src/allmydata/storage/server.py

   1 import os, re, weakref, struct, time
   2
   3 from foolscap import Referenceable
   4 from twisted.application import service
   5
   6 from zope.interface import implements
   7 from allmydata.interfaces import RIStorageServer, IStatsProducer
   8 from allmydata.util import base32, fileutil, log, time_format
   9 import allmydata # for __full_version__
  10
  11 from allmydata.storage.common import si_b2a, si_a2b, storage_index_to_dir
  12 _pyflakes_hush = [si_b2a, si_a2b, storage_index_to_dir] # re-exported
  13 from allmydata.storage.lease import LeaseInfo
  14 from allmydata.storage.mutable import MutableShareFile, EmptyShare, \
  15      create_mutable_sharefile
  16 from allmydata.storage.immutable import ShareFile, BucketWriter, BucketReader
  17
  18 # storage/
  19 # storage/shares/incoming
  20 #   incoming/ holds temp dirs named $START/$STORAGEINDEX/$SHARENUM which will
  21 #   be moved to storage/shares/$START/$STORAGEINDEX/$SHARENUM upon success
  22 # storage/shares/$START/$STORAGEINDEX
  23 # storage/shares/$START/$STORAGEINDEX/$SHARENUM
  24
  25 # Where "$START" denotes the first 10 bits worth of $STORAGEINDEX (that's 2
  26 # base-32 chars).
  27
  28 # $SHARENUM matches this regex:
  29 NUM_RE=re.compile("^[0-9]+$")
  30
  31
  32
  33 class StorageServer(service.MultiService, Referenceable):
  34     implements(RIStorageServer, IStatsProducer)
  35     name = 'storage'
  36
  37     def __init__(self, storedir, nodeid, reserved_space=0,
  38                  discard_storage=False, readonly_storage=False,
  39                  stats_provider=None):
  40         service.MultiService.__init__(self)
  41         assert isinstance(nodeid, str)
  42         assert len(nodeid) == 20
  43         self.my_nodeid = nodeid
  44         self.storedir = storedir
  45         sharedir = os.path.join(storedir, "shares")
  46         fileutil.make_dirs(sharedir)
  47         self.sharedir = sharedir
  48         # we don't actually create the corruption-advisory dir until necessary
  49         self.corruption_advisory_dir = os.path.join(storedir,
  50                                                     "corruption-advisories")
  51         self.reserved_space = int(reserved_space)
  52         self.no_storage = discard_storage
  53         self.readonly_storage = readonly_storage
  54         self.stats_provider = stats_provider
  55         if self.stats_provider:
  56             self.stats_provider.register_producer(self)
  57         self.incomingdir = os.path.join(sharedir, 'incoming')
  58         self._clean_incomplete()
  59         fileutil.make_dirs(self.incomingdir)
  60         self._active_writers = weakref.WeakKeyDictionary()
  61         lp = log.msg("StorageServer created", facility="tahoe.storage")
  62
  63         if reserved_space:
  64             if self.get_available_space() is None:
  65                 log.msg("warning: [storage]reserved_space= is set, but this platform does not support statvfs(2), so this reservation cannot be honored",
  66                         umin="0wZ27w", level=log.UNUSUAL)
  67
  68         self.latencies = {"allocate": [], # immutable
  69                           "write": [],
  70                           "close": [],
  71                           "read": [],
  72                           "get": [],
  73                           "writev": [], # mutable
  74                           "readv": [],
  75                           "add-lease": [], # both
  76                           "renew": [],
  77                           "cancel": [],
  78                           }
  79
  80     def count(self, name, delta=1):
  81         if self.stats_provider:
  82             self.stats_provider.count("storage_server." + name, delta)
  83
  84     def add_latency(self, category, latency):
  85         a = self.latencies[category]
  86         a.append(latency)
  87         if len(a) > 1000:
  88             self.latencies[category] = a[-1000:]
  89
  90     def get_latencies(self):
  91         """Return a dict, indexed by category, that contains a dict of
  92         latency numbers for each category. Each dict will contain the
  93         following keys: mean, 01_0_percentile, 10_0_percentile,
  94         50_0_percentile (median), 90_0_percentile, 95_0_percentile,
  95         99_0_percentile, 99_9_percentile. If no samples have been collected
  96         for the given category, then that category name will not be present
  97         in the return value."""
  98         # note that Amazon's Dynamo paper says they use 99.9% percentile.
  99         output = {}
 100         for category in self.latencies:
 101             if not self.latencies[category]:
 102                 continue
 103             stats = {}
 104             samples = self.latencies[category][:]
 105             samples.sort()
 106             count = len(samples)
 107             stats["mean"] = sum(samples) / count
 108             stats["01_0_percentile"] = samples[int(0.01 * count)]
 109             stats["10_0_percentile"] = samples[int(0.1 * count)]
 110             stats["50_0_percentile"] = samples[int(0.5 * count)]
 111             stats["90_0_percentile"] = samples[int(0.9 * count)]
 112             stats["95_0_percentile"] = samples[int(0.95 * count)]
 113             stats["99_0_percentile"] = samples[int(0.99 * count)]
 114             stats["99_9_percentile"] = samples[int(0.999 * count)]
 115             output[category] = stats
 116         return output
 117
 118     def log(self, *args, **kwargs):
 119         if "facility" not in kwargs:
 120             kwargs["facility"] = "tahoe.storage"
 121         return log.msg(*args, **kwargs)
 122
 123     def _clean_incomplete(self):
 124         fileutil.rm_dir(self.incomingdir)
 125
 126     def do_statvfs(self):
 127         return os.statvfs(self.storedir)
 128
 129     def get_stats(self):
 130         # remember: RIStatsProvider requires that our return dict
 131         # contains numeric values.
 132         stats = { 'storage_server.allocated': self.allocated_size(), }
 133         stats["storage_server.reserved_space"] = self.reserved_space
 134         for category,ld in self.get_latencies().items():
 135             for name,v in ld.items():
 136                 stats['storage_server.latencies.%s.%s' % (category, name)] = v
 137         writeable = True
 138         if self.readonly_storage:
 139             writeable = False
 140         try:
 141             s = self.do_statvfs()
 142             disk_total = s.f_bsize * s.f_blocks
 143             disk_used = s.f_bsize * (s.f_blocks - s.f_bfree)
 144             # spacetime predictors should look at the slope of disk_used.
 145             disk_avail = s.f_bsize * s.f_bavail # available to non-root users
 146             # include our local policy here: if we stop accepting shares when
 147             # the available space drops below 1GB, then include that fact in
 148             # disk_avail.
 149             disk_avail -= self.reserved_space
 150             disk_avail = max(disk_avail, 0)
 151             if self.readonly_storage:
 152                 disk_avail = 0
 153             if disk_avail == 0:
 154                 writeable = False
 155
 156             # spacetime predictors should use disk_avail / (d(disk_used)/dt)
 157             stats["storage_server.disk_total"] = disk_total
 158             stats["storage_server.disk_used"] = disk_used
 159             stats["storage_server.disk_avail"] = disk_avail
 160         except AttributeError:
 161             # os.statvfs is available only on unix
 162             pass
 163         stats["storage_server.accepting_immutable_shares"] = int(writeable)
 164         return stats
 165
 166
 167     def stat_disk(self, d):
 168         s = os.statvfs(d)
 169         # s.f_bavail: available to non-root users
 170         disk_avail = s.f_bsize * s.f_bavail
 171         return disk_avail
 172
 173     def get_available_space(self):
 174         # returns None if it cannot be measured (windows)
 175         try:
 176             disk_avail = self.stat_disk(self.storedir)
 177             disk_avail -= self.reserved_space
 178         except AttributeError:
 179             disk_avail = None
 180         if self.readonly_storage:
 181             disk_avail = 0
 182         return disk_avail
 183
 184     def allocated_size(self):
 185         space = 0
 186         for bw in self._active_writers:
 187             space += bw.allocated_size()
 188         return space
 189
 190     def remote_get_version(self):
 191         remaining_space = self.get_available_space()
 192         if remaining_space is None:
 193             # we're on a platform that doesn't have 'df', so make a vague
 194             # guess.
 195             remaining_space = 2**64
 196         version = { "http://allmydata.org/tahoe/protocols/storage/v1" :
 197                     { "maximum-immutable-share-size": remaining_space,
 198                       "tolerates-immutable-read-overrun": True,
 199                       "delete-mutable-shares-with-zero-length-writev": True,
 200                       },
 201                     "application-version": str(allmydata.__full_version__),
 202                     }
 203         return version
 204
 205     def remote_allocate_buckets(self, storage_index,
 206                                 renew_secret, cancel_secret,
 207                                 sharenums, allocated_size,
 208                                 canary, owner_num=0):
 209         # owner_num is not for clients to set, but rather it should be
 210         # curried into the PersonalStorageServer instance that is dedicated
 211         # to a particular owner.
 212         start = time.time()
 213         self.count("allocate")
 214         alreadygot = set()
 215         bucketwriters = {} # k: shnum, v: BucketWriter
 216         si_dir = storage_index_to_dir(storage_index)
 217         si_s = si_b2a(storage_index)
 218
 219         log.msg("storage: allocate_buckets %s" % si_s)
 220
 221         # in this implementation, the lease information (including secrets)
 222         # goes into the share files themselves. It could also be put into a
 223         # separate database. Note that the lease should not be added until
 224         # the BucketWriter has been closed.
 225         expire_time = time.time() + 31*24*60*60
 226         lease_info = LeaseInfo(owner_num,
 227                                renew_secret, cancel_secret,
 228                                expire_time, self.my_nodeid)
 229
 230         max_space_per_bucket = allocated_size
 231
 232         remaining_space = self.get_available_space()
 233         limited = remaining_space is not None
 234         if limited:
 235             # this is a bit conservative, since some of this allocated_size()
 236             # has already been written to disk, where it will show up in
 237             # get_available_space.
 238             remaining_space -= self.allocated_size()
 239
 240         # fill alreadygot with all shares that we have, not just the ones
 241         # they asked about: this will save them a lot of work. Add or update
 242         # leases for all of them: if they want us to hold shares for this
 243         # file, they'll want us to hold leases for this file.
 244         for (shnum, fn) in self._get_bucket_shares(storage_index):
 245             alreadygot.add(shnum)
 246             sf = ShareFile(fn)
 247             sf.add_or_renew_lease(lease_info)
 248
 249         # self.readonly_storage causes remaining_space=0
 250
 251         for shnum in sharenums:
 252             incominghome = os.path.join(self.incomingdir, si_dir, "%d" % shnum)
 253             finalhome = os.path.join(self.sharedir, si_dir, "%d" % shnum)
 254             if os.path.exists(finalhome):
 255                 # great! we already have it. easy.
 256                 pass
 257             elif os.path.exists(incominghome):
 258                 # Note that we don't create BucketWriters for shnums that
 259                 # have a partial share (in incoming/), so if a second upload
 260                 # occurs while the first is still in progress, the second
 261                 # uploader will use different storage servers.
 262                 pass
 263             elif (not limited) or (remaining_space >= max_space_per_bucket):
 264                 # ok! we need to create the new share file.
 265                 bw = BucketWriter(self, incominghome, finalhome,
 266                                   max_space_per_bucket, lease_info, canary)
 267                 if self.no_storage:
 268                     bw.throw_out_all_data = True
 269                 bucketwriters[shnum] = bw
 270                 self._active_writers[bw] = 1
 271                 if limited:
 272                     remaining_space -= max_space_per_bucket
 273             else:
 274                 # bummer! not enough space to accept this bucket
 275                 pass
 276
 277         if bucketwriters:
 278             fileutil.make_dirs(os.path.join(self.sharedir, si_dir))
 279
 280         self.add_latency("allocate", time.time() - start)
 281         return alreadygot, bucketwriters
 282
 283     def _iter_share_files(self, storage_index):
 284         for shnum, filename in self._get_bucket_shares(storage_index):
 285             f = open(filename, 'rb')
 286             header = f.read(32)
 287             f.close()
 288             if header[:32] == MutableShareFile.MAGIC:
 289                 sf = MutableShareFile(filename, self)
 290                 # note: if the share has been migrated, the renew_lease()
 291                 # call will throw an exception, with information to help the
 292                 # client update the lease.
 293             elif header[:4] == struct.pack(">L", 1):
 294                 sf = ShareFile(filename)
 295             else:
 296                 continue # non-sharefile
 297             yield sf
 298
 299     def remote_add_lease(self, storage_index, renew_secret, cancel_secret,
 300                          owner_num=1):
 301         start = time.time()
 302         self.count("add-lease")
 303         new_expire_time = time.time() + 31*24*60*60
 304         lease_info = LeaseInfo(owner_num,
 305                                renew_secret, cancel_secret,
 306                                new_expire_time, self.my_nodeid)
 307         for sf in self._iter_share_files(storage_index):
 308             sf.add_or_renew_lease(lease_info)
 309         self.add_latency("add-lease", time.time() - start)
 310         return None
 311
 312     def remote_renew_lease(self, storage_index, renew_secret):
 313         start = time.time()
 314         self.count("renew")
 315         new_expire_time = time.time() + 31*24*60*60
 316         found_buckets = False
 317         for sf in self._iter_share_files(storage_index):
 318             found_buckets = True
 319             sf.renew_lease(renew_secret, new_expire_time)
 320         self.add_latency("renew", time.time() - start)
 321         if not found_buckets:
 322             raise IndexError("no such lease to renew")
 323
 324     def remote_cancel_lease(self, storage_index, cancel_secret):
 325         start = time.time()
 326         self.count("cancel")
 327
 328         total_space_freed = 0
 329         found_buckets = False
 330         for sf in self._iter_share_files(storage_index):
 331             # note: if we can't find a lease on one share, we won't bother
 332             # looking in the others. Unless something broke internally
 333             # (perhaps we ran out of disk space while adding a lease), the
 334             # leases on all shares will be identical.
 335             found_buckets = True
 336             # this raises IndexError if the lease wasn't present XXXX
 337             total_space_freed += sf.cancel_lease(cancel_secret)
 338
 339         if found_buckets:
 340             storagedir = os.path.join(self.sharedir,
 341                                       storage_index_to_dir(storage_index))
 342             if not os.listdir(storagedir):
 343                 os.rmdir(storagedir)
 344
 345         if self.stats_provider:
 346             self.stats_provider.count('storage_server.bytes_freed',
 347                                       total_space_freed)
 348         self.add_latency("cancel", time.time() - start)
 349         if not found_buckets:
 350             raise IndexError("no such storage index")
 351
 352     def bucket_writer_closed(self, bw, consumed_size):
 353         if self.stats_provider:
 354             self.stats_provider.count('storage_server.bytes_added', consumed_size)
 355         del self._active_writers[bw]
 356
 357     def _get_bucket_shares(self, storage_index):
 358         """Return a list of (shnum, pathname) tuples for files that hold
 359         shares for this storage_index. In each tuple, 'shnum' will always be
 360         the integer form of the last component of 'pathname'."""
 361         storagedir = os.path.join(self.sharedir, storage_index_to_dir(storage_index))
 362         try:
 363             for f in os.listdir(storagedir):
 364                 if NUM_RE.match(f):
 365                     filename = os.path.join(storagedir, f)
 366                     yield (int(f), filename)
 367         except OSError:
 368             # Commonly caused by there being no buckets at all.
 369             pass
 370
 371     def remote_get_buckets(self, storage_index):
 372         start = time.time()
 373         self.count("get")
 374         si_s = si_b2a(storage_index)
 375         log.msg("storage: get_buckets %s" % si_s)
 376         bucketreaders = {} # k: sharenum, v: BucketReader
 377         for shnum, filename in self._get_bucket_shares(storage_index):
 378             bucketreaders[shnum] = BucketReader(self, filename,
 379                                                 storage_index, shnum)
 380         self.add_latency("get", time.time() - start)
 381         return bucketreaders
 382
 383     def get_leases(self, storage_index):
 384         """Provide an iterator that yields all of the leases attached to this
 385         bucket. Each lease is returned as a tuple of (owner_num,
 386         renew_secret, cancel_secret, expiration_time).
 387
 388         This method is not for client use.
 389         """
 390
 391         # since all shares get the same lease data, we just grab the leases
 392         # from the first share
 393         try:
 394             shnum, filename = self._get_bucket_shares(storage_index).next()
 395             sf = ShareFile(filename)
 396             return sf.iter_leases()
 397         except StopIteration:
 398             return iter([])
 399
 400     def remote_slot_testv_and_readv_and_writev(self, storage_index,
 401                                                secrets,
 402                                                test_and_write_vectors,
 403                                                read_vector):
 404         start = time.time()
 405         self.count("writev")
 406         si_s = si_b2a(storage_index)
 407         lp = log.msg("storage: slot_writev %s" % si_s)
 408         si_dir = storage_index_to_dir(storage_index)
 409         (write_enabler, renew_secret, cancel_secret) = secrets
 410         # shares exist if there is a file for them
 411         bucketdir = os.path.join(self.sharedir, si_dir)
 412         shares = {}
 413         if os.path.isdir(bucketdir):
 414             for sharenum_s in os.listdir(bucketdir):
 415                 try:
 416                     sharenum = int(sharenum_s)
 417                 except ValueError:
 418                     continue
 419                 filename = os.path.join(bucketdir, sharenum_s)
 420                 msf = MutableShareFile(filename, self)
 421                 msf.check_write_enabler(write_enabler, si_s)
 422                 shares[sharenum] = msf
 423         # write_enabler is good for all existing shares.
 424
 425         # Now evaluate test vectors.
 426         testv_is_good = True
 427         for sharenum in test_and_write_vectors:
 428             (testv, datav, new_length) = test_and_write_vectors[sharenum]
 429             if sharenum in shares:
 430                 if not shares[sharenum].check_testv(testv):
 431                     self.log("testv failed: [%d]: %r" % (sharenum, testv))
 432                     testv_is_good = False
 433                     break
 434             else:
 435                 # compare the vectors against an empty share, in which all
 436                 # reads return empty strings.
 437                 if not EmptyShare().check_testv(testv):
 438                     self.log("testv failed (empty): [%d] %r" % (sharenum,
 439                                                                 testv))
 440                     testv_is_good = False
 441                     break
 442
 443         # now gather the read vectors, before we do any writes
 444         read_data = {}
 445         for sharenum, share in shares.items():
 446             read_data[sharenum] = share.readv(read_vector)
 447
 448         ownerid = 1 # TODO
 449         expire_time = time.time() + 31*24*60*60   # one month
 450         lease_info = LeaseInfo(ownerid,
 451                                renew_secret, cancel_secret,
 452                                expire_time, self.my_nodeid)
 453
 454         if testv_is_good:
 455             # now apply the write vectors
 456             for sharenum in test_and_write_vectors:
 457                 (testv, datav, new_length) = test_and_write_vectors[sharenum]
 458                 if new_length == 0:
 459                     if sharenum in shares:
 460                         shares[sharenum].unlink()
 461                 else:
 462                     if sharenum not in shares:
 463                         # allocate a new share
 464                         allocated_size = 2000 # arbitrary, really
 465                         share = self._allocate_slot_share(bucketdir, secrets,
 466                                                           sharenum,
 467                                                           allocated_size,
 468                                                           owner_num=0)
 469                         shares[sharenum] = share
 470                     shares[sharenum].writev(datav, new_length)
 471                     # and update the lease
 472                     shares[sharenum].add_or_renew_lease(lease_info)
 473
 474             if new_length == 0:
 475                 # delete empty bucket directories
 476                 if not os.listdir(bucketdir):
 477                     os.rmdir(bucketdir)
 478
 479
 480         # all done
 481         self.add_latency("writev", time.time() - start)
 482         return (testv_is_good, read_data)
 483
 484     def _allocate_slot_share(self, bucketdir, secrets, sharenum,
 485                              allocated_size, owner_num=0):
 486         (write_enabler, renew_secret, cancel_secret) = secrets
 487         my_nodeid = self.my_nodeid
 488         fileutil.make_dirs(bucketdir)
 489         filename = os.path.join(bucketdir, "%d" % sharenum)
 490         share = create_mutable_sharefile(filename, my_nodeid, write_enabler,
 491                                          self)
 492         return share
 493
 494     def remote_slot_readv(self, storage_index, shares, readv):
 495         start = time.time()
 496         self.count("readv")
 497         si_s = si_b2a(storage_index)
 498         lp = log.msg("storage: slot_readv %s %s" % (si_s, shares),
 499                      facility="tahoe.storage", level=log.OPERATIONAL)
 500         si_dir = storage_index_to_dir(storage_index)
 501         # shares exist if there is a file for them
 502         bucketdir = os.path.join(self.sharedir, si_dir)
 503         if not os.path.isdir(bucketdir):
 504             self.add_latency("readv", time.time() - start)
 505             return {}
 506         datavs = {}
 507         for sharenum_s in os.listdir(bucketdir):
 508             try:
 509                 sharenum = int(sharenum_s)
 510             except ValueError:
 511                 continue
 512             if sharenum in shares or not shares:
 513                 filename = os.path.join(bucketdir, sharenum_s)
 514                 msf = MutableShareFile(filename, self)
 515                 datavs[sharenum] = msf.readv(readv)
 516         log.msg("returning shares %s" % (datavs.keys(),),
 517                 facility="tahoe.storage", level=log.NOISY, parent=lp)
 518         self.add_latency("readv", time.time() - start)
 519         return datavs
 520
 521     def remote_advise_corrupt_share(self, share_type, storage_index, shnum,
 522                                     reason):
 523         fileutil.make_dirs(self.corruption_advisory_dir)
 524         now = time_format.iso_utc(sep="T")
 525         si_s = base32.b2a(storage_index)
 526         # windows can't handle colons in the filename
 527         fn = os.path.join(self.corruption_advisory_dir,
 528                           "%s--%s-%d" % (now, si_s, shnum)).replace(":","")
 529         f = open(fn, "w")
 530         f.write("report: Share Corruption\n")
 531         f.write("type: %s\n" % share_type)
 532         f.write("storage_index: %s\n" % si_s)
 533         f.write("share_number: %d\n" % shnum)
 534         f.write("\n")
 535         f.write(reason)
 536         f.write("\n")
 537         f.close()
 538         log.msg(format=("client claims corruption in (%(share_type)s) " +
 539                         "%(si)s-%(shnum)d: %(reason)s"),
 540                 share_type=share_type, si=si_s, shnum=shnum, reason=reason,
 541                 level=log.SCARY, umid="SGx2fA")
 542         return None
 543