        rb.add_dev(make_random_dev(NDEVS + 2))
        rb.add_dev(make_random_dev(NDEVS + 3))

        rb.pretend_min_part_hours_passed()
        rb.rebalance()

        return None
    except Exception:
        #print traceback.format_exc()
        return buf


def main():
    baddie = go_once()
    nchecked = 1
    while not baddie:
        baddie = go_once()
        nchecked += 1
        if nchecked % 25 == 0:
            print str(nchecked)

    fname = "horked-%d-%f.builder" % (os.getpid(), time.time())
    with open(fname, "w") as badfh:
        badfh.write(baddie.read())
    print "Got one! Builder file is %s" % fname


if __name__ == '__main__':
    main()