From: Zooko O'Whielacronx Date: Fri, 2 Jan 2009 23:54:59 +0000 (-0700) Subject: immutable: add more detailed tests of download, including testing the count of how... X-Git-Url: https://git.rkrishnan.org/pf/content/en/seg/bcase?a=commitdiff_plain;h=e26cec2502c47928fced879c9f92a41c634ab07a;p=tahoe-lafs%2Ftahoe-lafs.git immutable: add more detailed tests of download, including testing the count of how many reads different sorts of downloads take --- diff --git a/src/allmydata/immutable/download.py b/src/allmydata/immutable/download.py index cae5864b..4e84bdc5 100644 --- a/src/allmydata/immutable/download.py +++ b/src/allmydata/immutable/download.py @@ -880,7 +880,7 @@ class FileDownloader(log.PrefixingLogMixin): handled_shnums = set(self.active_buckets.keys()) available_shnums = set(self._share_vbuckets.keys()) potential_shnums = list(available_shnums - handled_shnums) - if not potential_shnums: + if len(potential_shnums) < (self._uri.needed_shares - len(self.active_buckets)): raise NotEnoughSharesError # For the next share, choose a primary share if available, else a randomly chosen # secondary share. diff --git a/src/allmydata/test/test_immutable.py b/src/allmydata/test/test_immutable.py index 5614a54a..2a2dc6b8 100644 --- a/src/allmydata/test/test_immutable.py +++ b/src/allmydata/test/test_immutable.py @@ -333,15 +333,121 @@ class Test(ShareManglingMixin, unittest.TestCase): sum_of_allocate_counts += counters.get('storage_server.allocate', 0) return sum_of_allocate_counts + def _corrupt_a_share(self, unused, corruptor_func, sharenum): + shares = self.find_shares() + ks = [ key for key in shares.keys() if key[1] == sharenum ] + assert ks, (shares.keys(), sharenum) + k = ks[0] + shares[k] = corruptor_func(shares[k]) + self.replace_shares(shares, storage_index=self.uri.storage_index) + def _corrupt_a_random_share(self, unused, corruptor_func): """ Exactly one share on disk will be corrupted by corruptor_func. """ shares = self.find_shares() ks = shares.keys() k = random.choice(ks) + return self._corrupt_a_share(unused, corruptor_func, k) - shares[k] = corruptor_func(shares[k]) + def test_download(self): + """ Basic download. (This functionality is more or less already tested by test code in + other modules, but this module is also going to test some more specific things about + immutable download.) + """ + d = defer.succeed(None) + before_download_reads = self._count_reads() + def _after_download(unused=None): + after_download_reads = self._count_reads() + # To pass this test, you have to download the file using only 10 reads to get the + # UEB (in parallel from all shares), plus one read for each of the 3 shares. + self.failIf(after_download_reads-before_download_reads > 13, (after_download_reads, before_download_reads)) + d.addCallback(self._download_and_check_plaintext) + d.addCallback(_after_download) + return d - self.replace_shares(shares, storage_index=self.uri.storage_index) + def test_download_from_only_3_remaining_shares(self): + """ Test download after 7 random shares (of the 10) have been removed. """ + d = defer.succeed(None) + def _then_delete_7(unused=None): + for i in range(7): + self._delete_a_share() + before_download_reads = self._count_reads() + d.addCallback(_then_delete_7) + def _after_download(unused=None): + after_download_reads = self._count_reads() + # To pass this test, you have to download the file using only 10 reads to get the + # UEB (in parallel from all shares), plus one read for each of the 3 shares. + self.failIf(after_download_reads-before_download_reads > 13, (after_download_reads, before_download_reads)) + d.addCallback(self._download_and_check_plaintext) + d.addCallback(_after_download) + return d + + def test_download_abort_if_too_many_missing_shares(self): + """ Test that download gives up quickly when it realizes there aren't enough shares out + there.""" + d = defer.succeed(None) + def _then_delete_8(unused=None): + for i in range(8): + self._delete_a_share() + d.addCallback(_then_delete_8) + + before_download_reads = self._count_reads() + def _attempt_to_download(unused=None): + downloader = self.clients[1].getServiceNamed("downloader") + d = downloader.download_to_data(self.uri) + + def _callb(res): + self.fail("Should have gotten an error from attempt to download, not %r" % (res,)) + def _errb(f): + self.failUnless(f.check(NotEnoughSharesError)) + d.addCallbacks(_callb, _errb) + return d + + d.addCallback(_attempt_to_download) + + def _after_attempt(unused=None): + after_download_reads = self._count_reads() + # To pass this test, you are required to give up before actually trying to read any + # share data. + self.failIf(after_download_reads-before_download_reads > 0, (after_download_reads, before_download_reads)) + d.addCallback(_after_attempt) + return d + + def test_download_abort_if_too_many_corrupted_shares(self): + """ Test that download gives up quickly when it realizes there aren't enough uncorrupted + shares out there. It should be able to tell because the corruption occurs in the + sharedata version number, which it checks first.""" + d = defer.succeed(None) + def _then_corrupt_8(unused=None): + shnums = range(10) + random.shuffle(shnums) + for shnum in shnums[:8]: + self._corrupt_a_share(None, _corrupt_sharedata_version_number, shnum) + d.addCallback(_then_corrupt_8) + + before_download_reads = self._count_reads() + def _attempt_to_download(unused=None): + downloader = self.clients[1].getServiceNamed("downloader") + d = downloader.download_to_data(self.uri) + + def _callb(res): + self.fail("Should have gotten an error from attempt to download, not %r" % (res,)) + def _errb(f): + self.failUnless(f.check(NotEnoughSharesError)) + d.addCallbacks(_callb, _errb) + return d + + d.addCallback(_attempt_to_download) + + def _after_attempt(unused=None): + after_download_reads = self._count_reads() + # To pass this test, you are required to give up before reading all of the share + # data. Actually, we could give up sooner than 37 reads, but currently our download + # code does 37 reads. This test then serves as a "performance regression detector" + # -- if you change download code so that it takes *more* reads, then this test will + # fail. + self.failIf(after_download_reads-before_download_reads > 37, (after_download_reads, before_download_reads)) + d.addCallback(_after_attempt) + return d def test_check_without_verify(self): """ Check says the file is healthy when none of the shares have been touched. It says