Changeset 56a3258 in trunk


Ignore:
Timestamp:
2010-09-09T04:16:54Z (14 years ago)
Author:
Zooko O'Whielacronx <zooko@…>
Branches:
master
Children:
0475bd8
Parents:
95c62dc
Message:

immutable downloader: add a test specifically of whether the finder sometimes announces "no more shares ever" and then announces a newly found share
(The current code fails this test, ref #1191.)

File:
1 edited

Legend:

Unmodified
Added
Removed
  • TabularUnified src/allmydata/test/test_immutable.py

    r95c62dc r56a3258  
    22from allmydata.interfaces import NotEnoughSharesError
    33from allmydata.util.consumer import download_to_data
     4from allmydata import uri
    45from twisted.internet import defer
    56from twisted.trial import unittest
    67import random
     8
     9from foolscap.api import eventually
     10from allmydata.util import log
     11
     12from allmydata.immutable.downloader import finder
     13
     14import mock
     15
     16class MockNode(object):
     17    def __init__(self, check_reneging, check_fetch_failed):
     18        self.got = 0
     19        self.finished_d = defer.Deferred()
     20        self.segment_size = 78
     21        self.guessed_segment_size = 78
     22        self._no_more_shares = False
     23        self.check_reneging = check_reneging
     24        self.check_fetch_failed = check_fetch_failed
     25        self._si_prefix='aa'
     26        self.have_UEB = True
     27        self.share_hash_tree = mock.Mock()
     28        self.share_hash_tree.needed_hashes.return_value = False
     29        self.on_want_more_shares = None
     30
     31    def when_finished(self):
     32        return self.finished_d
     33    def get_num_segments(self):
     34        return (5, True)
     35    def _calculate_sizes(self, guessed_segment_size):
     36        return {'block_size': 4, 'num_segments': 5}
     37    def no_more_shares(self):
     38        self._no_more_shares = True
     39    def got_shares(self, shares):
     40        if self.check_reneging:
     41            if self._no_more_shares:
     42                self.finished_d.errback(unittest.FailTest("The node was told by the share finder that it is destined to remain hungry, then was given another share."))
     43                return
     44        self.got += len(shares)
     45        log.msg("yyy 3 %s.got_shares(%s) got: %s" % (self, shares, self.got))
     46        if self.got == 3:
     47            self.finished_d.callback(True)
     48    def get_desired_ciphertext_hashes(self, *args, **kwargs):
     49        return iter([])
     50    def fetch_failed(self, *args, **kwargs):
     51        if self.check_fetch_failed:
     52            if self.finished_d:
     53                self.finished_d.errback(unittest.FailTest("The node was told by the segment fetcher that the download failed."))
     54                self.finished_d = None
     55    def want_more_shares(self):
     56        if self.on_want_more_shares:
     57            self.on_want_more_shares()
     58    def process_blocks(self, *args, **kwargs):
     59        if self.finished_d:
     60            self.finished_d.callback(None)
     61
     62class TestShareFinder(unittest.TestCase):
     63    def test_no_reneging_on_no_more_shares_ever(self):
     64        # ticket #1191
     65
     66        # Suppose that K=3 and you send two DYHB requests, the first
     67        # response offers two shares, and then the last offers one
     68        # share. If you tell your share consumer "no more shares,
     69        # ever", and then immediately tell them "oh, and here's
     70        # another share", then you lose.
     71
     72        rcap = uri.CHKFileURI('a'*32, 'a'*32, 3, 99, 100)
     73        vcap = rcap.get_verify_cap()
     74
     75        class MockServer(object):
     76            def __init__(self, buckets):
     77                self.version = {
     78                    'http://allmydata.org/tahoe/protocols/storage/v1': {
     79                        "tolerates-immutable-read-overrun": True
     80                        }
     81                    }
     82                self.buckets = buckets
     83                self.d = defer.Deferred()
     84                self.s = None
     85            def callRemote(self, methname, *args, **kwargs):
     86                d = defer.Deferred()
     87
     88                # Even after the 3rd answer we're still hungry because
     89                # we're interested in finding a share on a 3rd server
     90                # so we don't have to download more than one share
     91                # from the first server. This is actually necessary to
     92                # trigger the bug.
     93                def _give_buckets_and_hunger_again():
     94                    d.callback(self.buckets)
     95                    self.s.hungry()
     96                eventually(_give_buckets_and_hunger_again)
     97                return d
     98
     99        mockserver1 = MockServer({1: mock.Mock(), 2: mock.Mock()})
     100        mockserver2 = MockServer({})
     101        mockserver3 = MockServer({3: mock.Mock()})
     102        mockstoragebroker = mock.Mock()
     103        mockstoragebroker.get_servers_for_index.return_value = [ ('ms1', mockserver1), ('ms2', mockserver2), ('ms3', mockserver3), ]
     104        mockdownloadstatus = mock.Mock()
     105        mocknode = MockNode(check_reneging=True, check_fetch_failed=True)
     106
     107        s = finder.ShareFinder(mockstoragebroker, vcap, mocknode, mockdownloadstatus)
     108
     109        mockserver1.s = s
     110        mockserver2.s = s
     111        mockserver3.s = s
     112
     113        s.hungry()
     114
     115        return mocknode.when_finished()
    7116
    8117class Test(common.ShareManglingMixin, common.ShouldFailMixin, unittest.TestCase):
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