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 from allmydata.storage.crawler import BucketCountingCrawler
  18
  19 # storage/
  20 # storage/shares/incoming
  21 #   incoming/ holds temp dirs named $START/$STORAGEINDEX/$SHARENUM which will
  22 #   be moved to storage/shares/$START/$STORAGEINDEX/$SHARENUM upon success
  23 # storage/shares/$START/$STORAGEINDEX
  24 # storage/shares/$START/$STORAGEINDEX/$SHARENUM
  25
  26 # Where "$START" denotes the first 10 bits worth of $STORAGEINDEX (that's 2
  27 # base-32 chars).
  28
  29 # $SHARENUM matches this regex:
  30 NUM_RE=re.compile("^[0-9]+$")
  31
  32
  33
  34 class StorageServer(service.MultiService, Referenceable):
  35     implements(RIStorageServer, IStatsProducer)
  36     name = 'storage'
  37
  38     def __init__(self, storedir, nodeid, reserved_space=0,
  39                  discard_storage=False, readonly_storage=False,
  40                  stats_provider=None):
  41         service.MultiService.__init__(self)
  42         assert isinstance(nodeid, str)
  43         assert len(nodeid) == 20
  44         self.my_nodeid = nodeid
  45         self.storedir = storedir
  46         sharedir = os.path.join(storedir, "shares")
  47         fileutil.make_dirs(sharedir)
  48         self.sharedir = sharedir
  49         # we don't actually create the corruption-advisory dir until necessary
  50         self.corruption_advisory_dir = os.path.join(storedir,
  51                                                     "corruption-advisories")
  52         self.reserved_space = int(reserved_space)
  53         self.no_storage = discard_storage
  54         self.readonly_storage = readonly_storage
  55         self.stats_provider = stats_provider
  56         if self.stats_provider:
  57             self.stats_provider.register_producer(self)
  58         self.incomingdir = os.path.join(sharedir, 'incoming')
  59         self._clean_incomplete()
  60         fileutil.make_dirs(self.incomingdir)
  61         self._active_writers = weakref.WeakKeyDictionary()
  62         lp = log.msg("StorageServer created", facility="tahoe.storage")
  63
  64         if reserved_space:
  65             if self.get_available_space() is None:
  66                 log.msg("warning: [storage]reserved_space= is set, but this platform does not support statvfs(2), so this reservation cannot be honored",
  67                         umin="0wZ27w", level=log.UNUSUAL)
  68
  69         self.latencies = {"allocate": [], # immutable
  70                           "write": [],
  71                           "close": [],
  72                           "read": [],
  73                           "get": [],
  74                           "writev": [], # mutable
  75                           "readv": [],
  76                           "add-lease": [], # both
  77                           "renew": [],
  78                           "cancel": [],
  79                           }
  80         self.add_bucket_counter()
  81
  82     def add_bucket_counter(self):
  83         statefile = os.path.join(self.storedir, "bucket_counter.state")
  84         self.bucket_counter = BucketCountingCrawler(self, statefile)
  85         self.bucket_counter.setServiceParent(self)
  86
  87     def count(self, name, delta=1):
  88         if self.stats_provider:
  89             self.stats_provider.count("storage_server." + name, delta)
  90
  91     def add_latency(self, category, latency):
  92         a = self.latencies[category]
  93         a.append(latency)
  94         if len(a) > 1000:
  95             self.latencies[category] = a[-1000:]
  96
  97     def get_latencies(self):
  98         """Return a dict, indexed by category, that contains a dict of
  99         latency numbers for each category. Each dict will contain the
 100         following keys: mean, 01_0_percentile, 10_0_percentile,
 101         50_0_percentile (median), 90_0_percentile, 95_0_percentile,
 102         99_0_percentile, 99_9_percentile. If no samples have been collected
 103         for the given category, then that category name will not be present
 104         in the return value."""
 105         # note that Amazon's Dynamo paper says they use 99.9% percentile.
 106         output = {}
 107         for category in self.latencies:
 108             if not self.latencies[category]:
 109                 continue
 110             stats = {}
 111             samples = self.latencies[category][:]
 112             samples.sort()
 113             count = len(samples)
 114             stats["mean"] = sum(samples) / count
 115             stats["01_0_percentile"] = samples[int(0.01 * count)]
 116             stats["10_0_percentile"] = samples[int(0.1 * count)]
 117             stats["50_0_percentile"] = samples[int(0.5 * count)]
 118             stats["90_0_percentile"] = samples[int(0.9 * count)]
 119             stats["95_0_percentile"] = samples[int(0.95 * count)]
 120             stats["99_0_percentile"] = samples[int(0.99 * count)]
 121             stats["99_9_percentile"] = samples[int(0.999 * count)]
 122             output[category] = stats
 123         return output
 124
 125     def log(self, *args, **kwargs):
 126         if "facility" not in kwargs:
 127             kwargs["facility"] = "tahoe.storage"
 128         return log.msg(*args, **kwargs)
 129
 130     def _clean_incomplete(self):
 131         fileutil.rm_dir(self.incomingdir)
 132
 133     def do_statvfs(self):
 134         return os.statvfs(self.storedir)
 135
 136     def get_stats(self):
 137         # remember: RIStatsProvider requires that our return dict
 138         # contains numeric values.
 139         stats = { 'storage_server.allocated': self.allocated_size(), }
 140         stats["storage_server.reserved_space"] = self.reserved_space
 141         for category,ld in self.get_latencies().items():
 142             for name,v in ld.items():
 143                 stats['storage_server.latencies.%s.%s' % (category, name)] = v
 144         writeable = True
 145         if self.readonly_storage:
 146             writeable = False
 147         try:
 148             s = self.do_statvfs()
 149             disk_total = s.f_bsize * s.f_blocks
 150             disk_used = s.f_bsize * (s.f_blocks - s.f_bfree)
 151             # spacetime predictors should look at the slope of disk_used.
 152             disk_free_for_root = s.f_bsize * s.f_bfree
 153             disk_free_for_nonroot = s.f_bsize * s.f_bavail
 154
 155             # include our local policy here: if we stop accepting shares when
 156             # the available space drops below 1GB, then include that fact in
 157             # disk_avail.
 158             disk_avail = disk_free_for_nonroot - self.reserved_space
 159             disk_avail = max(disk_avail, 0)
 160             if self.readonly_storage:
 161                 disk_avail = 0
 162             if disk_avail == 0:
 163                 writeable = False
 164
 165             # spacetime predictors should use disk_avail / (d(disk_used)/dt)
 166             stats["storage_server.disk_total"] = disk_total
 167             stats["storage_server.disk_used"] = disk_used
 168             stats["storage_server.disk_free_for_root"] = disk_free_for_root
 169             stats["storage_server.disk_free_for_nonroot"] = disk_free_for_nonroot
 170             stats["storage_server.disk_avail"] = disk_avail
 171         except AttributeError:
 172             # os.statvfs is available only on unix
 173             pass
 174         stats["storage_server.accepting_immutable_shares"] = int(writeable)
 175         s = self.bucket_counter.get_state()
 176         bucket_count = s.get("last-complete-bucket-count")
 177         if bucket_count:
 178             stats["storage_server.total_bucket_count"] = bucket_count
 179         return stats
 180
 181
 182     def stat_disk(self, d):
 183         s = os.statvfs(d)
 184         # s.f_bavail: available to non-root users
 185         disk_avail = s.f_bsize * s.f_bavail
 186         return disk_avail
 187
 188     def get_available_space(self):
 189         # returns None if it cannot be measured (windows)
 190         try:
 191             disk_avail = self.stat_disk(self.storedir)
 192             disk_avail -= self.reserved_space
 193         except AttributeError:
 194             disk_avail = None
 195         if self.readonly_storage:
 196             disk_avail = 0
 197         return disk_avail
 198
 199     def allocated_size(self):
 200         space = 0
 201         for bw in self._active_writers:
 202             space += bw.allocated_size()
 203         return space
 204
 205     def remote_get_version(self):
 206         remaining_space = self.get_available_space()
 207         if remaining_space is None:
 208             # we're on a platform that doesn't have 'df', so make a vague
 209             # guess.
 210             remaining_space = 2**64
 211         version = { "http://allmydata.org/tahoe/protocols/storage/v1" :
 212                     { "maximum-immutable-share-size": remaining_space,
 213                       "tolerates-immutable-read-overrun": True,
 214                       "delete-mutable-shares-with-zero-length-writev": True,
 215                       },
 216                     "application-version": str(allmydata.__full_version__),
 217                     }
 218         return version
 219
 220     def remote_allocate_buckets(self, storage_index,
 221                                 renew_secret, cancel_secret,
 222                                 sharenums, allocated_size,
 223                                 canary, owner_num=0):
 224         # owner_num is not for clients to set, but rather it should be
 225         # curried into the PersonalStorageServer instance that is dedicated
 226         # to a particular owner.
 227         start = time.time()
 228         self.count("allocate")
 229         alreadygot = set()
 230         bucketwriters = {} # k: shnum, v: BucketWriter
 231         si_dir = storage_index_to_dir(storage_index)
 232         si_s = si_b2a(storage_index)
 233
 234         log.msg("storage: allocate_buckets %s" % si_s)
 235
 236         # in this implementation, the lease information (including secrets)
 237         # goes into the share files themselves. It could also be put into a
 238         # separate database. Note that the lease should not be added until
 239         # the BucketWriter has been closed.
 240         expire_time = time.time() + 31*24*60*60
 241         lease_info = LeaseInfo(owner_num,
 242                                renew_secret, cancel_secret,
 243                                expire_time, self.my_nodeid)
 244
 245         max_space_per_bucket = allocated_size
 246
 247         remaining_space = self.get_available_space()
 248         limited = remaining_space is not None
 249         if limited:
 250             # this is a bit conservative, since some of this allocated_size()
 251             # has already been written to disk, where it will show up in
 252             # get_available_space.
 253             remaining_space -= self.allocated_size()
 254
 255         # fill alreadygot with all shares that we have, not just the ones
 256         # they asked about: this will save them a lot of work. Add or update
 257         # leases for all of them: if they want us to hold shares for this
 258         # file, they'll want us to hold leases for this file.
 259         for (shnum, fn) in self._get_bucket_shares(storage_index):
 260             alreadygot.add(shnum)
 261             sf = ShareFile(fn)
 262             sf.add_or_renew_lease(lease_info)
 263
 264         # self.readonly_storage causes remaining_space=0
 265
 266         for shnum in sharenums:
 267             incominghome = os.path.join(self.incomingdir, si_dir, "%d" % shnum)
 268             finalhome = os.path.join(self.sharedir, si_dir, "%d" % shnum)
 269             if os.path.exists(finalhome):
 270                 # great! we already have it. easy.
 271                 pass
 272             elif os.path.exists(incominghome):
 273                 # Note that we don't create BucketWriters for shnums that
 274                 # have a partial share (in incoming/), so if a second upload
 275                 # occurs while the first is still in progress, the second
 276                 # uploader will use different storage servers.
 277                 pass
 278             elif (not limited) or (remaining_space >= max_space_per_bucket):
 279                 # ok! we need to create the new share file.
 280                 bw = BucketWriter(self, incominghome, finalhome,
 281                                   max_space_per_bucket, lease_info, canary)
 282                 if self.no_storage:
 283                     bw.throw_out_all_data = True
 284                 bucketwriters[shnum] = bw
 285                 self._active_writers[bw] = 1
 286                 if limited:
 287                     remaining_space -= max_space_per_bucket
 288             else:
 289                 # bummer! not enough space to accept this bucket
 290                 pass
 291
 292         if bucketwriters:
 293             fileutil.make_dirs(os.path.join(self.sharedir, si_dir))
 294
 295         self.add_latency("allocate", time.time() - start)
 296         return alreadygot, bucketwriters
 297
 298     def _iter_share_files(self, storage_index):
 299         for shnum, filename in self._get_bucket_shares(storage_index):
 300             f = open(filename, 'rb')
 301             header = f.read(32)
 302             f.close()
 303             if header[:32] == MutableShareFile.MAGIC:
 304                 sf = MutableShareFile(filename, self)
 305                 # note: if the share has been migrated, the renew_lease()
 306                 # call will throw an exception, with information to help the
 307                 # client update the lease.
 308             elif header[:4] == struct.pack(">L", 1):
 309                 sf = ShareFile(filename)
 310             else:
 311                 continue # non-sharefile
 312             yield sf
 313
 314     def remote_add_lease(self, storage_index, renew_secret, cancel_secret,
 315                          owner_num=1):
 316         start = time.time()
 317         self.count("add-lease")
 318         new_expire_time = time.time() + 31*24*60*60
 319         lease_info = LeaseInfo(owner_num,
 320                                renew_secret, cancel_secret,
 321                                new_expire_time, self.my_nodeid)
 322         for sf in self._iter_share_files(storage_index):
 323             sf.add_or_renew_lease(lease_info)
 324         self.add_latency("add-lease", time.time() - start)
 325         return None
 326
 327     def remote_renew_lease(self, storage_index, renew_secret):
 328         start = time.time()
 329         self.count("renew")
 330         new_expire_time = time.time() + 31*24*60*60
 331         found_buckets = False
 332         for sf in self._iter_share_files(storage_index):
 333             found_buckets = True
 334             sf.renew_lease(renew_secret, new_expire_time)
 335         self.add_latency("renew", time.time() - start)
 336         if not found_buckets:
 337             raise IndexError("no such lease to renew")
 338
 339     def remote_cancel_lease(self, storage_index, cancel_secret):
 340         start = time.time()
 341         self.count("cancel")
 342
 343         total_space_freed = 0
 344         found_buckets = False
 345         for sf in self._iter_share_files(storage_index):
 346             # note: if we can't find a lease on one share, we won't bother
 347             # looking in the others. Unless something broke internally
 348             # (perhaps we ran out of disk space while adding a lease), the
 349             # leases on all shares will be identical.
 350             found_buckets = True
 351             # this raises IndexError if the lease wasn't present XXXX
 352             total_space_freed += sf.cancel_lease(cancel_secret)
 353
 354         if found_buckets:
 355             storagedir = os.path.join(self.sharedir,
 356                                       storage_index_to_dir(storage_index))
 357             if not os.listdir(storagedir):
 358                 os.rmdir(storagedir)
 359
 360         if self.stats_provider:
 361             self.stats_provider.count('storage_server.bytes_freed',
 362                                       total_space_freed)
 363         self.add_latency("cancel", time.time() - start)
 364         if not found_buckets:
 365             raise IndexError("no such storage index")
 366
 367     def bucket_writer_closed(self, bw, consumed_size):
 368         if self.stats_provider:
 369             self.stats_provider.count('storage_server.bytes_added', consumed_size)
 370         del self._active_writers[bw]
 371
 372     def _get_bucket_shares(self, storage_index):
 373         """Return a list of (shnum, pathname) tuples for files that hold
 374         shares for this storage_index. In each tuple, 'shnum' will always be
 375         the integer form of the last component of 'pathname'."""
 376         storagedir = os.path.join(self.sharedir, storage_index_to_dir(storage_index))
 377         try:
 378             for f in os.listdir(storagedir):
 379                 if NUM_RE.match(f):
 380                     filename = os.path.join(storagedir, f)
 381                     yield (int(f), filename)
 382         except OSError:
 383             # Commonly caused by there being no buckets at all.
 384             pass
 385
 386     def remote_get_buckets(self, storage_index):
 387         start = time.time()
 388         self.count("get")
 389         si_s = si_b2a(storage_index)
 390         log.msg("storage: get_buckets %s" % si_s)
 391         bucketreaders = {} # k: sharenum, v: BucketReader
 392         for shnum, filename in self._get_bucket_shares(storage_index):
 393             bucketreaders[shnum] = BucketReader(self, filename,
 394                                                 storage_index, shnum)
 395         self.add_latency("get", time.time() - start)
 396         return bucketreaders
 397
 398     def get_leases(self, storage_index):
 399         """Provide an iterator that yields all of the leases attached to this
 400         bucket. Each lease is returned as a tuple of (owner_num,
 401         renew_secret, cancel_secret, expiration_time).
 402
 403         This method is not for client use.
 404         """
 405
 406         # since all shares get the same lease data, we just grab the leases
 407         # from the first share
 408         try:
 409             shnum, filename = self._get_bucket_shares(storage_index).next()
 410             sf = ShareFile(filename)
 411             return sf.iter_leases()
 412         except StopIteration:
 413             return iter([])
 414
 415     def remote_slot_testv_and_readv_and_writev(self, storage_index,
 416                                                secrets,
 417                                                test_and_write_vectors,
 418                                                read_vector):
 419         start = time.time()
 420         self.count("writev")
 421         si_s = si_b2a(storage_index)
 422         lp = log.msg("storage: slot_writev %s" % si_s)
 423         si_dir = storage_index_to_dir(storage_index)
 424         (write_enabler, renew_secret, cancel_secret) = secrets
 425         # shares exist if there is a file for them
 426         bucketdir = os.path.join(self.sharedir, si_dir)
 427         shares = {}
 428         if os.path.isdir(bucketdir):
 429             for sharenum_s in os.listdir(bucketdir):
 430                 try:
 431                     sharenum = int(sharenum_s)
 432                 except ValueError:
 433                     continue
 434                 filename = os.path.join(bucketdir, sharenum_s)
 435                 msf = MutableShareFile(filename, self)
 436                 msf.check_write_enabler(write_enabler, si_s)
 437                 shares[sharenum] = msf
 438         # write_enabler is good for all existing shares.
 439
 440         # Now evaluate test vectors.
 441         testv_is_good = True
 442         for sharenum in test_and_write_vectors:
 443             (testv, datav, new_length) = test_and_write_vectors[sharenum]
 444             if sharenum in shares:
 445                 if not shares[sharenum].check_testv(testv):
 446                     self.log("testv failed: [%d]: %r" % (sharenum, testv))
 447                     testv_is_good = False
 448                     break
 449             else:
 450                 # compare the vectors against an empty share, in which all
 451                 # reads return empty strings.
 452                 if not EmptyShare().check_testv(testv):
 453                     self.log("testv failed (empty): [%d] %r" % (sharenum,
 454                                                                 testv))
 455                     testv_is_good = False
 456                     break
 457
 458         # now gather the read vectors, before we do any writes
 459         read_data = {}
 460         for sharenum, share in shares.items():
 461             read_data[sharenum] = share.readv(read_vector)
 462
 463         ownerid = 1 # TODO
 464         expire_time = time.time() + 31*24*60*60   # one month
 465         lease_info = LeaseInfo(ownerid,
 466                                renew_secret, cancel_secret,
 467                                expire_time, self.my_nodeid)
 468
 469         if testv_is_good:
 470             # now apply the write vectors
 471             for sharenum in test_and_write_vectors:
 472                 (testv, datav, new_length) = test_and_write_vectors[sharenum]
 473                 if new_length == 0:
 474                     if sharenum in shares:
 475                         shares[sharenum].unlink()
 476                 else:
 477                     if sharenum not in shares:
 478                         # allocate a new share
 479                         allocated_size = 2000 # arbitrary, really
 480                         share = self._allocate_slot_share(bucketdir, secrets,
 481                                                           sharenum,
 482                                                           allocated_size,
 483                                                           owner_num=0)
 484                         shares[sharenum] = share
 485                     shares[sharenum].writev(datav, new_length)
 486                     # and update the lease
 487                     shares[sharenum].add_or_renew_lease(lease_info)
 488
 489             if new_length == 0:
 490                 # delete empty bucket directories
 491                 if not os.listdir(bucketdir):
 492                     os.rmdir(bucketdir)
 493
 494
 495         # all done
 496         self.add_latency("writev", time.time() - start)
 497         return (testv_is_good, read_data)
 498
 499     def _allocate_slot_share(self, bucketdir, secrets, sharenum,
 500                              allocated_size, owner_num=0):
 501         (write_enabler, renew_secret, cancel_secret) = secrets
 502         my_nodeid = self.my_nodeid
 503         fileutil.make_dirs(bucketdir)
 504         filename = os.path.join(bucketdir, "%d" % sharenum)
 505         share = create_mutable_sharefile(filename, my_nodeid, write_enabler,
 506                                          self)
 507         return share
 508
 509     def remote_slot_readv(self, storage_index, shares, readv):
 510         start = time.time()
 511         self.count("readv")
 512         si_s = si_b2a(storage_index)
 513         lp = log.msg("storage: slot_readv %s %s" % (si_s, shares),
 514                      facility="tahoe.storage", level=log.OPERATIONAL)
 515         si_dir = storage_index_to_dir(storage_index)
 516         # shares exist if there is a file for them
 517         bucketdir = os.path.join(self.sharedir, si_dir)
 518         if not os.path.isdir(bucketdir):
 519             self.add_latency("readv", time.time() - start)
 520             return {}
 521         datavs = {}
 522         for sharenum_s in os.listdir(bucketdir):
 523             try:
 524                 sharenum = int(sharenum_s)
 525             except ValueError:
 526                 continue
 527             if sharenum in shares or not shares:
 528                 filename = os.path.join(bucketdir, sharenum_s)
 529                 msf = MutableShareFile(filename, self)
 530                 datavs[sharenum] = msf.readv(readv)
 531         log.msg("returning shares %s" % (datavs.keys(),),
 532                 facility="tahoe.storage", level=log.NOISY, parent=lp)
 533         self.add_latency("readv", time.time() - start)
 534         return datavs
 535
 536     def remote_advise_corrupt_share(self, share_type, storage_index, shnum,
 537                                     reason):
 538         fileutil.make_dirs(self.corruption_advisory_dir)
 539         now = time_format.iso_utc(sep="T")
 540         si_s = si_b2a(storage_index)
 541         # windows can't handle colons in the filename
 542         fn = os.path.join(self.corruption_advisory_dir,
 543                           "%s--%s-%d" % (now, si_s, shnum)).replace(":","")
 544         f = open(fn, "w")
 545         f.write("report: Share Corruption\n")
 546         f.write("type: %s\n" % share_type)
 547         f.write("storage_index: %s\n" % si_s)
 548         f.write("share_number: %d\n" % shnum)
 549         f.write("\n")
 550         f.write(reason)
 551         f.write("\n")
 552         f.close()
 553         log.msg(format=("client claims corruption in (%(share_type)s) " +
 554                         "%(si)s-%(shnum)d: %(reason)s"),
 555                 share_type=share_type, si=si_s, shnum=shnum, reason=reason,
 556                 level=log.SCARY, umid="SGx2fA")
 557         return None
 558