tahoe-lafs/src/allmydata/test/test_storage.py

from twisted.trial import unittest

from twisted.application import service
from twisted.internet import defer
from foolscap import Referenceable
import os.path
from allmydata import interfaces
from allmydata.util import fileutil, hashutil
from allmydata.storage import BucketWriter, BucketReader, \
     WriteBucketProxy, ReadBucketProxy, StorageServer


class Bucket(unittest.TestCase):
    def make_workdir(self, name):
        basedir = os.path.join("storage", "Bucket", name)
        incoming = os.path.join(basedir, "tmp", "bucket")
        final = os.path.join(basedir, "bucket")
        fileutil.make_dirs(basedir)
        fileutil.make_dirs(os.path.join(basedir, "tmp"))
        return incoming, final

    def bucket_writer_closed(self, bw, consumed):
        pass

    def test_create(self):
        incoming, final = self.make_workdir("test_create")
        bw = BucketWriter(self, incoming, final, 200)
        bw.remote_write(0, "a"*25)
        bw.remote_write(25, "b"*25)
        bw.remote_write(50, "c"*25)
        bw.remote_write(75, "d"*7)
        bw.remote_close()

    def test_readwrite(self):
        incoming, final = self.make_workdir("test_readwrite")
        bw = BucketWriter(self, incoming, final, 200)
        bw.remote_write(0, "a"*25)
        bw.remote_write(25, "b"*25)
        bw.remote_write(50, "c"*7) # last block may be short
        bw.remote_close()

        # now read from it
        br = BucketReader(final)
        self.failUnlessEqual(br.remote_read(0, 25), "a"*25)
        self.failUnlessEqual(br.remote_read(25, 25), "b"*25)
        self.failUnlessEqual(br.remote_read(50, 7), "c"*7)

class RemoteBucket:

    def callRemote(self, methname, *args, **kwargs):
        def _call():
            meth = getattr(self.target, "remote_" + methname)
            return meth(*args, **kwargs)
        return defer.maybeDeferred(_call)

class BucketProxy(unittest.TestCase):
    def make_bucket(self, name, size):
        basedir = os.path.join("storage", "BucketProxy", name)
        incoming = os.path.join(basedir, "tmp", "bucket")
        final = os.path.join(basedir, "bucket")
        fileutil.make_dirs(basedir)
        fileutil.make_dirs(os.path.join(basedir, "tmp"))
        bw = BucketWriter(self, incoming, final, size)
        rb = RemoteBucket()
        rb.target = bw
        return bw, rb, final

    def bucket_writer_closed(self, bw, consumed):
        pass

    def test_create(self):
        bw, rb, final = self.make_bucket("test_create", 500)
        bp = WriteBucketProxy(rb,
                              data_size=300,
                              segment_size=10,
                              num_segments=5,
                              num_share_hashes=3,
                              uri_extension_size=500)
        self.failUnless(interfaces.IStorageBucketWriter.providedBy(bp))

    def test_readwrite(self):
        # Let's pretend each share has 100 bytes of data, and that there are
        # 4 segments (25 bytes each), and 8 shares total. So the three
        # per-segment merkle trees (plaintext_hash_tree, crypttext_hash_tree,
        # block_hashes) will have 4 leaves and 7 nodes each. The per-share
        # merkle tree (share_hashes) has 8 leaves and 15 nodes, and we need 3
        # nodes. Furthermore, let's assume the uri_extension is 500 bytes
        # long. That should make the whole share:
        #
        # 0x1c + 100 + 7*32 + 7*32 + 7*32 + 3*(2+32) + 4+500 = 1406 bytes long

        plaintext_hashes = [hashutil.tagged_hash("plain", "bar%d" % i)
                            for i in range(7)]
        crypttext_hashes = [hashutil.tagged_hash("crypt", "bar%d" % i)
                            for i in range(7)]
        block_hashes = [hashutil.tagged_hash("block", "bar%d" % i)
                        for i in range(7)]
        share_hashes = [(i, hashutil.tagged_hash("share", "bar%d" % i))
                        for i in (1,9,13)]
        uri_extension = "s" + "E"*498 + "e"

        bw, rb, final = self.make_bucket("test_readwrite", 1406)
        bp = WriteBucketProxy(rb,
                              data_size=95,
                              segment_size=25,
                              num_segments=4,
                              num_share_hashes=3,
                              uri_extension_size=len(uri_extension))

        d = bp.start()
        d.addCallback(lambda res: bp.put_block(0, "a"*25))
        d.addCallback(lambda res: bp.put_block(1, "b"*25))
        d.addCallback(lambda res: bp.put_block(2, "c"*25))
        d.addCallback(lambda res: bp.put_block(3, "d"*20))
        d.addCallback(lambda res: bp.put_plaintext_hashes(plaintext_hashes))
        d.addCallback(lambda res: bp.put_crypttext_hashes(crypttext_hashes))
        d.addCallback(lambda res: bp.put_block_hashes(block_hashes))
        d.addCallback(lambda res: bp.put_share_hashes(share_hashes))
        d.addCallback(lambda res: bp.put_uri_extension(uri_extension))
        d.addCallback(lambda res: bp.close())

        # now read everything back
        def _start_reading(res):
            br = BucketReader(final)
            rb = RemoteBucket()
            rb.target = br
            rbp = ReadBucketProxy(rb)
            self.failUnless(interfaces.IStorageBucketReader.providedBy(rbp))

            d1 = rbp.startIfNecessary()
            d1.addCallback(lambda res: rbp.get_block(0))
            d1.addCallback(lambda res: self.failUnlessEqual(res, "a"*25))
            d1.addCallback(lambda res: rbp.get_block(1))
            d1.addCallback(lambda res: self.failUnlessEqual(res, "b"*25))
            d1.addCallback(lambda res: rbp.get_block(2))
            d1.addCallback(lambda res: self.failUnlessEqual(res, "c"*25))
            d1.addCallback(lambda res: rbp.get_block(3))
            d1.addCallback(lambda res: self.failUnlessEqual(res, "d"*20))

            d1.addCallback(lambda res: rbp.get_plaintext_hashes())
            d1.addCallback(lambda res:
                           self.failUnlessEqual(res, plaintext_hashes))
            d1.addCallback(lambda res: rbp.get_crypttext_hashes())
            d1.addCallback(lambda res:
                           self.failUnlessEqual(res, crypttext_hashes))
            d1.addCallback(lambda res: rbp.get_block_hashes())
            d1.addCallback(lambda res: self.failUnlessEqual(res, block_hashes))
            d1.addCallback(lambda res: rbp.get_share_hashes())
            d1.addCallback(lambda res: self.failUnlessEqual(res, share_hashes))
            d1.addCallback(lambda res: rbp.get_uri_extension())
            d1.addCallback(lambda res:
                           self.failUnlessEqual(res, uri_extension))

            return d1

        d.addCallback(_start_reading)

        return d



class Server(unittest.TestCase):

    def setUp(self):
        self.sparent = service.MultiService()
    def tearDown(self):
        return self.sparent.stopService()

    def workdir(self, name):
        basedir = os.path.join("storage", "Server", name)
        return basedir

    def create(self, name, sizelimit=None):
        workdir = self.workdir(name)
        ss = StorageServer(workdir, sizelimit)
        ss.setServiceParent(self.sparent)
        return ss

    def test_create(self):
        ss = self.create("test_create")

    def test_allocate(self):
        ss = self.create("test_allocate")

        self.failUnlessEqual(ss.remote_get_buckets("vid"), {})

        canary = Referenceable()
        already,writers = ss.remote_allocate_buckets("vid", [0,1,2],
                                                     75, canary)
        self.failUnlessEqual(already, set())
        self.failUnlessEqual(set(writers.keys()), set([0,1,2]))

        # while the buckets are open, they should not count as readable
        self.failUnlessEqual(ss.remote_get_buckets("vid"), {})

        for i,wb in writers.items():
            wb.remote_write(0, "%25d" % i)
            wb.remote_close()

        # now they should be readable
        b = ss.remote_get_buckets("vid")
        self.failUnlessEqual(set(b.keys()), set([0,1,2]))
        self.failUnlessEqual(b[0].remote_read(0, 25), "%25d" % 0)

        # now if we about writing again, the server should offer those three
        # buckets as already present
        already,writers = ss.remote_allocate_buckets("vid", [0,1,2,3,4],
                                                     75, canary)
        self.failUnlessEqual(already, set([0,1,2]))
        self.failUnlessEqual(set(writers.keys()), set([3,4]))

        # while those two buckets are open for writing, the server should
        # tell new uploaders that they already exist (so that we don't try to
        # upload into them a second time)

        already,writers = ss.remote_allocate_buckets("vid", [2,3,4,5],
                                                     75, canary)
        self.failUnlessEqual(already, set([2,3,4]))
        self.failUnlessEqual(set(writers.keys()), set([5]))

    def test_sizelimits(self):
        ss = self.create("test_sizelimits", 100)
        canary = Referenceable()
        
        already,writers = ss.remote_allocate_buckets("vid1", [0,1,2],
                                                     25, canary)
        self.failUnlessEqual(len(writers), 3)
        # now the StorageServer should have 75 bytes provisionally allocated,
        # allowing only 25 more to be claimed
        self.failUnlessEqual(len(ss._active_writers), 3)

        already2,writers2 = ss.remote_allocate_buckets("vid2", [0,1,2],
                                                       25, canary)
        self.failUnlessEqual(len(writers2), 1)
        self.failUnlessEqual(len(ss._active_writers), 4)

        # we abandon the first set, so their provisional allocation should be
        # returned
        del already
        del writers
        self.failUnlessEqual(len(ss._active_writers), 1)

        # and we close the second set, so their provisional allocation should
        # become real, long-term allocation
        for bw in writers2.values():
            bw.remote_write(0, "a"*25)
            bw.remote_close()
        del already2
        del writers2
        del bw
        self.failUnlessEqual(len(ss._active_writers), 0)

        # now there should be 25 bytes allocated, and 75 free
        already3,writers3 = ss.remote_allocate_buckets("vid3", [0,1,2,3],
                                                       25, canary)
        self.failUnlessEqual(len(writers3), 3)
        self.failUnlessEqual(len(ss._active_writers), 3)

        del already3
        del writers3
        self.failUnlessEqual(len(ss._active_writers), 0)
        ss.disownServiceParent()
        del ss

        # creating a new StorageServer in the same directory should see the
        # same usage. note that metadata will be counted at startup but not
        # during runtime, so if we were creating any metadata, the allocation
        # would be more than 25 bytes and this test would need to be changed.
        ss = self.create("test_sizelimits", 100)
        already4,writers4 = ss.remote_allocate_buckets("vid4", [0,1,2,3],
                                                       25, canary)
        self.failUnlessEqual(len(writers4), 3)
        self.failUnlessEqual(len(ss._active_writers), 3)