2 from zope.interface import Interface
3 from foolscap.schema import StringConstraint, ListOf, TupleOf, SetOf, DictOf, \
4 ChoiceOf, IntegerConstraint, Any
5 from foolscap import RemoteInterface, Referenceable
9 Hash = StringConstraint(maxLength=HASH_SIZE,
10 minLength=HASH_SIZE)# binary format 32-byte SHA256 hash
11 Nodeid = StringConstraint(maxLength=20,
12 minLength=20) # binary format 20-byte SHA1 hash
13 FURL = StringConstraint(1000)
14 StorageIndex = StringConstraint(16)
15 URI = StringConstraint(300) # kind of arbitrary
17 MAX_BUCKETS = 256 # per peer -- zfec offers at most 256 shares per file
19 ShareData = StringConstraint(None)
20 URIExtensionData = StringConstraint(1000)
21 Number = IntegerConstraint(8) # 2**(8*8) == 16EiB ~= 18e18 ~= 18 exabytes
23 ReadSize = int # the 'int' constraint is 2**31 == 2Gib -- large files are processed in not-so-large increments
24 WriteEnablerSecret = Hash # used to protect mutable bucket modifications
25 LeaseRenewSecret = Hash # used to protect bucket lease renewal requests
26 LeaseCancelSecret = Hash # used to protect bucket lease cancellation requests
28 class RIStubClient(RemoteInterface):
29 """Each client publishes a service announcement for a dummy object called
30 the StubClient. This object doesn't actually offer any services, but the
31 announcement helps the Introducer keep track of which clients are
32 subscribed (so the grid admin can keep track of things like the size of
33 the grid and the client versions in use. This is the (empty)
34 RemoteInterface for the StubClient."""
36 class RIBucketWriter(RemoteInterface):
37 """ Objects of this kind live on the server side. """
38 def write(offset=Offset, data=ShareData):
43 If the data that has been written is incomplete or inconsistent then
44 the server will throw the data away, else it will store it for future
50 """Abandon all the data that has been written.
54 class RIBucketReader(RemoteInterface):
55 def read(offset=Offset, length=ReadSize):
58 def advise_corrupt_share(reason=str):
59 """Clients who discover hash failures in shares that they have
60 downloaded from me will use this method to inform me about the
61 failures. I will record their concern so that my operator can
62 manually inspect the shares in question. I return None.
64 This is a wrapper around RIStorageServer.advise_corrupt_share(),
65 which is tied to a specific share, and therefore does not need the
66 extra share-identifying arguments. Please see that method for full
70 TestVector = ListOf(TupleOf(Offset, ReadSize, str, str))
71 # elements are (offset, length, operator, specimen)
72 # operator is one of "lt, le, eq, ne, ge, gt"
73 # nop always passes and is used to fetch data while writing.
74 # you should use length==len(specimen) for everything except nop
75 DataVector = ListOf(TupleOf(Offset, ShareData))
76 # (offset, data). This limits us to 30 writes of 1MiB each per call
77 TestAndWriteVectorsForShares = DictOf(int,
80 ChoiceOf(None, Offset), # new_length
82 ReadVector = ListOf(TupleOf(Offset, ReadSize))
83 ReadData = ListOf(ShareData)
84 # returns data[offset:offset+length] for each element of TestVector
86 class RIStorageServer(RemoteInterface):
87 __remote_name__ = "RIStorageServer.tahoe.allmydata.com"
91 Return a dictionary of version information.
93 return DictOf(str, Any())
95 def allocate_buckets(storage_index=StorageIndex,
96 renew_secret=LeaseRenewSecret,
97 cancel_secret=LeaseCancelSecret,
98 sharenums=SetOf(int, maxLength=MAX_BUCKETS),
99 allocated_size=Offset, canary=Referenceable):
101 @param storage_index: the index of the bucket to be created or
103 @param sharenums: these are the share numbers (probably between 0 and
104 99) that the sender is proposing to store on this
106 @param renew_secret: This is the secret used to protect bucket refresh
107 This secret is generated by the client and
108 stored for later comparison by the server. Each
109 server is given a different secret.
110 @param cancel_secret: Like renew_secret, but protects bucket decref.
111 @param canary: If the canary is lost before close(), the bucket is
113 @return: tuple of (alreadygot, allocated), where alreadygot is what we
114 already have and is what we hereby agree to accept. New
115 leases are added for shares in both lists.
117 return TupleOf(SetOf(int, maxLength=MAX_BUCKETS),
118 DictOf(int, RIBucketWriter, maxKeys=MAX_BUCKETS))
120 def add_lease(storage_index=StorageIndex,
121 renew_secret=LeaseRenewSecret,
122 cancel_secret=LeaseCancelSecret):
124 Add a new lease on the given bucket. If the renew_secret matches an
125 existing lease, that lease will be renewed instead.
129 def renew_lease(storage_index=StorageIndex, renew_secret=LeaseRenewSecret):
131 Renew the lease on a given bucket. Some networks will use this, some
136 def cancel_lease(storage_index=StorageIndex,
137 cancel_secret=LeaseCancelSecret):
139 Cancel the lease on a given bucket. If this was the last lease on the
140 bucket, the bucket will be deleted.
144 def get_buckets(storage_index=StorageIndex):
145 return DictOf(int, RIBucketReader, maxKeys=MAX_BUCKETS)
149 def slot_readv(storage_index=StorageIndex,
150 shares=ListOf(int), readv=ReadVector):
151 """Read a vector from the numbered shares associated with the given
152 storage index. An empty shares list means to return data from all
153 known shares. Returns a dictionary with one key per share."""
154 return DictOf(int, ReadData) # shnum -> results
156 def slot_testv_and_readv_and_writev(storage_index=StorageIndex,
157 secrets=TupleOf(WriteEnablerSecret,
160 tw_vectors=TestAndWriteVectorsForShares,
163 """General-purpose test-and-set operation for mutable slots. Perform
164 a bunch of comparisons against the existing shares. If they all pass,
165 then apply a bunch of write vectors to those shares. Then use the
166 read vectors to extract data from all the shares and return the data.
168 This method is, um, large. The goal is to allow clients to update all
169 the shares associated with a mutable file in a single round trip.
171 @param storage_index: the index of the bucket to be created or
173 @param write_enabler: a secret that is stored along with the slot.
174 Writes are accepted from any caller who can
175 present the matching secret. A different secret
176 should be used for each slot*server pair.
177 @param renew_secret: This is the secret used to protect bucket refresh
178 This secret is generated by the client and
179 stored for later comparison by the server. Each
180 server is given a different secret.
181 @param cancel_secret: Like renew_secret, but protects bucket decref.
183 The 'secrets' argument is a tuple of (write_enabler, renew_secret,
184 cancel_secret). The first is required to perform any write. The
185 latter two are used when allocating new shares. To simply acquire a
186 new lease on existing shares, use an empty testv and an empty writev.
188 Each share can have a separate test vector (i.e. a list of
189 comparisons to perform). If all vectors for all shares pass, then all
190 writes for all shares are recorded. Each comparison is a 4-tuple of
191 (offset, length, operator, specimen), which effectively does a bool(
192 (read(offset, length)) OPERATOR specimen ) and only performs the
193 write if all these evaluate to True. Basic test-and-set uses 'eq'.
194 Write-if-newer uses a seqnum and (offset, length, 'lt', specimen).
195 Write-if-same-or-newer uses 'le'.
197 Reads from the end of the container are truncated, and missing shares
198 behave like empty ones, so to assert that a share doesn't exist (for
199 use when creating a new share), use (0, 1, 'eq', '').
201 The write vector will be applied to the given share, expanding it if
202 necessary. A write vector applied to a share number that did not
203 exist previously will cause that share to be created.
205 Each write vector is accompanied by a 'new_length' argument. If
206 new_length is not None, use it to set the size of the container. This
207 can be used to pre-allocate space for a series of upcoming writes, or
208 truncate existing data. If the container is growing, new_length will
209 be applied before datav. If the container is shrinking, it will be
212 The read vector is used to extract data from all known shares,
213 *before* any writes have been applied. The same vector is used for
214 all shares. This captures the state that was tested by the test
217 This method returns two values: a boolean and a dict. The boolean is
218 True if the write vectors were applied, False if not. The dict is
219 keyed by share number, and each value contains a list of strings, one
220 for each element of the read vector.
222 If the write_enabler is wrong, this will raise BadWriteEnablerError.
223 To enable share migration (using update_write_enabler), the exception
224 will have the nodeid used for the old write enabler embedded in it,
225 in the following string::
227 The write enabler was recorded by nodeid '%s'.
229 Note that the nodeid here is encoded using the same base32 encoding
230 used by Foolscap and allmydata.util.idlib.nodeid_b2a().
233 return TupleOf(bool, DictOf(int, ReadData))
235 def advise_corrupt_share(share_type=str, storage_index=StorageIndex,
236 shnum=int, reason=str):
237 """Clients who discover hash failures in shares that they have
238 downloaded from me will use this method to inform me about the
239 failures. I will record their concern so that my operator can
240 manually inspect the shares in question. I return None.
242 'share_type' is either 'mutable' or 'immutable'. 'storage_index' is a
243 (binary) storage index string, and 'shnum' is the integer share
244 number. 'reason' is a human-readable explanation of the problem,
245 probably including some expected hash values and the computed ones
246 which did not match. Corruption advisories for mutable shares should
247 include a hash of the public key (the same value that appears in the
248 mutable-file verify-cap), since the current share format does not
252 class IStorageBucketWriter(Interface):
254 Objects of this kind live on the client side.
256 def put_block(segmentnum=int, data=ShareData):
257 """@param data: For most segments, this data will be 'blocksize'
258 bytes in length. The last segment might be shorter.
259 @return: a Deferred that fires (with None) when the operation completes
262 def put_plaintext_hashes(hashes=ListOf(Hash)):
264 @return: a Deferred that fires (with None) when the operation completes
267 def put_crypttext_hashes(hashes=ListOf(Hash)):
269 @return: a Deferred that fires (with None) when the operation completes
272 def put_block_hashes(blockhashes=ListOf(Hash)):
274 @return: a Deferred that fires (with None) when the operation completes
277 def put_share_hashes(sharehashes=ListOf(TupleOf(int, Hash))):
279 @return: a Deferred that fires (with None) when the operation completes
282 def put_uri_extension(data=URIExtensionData):
283 """This block of data contains integrity-checking information (hashes
284 of plaintext, crypttext, and shares), as well as encoding parameters
285 that are necessary to recover the data. This is a serialized dict
286 mapping strings to other strings. The hash of this data is kept in
287 the URI and verified before any of the data is used. All buckets for
288 a given file contain identical copies of this data.
290 The serialization format is specified with the following pseudocode:
291 for k in sorted(dict.keys()):
292 assert re.match(r'^[a-zA-Z_\-]+$', k)
293 write(k + ':' + netstring(dict[k]))
295 @return: a Deferred that fires (with None) when the operation completes
299 """Finish writing and close the bucket. The share is not finalized
300 until this method is called: if the uploading client disconnects
301 before calling close(), the partially-written share will be
304 @return: a Deferred that fires (with None) when the operation completes
307 class IStorageBucketReader(Interface):
309 def get_block(blocknum=int):
310 """Most blocks will be the same size. The last block might be shorter
316 def get_plaintext_hashes():
318 @return: ListOf(Hash)
321 def get_crypttext_hashes():
323 @return: ListOf(Hash)
326 def get_block_hashes():
328 @return: ListOf(Hash)
331 def get_share_hashes():
333 @return: ListOf(TupleOf(int, Hash))
336 def get_uri_extension():
338 @return: URIExtensionData
343 # hm, we need a solution for forward references in schemas
344 FileNode_ = Any() # TODO: foolscap needs constraints on copyables
345 DirectoryNode_ = Any() # TODO: same
346 AnyNode_ = ChoiceOf(FileNode_, DirectoryNode_)
349 class IURI(Interface):
350 def init_from_string(uri):
351 """Accept a string (as created by my to_string() method) and populate
352 this instance with its data. I am not normally called directly,
353 please use the module-level uri.from_string() function to convert
354 arbitrary URI strings into IURI-providing instances."""
357 """Return False if this URI be used to modify the data. Return True
358 if this URI cannot be used to modify the data."""
361 """Return True if the data can be modified by *somebody* (perhaps
362 someone who has a more powerful URI than this one)."""
365 """Return another IURI instance, which represents a read-only form of
366 this one. If is_readonly() is True, this returns self."""
369 """Return an instance that provides IVerifierURI, which can be used
370 to check on the availability of the file or directory, without
371 providing enough capabilities to actually read or modify the
372 contents. This may return None if the file does not need checking or
373 verification (e.g. LIT URIs).
377 """Return a string of printable ASCII characters, suitable for
378 passing into init_from_string."""
380 class IVerifierURI(Interface):
381 def init_from_string(uri):
382 """Accept a string (as created by my to_string() method) and populate
383 this instance with its data. I am not normally called directly,
384 please use the module-level uri.from_string() function to convert
385 arbitrary URI strings into IURI-providing instances."""
388 """Return a string of printable ASCII characters, suitable for
389 passing into init_from_string."""
391 class IDirnodeURI(Interface):
392 """I am a URI which represents a dirnode."""
395 class IFileURI(Interface):
396 """I am a URI which represents a filenode."""
398 """Return the length (in bytes) of the file that I represent."""
400 class IMutableFileURI(Interface):
401 """I am a URI which represents a mutable filenode."""
402 class INewDirectoryURI(Interface):
404 class IReadonlyNewDirectoryURI(Interface):
408 class IFilesystemNode(Interface):
411 Return the URI that can be used by others to get access to this
412 node. If this node is read-only, the URI will only offer read-only
413 access. If this node is read-write, the URI will offer read-write
416 If you have read-write access to a node and wish to share merely
417 read-only access with others, use get_readonly_uri().
420 def get_readonly_uri():
421 """Return the directory URI that can be used by others to get
422 read-only access to this directory node. The result is a read-only
423 URI, regardless of whether this dirnode is read-only or read-write.
425 If you have merely read-only access to this dirnode,
426 get_readonly_uri() will return the same thing as get_uri().
430 """Return an IVerifierURI instance that represents the
431 'verifiy/refresh capability' for this node. The holder of this
432 capability will be able to renew the lease for this node, protecting
433 it from garbage-collection. They will also be able to ask a server if
434 it holds a share for the file or directory.
437 def get_storage_index():
438 """Return a string with the (binary) storage index in use on this
439 download. This may be None if there is no storage index (i.e. LIT
443 """Return True if this reference provides mutable access to the given
444 file or directory (i.e. if you can modify it), or False if not. Note
445 that even if this reference is read-only, someone else may hold a
446 read-write reference to it."""
449 """Return True if this file or directory is mutable (by *somebody*,
450 not necessarily you), False if it is is immutable. Note that a file
451 might be mutable overall, but your reference to it might be
452 read-only. On the other hand, all references to an immutable file
453 will be read-only; there are no read-write references to an immutable
457 class IMutableFilesystemNode(IFilesystemNode):
460 class IFileNode(IFilesystemNode):
461 def download(target):
462 """Download the file's contents to a given IDownloadTarget"""
464 def download_to_data():
465 """Download the file's contents. Return a Deferred that fires
466 with those contents."""
469 """Return the length (in bytes) of the data this node represents."""
471 def read(consumer, offset=0, size=None):
472 """Download a portion (possibly all) of the file's contents, making
473 them available to the given IConsumer. Return a Deferred that fires
474 (with the consumer) when the consumer is unregistered (either because
475 the last byte has been given to it, or because the consumer threw an
476 exception during write(), possibly because it no longer wants to
477 receive data). The portion downloaded will start at 'offset' and
478 contain 'size' bytes (or the remainder of the file if size==None).
480 The consumer will be used in non-streaming mode: an IPullProducer
481 will be attached to it.
483 The consumer will not receive data right away: several network trips
484 must occur first. The order of events will be::
486 consumer.registerProducer(p, streaming)
487 (if streaming == False)::
488 consumer does p.resumeProducing()
490 consumer does p.resumeProducing()
491 consumer.write(data).. (repeat until all data is written)
492 consumer.unregisterProducer()
493 deferred.callback(consumer)
495 If a download error occurs, or an exception is raised by
496 consumer.registerProducer() or consumer.write(), I will call
497 consumer.unregisterProducer() and then deliver the exception via
498 deferred.errback(). To cancel the download, the consumer should call
499 p.stopProducing(), which will result in an exception being delivered
500 via deferred.errback().
502 A simple download-to-memory consumer example would look like this::
504 class MemoryConsumer:
505 implements(IConsumer)
509 def registerProducer(self, p, streaming):
510 assert streaming == False
513 def write(self, data):
514 self.chunks.append(data)
515 def unregisterProducer(self):
517 d = filenode.read(MemoryConsumer())
518 d.addCallback(lambda mc: "".join(mc.chunks))
523 class IMutableFileNode(IFileNode, IMutableFilesystemNode):
524 """I provide access to a 'mutable file', which retains its identity
525 regardless of what contents are put in it.
527 The consistency-vs-availability problem means that there might be
528 multiple versions of a file present in the grid, some of which might be
529 unrecoverable (i.e. have fewer than 'k' shares). These versions are
530 loosely ordered: each has a sequence number and a hash, and any version
531 with seqnum=N was uploaded by a node which has seen at least one version
534 The 'servermap' (an instance of IMutableFileServerMap) is used to
535 describe the versions that are known to be present in the grid, and which
536 servers are hosting their shares. It is used to represent the 'state of
537 the world', and is used for this purpose by my test-and-set operations.
538 Downloading the contents of the mutable file will also return a
539 servermap. Uploading a new version into the mutable file requires a
540 servermap as input, and the semantics of the replace operation is
541 'replace the file with my new version if it looks like nobody else has
542 changed the file since my previous download'. Because the file is
543 distributed, this is not a perfect test-and-set operation, but it will do
544 its best. If the replace process sees evidence of a simultaneous write,
545 it will signal an UncoordinatedWriteError, so that the caller can take
549 Most readers will want to use the 'best' current version of the file, and
550 should use my 'download_best_version()' method.
552 To unconditionally replace the file, callers should use overwrite(). This
553 is the mode that user-visible mutable files will probably use.
555 To apply some delta to the file, call modify() with a callable modifier
556 function that can apply the modification that you want to make. This is
557 the mode that dirnodes will use, since most directory modification
558 operations can be expressed in terms of deltas to the directory state.
561 Three methods are available for users who need to perform more complex
562 operations. The first is get_servermap(), which returns an up-to-date
563 servermap using a specified mode. The second is download_version(), which
564 downloads a specific version (not necessarily the 'best' one). The third
565 is 'upload', which accepts new contents and a servermap (which must have
566 been updated with MODE_WRITE). The upload method will attempt to apply
567 the new contents as long as no other node has modified the file since the
568 servermap was updated. This might be useful to a caller who wants to
569 merge multiple versions into a single new one.
571 Note that each time the servermap is updated, a specific 'mode' is used,
572 which determines how many peers are queried. To use a servermap for my
573 replace() method, that servermap must have been updated in MODE_WRITE.
574 These modes are defined in allmydata.mutable.common, and consist of
575 MODE_READ, MODE_WRITE, MODE_ANYTHING, and MODE_CHECK. Please look in
576 allmydata/mutable/servermap.py for details about the differences.
578 Mutable files are currently limited in size (about 3.5MB max) and can
579 only be retrieved and updated all-at-once, as a single big string. Future
580 versions of our mutable files will remove this restriction.
583 def download_best_version():
584 """Download the 'best' available version of the file, meaning one of
585 the recoverable versions with the highest sequence number. If no
586 uncoordinated writes have occurred, and if enough shares are
587 available, then this will be the most recent version that has been
590 I update an internal servermap with MODE_READ, determine which
591 version of the file is indicated by
592 servermap.best_recoverable_version(), and return a Deferred that
593 fires with its contents. If no version is recoverable, the Deferred
594 will errback with UnrecoverableFileError.
597 def get_size_of_best_version():
598 """Find the size of the version that would be downloaded with
599 download_best_version(), without actually downloading the whole file.
601 I return a Deferred that fires with an integer.
604 def overwrite(new_contents):
605 """Unconditionally replace the contents of the mutable file with new
606 ones. This simply chains get_servermap(MODE_WRITE) and upload(). This
607 is only appropriate to use when the new contents of the file are
608 completely unrelated to the old ones, and you do not care about other
611 I return a Deferred that fires (with a PublishStatus object) when the
612 update has completed.
615 def modify(modifier_cb):
616 """Modify the contents of the file, by downloading the current
617 version, applying the modifier function (or bound method), then
618 uploading the new version. I return a Deferred that fires (with a
619 PublishStatus object) when the update is complete.
621 The modifier callable will be given two arguments: a string (with the
622 old contents) and a servermap. As with download_best_version(), the
623 old contents will be from the best recoverable version, but the
624 modifier can use the servermap to make other decisions (such as
625 refusing to apply the delta if there are multiple parallel versions,
626 or if there is evidence of a newer unrecoverable version).
628 The callable should return a string with the new contents. The
629 callable must be prepared to be called multiple times, and must
630 examine the input string to see if the change that it wants to make
631 is already present in the old version. If it does not need to make
632 any changes, it can either return None, or return its input string.
634 If the modifier raises an exception, it will be returned in the
639 def get_servermap(mode):
640 """Return a Deferred that fires with an IMutableFileServerMap
641 instance, updated using the given mode.
644 def download_version(servermap, version):
645 """Download a specific version of the file, using the servermap
646 as a guide to where the shares are located.
648 I return a Deferred that fires with the requested contents, or
649 errbacks with UnrecoverableFileError. Note that a servermap which was
650 updated with MODE_ANYTHING or MODE_READ may not know about shares for
651 all versions (those modes stop querying servers as soon as they can
652 fulfil their goals), so you may want to use MODE_CHECK (which checks
653 everything) to get increased visibility.
656 def upload(new_contents, servermap):
657 """Replace the contents of the file with new ones. This requires a
658 servermap that was previously updated with MODE_WRITE.
660 I attempt to provide test-and-set semantics, in that I will avoid
661 modifying any share that is different than the version I saw in the
662 servermap. However, if another node is writing to the file at the
663 same time as me, I may manage to update some shares while they update
664 others. If I see any evidence of this, I will signal
665 UncoordinatedWriteError, and the file will be left in an inconsistent
666 state (possibly the version you provided, possibly the old version,
667 possibly somebody else's version, and possibly a mix of shares from
670 The recommended response to UncoordinatedWriteError is to either
671 return it to the caller (since they failed to coordinate their
672 writes), or to attempt some sort of recovery. It may be sufficient to
673 wait a random interval (with exponential backoff) and repeat your
674 operation. If I do not signal UncoordinatedWriteError, then I was
675 able to write the new version without incident.
677 I return a Deferred that fires (with a PublishStatus object) when the
678 publish has completed. I will update the servermap in-place with the
679 location of all new shares.
683 """Return this filenode's writekey, or None if the node does not have
684 write-capability. This may be used to assist with data structures
685 that need to make certain data available only to writers, such as the
686 read-write child caps in dirnodes. The recommended process is to have
687 reader-visible data be submitted to the filenode in the clear (where
688 it will be encrypted by the filenode using the readkey), but encrypt
689 writer-visible data using this writekey.
692 class NotEnoughSharesError(Exception):
695 class ExistingChildError(Exception):
696 """A directory node was asked to add or replace a child that already
697 exists, and overwrite= was set to False."""
699 class NoSuchChildError(Exception):
700 """A directory node was asked to fetch a child which does not exist."""
702 class IDirectoryNode(IMutableFilesystemNode):
703 """I represent a name-to-child mapping, holding the tahoe equivalent of a
704 directory. All child names are unicode strings, and all children are some
705 sort of IFilesystemNode (either files or subdirectories).
710 The dirnode ('1') URI returned by this method can be used in
711 set_uri() on a different directory ('2') to 'mount' a reference to
712 this directory ('1') under the other ('2'). This URI is just a
713 string, so it can be passed around through email or other out-of-band
717 def get_readonly_uri():
719 The dirnode ('1') URI returned by this method can be used in
720 set_uri() on a different directory ('2') to 'mount' a reference to
721 this directory ('1') under the other ('2'). This URI is just a
722 string, so it can be passed around through email or other out-of-band
727 """I return a Deferred that fires with a dictionary mapping child
728 name (a unicode string) to (node, metadata_dict) tuples, in which
729 'node' is either an IFileNode or IDirectoryNode, and 'metadata_dict'
730 is a dictionary of metadata."""
733 """I return a Deferred that fires with a boolean, True if there
734 exists a child of the given name, False if not. The child name must
735 be a unicode string."""
738 """I return a Deferred that fires with a specific named child node,
739 either an IFileNode or an IDirectoryNode. The child name must be a
740 unicode string. I raise NoSuchChildError if I do not have a child by
743 def get_metadata_for(name):
744 """I return a Deferred that fires with the metadata dictionary for a
745 specific named child node. This metadata is stored in the *edge*, not
746 in the child, so it is attached to the parent dirnode rather than the
747 child dir-or-file-node. The child name must be a unicode string. I
748 raise NoSuchChildError if I do not have a child by that name."""
750 def set_metadata_for(name, metadata):
751 """I replace any existing metadata for the named child with the new
752 metadata. The child name must be a unicode string. This metadata is
753 stored in the *edge*, not in the child, so it is attached to the
754 parent dirnode rather than the child dir-or-file-node. I return a
755 Deferred (that fires with this dirnode) when the operation is
756 complete. I raise NoSuchChildError if I do not have a child by that
759 def get_child_at_path(path):
760 """Transform a child path into an IDirectoryNode or IFileNode.
762 I perform a recursive series of 'get' operations to find the named
763 descendant node. I return a Deferred that fires with the node, or
764 errbacks with NoSuchChildError if the node could not be found.
766 The path can be either a single string (slash-separated) or a list of
767 path-name elements. All elements must be unicode strings.
770 def get_child_and_metadata_at_path(path):
771 """Transform a child path into an IDirectoryNode/IFileNode and
774 I am like get_child_at_path(), but my Deferred fires with a tuple of
775 (node, metadata). The metadata comes from the last edge. If the path
776 is empty, the metadata will be an empty dictionary.
779 def set_uri(name, child_uri, metadata=None, overwrite=True):
780 """I add a child (by URI) at the specific name. I return a Deferred
781 that fires when the operation finishes. If overwrite= is True, I will
782 replace any existing child of the same name, otherwise an existing
783 child will cause me to return ExistingChildError. The child name must
786 The child_uri could be for a file, or for a directory (either
787 read-write or read-only, using a URI that came from get_uri() ).
789 If metadata= is provided, I will use it as the metadata for the named
790 edge. This will replace any existing metadata. If metadata= is left
791 as the default value of None, I will set ['mtime'] to the current
792 time, and I will set ['ctime'] to the current time if there was not
793 already a child by this name present. This roughly matches the
794 ctime/mtime semantics of traditional filesystems.
796 If this directory node is read-only, the Deferred will errback with a
799 def set_children(entries, overwrite=True):
800 """Add multiple (name, child_uri) pairs (or (name, child_uri,
801 metadata) triples) to a directory node. Returns a Deferred that fires
802 (with None) when the operation finishes. This is equivalent to
803 calling set_uri() multiple times, but is much more efficient. All
804 child names must be unicode strings.
807 def set_node(name, child, metadata=None, overwrite=True):
808 """I add a child at the specific name. I return a Deferred that fires
809 when the operation finishes. This Deferred will fire with the child
810 node that was just added. I will replace any existing child of the
811 same name. The child name must be a unicode string. The 'child'
812 instance must be an instance providing IDirectoryNode or IFileNode.
814 If metadata= is provided, I will use it as the metadata for the named
815 edge. This will replace any existing metadata. If metadata= is left
816 as the default value of None, I will set ['mtime'] to the current
817 time, and I will set ['ctime'] to the current time if there was not
818 already a child by this name present. This roughly matches the
819 ctime/mtime semantics of traditional filesystems.
821 If this directory node is read-only, the Deferred will errback with a
824 def set_nodes(entries, overwrite=True):
825 """Add multiple (name, child_node) pairs (or (name, child_node,
826 metadata) triples) to a directory node. Returns a Deferred that fires
827 (with None) when the operation finishes. This is equivalent to
828 calling set_node() multiple times, but is much more efficient. All
829 child names must be unicode strings."""
832 def add_file(name, uploadable, metadata=None, overwrite=True):
833 """I upload a file (using the given IUploadable), then attach the
834 resulting FileNode to the directory at the given name. I set metadata
835 the same way as set_uri and set_node. The child name must be a
838 I return a Deferred that fires (with the IFileNode of the uploaded
839 file) when the operation completes."""
842 """I remove the child at the specific name. I return a Deferred that
843 fires when the operation finishes. The child name must be a unicode
844 string. I raise NoSuchChildError if I do not have a child by that
847 def create_empty_directory(name, overwrite=True):
848 """I create and attach an empty directory at the given name. The
849 child name must be a unicode string. I return a Deferred that fires
850 when the operation finishes."""
852 def move_child_to(current_child_name, new_parent, new_child_name=None,
854 """I take one of my children and move them to a new parent. The child
855 is referenced by name. On the new parent, the child will live under
856 'new_child_name', which defaults to 'current_child_name'. TODO: what
857 should we do about metadata? I return a Deferred that fires when the
858 operation finishes. The child name must be a unicode string. I raise
859 NoSuchChildError if I do not have a child by that name."""
861 def build_manifest():
862 """I generate a table of everything reachable from this directory.
863 I also compute deep-stats as described below.
865 I return a Monitor. The Monitor's results will be a dictionary with
868 res['manifest']: a list of (path, cap) tuples for all nodes
869 (directories and files) reachable from this one.
870 'path' will be a tuple of unicode strings. The
871 origin dirnode will be represented by an empty path
873 res['verifycaps']: a list of (printable) verifycap strings, one for
874 each reachable non-LIT node. This is a set:
875 it will contain no duplicates.
876 res['storage-index']: a list of (base32) storage index strings,
877 one for each reachable non-LIT node. This is
878 a set: it will contain no duplicates.
879 res['stats']: a dictionary, the same that is generated by
880 start_deep_stats() below.
882 The Monitor will also have an .origin_si attribute with the (binary)
883 storage index of the starting point.
886 def start_deep_stats():
887 """Return a Monitor, examining all nodes (directories and files)
888 reachable from this one. The Monitor's results will be a dictionary
889 with the following keys::
891 count-immutable-files: count of how many CHK files are in the set
892 count-mutable-files: same, for mutable files (does not include
894 count-literal-files: same, for LIT files
895 count-files: sum of the above three
897 count-directories: count of directories
899 size-immutable-files: total bytes for all CHK files in the set
900 size-mutable-files (TODO): same, for current version of all mutable
901 files, does not include directories
902 size-literal-files: same, for LIT files
903 size-directories: size of mutable files used by directories
905 largest-directory: number of bytes in the largest directory
906 largest-directory-children: number of children in the largest
908 largest-immutable-file: number of bytes in the largest CHK file
910 size-mutable-files is not yet implemented, because it would involve
911 even more queries than deep_stats does.
913 The Monitor will also have an .origin_si attribute with the (binary)
914 storage index of the starting point.
916 This operation will visit every directory node underneath this one,
917 and can take a long time to run. On a typical workstation with good
918 bandwidth, this can examine roughly 15 directories per second (and
919 takes several minutes of 100% CPU for ~1700 directories).
922 class ICodecEncoder(Interface):
923 def set_params(data_size, required_shares, max_shares):
924 """Set up the parameters of this encoder.
926 This prepares the encoder to perform an operation that converts a
927 single block of data into a number of shares, such that a future
928 ICodecDecoder can use a subset of these shares to recover the
929 original data. This operation is invoked by calling encode(). Once
930 the encoding parameters are set up, the encode operation can be
931 invoked multiple times.
933 set_params() prepares the encoder to accept blocks of input data that
934 are exactly 'data_size' bytes in length. The encoder will be prepared
935 to produce 'max_shares' shares for each encode() operation (although
936 see the 'desired_share_ids' to use less CPU). The encoding math will
937 be chosen such that the decoder can get by with as few as
938 'required_shares' of these shares and still reproduce the original
939 data. For example, set_params(1000, 5, 5) offers no redundancy at
940 all, whereas set_params(1000, 1, 10) provides 10x redundancy.
942 Numerical Restrictions: 'data_size' is required to be an integral
943 multiple of 'required_shares'. In general, the caller should choose
944 required_shares and max_shares based upon their reliability
945 requirements and the number of peers available (the total storage
946 space used is roughly equal to max_shares*data_size/required_shares),
947 then choose data_size to achieve the memory footprint desired (larger
948 data_size means more efficient operation, smaller data_size means
949 smaller memory footprint).
951 In addition, 'max_shares' must be equal to or greater than
952 'required_shares'. Of course, setting them to be equal causes
953 encode() to degenerate into a particularly slow form of the 'split'
956 See encode() for more details about how these parameters are used.
958 set_params() must be called before any other ICodecEncoder methods
962 def get_encoder_type():
963 """Return a short string that describes the type of this encoder.
965 There is required to be a global table of encoder classes. This method
966 returns an index into this table; the value at this index is an
967 encoder class, and this encoder is an instance of that class.
970 def get_serialized_params(): # TODO: maybe, maybe not
971 """Return a string that describes the parameters of this encoder.
973 This string can be passed to the decoder to prepare it for handling
974 the encoded shares we create. It might contain more information than
975 was presented to set_params(), if there is some flexibility of
978 This string is intended to be embedded in the URI, so there are
979 several restrictions on its contents. At the moment I'm thinking that
980 this means it may contain hex digits and hyphens, and nothing else.
981 The idea is that the URI contains something like '%s:%s:%s' %
982 (encoder.get_encoder_name(), encoder.get_serialized_params(),
983 b2a(crypttext_hash)), and this is enough information to construct a
987 def get_block_size():
988 """Return the length of the shares that encode() will produce.
991 def encode_proposal(data, desired_share_ids=None):
994 'data' must be a string (or other buffer object), and len(data) must
995 be equal to the 'data_size' value passed earlier to set_params().
997 This will return a Deferred that will fire with two lists. The first
998 is a list of shares, each of which is a string (or other buffer
999 object) such that len(share) is the same as what get_share_size()
1000 returned earlier. The second is a list of shareids, in which each is
1001 an integer. The lengths of the two lists will always be equal to each
1002 other. The user should take care to keep each share closely
1003 associated with its shareid, as one is useless without the other.
1005 The length of this output list will normally be the same as the value
1006 provided to the 'max_shares' parameter of set_params(). This may be
1007 different if 'desired_share_ids' is provided.
1009 'desired_share_ids', if provided, is required to be a sequence of
1010 ints, each of which is required to be >= 0 and < max_shares. If not
1011 provided, encode() will produce 'max_shares' shares, as if
1012 'desired_share_ids' were set to range(max_shares). You might use this
1013 if you initially thought you were going to use 10 peers, started
1014 encoding, and then two of the peers dropped out: you could use
1015 desired_share_ids= to skip the work (both memory and CPU) of
1016 producing shares for the peers which are no longer available.
1020 def encode(inshares, desired_share_ids=None):
1021 """Encode some data. This may be called multiple times. Each call is
1024 inshares is a sequence of length required_shares, containing buffers
1025 (i.e. strings), where each buffer contains the next contiguous
1026 non-overlapping segment of the input data. Each buffer is required to
1027 be the same length, and the sum of the lengths of the buffers is
1028 required to be exactly the data_size promised by set_params(). (This
1029 implies that the data has to be padded before being passed to
1030 encode(), unless of course it already happens to be an even multiple
1031 of required_shares in length.)
1033 ALSO: the requirement to break up your data into 'required_shares'
1034 chunks before calling encode() feels a bit surprising, at least from
1035 the point of view of a user who doesn't know how FEC works. It feels
1036 like an implementation detail that has leaked outside the
1037 abstraction barrier. Can you imagine a use case in which the data to
1038 be encoded might already be available in pre-segmented chunks, such
1039 that it is faster or less work to make encode() take a list rather
1040 than splitting a single string?
1042 ALSO ALSO: I think 'inshares' is a misleading term, since encode()
1043 is supposed to *produce* shares, so what it *accepts* should be
1044 something other than shares. Other places in this interface use the
1045 word 'data' for that-which-is-not-shares.. maybe we should use that
1048 'desired_share_ids', if provided, is required to be a sequence of
1049 ints, each of which is required to be >= 0 and < max_shares. If not
1050 provided, encode() will produce 'max_shares' shares, as if
1051 'desired_share_ids' were set to range(max_shares). You might use this
1052 if you initially thought you were going to use 10 peers, started
1053 encoding, and then two of the peers dropped out: you could use
1054 desired_share_ids= to skip the work (both memory and CPU) of
1055 producing shares for the peers which are no longer available.
1057 For each call, encode() will return a Deferred that fires with two
1058 lists, one containing shares and the other containing the shareids.
1059 The get_share_size() method can be used to determine the length of
1060 the share strings returned by encode(). Each shareid is a small
1061 integer, exactly as passed into 'desired_share_ids' (or
1062 range(max_shares), if desired_share_ids was not provided).
1064 The shares and their corresponding shareids are required to be kept
1065 together during storage and retrieval. Specifically, the share data is
1066 useless by itself: the decoder needs to be told which share is which
1067 by providing it with both the shareid and the actual share data.
1069 This function will allocate an amount of memory roughly equal to::
1071 (max_shares - required_shares) * get_share_size()
1073 When combined with the memory that the caller must allocate to
1074 provide the input data, this leads to a memory footprint roughly
1075 equal to the size of the resulting encoded shares (i.e. the expansion
1076 factor times the size of the input segment).
1081 # returning a list of (shareidN,shareN) tuples instead of a pair of
1082 # lists (shareids..,shares..). Brian thought the tuples would
1083 # encourage users to keep the share and shareid together throughout
1084 # later processing, Zooko pointed out that the code to iterate
1085 # through two lists is not really more complicated than using a list
1086 # of tuples and there's also a performance improvement
1088 # having 'data_size' not required to be an integral multiple of
1089 # 'required_shares'. Doing this would require encode() to perform
1090 # padding internally, and we'd prefer to have any padding be done
1091 # explicitly by the caller. Yes, it is an abstraction leak, but
1092 # hopefully not an onerous one.
1095 class ICodecDecoder(Interface):
1096 def set_serialized_params(params):
1097 """Set up the parameters of this encoder, from a string returned by
1098 encoder.get_serialized_params()."""
1100 def get_needed_shares():
1101 """Return the number of shares needed to reconstruct the data.
1102 set_serialized_params() is required to be called before this."""
1104 def decode(some_shares, their_shareids):
1105 """Decode a partial list of shares into data.
1107 'some_shares' is required to be a sequence of buffers of sharedata, a
1108 subset of the shares returned by ICodecEncode.encode(). Each share is
1109 required to be of the same length. The i'th element of their_shareids
1110 is required to be the shareid of the i'th buffer in some_shares.
1112 This returns a Deferred which fires with a sequence of buffers. This
1113 sequence will contain all of the segments of the original data, in
1114 order. The sum of the lengths of all of the buffers will be the
1115 'data_size' value passed into the original ICodecEncode.set_params()
1116 call. To get back the single original input block of data, use
1117 ''.join(output_buffers), or you may wish to simply write them in
1118 order to an output file.
1120 Note that some of the elements in the result sequence may be
1121 references to the elements of the some_shares input sequence. In
1122 particular, this means that if those share objects are mutable (e.g.
1123 arrays) and if they are changed, then both the input (the
1124 'some_shares' parameter) and the output (the value given when the
1125 deferred is triggered) will change.
1127 The length of 'some_shares' is required to be exactly the value of
1128 'required_shares' passed into the original ICodecEncode.set_params()
1132 class IEncoder(Interface):
1133 """I take an object that provides IEncryptedUploadable, which provides
1134 encrypted data, and a list of shareholders. I then encode, hash, and
1135 deliver shares to those shareholders. I will compute all the necessary
1136 Merkle hash trees that are necessary to validate the crypttext that
1137 eventually comes back from the shareholders. I provide the URI Extension
1138 Block Hash, and the encoding parameters, both of which must be included
1141 I do not choose shareholders, that is left to the IUploader. I must be
1142 given a dict of RemoteReferences to storage buckets that are ready and
1143 willing to receive data.
1147 """Specify the number of bytes that will be encoded. This must be
1148 peformed before get_serialized_params() can be called.
1150 def set_params(params):
1151 """Override the default encoding parameters. 'params' is a tuple of
1152 (k,d,n), where 'k' is the number of required shares, 'd' is the
1153 shares_of_happiness, and 'n' is the total number of shares that will
1156 Encoding parameters can be set in three ways. 1: The Encoder class
1157 provides defaults (3/7/10). 2: the Encoder can be constructed with
1158 an 'options' dictionary, in which the
1159 needed_and_happy_and_total_shares' key can be a (k,d,n) tuple. 3:
1160 set_params((k,d,n)) can be called.
1162 If you intend to use set_params(), you must call it before
1163 get_share_size or get_param are called.
1166 def set_encrypted_uploadable(u):
1167 """Provide a source of encrypted upload data. 'u' must implement
1168 IEncryptedUploadable.
1170 When this is called, the IEncryptedUploadable will be queried for its
1171 length and the storage_index that should be used.
1173 This returns a Deferred that fires with this Encoder instance.
1175 This must be performed before start() can be called.
1178 def get_param(name):
1179 """Return an encoding parameter, by name.
1181 'storage_index': return a string with the (16-byte truncated SHA-256
1182 hash) storage index to which these shares should be
1185 'share_counts': return a tuple describing how many shares are used:
1186 (needed_shares, shares_of_happiness, total_shares)
1188 'num_segments': return an int with the number of segments that
1191 'segment_size': return an int with the size of each segment.
1193 'block_size': return the size of the individual blocks that will
1194 be delivered to a shareholder's put_block() method. By
1195 knowing this, the shareholder will be able to keep all
1196 blocks in a single file and still provide random access
1197 when reading them. # TODO: can we avoid exposing this?
1199 'share_size': an int with the size of the data that will be stored
1200 on each shareholder. This is aggregate amount of data
1201 that will be sent to the shareholder, summed over all
1202 the put_block() calls I will ever make. It is useful to
1203 determine this size before asking potential
1204 shareholders whether they will grant a lease or not,
1205 since their answers will depend upon how much space we
1206 need. TODO: this might also include some amount of
1207 overhead, like the size of all the hashes. We need to
1208 decide whether this is useful or not.
1210 'serialized_params': a string with a concise description of the
1211 codec name and its parameters. This may be passed
1212 into the IUploadable to let it make sure that
1213 the same file encoded with different parameters
1214 will result in different storage indexes.
1216 Once this is called, set_size() and set_params() may not be called.
1219 def set_shareholders(shareholders):
1220 """Tell the encoder where to put the encoded shares. 'shareholders'
1221 must be a dictionary that maps share number (an integer ranging from
1222 0 to n-1) to an instance that provides IStorageBucketWriter. This
1223 must be performed before start() can be called."""
1226 """Begin the encode/upload process. This involves reading encrypted
1227 data from the IEncryptedUploadable, encoding it, uploading the shares
1228 to the shareholders, then sending the hash trees.
1230 set_encrypted_uploadable() and set_shareholders() must be called
1231 before this can be invoked.
1233 This returns a Deferred that fires with a tuple of
1234 (uri_extension_hash, needed_shares, total_shares, size) when the
1235 upload process is complete. This information, plus the encryption
1236 key, is sufficient to construct the URI.
1239 class IDecoder(Interface):
1240 """I take a list of shareholders and some setup information, then
1241 download, validate, decode, and decrypt data from them, writing the
1242 results to an output file.
1244 I do not locate the shareholders, that is left to the IDownloader. I must
1245 be given a dict of RemoteReferences to storage buckets that are ready to
1250 """I take a file-like object (providing write and close) to which all
1251 the plaintext data will be written.
1253 TODO: producer/consumer . Maybe write() should return a Deferred that
1254 indicates when it will accept more data? But probably having the
1255 IDecoder be a producer is easier to glue to IConsumer pieces.
1258 def set_shareholders(shareholders):
1259 """I take a dictionary that maps share identifiers (small integers)
1260 to RemoteReferences that provide RIBucketReader. This must be called
1264 """I start the download. This process involves retrieving data and
1265 hash chains from the shareholders, using the hashes to validate the
1266 data, decoding the shares into segments, decrypting the segments,
1267 then writing the resulting plaintext to the output file.
1269 I return a Deferred that will fire (with self) when the download is
1273 class IDownloadTarget(Interface):
1274 # Note that if the IDownloadTarget is also an IConsumer, the downloader
1275 # will register itself as a producer. This allows the target to invoke
1276 # downloader.pauseProducing, resumeProducing, and stopProducing.
1278 """Called before any calls to write() or close(). If an error
1279 occurs before any data is available, fail() may be called without
1280 a previous call to open().
1282 'size' is the length of the file being downloaded, in bytes."""
1285 """Output some data to the target."""
1287 """Inform the target that there is no more data to be written."""
1289 """fail() is called to indicate that the download has failed. 'why'
1290 is a Failure object indicating what went wrong. No further methods
1291 will be invoked on the IDownloadTarget after fail()."""
1292 def register_canceller(cb):
1293 """The FileDownloader uses this to register a no-argument function
1294 that the target can call to cancel the download. Once this canceller
1295 is invoked, no further calls to write() or close() will be made."""
1297 """When the FileDownloader is done, this finish() function will be
1298 called. Whatever it returns will be returned to the invoker of
1299 Downloader.download.
1302 class IDownloader(Interface):
1303 def download(uri, target):
1304 """Perform a CHK download, sending the data to the given target.
1305 'target' must provide IDownloadTarget.
1307 Returns a Deferred that fires (with the results of target.finish)
1308 when the download is finished, or errbacks if something went wrong."""
1310 class IEncryptedUploadable(Interface):
1311 def set_upload_status(upload_status):
1312 """Provide an IUploadStatus object that should be filled with status
1313 information. The IEncryptedUploadable is responsible for setting
1314 key-determination progress ('chk'), size, storage_index, and
1315 ciphertext-fetch progress. It may delegate some of this
1316 responsibility to others, in particular to the IUploadable."""
1319 """This behaves just like IUploadable.get_size()."""
1321 def get_all_encoding_parameters():
1322 """Return a Deferred that fires with a tuple of
1323 (k,happy,n,segment_size). The segment_size will be used as-is, and
1324 must match the following constraints: it must be a multiple of k, and
1325 it shouldn't be unreasonably larger than the file size (if
1326 segment_size is larger than filesize, the difference must be stored
1329 This usually passes through to the IUploadable method of the same
1332 The encoder strictly obeys the values returned by this method. To
1333 make an upload use non-default encoding parameters, you must arrange
1334 to control the values that this method returns.
1337 def get_storage_index():
1338 """Return a Deferred that fires with a 16-byte storage index.
1341 def read_encrypted(length, hash_only):
1342 """This behaves just like IUploadable.read(), but returns crypttext
1343 instead of plaintext. If hash_only is True, then this discards the
1344 data (and returns an empty list); this improves efficiency when
1345 resuming an interrupted upload (where we need to compute the
1346 plaintext hashes, but don't need the redundant encrypted data)."""
1348 def get_plaintext_hashtree_leaves(first, last, num_segments):
1349 """Get the leaf nodes of a merkle hash tree over the plaintext
1350 segments, i.e. get the tagged hashes of the given segments. The
1351 segment size is expected to be generated by the IEncryptedUploadable
1352 before any plaintext is read or ciphertext produced, so that the
1353 segment hashes can be generated with only a single pass.
1355 This returns a Deferred which fires with a sequence of hashes, using:
1357 tuple(segment_hashes[first:last])
1359 'num_segments' is used to assert that the number of segments that the
1360 IEncryptedUploadable handled matches the number of segments that the
1361 encoder was expecting.
1363 This method must not be called until the final byte has been read
1364 from read_encrypted(). Once this method is called, read_encrypted()
1365 can never be called again.
1368 def get_plaintext_hash():
1369 """Get the hash of the whole plaintext.
1371 This returns a Deferred which fires with a tagged SHA-256 hash of the
1372 whole plaintext, obtained from hashutil.plaintext_hash(data).
1376 """Just like IUploadable.close()."""
1378 class IUploadable(Interface):
1379 def set_upload_status(upload_status):
1380 """Provide an IUploadStatus object that should be filled with status
1381 information. The IUploadable is responsible for setting
1382 key-determination progress ('chk')."""
1384 def set_default_encoding_parameters(params):
1385 """Set the default encoding parameters, which must be a dict mapping
1386 strings to ints. The meaningful keys are 'k', 'happy', 'n', and
1387 'max_segment_size'. These might have an influence on the final
1388 encoding parameters returned by get_all_encoding_parameters(), if the
1389 Uploadable doesn't have more specific preferences.
1391 This call is optional: if it is not used, the Uploadable will use
1392 some built-in defaults. If used, this method must be called before
1393 any other IUploadable methods to have any effect.
1397 """Return a Deferred that will fire with the length of the data to be
1398 uploaded, in bytes. This will be called before the data is actually
1399 used, to compute encoding parameters.
1402 def get_all_encoding_parameters():
1403 """Return a Deferred that fires with a tuple of
1404 (k,happy,n,segment_size). The segment_size will be used as-is, and
1405 must match the following constraints: it must be a multiple of k, and
1406 it shouldn't be unreasonably larger than the file size (if
1407 segment_size is larger than filesize, the difference must be stored
1410 The relative values of k and n allow some IUploadables to request
1411 better redundancy than others (in exchange for consuming more space
1414 Larger values of segment_size reduce hash overhead, while smaller
1415 values reduce memory footprint and cause data to be delivered in
1416 smaller pieces (which may provide a smoother and more predictable
1417 download experience).
1419 The encoder strictly obeys the values returned by this method. To
1420 make an upload use non-default encoding parameters, you must arrange
1421 to control the values that this method returns. One way to influence
1422 them may be to call set_encoding_parameters() before calling
1423 get_all_encoding_parameters().
1426 def get_encryption_key():
1427 """Return a Deferred that fires with a 16-byte AES key. This key will
1428 be used to encrypt the data. The key will also be hashed to derive
1431 Uploadables which want to achieve convergence should hash their file
1432 contents and the serialized_encoding_parameters to form the key
1433 (which of course requires a full pass over the data). Uploadables can
1434 use the upload.ConvergentUploadMixin class to achieve this
1437 Uploadables which do not care about convergence (or do not wish to
1438 make multiple passes over the data) can simply return a
1439 strongly-random 16 byte string.
1441 get_encryption_key() may be called multiple times: the IUploadable is
1442 required to return the same value each time.
1446 """Return a Deferred that fires with a list of strings (perhaps with
1447 only a single element) which, when concatenated together, contain the
1448 next 'length' bytes of data. If EOF is near, this may provide fewer
1449 than 'length' bytes. The total number of bytes provided by read()
1450 before it signals EOF must equal the size provided by get_size().
1452 If the data must be acquired through multiple internal read
1453 operations, returning a list instead of a single string may help to
1454 reduce string copies.
1456 'length' will typically be equal to (min(get_size(),1MB)/req_shares),
1457 so a 10kB file means length=3kB, 100kB file means length=30kB,
1458 and >=1MB file means length=300kB.
1460 This method provides for a single full pass through the data. Later
1461 use cases may desire multiple passes or access to only parts of the
1462 data (such as a mutable file making small edits-in-place). This API
1463 will be expanded once those use cases are better understood.
1467 """The upload is finished, and whatever filehandle was in use may be
1470 class IUploadResults(Interface):
1471 """I am returned by upload() methods. I contain a number of public
1472 attributes which can be read to determine the results of the upload. Some
1473 of these are functional, some are timing information. All of these may be
1476 .file_size : the size of the file, in bytes
1477 .uri : the CHK read-cap for the file
1478 .ciphertext_fetched : how many bytes were fetched by the helper
1479 .sharemap : dict mapping share number to placement string
1480 .servermap : dict mapping server peerid to a set of share numbers
1481 .timings : dict of timing information, mapping name to seconds (float)
1482 total : total upload time, start to finish
1483 storage_index : time to compute the storage index
1484 peer_selection : time to decide which peers will be used
1485 contacting_helper : initial helper query to upload/no-upload decision
1486 existence_check : helper pre-upload existence check
1487 helper_total : initial helper query to helper finished pushing
1488 cumulative_fetch : helper waiting for ciphertext requests
1489 total_fetch : helper start to last ciphertext response
1490 cumulative_encoding : just time spent in zfec
1491 cumulative_sending : just time spent waiting for storage servers
1492 hashes_and_close : last segment push to shareholder close
1493 total_encode_and_push : first encode to shareholder close
1497 class IDownloadResults(Interface):
1498 """I am created internally by download() methods. I contain a number of
1499 public attributes which contain details about the download process.::
1501 .file_size : the size of the file, in bytes
1502 .servers_used : set of server peerids that were used during download
1503 .server_problems : dict mapping server peerid to a problem string. Only
1504 servers that had problems (bad hashes, disconnects) are
1506 .servermap : dict mapping server peerid to a set of share numbers. Only
1507 servers that had any shares are listed here.
1508 .timings : dict of timing information, mapping name to seconds (float)
1509 peer_selection : time to ask servers about shares
1510 servers_peer_selection : dict of peerid to DYHB-query time
1511 uri_extension : time to fetch a copy of the URI extension block
1512 hashtrees : time to fetch the hash trees
1513 segments : time to fetch, decode, and deliver segments
1514 cumulative_fetch : time spent waiting for storage servers
1515 cumulative_decode : just time spent in zfec
1516 cumulative_decrypt : just time spent in decryption
1517 total : total download time, start to finish
1518 fetch_per_server : dict of peerid to list of per-segment fetch times
1522 class IUploader(Interface):
1523 def upload(uploadable):
1524 """Upload the file. 'uploadable' must impement IUploadable. This
1525 returns a Deferred which fires with an UploadResults instance, from
1526 which the URI of the file can be obtained as results.uri ."""
1528 def upload_ssk(write_capability, new_version, uploadable):
1529 """TODO: how should this work?"""
1531 class ICheckable(Interface):
1532 def check(monitor, verify=False):
1533 """Check upon my health, optionally repairing any problems.
1535 This returns a Deferred that fires with an instance that provides
1536 ICheckerResults, or None if the object is non-distributed (i.e. LIT
1539 The monitor will be checked periodically to see if the operation has
1540 been cancelled. If so, no new queries will be sent, and the Deferred
1541 will fire (with a OperationCancelledError) immediately.
1543 Filenodes and dirnodes (which provide IFilesystemNode) are also
1544 checkable. Instances that represent verifier-caps will be checkable
1545 but not downloadable. Some objects (like LIT files) do not actually
1546 live in the grid, and their checkers return None (non-distributed
1547 files are always healthy).
1549 If verify=False, a relatively lightweight check will be performed: I
1550 will ask all servers if they have a share for me, and I will believe
1551 whatever they say. If there are at least N distinct shares on the
1552 grid, my results will indicate r.is_healthy()==True. This requires a
1553 roundtrip to each server, but does not transfer very much data, so
1554 the network bandwidth is fairly low.
1556 If verify=True, a more resource-intensive check will be performed:
1557 every share will be downloaded, and the hashes will be validated on
1558 every bit. I will ignore any shares that failed their hash checks. If
1559 there are at least N distinct valid shares on the grid, my results
1560 will indicate r.is_healthy()==True. This requires N/k times as much
1561 download bandwidth (and server disk IO) as a regular download. If a
1562 storage server is holding a corrupt share, or is experiencing memory
1563 failures during retrieval, or is malicious or buggy, then
1564 verification will detect the problem, but checking will not.
1566 TODO: any problems seen during checking will be reported to the
1567 health-manager.furl, a centralized object which is responsible for
1568 figuring out why files are unhealthy so corrective action can be
1572 def check_and_repair(monitor, verify=False):
1573 """Like check(), but if the file/directory is not healthy, attempt to
1576 Any non-healthy result will cause an immediate repair operation, to
1577 generate and upload new shares. After repair, the file will be as
1578 healthy as we can make it. Details about what sort of repair is done
1579 will be put in the check-and-repair results. The Deferred will not
1580 fire until the repair is complete.
1582 This returns a Deferred which fires with an instance of
1583 ICheckAndRepairResults."""
1585 class IDeepCheckable(Interface):
1586 def start_deep_check(verify=False):
1587 """Check upon the health of me and everything I can reach.
1589 This is a recursive form of check(), useable only on dirnodes.
1591 I return a Monitor, with results that are an IDeepCheckResults
1595 def start_deep_check_and_repair(verify=False):
1596 """Check upon the health of me and everything I can reach. Repair
1597 anything that isn't healthy.
1599 This is a recursive form of check_and_repair(), useable only on
1602 I return a Monitor, with results that are an
1603 IDeepCheckAndRepairResults object.
1606 class ICheckerResults(Interface):
1607 """I contain the detailed results of a check/verify operation.
1610 def get_storage_index():
1611 """Return a string with the (binary) storage index."""
1612 def get_storage_index_string():
1613 """Return a string with the (printable) abbreviated storage index."""
1615 """Return the (string) URI of the object that was checked."""
1618 """Return a boolean, True if the file/dir is fully healthy, False if
1619 it is damaged in any way. Non-distributed LIT files always return
1622 def is_recoverable():
1623 """Return a boolean, True if the file/dir can be recovered, False if
1624 not. Unrecoverable files are obviously unhealthy. Non-distributed LIT
1625 files always return True."""
1627 def needs_rebalancing():
1628 """Return a boolean, True if the file/dir's reliability could be
1629 improved by moving shares to new servers. Non-distributed LIT files
1630 always returne False."""
1634 """Return a dictionary that describes the state of the file/dir.
1635 Non-distributed LIT files always return an empty dictionary. Normal
1636 files and directories return a dictionary with the following keys
1637 (note that these use base32-encoded strings rather than binary ones)
1638 (also note that for mutable files, these counts are for the 'best'
1641 count-shares-good: the number of distinct good shares that were found
1642 count-shares-needed: 'k', the number of shares required for recovery
1643 count-shares-expected: 'N', the number of total shares generated
1644 count-good-share-hosts: the number of distinct storage servers with
1645 good shares. If this number is less than
1646 count-shares-good, then some shares are
1647 doubled up, increasing the correlation of
1648 failures. This indicates that one or more
1649 shares should be moved to an otherwise unused
1650 server, if one is available.
1651 count-corrupt-shares: the number of shares with integrity failures
1652 list-corrupt-shares: a list of 'share locators', one for each share
1653 that was found to be corrupt. Each share
1654 locator is a list of (serverid, storage_index,
1656 servers-responding: list of (binary) storage server identifiers,
1657 one for each server which responded to the share
1659 sharemap: dict mapping share identifier to list of serverids
1660 (binary strings). This indicates which servers are holding
1661 which shares. For immutable files, the shareid is an
1662 integer (the share number, from 0 to N-1). For mutable
1663 files, it is a string of the form 'seq%d-%s-sh%d',
1664 containing the sequence number, the roothash, and the
1667 The following keys are most relevant for mutable files, but immutable
1668 files will provide sensible values too::
1670 count-wrong-shares: the number of shares for versions other than the
1671 'best' one (which is defined as being the
1672 recoverable version with the highest sequence
1673 number, then the highest roothash). These are
1674 either leftover shares from an older version
1675 (perhaps on a server that was offline when an
1676 update occurred), shares from an unrecoverable
1677 newer version, or shares from an alternate
1678 current version that results from an
1679 uncoordinated write collision. For a healthy
1680 file, this will equal 0.
1682 count-recoverable-versions: the number of recoverable versions of
1683 the file. For a healthy file, this will
1686 count-unrecoverable-versions: the number of unrecoverable versions
1687 of the file. For a healthy file, this
1693 """Return a string with a brief (one-line) summary of the results."""
1696 """Return a list of strings with more detailed results."""
1698 class ICheckAndRepairResults(Interface):
1699 """I contain the detailed results of a check/verify/repair operation.
1701 The IFilesystemNode.check()/verify()/repair() methods all return
1702 instances that provide ICheckAndRepairResults.
1705 def get_storage_index():
1706 """Return a string with the (binary) storage index."""
1707 def get_storage_index_string():
1708 """Return a string with the (printable) abbreviated storage index."""
1709 def get_repair_attempted():
1710 """Return a boolean, True if a repair was attempted."""
1711 def get_repair_successful():
1712 """Return a boolean, True if repair was attempted and the file/dir
1713 was fully healthy afterwards. False if no repair was attempted or if
1714 a repair attempt failed."""
1715 def get_pre_repair_results():
1716 """Return an ICheckerResults instance that describes the state of the
1717 file/dir before any repair was attempted."""
1718 def get_post_repair_results():
1719 """Return an ICheckerResults instance that describes the state of the
1720 file/dir after any repair was attempted. If no repair was attempted,
1721 the pre-repair and post-repair results will be identical."""
1724 class IDeepCheckResults(Interface):
1725 """I contain the results of a deep-check operation.
1727 This is returned by a call to ICheckable.deep_check().
1730 def get_root_storage_index_string():
1731 """Return the storage index (abbreviated human-readable string) of
1732 the first object checked."""
1734 """Return a dictionary with the following keys::
1736 count-objects-checked: count of how many objects were checked
1737 count-objects-healthy: how many of those objects were completely
1739 count-objects-unhealthy: how many were damaged in some way
1740 count-objects-unrecoverable: how many were unrecoverable
1741 count-corrupt-shares: how many shares were found to have
1742 corruption, summed over all objects
1746 def get_corrupt_shares():
1747 """Return a set of (serverid, storage_index, sharenum) for all shares
1748 that were found to be corrupt. Both serverid and storage_index are
1751 def get_all_results():
1752 """Return a dictionary mapping pathname (a tuple of strings, ready to
1753 be slash-joined) to an ICheckerResults instance, one for each object
1754 that was checked."""
1756 def get_results_for_storage_index(storage_index):
1757 """Retrive the ICheckerResults instance for the given (binary)
1758 storage index. Raises KeyError if there are no results for that
1762 """Return a dictionary with the same keys as
1763 IDirectoryNode.deep_stats()."""
1765 class IDeepCheckAndRepairResults(Interface):
1766 """I contain the results of a deep-check-and-repair operation.
1768 This is returned by a call to ICheckable.deep_check_and_repair().
1771 def get_root_storage_index_string():
1772 """Return the storage index (abbreviated human-readable string) of
1773 the first object checked."""
1775 """Return a dictionary with the following keys::
1777 count-objects-checked: count of how many objects were checked
1778 count-objects-healthy-pre-repair: how many of those objects were
1779 completely healthy (before any
1781 count-objects-unhealthy-pre-repair: how many were damaged in
1783 count-objects-unrecoverable-pre-repair: how many were unrecoverable
1784 count-objects-healthy-post-repair: how many of those objects were
1785 completely healthy (after any
1787 count-objects-unhealthy-post-repair: how many were damaged in
1789 count-objects-unrecoverable-post-repair: how many were
1791 count-repairs-attempted: repairs were attempted on this many
1792 objects. The count-repairs- keys will
1793 always be provided, however unless
1794 repair=true is present, they will all
1796 count-repairs-successful: how many repairs resulted in healthy
1798 count-repairs-unsuccessful: how many repairs resulted did not
1799 results in completely healthy objects
1800 count-corrupt-shares-pre-repair: how many shares were found to
1801 have corruption, summed over all
1802 objects examined (before any
1804 count-corrupt-shares-post-repair: how many shares were found to
1805 have corruption, summed over all
1806 objects examined (after any
1811 """Return a dictionary with the same keys as
1812 IDirectoryNode.deep_stats()."""
1814 def get_corrupt_shares():
1815 """Return a set of (serverid, storage_index, sharenum) for all shares
1816 that were found to be corrupt before any repair was attempted. Both
1817 serverid and storage_index are binary.
1819 def get_remaining_corrupt_shares():
1820 """Return a set of (serverid, storage_index, sharenum) for all shares
1821 that were found to be corrupt after any repair was completed. Both
1822 serverid and storage_index are binary. These are shares that need
1823 manual inspection and probably deletion.
1825 def get_all_results():
1826 """Return a dictionary mapping pathname (a tuple of strings, ready to
1827 be slash-joined) to an ICheckAndRepairResults instance, one for each
1828 object that was checked."""
1831 class IRepairable(Interface):
1832 def repair(checker_results):
1833 """Attempt to repair the given object. Returns a Deferred that fires
1834 with a IRepairResults object.
1836 I must be called with an object that implements ICheckerResults, as
1837 proof that you have actually discovered a problem with this file. I
1838 will use the data in the checker results to guide the repair process,
1839 such as which servers provided bad data and should therefore be
1840 avoided. The ICheckerResults object is inside the
1841 ICheckAndRepairResults object, which is returned by the
1842 ICheckable.check() method::
1844 d = filenode.check(repair=False)
1845 def _got_results(check_and_repair_results):
1846 check_results = check_and_repair_results.get_pre_repair_results()
1847 return filenode.repair(check_results)
1848 d.addCallback(_got_results)
1852 class IRepairResults(Interface):
1853 """I contain the results of a repair operation."""
1856 class IClient(Interface):
1857 def upload(uploadable):
1858 """Upload some data into a CHK, get back the UploadResults for it.
1859 @param uploadable: something that implements IUploadable
1860 @return: a Deferred that fires with the UploadResults instance.
1861 To get the URI for this file, use results.uri .
1864 def create_mutable_file(contents=""):
1865 """Create a new mutable file with contents, get back the URI string.
1866 @param contents: the initial contents to place in the file.
1867 @return: a Deferred that fires with tne (string) SSK URI for the new
1871 def create_empty_dirnode():
1872 """Create a new dirnode, empty and unattached.
1873 @return: a Deferred that fires with the new IDirectoryNode instance.
1876 def create_node_from_uri(uri):
1877 """Create a new IFilesystemNode instance from the uri, synchronously.
1878 @param uri: a string or IURI-providing instance. This could be for a
1879 LiteralFileNode, a CHK file node, a mutable file node, or
1881 @return: an instance that provides IFilesystemNode (or more usefully one
1882 of its subclasses). File-specifying URIs will result in
1883 IFileNode or IMutableFileNode -providing instances, like
1884 FileNode, LiteralFileNode, or MutableFileNode.
1885 Directory-specifying URIs will result in
1886 IDirectoryNode-providing instances, like NewDirectoryNode.
1889 class IClientStatus(Interface):
1890 def list_all_uploads():
1891 """Return a list of uploader objects, one for each upload which
1892 currently has an object available (tracked with weakrefs). This is
1893 intended for debugging purposes."""
1894 def list_active_uploads():
1895 """Return a list of active IUploadStatus objects."""
1896 def list_recent_uploads():
1897 """Return a list of IUploadStatus objects for the most recently
1900 def list_all_downloads():
1901 """Return a list of downloader objects, one for each download which
1902 currently has an object available (tracked with weakrefs). This is
1903 intended for debugging purposes."""
1904 def list_active_downloads():
1905 """Return a list of active IDownloadStatus objects."""
1906 def list_recent_downloads():
1907 """Return a list of IDownloadStatus objects for the most recently
1908 started downloads."""
1910 class IUploadStatus(Interface):
1912 """Return a timestamp (float with seconds since epoch) indicating
1913 when the operation was started."""
1914 def get_storage_index():
1915 """Return a string with the (binary) storage index in use on this
1916 upload. Returns None if the storage index has not yet been
1919 """Return an integer with the number of bytes that will eventually
1920 be uploaded for this file. Returns None if the size is not yet known.
1923 """Return True if this upload is using a Helper, False if not."""
1925 """Return a string describing the current state of the upload
1928 """Returns a tuple of floats, (chk, ciphertext, encode_and_push),
1929 each from 0.0 to 1.0 . 'chk' describes how much progress has been
1930 made towards hashing the file to determine a CHK encryption key: if
1931 non-convergent encryption is in use, this will be trivial, otherwise
1932 the whole file must be hashed. 'ciphertext' describes how much of the
1933 ciphertext has been pushed to the helper, and is '1.0' for non-helper
1934 uploads. 'encode_and_push' describes how much of the encode-and-push
1935 process has finished: for helper uploads this is dependent upon the
1936 helper providing progress reports. It might be reasonable to add all
1937 three numbers and report the sum to the user."""
1939 """Return True if the upload is currently active, False if not."""
1941 """Return an instance of UploadResults (which contains timing and
1942 sharemap information). Might return None if the upload is not yet
1945 """Each upload status gets a unique number: this method returns that
1946 number. This provides a handle to this particular upload, so a web
1947 page can generate a suitable hyperlink."""
1949 class IDownloadStatus(Interface):
1951 """Return a timestamp (float with seconds since epoch) indicating
1952 when the operation was started."""
1953 def get_storage_index():
1954 """Return a string with the (binary) storage index in use on this
1955 download. This may be None if there is no storage index (i.e. LIT
1958 """Return an integer with the number of bytes that will eventually be
1959 retrieved for this file. Returns None if the size is not yet known.
1962 """Return True if this download is using a Helper, False if not."""
1964 """Return a string describing the current state of the download
1967 """Returns a float (from 0.0 to 1.0) describing the amount of the
1968 download that has completed. This value will remain at 0.0 until the
1969 first byte of plaintext is pushed to the download target."""
1971 """Return True if the download is currently active, False if not."""
1973 """Each download status gets a unique number: this method returns
1974 that number. This provides a handle to this particular download, so a
1975 web page can generate a suitable hyperlink."""
1977 class IServermapUpdaterStatus(Interface):
1979 class IPublishStatus(Interface):
1981 class IRetrieveStatus(Interface):
1984 class NotCapableError(Exception):
1985 """You have tried to write to a read-only node."""
1987 class BadWriteEnablerError(Exception):
1990 class RIControlClient(RemoteInterface):
1992 def wait_for_client_connections(num_clients=int):
1993 """Do not return until we have connections to at least NUM_CLIENTS
1997 def upload_from_file_to_uri(filename=str, convergence=ChoiceOf(None, StringConstraint(2**20))):
1998 """Upload a file to the grid. This accepts a filename (which must be
1999 absolute) that points to a file on the node's local disk. The node will
2000 read the contents of this file, upload it to the grid, then return the
2001 URI at which it was uploaded. If convergence is None then a random
2002 encryption key will be used, else the plaintext will be hashed, then
2003 that hash will be mixed together with the "convergence" string to form
2008 def download_from_uri_to_file(uri=URI, filename=str):
2009 """Download a file from the grid, placing it on the node's local disk
2010 at the given filename (which must be absolute[?]). Returns the
2011 absolute filename where the file was written."""
2016 def get_memory_usage():
2017 """Return a dict describes the amount of memory currently in use. The
2018 keys are 'VmPeak', 'VmSize', and 'VmData'. The values are integers,
2019 measuring memory consupmtion in bytes."""
2020 return DictOf(str, int)
2022 def speed_test(count=int, size=int, mutable=Any()):
2023 """Write 'count' tempfiles to disk, all of the given size. Measure
2024 how long (in seconds) it takes to upload them all to the servers.
2025 Then measure how long it takes to download all of them. If 'mutable'
2026 is 'create', time creation of mutable files. If 'mutable' is
2027 'upload', then time access to the same mutable file instead of
2030 Returns a tuple of (upload_time, download_time).
2032 return (float, float)
2034 def measure_peer_response_time():
2035 """Send a short message to each connected peer, and measure the time
2036 it takes for them to respond to it. This is a rough measure of the
2037 application-level round trip time.
2039 @return: a dictionary mapping peerid to a float (RTT time in seconds)
2042 return DictOf(Nodeid, float)
2044 UploadResults = Any() #DictOf(str, str)
2046 class RIEncryptedUploadable(RemoteInterface):
2047 __remote_name__ = "RIEncryptedUploadable.tahoe.allmydata.com"
2052 def get_all_encoding_parameters():
2053 return (int, int, int, long)
2055 def read_encrypted(offset=Offset, length=ReadSize):
2058 def get_plaintext_hashtree_leaves(first=int, last=int, num_segments=int):
2061 def get_plaintext_hash():
2068 class RICHKUploadHelper(RemoteInterface):
2069 __remote_name__ = "RIUploadHelper.tahoe.allmydata.com"
2073 Return a dictionary of version information.
2075 return DictOf(str, Any())
2077 def upload(reader=RIEncryptedUploadable):
2078 return UploadResults
2081 class RIHelper(RemoteInterface):
2082 __remote_name__ = "RIHelper.tahoe.allmydata.com"
2086 Return a dictionary of version information.
2088 return DictOf(str, Any())
2090 def upload_chk(si=StorageIndex):
2091 """See if a file with a given storage index needs uploading. The
2092 helper will ask the appropriate storage servers to see if the file
2093 has already been uploaded. If so, the helper will return a set of
2094 'upload results' that includes whatever hashes are needed to build
2095 the read-cap, and perhaps a truncated sharemap.
2097 If the file has not yet been uploaded (or if it was only partially
2098 uploaded), the helper will return an empty upload-results dictionary
2099 and also an RICHKUploadHelper object that will take care of the
2100 upload process. The client should call upload() on this object and
2101 pass it a reference to an RIEncryptedUploadable object that will
2102 provide ciphertext. When the upload is finished, the upload() method
2103 will finish and return the upload results.
2105 return (UploadResults, ChoiceOf(RICHKUploadHelper, None))
2108 class RIStatsProvider(RemoteInterface):
2109 __remote_name__ = "RIStatsProvider.tahoe.allmydata.com"
2111 Provides access to statistics and monitoring information.
2116 returns a dictionary containing 'counters' and 'stats', each a dictionary
2117 with string counter/stat name keys, and numeric values. counters are
2118 monotonically increasing measures of work done, and stats are instantaneous
2119 measures (potentially time averaged internally)
2121 return DictOf(str, DictOf(str, ChoiceOf(float, int, long)))
2123 class RIStatsGatherer(RemoteInterface):
2124 __remote_name__ = "RIStatsGatherer.tahoe.allmydata.com"
2126 Provides a monitoring service for centralised collection of stats
2129 def provide(provider=RIStatsProvider, nickname=str):
2131 @param provider: a stats collector instance which should be polled
2132 periodically by the gatherer to collect stats.
2133 @param nickname: a name useful to identify the provided client
2138 class IStatsProducer(Interface):
2141 returns a dictionary, with str keys representing the names of stats
2142 to be monitored, and numeric values.
2145 class RIKeyGenerator(RemoteInterface):
2146 __remote_name__ = "RIKeyGenerator.tahoe.allmydata.com"
2148 Provides a service offering to make RSA key pairs.
2151 def get_rsa_key_pair(key_size=int):
2153 @param key_size: the size of the signature key.
2154 @return: tuple(verifying_key, signing_key)
2156 return TupleOf(str, str)
2159 class FileTooLargeError(Exception):
2163 class InsufficientVersionError(Exception):
2164 def __init__(self, needed, got):
2165 self.needed = needed
2168 return "InsufficientVersionError(need '%s', got %s)" % (self.needed,