src/allmydata/immutable/filenode.py

   1 import copy, os.path, stat
   2 from cStringIO import StringIO
   3 from zope.interface import implements
   4 from twisted.internet import defer
   5 from twisted.internet.interfaces import IPushProducer, IConsumer
   6 from twisted.protocols import basic
   7 from foolscap.api import eventually
   8 from allmydata.interfaces import IFileNode, ICheckable, \
   9      IDownloadTarget, IUploadResults
  10 from allmydata.util import dictutil, log, base32
  11 from allmydata import uri as urimodule
  12 from allmydata.immutable.checker import Checker
  13 from allmydata.check_results import CheckResults, CheckAndRepairResults
  14 from allmydata.immutable.repairer import Repairer
  15 from allmydata.immutable import download
  16
  17 class _ImmutableFileNodeBase(object):
  18     implements(IFileNode, ICheckable)
  19
  20     def get_readonly_uri(self):
  21         return self.get_uri()
  22
  23     def is_mutable(self):
  24         return False
  25
  26     def is_readonly(self):
  27         return True
  28
  29     def __hash__(self):
  30         return self.u.__hash__()
  31     def __eq__(self, other):
  32         if IFileNode.providedBy(other):
  33             return self.u.__eq__(other.u)
  34         else:
  35             return False
  36     def __ne__(self, other):
  37         if IFileNode.providedBy(other):
  38             return self.u.__eq__(other.u)
  39         else:
  40             return True
  41
  42 class PortionOfFile:
  43     # like a list slice (things[2:14]), but for a file on disk
  44     def __init__(self, fn, offset=0, size=None):
  45         self.f = open(fn, "rb")
  46         self.f.seek(offset)
  47         self.bytes_left = size
  48
  49     def read(self, size=None):
  50         # bytes_to_read = min(size, self.bytes_left), but None>anything
  51         if size is None:
  52             bytes_to_read = self.bytes_left
  53         elif self.bytes_left is None:
  54             bytes_to_read = size
  55         else:
  56             bytes_to_read = min(size, self.bytes_left)
  57         data = self.f.read(bytes_to_read)
  58         if self.bytes_left is not None:
  59             self.bytes_left -= len(data)
  60         return data
  61
  62 class DownloadCache:
  63     implements(IDownloadTarget)
  64
  65     def __init__(self, filecap, storage_index, downloader,
  66                  cachedirectorymanager):
  67         self._downloader = downloader
  68         self._uri = filecap
  69         self._storage_index = storage_index
  70         self.milestones = set() # of (offset,size,Deferred)
  71         self.cachedirectorymanager = cachedirectorymanager
  72         self.cachefile = None
  73         self.download_in_progress = False
  74         # five states:
  75         #  new FileNode, no downloads ever performed
  76         #  new FileNode, leftover file (partial)
  77         #  new FileNode, leftover file (whole)
  78         #  download in progress, not yet complete
  79         #  download complete
  80
  81     def when_range_available(self, offset, size):
  82         assert isinstance(offset, (int,long))
  83         assert isinstance(size, (int,long))
  84
  85         d = defer.Deferred()
  86         self.milestones.add( (offset,size,d) )
  87         self._check_milestones()
  88         if self.milestones and not self.download_in_progress:
  89             self.download_in_progress = True
  90             log.msg(format=("immutable filenode read [%(si)s]: " +
  91                             "starting download"),
  92                     si=base32.b2a(self._storage_index),
  93                     umid="h26Heg", level=log.OPERATIONAL)
  94             d2 = self._downloader.download(self._uri, self)
  95             d2.addBoth(self._download_done)
  96             d2.addErrback(self._download_failed)
  97             d2.addErrback(log.err, umid="cQaM9g")
  98         return d
  99
 100     def read(self, consumer, offset, size):
 101         assert offset+size <= self.get_filesize()
 102         if not self.cachefile:
 103             self.cachefile = self.cachedirectorymanager.get_file(base32.b2a(self._storage_index))
 104         f = PortionOfFile(self.cachefile.get_filename(), offset, size)
 105         d = basic.FileSender().beginFileTransfer(f, consumer)
 106         d.addCallback(lambda lastSent: consumer)
 107         return d
 108
 109     def _download_done(self, res):
 110         # clear download_in_progress, so failed downloads can be re-tried
 111         self.download_in_progress = False
 112         return res
 113
 114     def _download_failed(self, f):
 115         # tell anyone who's waiting that we failed
 116         for m in self.milestones:
 117             (offset,size,d) = m
 118             eventually(d.errback, f)
 119         self.milestones.clear()
 120
 121     def _check_milestones(self):
 122         current_size = self.get_filesize()
 123         for m in list(self.milestones):
 124             (offset,size,d) = m
 125             if offset+size <= current_size:
 126                 log.msg(format=("immutable filenode read [%(si)s] " +
 127                                 "%(offset)d+%(size)d vs %(filesize)d: " +
 128                                 "done"),
 129                         si=base32.b2a(self._storage_index),
 130                         offset=offset, size=size, filesize=current_size,
 131                         umid="nuedUg", level=log.NOISY)
 132                 self.milestones.discard(m)
 133                 eventually(d.callback, None)
 134             else:
 135                 log.msg(format=("immutable filenode read [%(si)s] " +
 136                                 "%(offset)d+%(size)d vs %(filesize)d: " +
 137                                 "still waiting"),
 138                         si=base32.b2a(self._storage_index),
 139                         offset=offset, size=size, filesize=current_size,
 140                         umid="8PKOhg", level=log.NOISY)
 141
 142     def get_filesize(self):
 143         if not self.cachefile:
 144             self.cachefile = self.cachedirectorymanager.get_file(base32.b2a(self._storage_index))
 145         try:
 146             filesize = os.stat(self.cachefile.get_filename())[stat.ST_SIZE]
 147         except OSError:
 148             filesize = 0
 149         return filesize
 150
 151
 152     def open(self, size):
 153         if not self.cachefile:
 154             self.cachefile = self.cachedirectorymanager.get_file(base32.b2a(self._storage_index))
 155         self.f = open(self.cachefile.get_filename(), "wb")
 156
 157     def write(self, data):
 158         self.f.write(data)
 159         self._check_milestones()
 160
 161     def close(self):
 162         self.f.close()
 163         self._check_milestones()
 164
 165     def fail(self, why):
 166         pass
 167     def register_canceller(self, cb):
 168         pass
 169     def finish(self):
 170         return None
 171     # The following methods are just because the target might be a
 172     # repairer.DownUpConnector, and just because the current CHKUpload object
 173     # expects to find the storage index and encoding parameters in its
 174     # Uploadable.
 175     def set_storageindex(self, storageindex):
 176         pass
 177     def set_encodingparams(self, encodingparams):
 178         pass
 179
 180
 181 class FileNode(_ImmutableFileNodeBase, log.PrefixingLogMixin):
 182     def __init__(self, filecap, storage_broker, secret_holder,
 183                  downloader, history, cachedirectorymanager):
 184         assert isinstance(filecap, str)
 185         self.u = urimodule.CHKFileURI.init_from_string(filecap)
 186         self._storage_broker = storage_broker
 187         self._secret_holder = secret_holder
 188         self._downloader = downloader
 189         self._history = history
 190         storage_index = self.get_storage_index()
 191         self.download_cache = DownloadCache(filecap, storage_index, downloader,
 192                                             cachedirectorymanager)
 193         prefix = self.u.get_verify_cap().to_string()
 194         log.PrefixingLogMixin.__init__(self, "allmydata.immutable.filenode", prefix=prefix)
 195         self.log("starting", level=log.OPERATIONAL)
 196
 197     def get_uri(self):
 198         return self.u.to_string()
 199
 200     def get_size(self):
 201         return self.u.get_size()
 202
 203     def get_verify_cap(self):
 204         return self.u.get_verify_cap()
 205
 206     def get_repair_cap(self):
 207         # CHK files can be repaired with just the verifycap
 208         return self.u.get_verify_cap()
 209
 210     def get_storage_index(self):
 211         return self.u.storage_index
 212
 213     def check_and_repair(self, monitor, verify=False, add_lease=False):
 214         verifycap = self.get_verify_cap()
 215         sb = self._storage_broker
 216         servers = sb.get_all_servers()
 217         sh = self._secret_holder
 218
 219         c = Checker(verifycap=verifycap, servers=servers,
 220                     verify=verify, add_lease=add_lease, secret_holder=sh,
 221                     monitor=monitor)
 222         d = c.start()
 223         def _maybe_repair(cr):
 224             crr = CheckAndRepairResults(self.u.storage_index)
 225             crr.pre_repair_results = cr
 226             if cr.is_healthy():
 227                 crr.post_repair_results = cr
 228                 return defer.succeed(crr)
 229             else:
 230                 crr.repair_attempted = True
 231                 crr.repair_successful = False # until proven successful
 232                 def _gather_repair_results(ur):
 233                     assert IUploadResults.providedBy(ur), ur
 234                     # clone the cr -- check results to form the basic of the prr -- post-repair results
 235                     prr = CheckResults(cr.uri, cr.storage_index)
 236                     prr.data = copy.deepcopy(cr.data)
 237
 238                     sm = prr.data['sharemap']
 239                     assert isinstance(sm, dictutil.DictOfSets), sm
 240                     sm.update(ur.sharemap)
 241                     servers_responding = set(prr.data['servers-responding'])
 242                     servers_responding.union(ur.sharemap.iterkeys())
 243                     prr.data['servers-responding'] = list(servers_responding)
 244                     prr.data['count-shares-good'] = len(sm)
 245                     prr.data['count-good-share-hosts'] = len(sm)
 246                     is_healthy = bool(len(sm) >= self.u.total_shares)
 247                     is_recoverable = bool(len(sm) >= self.u.needed_shares)
 248                     prr.set_healthy(is_healthy)
 249                     prr.set_recoverable(is_recoverable)
 250                     crr.repair_successful = is_healthy
 251                     prr.set_needs_rebalancing(len(sm) >= self.u.total_shares)
 252
 253                     crr.post_repair_results = prr
 254                     return crr
 255                 def _repair_error(f):
 256                     # as with mutable repair, I'm not sure if I want to pass
 257                     # through a failure or not. TODO
 258                     crr.repair_successful = False
 259                     crr.repair_failure = f
 260                     return f
 261                 r = Repairer(storage_broker=sb, secret_holder=sh,
 262                              verifycap=verifycap, monitor=monitor)
 263                 d = r.start()
 264                 d.addCallbacks(_gather_repair_results, _repair_error)
 265                 return d
 266
 267         d.addCallback(_maybe_repair)
 268         return d
 269
 270     def check(self, monitor, verify=False, add_lease=False):
 271         verifycap = self.get_verify_cap()
 272         sb = self._storage_broker
 273         servers = sb.get_all_servers()
 274         sh = self._secret_holder
 275
 276         v = Checker(verifycap=verifycap, servers=servers,
 277                     verify=verify, add_lease=add_lease, secret_holder=sh,
 278                     monitor=monitor)
 279         return v.start()
 280
 281     def read(self, consumer, offset=0, size=None):
 282         if size is None:
 283             size = self.get_size() - offset
 284         size = min(size, self.get_size() - offset)
 285
 286         if offset == 0 and size == self.get_size():
 287             # don't use the cache, just do a normal streaming download
 288             self.log("doing normal full download", umid="VRSBwg", level=log.OPERATIONAL)
 289             return self.download(download.ConsumerAdapter(consumer))
 290
 291         d = self.download_cache.when_range_available(offset, size)
 292         d.addCallback(lambda res:
 293                       self.download_cache.read(consumer, offset, size))
 294         return d
 295
 296     def download(self, target):
 297         return self._downloader.download(self.get_uri(), target,
 298                                          self._parentmsgid,
 299                                          history=self._history)
 300
 301     def download_to_data(self):
 302         return self._downloader.download_to_data(self.get_uri(),
 303                                                  history=self._history)
 304
 305 class LiteralProducer:
 306     implements(IPushProducer)
 307     def resumeProducing(self):
 308         pass
 309     def stopProducing(self):
 310         pass
 311
 312
 313 class LiteralFileNode(_ImmutableFileNodeBase):
 314
 315     def __init__(self, filecap):
 316         assert isinstance(filecap, str)
 317         self.u = urimodule.LiteralFileURI.init_from_string(filecap)
 318
 319     def get_uri(self):
 320         return self.u.to_string()
 321
 322     def get_size(self):
 323         return len(self.u.data)
 324
 325     def get_verify_cap(self):
 326         return None
 327
 328     def get_repair_cap(self):
 329         return None
 330
 331     def get_storage_index(self):
 332         return None
 333
 334     def check(self, monitor, verify=False, add_lease=False):
 335         return defer.succeed(None)
 336
 337     def check_and_repair(self, monitor, verify=False, add_lease=False):
 338         return defer.succeed(None)
 339
 340     def read(self, consumer, offset=0, size=None):
 341         if size is None:
 342             data = self.u.data[offset:]
 343         else:
 344             data = self.u.data[offset:offset+size]
 345
 346         # We use twisted.protocols.basic.FileSender, which only does
 347         # non-streaming, i.e. PullProducer, where the receiver/consumer must
 348         # ask explicitly for each chunk of data. There are only two places in
 349         # the Twisted codebase that can't handle streaming=False, both of
 350         # which are in the upload path for an FTP/SFTP server
 351         # (protocols.ftp.FileConsumer and
 352         # vfs.adapters.ftp._FileToConsumerAdapter), neither of which is
 353         # likely to be used as the target for a Tahoe download.
 354
 355         d = basic.FileSender().beginFileTransfer(StringIO(data), consumer)
 356         d.addCallback(lambda lastSent: consumer)
 357         return d
 358
 359     def download(self, target):
 360         # note that this does not update the stats_provider
 361         data = self.u.data
 362         if IConsumer.providedBy(target):
 363             target.registerProducer(LiteralProducer(), True)
 364         target.open(len(data))
 365         target.write(data)
 366         if IConsumer.providedBy(target):
 367             target.unregisterProducer()
 368         target.close()
 369         return defer.maybeDeferred(target.finish)
 370
 371     def download_to_data(self):
 372         data = self.u.data
 373         return defer.succeed(data)