from zope.interface import Interface from foolscap.api import StringConstraint, ListOf, TupleOf, SetOf, DictOf, \ ChoiceOf, IntegerConstraint, Any, RemoteInterface, Referenceable HASH_SIZE=32 Hash = StringConstraint(maxLength=HASH_SIZE, minLength=HASH_SIZE)# binary format 32-byte SHA256 hash Nodeid = StringConstraint(maxLength=20, minLength=20) # binary format 20-byte SHA1 hash FURL = StringConstraint(1000) StorageIndex = StringConstraint(16) URI = StringConstraint(300) # kind of arbitrary MAX_BUCKETS = 256 # per peer -- zfec offers at most 256 shares per file ShareData = StringConstraint(None) URIExtensionData = StringConstraint(1000) Number = IntegerConstraint(8) # 2**(8*8) == 16EiB ~= 18e18 ~= 18 exabytes Offset = Number ReadSize = int # the 'int' constraint is 2**31 == 2Gib -- large files are processed in not-so-large increments WriteEnablerSecret = Hash # used to protect mutable bucket modifications LeaseRenewSecret = Hash # used to protect bucket lease renewal requests LeaseCancelSecret = Hash # used to protect bucket lease cancellation requests class RIStubClient(RemoteInterface): """Each client publishes a service announcement for a dummy object called the StubClient. This object doesn't actually offer any services, but the announcement helps the Introducer keep track of which clients are subscribed (so the grid admin can keep track of things like the size of the grid and the client versions in use. This is the (empty) RemoteInterface for the StubClient.""" class RIBucketWriter(RemoteInterface): """ Objects of this kind live on the server side. """ def write(offset=Offset, data=ShareData): return None def close(): """ If the data that has been written is incomplete or inconsistent then the server will throw the data away, else it will store it for future retrieval. """ return None def abort(): """Abandon all the data that has been written. """ return None class RIBucketReader(RemoteInterface): def read(offset=Offset, length=ReadSize): return ShareData def advise_corrupt_share(reason=str): """Clients who discover hash failures in shares that they have downloaded from me will use this method to inform me about the failures. I will record their concern so that my operator can manually inspect the shares in question. I return None. This is a wrapper around RIStorageServer.advise_corrupt_share(), which is tied to a specific share, and therefore does not need the extra share-identifying arguments. Please see that method for full documentation. """ TestVector = ListOf(TupleOf(Offset, ReadSize, str, str)) # elements are (offset, length, operator, specimen) # operator is one of "lt, le, eq, ne, ge, gt" # nop always passes and is used to fetch data while writing. # you should use length==len(specimen) for everything except nop DataVector = ListOf(TupleOf(Offset, ShareData)) # (offset, data). This limits us to 30 writes of 1MiB each per call TestAndWriteVectorsForShares = DictOf(int, TupleOf(TestVector, DataVector, ChoiceOf(None, Offset), # new_length )) ReadVector = ListOf(TupleOf(Offset, ReadSize)) ReadData = ListOf(ShareData) # returns data[offset:offset+length] for each element of TestVector class RIStorageServer(RemoteInterface): __remote_name__ = "RIStorageServer.tahoe.allmydata.com" def get_version(): """ Return a dictionary of version information. """ return DictOf(str, Any()) def allocate_buckets(storage_index=StorageIndex, renew_secret=LeaseRenewSecret, cancel_secret=LeaseCancelSecret, sharenums=SetOf(int, maxLength=MAX_BUCKETS), allocated_size=Offset, canary=Referenceable): """ @param storage_index: the index of the bucket to be created or increfed. @param sharenums: these are the share numbers (probably between 0 and 99) that the sender is proposing to store on this server. @param renew_secret: This is the secret used to protect bucket refresh This secret is generated by the client and stored for later comparison by the server. Each server is given a different secret. @param cancel_secret: Like renew_secret, but protects bucket decref. @param canary: If the canary is lost before close(), the bucket is deleted. @return: tuple of (alreadygot, allocated), where alreadygot is what we already have and allocated is what we hereby agree to accept. New leases are added for shares in both lists. """ return TupleOf(SetOf(int, maxLength=MAX_BUCKETS), DictOf(int, RIBucketWriter, maxKeys=MAX_BUCKETS)) def add_lease(storage_index=StorageIndex, renew_secret=LeaseRenewSecret, cancel_secret=LeaseCancelSecret): """ Add a new lease on the given bucket. If the renew_secret matches an existing lease, that lease will be renewed instead. If there is no bucket for the given storage_index, return silently. (note that in tahoe-1.3.0 and earlier, IndexError was raised if there was no bucket) """ return Any() # returns None now, but future versions might change def renew_lease(storage_index=StorageIndex, renew_secret=LeaseRenewSecret): """ Renew the lease on a given bucket, resetting the timer to 31 days. Some networks will use this, some will not. If there is no bucket for the given storage_index, IndexError will be raised. For mutable shares, if the given renew_secret does not match an existing lease, IndexError will be raised with a note listing the server-nodeids on the existing leases, so leases on migrated shares can be renewed or cancelled. For immutable shares, IndexError (without the note) will be raised. """ return Any() def cancel_lease(storage_index=StorageIndex, cancel_secret=LeaseCancelSecret): """ Cancel the lease on a given bucket. If this was the last lease on the bucket, the bucket will be deleted. If there is no bucket for the given storage_index, IndexError will be raised. For mutable shares, if the given cancel_secret does not match an existing lease, IndexError will be raised with a note listing the server-nodeids on the existing leases, so leases on migrated shares can be renewed or cancelled. For immutable shares, IndexError (without the note) will be raised. """ return Any() def get_buckets(storage_index=StorageIndex): return DictOf(int, RIBucketReader, maxKeys=MAX_BUCKETS) def slot_readv(storage_index=StorageIndex, shares=ListOf(int), readv=ReadVector): """Read a vector from the numbered shares associated with the given storage index. An empty shares list means to return data from all known shares. Returns a dictionary with one key per share.""" return DictOf(int, ReadData) # shnum -> results def slot_testv_and_readv_and_writev(storage_index=StorageIndex, secrets=TupleOf(WriteEnablerSecret, LeaseRenewSecret, LeaseCancelSecret), tw_vectors=TestAndWriteVectorsForShares, r_vector=ReadVector, ): """General-purpose test-and-set operation for mutable slots. Perform a bunch of comparisons against the existing shares. If they all pass, then apply a bunch of write vectors to those shares. Then use the read vectors to extract data from all the shares and return the data. This method is, um, large. The goal is to allow clients to update all the shares associated with a mutable file in a single round trip. @param storage_index: the index of the bucket to be created or increfed. @param write_enabler: a secret that is stored along with the slot. Writes are accepted from any caller who can present the matching secret. A different secret should be used for each slot*server pair. @param renew_secret: This is the secret used to protect bucket refresh This secret is generated by the client and stored for later comparison by the server. Each server is given a different secret. @param cancel_secret: Like renew_secret, but protects bucket decref. The 'secrets' argument is a tuple of (write_enabler, renew_secret, cancel_secret). The first is required to perform any write. The latter two are used when allocating new shares. To simply acquire a new lease on existing shares, use an empty testv and an empty writev. Each share can have a separate test vector (i.e. a list of comparisons to perform). If all vectors for all shares pass, then all writes for all shares are recorded. Each comparison is a 4-tuple of (offset, length, operator, specimen), which effectively does a bool( (read(offset, length)) OPERATOR specimen ) and only performs the write if all these evaluate to True. Basic test-and-set uses 'eq'. Write-if-newer uses a seqnum and (offset, length, 'lt', specimen). Write-if-same-or-newer uses 'le'. Reads from the end of the container are truncated, and missing shares behave like empty ones, so to assert that a share doesn't exist (for use when creating a new share), use (0, 1, 'eq', ''). The write vector will be applied to the given share, expanding it if necessary. A write vector applied to a share number that did not exist previously will cause that share to be created. Each write vector is accompanied by a 'new_length' argument. If new_length is not None, use it to set the size of the container. This can be used to pre-allocate space for a series of upcoming writes, or truncate existing data. If the container is growing, new_length will be applied before datav. If the container is shrinking, it will be applied afterwards. If new_length==0, the share will be deleted. The read vector is used to extract data from all known shares, *before* any writes have been applied. The same vector is used for all shares. This captures the state that was tested by the test vector. This method returns two values: a boolean and a dict. The boolean is True if the write vectors were applied, False if not. The dict is keyed by share number, and each value contains a list of strings, one for each element of the read vector. If the write_enabler is wrong, this will raise BadWriteEnablerError. To enable share migration (using update_write_enabler), the exception will have the nodeid used for the old write enabler embedded in it, in the following string:: The write enabler was recorded by nodeid '%s'. Note that the nodeid here is encoded using the same base32 encoding used by Foolscap and allmydata.util.idlib.nodeid_b2a(). """ return TupleOf(bool, DictOf(int, ReadData)) def advise_corrupt_share(share_type=str, storage_index=StorageIndex, shnum=int, reason=str): """Clients who discover hash failures in shares that they have downloaded from me will use this method to inform me about the failures. I will record their concern so that my operator can manually inspect the shares in question. I return None. 'share_type' is either 'mutable' or 'immutable'. 'storage_index' is a (binary) storage index string, and 'shnum' is the integer share number. 'reason' is a human-readable explanation of the problem, probably including some expected hash values and the computed ones which did not match. Corruption advisories for mutable shares should include a hash of the public key (the same value that appears in the mutable-file verify-cap), since the current share format does not store that on disk. """ class IStorageBucketWriter(Interface): """ Objects of this kind live on the client side. """ def put_block(segmentnum=int, data=ShareData): """@param data: For most segments, this data will be 'blocksize' bytes in length. The last segment might be shorter. @return: a Deferred that fires (with None) when the operation completes """ def put_plaintext_hashes(hashes=ListOf(Hash)): """ @return: a Deferred that fires (with None) when the operation completes """ def put_crypttext_hashes(hashes=ListOf(Hash)): """ @return: a Deferred that fires (with None) when the operation completes """ def put_block_hashes(blockhashes=ListOf(Hash)): """ @return: a Deferred that fires (with None) when the operation completes """ def put_share_hashes(sharehashes=ListOf(TupleOf(int, Hash))): """ @return: a Deferred that fires (with None) when the operation completes """ def put_uri_extension(data=URIExtensionData): """This block of data contains integrity-checking information (hashes of plaintext, crypttext, and shares), as well as encoding parameters that are necessary to recover the data. This is a serialized dict mapping strings to other strings. The hash of this data is kept in the URI and verified before any of the data is used. All buckets for a given file contain identical copies of this data. The serialization format is specified with the following pseudocode: for k in sorted(dict.keys()): assert re.match(r'^[a-zA-Z_\-]+$', k) write(k + ':' + netstring(dict[k])) @return: a Deferred that fires (with None) when the operation completes """ def close(): """Finish writing and close the bucket. The share is not finalized until this method is called: if the uploading client disconnects before calling close(), the partially-written share will be discarded. @return: a Deferred that fires (with None) when the operation completes """ class IStorageBucketReader(Interface): def get_block_data(blocknum=int, blocksize=int, size=int): """Most blocks will be the same size. The last block might be shorter than the others. @return: ShareData """ def get_crypttext_hashes(): """ @return: ListOf(Hash) """ def get_block_hashes(at_least_these=SetOf(int)): """ @return: ListOf(Hash) """ def get_share_hashes(at_least_these=SetOf(int)): """ @return: ListOf(TupleOf(int, Hash)) """ def get_uri_extension(): """ @return: URIExtensionData """ # hm, we need a solution for forward references in schemas FileNode_ = Any() # TODO: foolscap needs constraints on copyables DirectoryNode_ = Any() # TODO: same AnyNode_ = ChoiceOf(FileNode_, DirectoryNode_) EncryptedThing = str class IURI(Interface): def init_from_string(uri): """Accept a string (as created by my to_string() method) and populate this instance with its data. I am not normally called directly, please use the module-level uri.from_string() function to convert arbitrary URI strings into IURI-providing instances.""" def is_readonly(): """Return False if this URI be used to modify the data. Return True if this URI cannot be used to modify the data.""" def is_mutable(): """Return True if the data can be modified by *somebody* (perhaps someone who has a more powerful URI than this one).""" def get_readonly(): """Return another IURI instance, which represents a read-only form of this one. If is_readonly() is True, this returns self.""" def get_verify_cap(): """Return an instance that provides IVerifierURI, which can be used to check on the availability of the file or directory, without providing enough capabilities to actually read or modify the contents. This may return None if the file does not need checking or verification (e.g. LIT URIs). """ def to_string(): """Return a string of printable ASCII characters, suitable for passing into init_from_string.""" class IVerifierURI(Interface, IURI): def init_from_string(uri): """Accept a string (as created by my to_string() method) and populate this instance with its data. I am not normally called directly, please use the module-level uri.from_string() function to convert arbitrary URI strings into IURI-providing instances.""" def to_string(): """Return a string of printable ASCII characters, suitable for passing into init_from_string.""" class IDirnodeURI(Interface): """I am a URI which represents a dirnode.""" class IFileURI(Interface): """I am a URI which represents a filenode.""" def get_size(): """Return the length (in bytes) of the file that I represent.""" class IImmutableFileURI(IFileURI): pass class IMutableFileURI(Interface): """I am a URI which represents a mutable filenode.""" class INewDirectoryURI(Interface): pass class IReadonlyNewDirectoryURI(Interface): pass class IFilesystemNode(Interface): def get_uri(): """ Return the URI that can be used by others to get access to this node. If this node is read-only, the URI will only offer read-only access. If this node is read-write, the URI will offer read-write access. If you have read-write access to a node and wish to share merely read-only access with others, use get_readonly_uri(). """ def get_readonly_uri(): """Return the directory URI that can be used by others to get read-only access to this directory node. The result is a read-only URI, regardless of whether this dirnode is read-only or read-write. If you have merely read-only access to this dirnode, get_readonly_uri() will return the same thing as get_uri(). """ def get_repair_cap(): """Return an IURI instance that can be used to repair the file, or None if this node cannot be repaired (either because it is not distributed, like a LIT file, or because the node does not represent sufficient authority to create a repair-cap, like a read-only RSA mutable file node [which cannot create the correct write-enablers]). """ def get_verify_cap(): """Return an IVerifierURI instance that represents the 'verifiy/refresh capability' for this node. The holder of this capability will be able to renew the lease for this node, protecting it from garbage-collection. They will also be able to ask a server if it holds a share for the file or directory. """ def get_storage_index(): """Return a string with the (binary) storage index in use on this download. This may be None if there is no storage index (i.e. LIT files).""" def is_readonly(): """Return True if this reference provides mutable access to the given file or directory (i.e. if you can modify it), or False if not. Note that even if this reference is read-only, someone else may hold a read-write reference to it.""" def is_mutable(): """Return True if this file or directory is mutable (by *somebody*, not necessarily you), False if it is is immutable. Note that a file might be mutable overall, but your reference to it might be read-only. On the other hand, all references to an immutable file will be read-only; there are no read-write references to an immutable file. """ class IMutableFilesystemNode(IFilesystemNode): pass class IFileNode(IFilesystemNode): def download(target): """Download the file's contents to a given IDownloadTarget""" def download_to_data(): """Download the file's contents. Return a Deferred that fires with those contents.""" def get_size(): """Return the length (in bytes) of the data this node represents.""" def read(consumer, offset=0, size=None): """Download a portion (possibly all) of the file's contents, making them available to the given IConsumer. Return a Deferred that fires (with the consumer) when the consumer is unregistered (either because the last byte has been given to it, or because the consumer threw an exception during write(), possibly because it no longer wants to receive data). The portion downloaded will start at 'offset' and contain 'size' bytes (or the remainder of the file if size==None). The consumer will be used in non-streaming mode: an IPullProducer will be attached to it. The consumer will not receive data right away: several network trips must occur first. The order of events will be:: consumer.registerProducer(p, streaming) (if streaming == False):: consumer does p.resumeProducing() consumer.write(data) consumer does p.resumeProducing() consumer.write(data).. (repeat until all data is written) consumer.unregisterProducer() deferred.callback(consumer) If a download error occurs, or an exception is raised by consumer.registerProducer() or consumer.write(), I will call consumer.unregisterProducer() and then deliver the exception via deferred.errback(). To cancel the download, the consumer should call p.stopProducing(), which will result in an exception being delivered via deferred.errback(). A simple download-to-memory consumer example would look like this:: class MemoryConsumer: implements(IConsumer) def __init__(self): self.chunks = [] self.done = False def registerProducer(self, p, streaming): assert streaming == False while not self.done: p.resumeProducing() def write(self, data): self.chunks.append(data) def unregisterProducer(self): self.done = True d = filenode.read(MemoryConsumer()) d.addCallback(lambda mc: "".join(mc.chunks)) return d """ class IMutableFileNode(IFileNode, IMutableFilesystemNode): """I provide access to a 'mutable file', which retains its identity regardless of what contents are put in it. The consistency-vs-availability problem means that there might be multiple versions of a file present in the grid, some of which might be unrecoverable (i.e. have fewer than 'k' shares). These versions are loosely ordered: each has a sequence number and a hash, and any version with seqnum=N was uploaded by a node which has seen at least one version with seqnum=N-1. The 'servermap' (an instance of IMutableFileServerMap) is used to describe the versions that are known to be present in the grid, and which servers are hosting their shares. It is used to represent the 'state of the world', and is used for this purpose by my test-and-set operations. Downloading the contents of the mutable file will also return a servermap. Uploading a new version into the mutable file requires a servermap as input, and the semantics of the replace operation is 'replace the file with my new version if it looks like nobody else has changed the file since my previous download'. Because the file is distributed, this is not a perfect test-and-set operation, but it will do its best. If the replace process sees evidence of a simultaneous write, it will signal an UncoordinatedWriteError, so that the caller can take corrective action. Most readers will want to use the 'best' current version of the file, and should use my 'download_best_version()' method. To unconditionally replace the file, callers should use overwrite(). This is the mode that user-visible mutable files will probably use. To apply some delta to the file, call modify() with a callable modifier function that can apply the modification that you want to make. This is the mode that dirnodes will use, since most directory modification operations can be expressed in terms of deltas to the directory state. Three methods are available for users who need to perform more complex operations. The first is get_servermap(), which returns an up-to-date servermap using a specified mode. The second is download_version(), which downloads a specific version (not necessarily the 'best' one). The third is 'upload', which accepts new contents and a servermap (which must have been updated with MODE_WRITE). The upload method will attempt to apply the new contents as long as no other node has modified the file since the servermap was updated. This might be useful to a caller who wants to merge multiple versions into a single new one. Note that each time the servermap is updated, a specific 'mode' is used, which determines how many peers are queried. To use a servermap for my replace() method, that servermap must have been updated in MODE_WRITE. These modes are defined in allmydata.mutable.common, and consist of MODE_READ, MODE_WRITE, MODE_ANYTHING, and MODE_CHECK. Please look in allmydata/mutable/servermap.py for details about the differences. Mutable files are currently limited in size (about 3.5MB max) and can only be retrieved and updated all-at-once, as a single big string. Future versions of our mutable files will remove this restriction. """ def download_best_version(): """Download the 'best' available version of the file, meaning one of the recoverable versions with the highest sequence number. If no uncoordinated writes have occurred, and if enough shares are available, then this will be the most recent version that has been uploaded. I update an internal servermap with MODE_READ, determine which version of the file is indicated by servermap.best_recoverable_version(), and return a Deferred that fires with its contents. If no version is recoverable, the Deferred will errback with UnrecoverableFileError. """ def get_size_of_best_version(): """Find the size of the version that would be downloaded with download_best_version(), without actually downloading the whole file. I return a Deferred that fires with an integer. """ def overwrite(new_contents): """Unconditionally replace the contents of the mutable file with new ones. This simply chains get_servermap(MODE_WRITE) and upload(). This is only appropriate to use when the new contents of the file are completely unrelated to the old ones, and you do not care about other clients' changes. I return a Deferred that fires (with a PublishStatus object) when the update has completed. """ def modify(modifier_cb): """Modify the contents of the file, by downloading the current version, applying the modifier function (or bound method), then uploading the new version. I return a Deferred that fires (with a PublishStatus object) when the update is complete. The modifier callable will be given three arguments: a string (with the old contents), a 'first_time' boolean, and a servermap. As with download_best_version(), the old contents will be from the best recoverable version, but the modifier can use the servermap to make other decisions (such as refusing to apply the delta if there are multiple parallel versions, or if there is evidence of a newer unrecoverable version). 'first_time' will be True the first time the modifier is called, and False on any subsequent calls. The callable should return a string with the new contents. The callable must be prepared to be called multiple times, and must examine the input string to see if the change that it wants to make is already present in the old version. If it does not need to make any changes, it can either return None, or return its input string. If the modifier raises an exception, it will be returned in the errback. """ def get_servermap(mode): """Return a Deferred that fires with an IMutableFileServerMap instance, updated using the given mode. """ def download_version(servermap, version): """Download a specific version of the file, using the servermap as a guide to where the shares are located. I return a Deferred that fires with the requested contents, or errbacks with UnrecoverableFileError. Note that a servermap which was updated with MODE_ANYTHING or MODE_READ may not know about shares for all versions (those modes stop querying servers as soon as they can fulfil their goals), so you may want to use MODE_CHECK (which checks everything) to get increased visibility. """ def upload(new_contents, servermap): """Replace the contents of the file with new ones. This requires a servermap that was previously updated with MODE_WRITE. I attempt to provide test-and-set semantics, in that I will avoid modifying any share that is different than the version I saw in the servermap. However, if another node is writing to the file at the same time as me, I may manage to update some shares while they update others. If I see any evidence of this, I will signal UncoordinatedWriteError, and the file will be left in an inconsistent state (possibly the version you provided, possibly the old version, possibly somebody else's version, and possibly a mix of shares from all of these). The recommended response to UncoordinatedWriteError is to either return it to the caller (since they failed to coordinate their writes), or to attempt some sort of recovery. It may be sufficient to wait a random interval (with exponential backoff) and repeat your operation. If I do not signal UncoordinatedWriteError, then I was able to write the new version without incident. I return a Deferred that fires (with a PublishStatus object) when the publish has completed. I will update the servermap in-place with the location of all new shares. """ def get_writekey(): """Return this filenode's writekey, or None if the node does not have write-capability. This may be used to assist with data structures that need to make certain data available only to writers, such as the read-write child caps in dirnodes. The recommended process is to have reader-visible data be submitted to the filenode in the clear (where it will be encrypted by the filenode using the readkey), but encrypt writer-visible data using this writekey. """ class NotEnoughSharesError(Exception): def __init__(self, msg, got, needed): Exception.__init__(self, msg) self.got = got self.needed = needed self.servermap = None class UnableToFetchCriticalDownloadDataError(Exception): """I was unable to fetch some piece of critical data which is supposed to be identically present in all shares.""" class NoServersError(Exception): """Upload wasn't given any servers to work with, usually indicating a network or Introducer problem.""" class ExistingChildError(Exception): """A directory node was asked to add or replace a child that already exists, and overwrite= was set to False.""" class NoSuchChildError(Exception): """A directory node was asked to fetch a child which does not exist.""" class IDirectoryNode(IMutableFilesystemNode): """I represent a name-to-child mapping, holding the tahoe equivalent of a directory. All child names are unicode strings, and all children are some sort of IFilesystemNode (either files or subdirectories). """ def get_uri(): """ The dirnode ('1') URI returned by this method can be used in set_uri() on a different directory ('2') to 'mount' a reference to this directory ('1') under the other ('2'). This URI is just a string, so it can be passed around through email or other out-of-band protocol. """ def get_readonly_uri(): """ The dirnode ('1') URI returned by this method can be used in set_uri() on a different directory ('2') to 'mount' a reference to this directory ('1') under the other ('2'). This URI is just a string, so it can be passed around through email or other out-of-band protocol. """ def list(): """I return a Deferred that fires with a dictionary mapping child name (a unicode string) to (node, metadata_dict) tuples, in which 'node' is either an IFileNode or IDirectoryNode, and 'metadata_dict' is a dictionary of metadata.""" def has_child(name): """I return a Deferred that fires with a boolean, True if there exists a child of the given name, False if not. The child name must be a unicode string.""" def get(name): """I return a Deferred that fires with a specific named child node, either an IFileNode or an IDirectoryNode. The child name must be a unicode string. I raise NoSuchChildError if I do not have a child by that name.""" def get_metadata_for(name): """I return a Deferred that fires with the metadata dictionary for a specific named child node. This metadata is stored in the *edge*, not in the child, so it is attached to the parent dirnode rather than the child dir-or-file-node. The child name must be a unicode string. I raise NoSuchChildError if I do not have a child by that name.""" def set_metadata_for(name, metadata): """I replace any existing metadata for the named child with the new metadata. The child name must be a unicode string. This metadata is stored in the *edge*, not in the child, so it is attached to the parent dirnode rather than the child dir-or-file-node. I return a Deferred (that fires with this dirnode) when the operation is complete. I raise NoSuchChildError if I do not have a child by that name.""" def get_child_at_path(path): """Transform a child path into an IDirectoryNode or IFileNode. I perform a recursive series of 'get' operations to find the named descendant node. I return a Deferred that fires with the node, or errbacks with NoSuchChildError if the node could not be found. The path can be either a single string (slash-separated) or a list of path-name elements. All elements must be unicode strings. """ def get_child_and_metadata_at_path(path): """Transform a child path into an IDirectoryNode/IFileNode and metadata. I am like get_child_at_path(), but my Deferred fires with a tuple of (node, metadata). The metadata comes from the last edge. If the path is empty, the metadata will be an empty dictionary. """ def set_uri(name, child_uri, metadata=None, overwrite=True): """I add a child (by URI) at the specific name. I return a Deferred that fires when the operation finishes. If overwrite= is True, I will replace any existing child of the same name, otherwise an existing child will cause me to return ExistingChildError. The child name must be a unicode string. The child_uri could be for a file, or for a directory (either read-write or read-only, using a URI that came from get_uri() ). If metadata= is provided, I will use it as the metadata for the named edge. This will replace any existing metadata. If metadata= is left as the default value of None, I will set ['mtime'] to the current time, and I will set ['ctime'] to the current time if there was not already a child by this name present. This roughly matches the ctime/mtime semantics of traditional filesystems. If this directory node is read-only, the Deferred will errback with a NotMutableError.""" def set_children(entries, overwrite=True): """Add multiple (name, child_uri) pairs (or (name, child_uri, metadata) triples) to a directory node. Returns a Deferred that fires (with None) when the operation finishes. This is equivalent to calling set_uri() multiple times, but is much more efficient. All child names must be unicode strings. """ def set_node(name, child, metadata=None, overwrite=True): """I add a child at the specific name. I return a Deferred that fires when the operation finishes. This Deferred will fire with the child node that was just added. I will replace any existing child of the same name. The child name must be a unicode string. The 'child' instance must be an instance providing IDirectoryNode or IFileNode. If metadata= is provided, I will use it as the metadata for the named edge. This will replace any existing metadata. If metadata= is left as the default value of None, I will set ['mtime'] to the current time, and I will set ['ctime'] to the current time if there was not already a child by this name present. This roughly matches the ctime/mtime semantics of traditional filesystems. If this directory node is read-only, the Deferred will errback with a NotMutableError.""" def set_nodes(entries, overwrite=True): """Add multiple (name, child_node) pairs (or (name, child_node, metadata) triples) to a directory node. Returns a Deferred that fires (with None) when the operation finishes. This is equivalent to calling set_node() multiple times, but is much more efficient. All child names must be unicode strings.""" def add_file(name, uploadable, metadata=None, overwrite=True): """I upload a file (using the given IUploadable), then attach the resulting FileNode to the directory at the given name. I set metadata the same way as set_uri and set_node. The child name must be a unicode string. I return a Deferred that fires (with the IFileNode of the uploaded file) when the operation completes.""" def delete(name): """I remove the child at the specific name. I return a Deferred that fires when the operation finishes. The child name must be a unicode string. I raise NoSuchChildError if I do not have a child by that name.""" def create_empty_directory(name, overwrite=True): """I create and attach an empty directory at the given name. The child name must be a unicode string. I return a Deferred that fires when the operation finishes.""" def move_child_to(current_child_name, new_parent, new_child_name=None, overwrite=True): """I take one of my children and move them to a new parent. The child is referenced by name. On the new parent, the child will live under 'new_child_name', which defaults to 'current_child_name'. TODO: what should we do about metadata? I return a Deferred that fires when the operation finishes. The child name must be a unicode string. I raise NoSuchChildError if I do not have a child by that name.""" def build_manifest(): """I generate a table of everything reachable from this directory. I also compute deep-stats as described below. I return a Monitor. The Monitor's results will be a dictionary with four elements: res['manifest']: a list of (path, cap) tuples for all nodes (directories and files) reachable from this one. 'path' will be a tuple of unicode strings. The origin dirnode will be represented by an empty path tuple. res['verifycaps']: a list of (printable) verifycap strings, one for each reachable non-LIT node. This is a set: it will contain no duplicates. res['storage-index']: a list of (base32) storage index strings, one for each reachable non-LIT node. This is a set: it will contain no duplicates. res['stats']: a dictionary, the same that is generated by start_deep_stats() below. The Monitor will also have an .origin_si attribute with the (binary) storage index of the starting point. """ def start_deep_stats(): """Return a Monitor, examining all nodes (directories and files) reachable from this one. The Monitor's results will be a dictionary with the following keys:: count-immutable-files: count of how many CHK files are in the set count-mutable-files: same, for mutable files (does not include directories) count-literal-files: same, for LIT files count-files: sum of the above three count-directories: count of directories size-immutable-files: total bytes for all CHK files in the set size-mutable-files (TODO): same, for current version of all mutable files, does not include directories size-literal-files: same, for LIT files size-directories: size of mutable files used by directories largest-directory: number of bytes in the largest directory largest-directory-children: number of children in the largest directory largest-immutable-file: number of bytes in the largest CHK file size-mutable-files is not yet implemented, because it would involve even more queries than deep_stats does. The Monitor will also have an .origin_si attribute with the (binary) storage index of the starting point. This operation will visit every directory node underneath this one, and can take a long time to run. On a typical workstation with good bandwidth, this can examine roughly 15 directories per second (and takes several minutes of 100% CPU for ~1700 directories). """ class ICodecEncoder(Interface): def set_params(data_size, required_shares, max_shares): """Set up the parameters of this encoder. This prepares the encoder to perform an operation that converts a single block of data into a number of shares, such that a future ICodecDecoder can use a subset of these shares to recover the original data. This operation is invoked by calling encode(). Once the encoding parameters are set up, the encode operation can be invoked multiple times. set_params() prepares the encoder to accept blocks of input data that are exactly 'data_size' bytes in length. The encoder will be prepared to produce 'max_shares' shares for each encode() operation (although see the 'desired_share_ids' to use less CPU). The encoding math will be chosen such that the decoder can get by with as few as 'required_shares' of these shares and still reproduce the original data. For example, set_params(1000, 5, 5) offers no redundancy at all, whereas set_params(1000, 1, 10) provides 10x redundancy. Numerical Restrictions: 'data_size' is required to be an integral multiple of 'required_shares'. In general, the caller should choose required_shares and max_shares based upon their reliability requirements and the number of peers available (the total storage space used is roughly equal to max_shares*data_size/required_shares), then choose data_size to achieve the memory footprint desired (larger data_size means more efficient operation, smaller data_size means smaller memory footprint). In addition, 'max_shares' must be equal to or greater than 'required_shares'. Of course, setting them to be equal causes encode() to degenerate into a particularly slow form of the 'split' utility. See encode() for more details about how these parameters are used. set_params() must be called before any other ICodecEncoder methods may be invoked. """ def get_params(): """Return the 3-tuple of data_size, required_shares, max_shares""" def get_encoder_type(): """Return a short string that describes the type of this encoder. There is required to be a global table of encoder classes. This method returns an index into this table; the value at this index is an encoder class, and this encoder is an instance of that class. """ def get_block_size(): """Return the length of the shares that encode() will produce. """ def encode_proposal(data, desired_share_ids=None): """Encode some data. 'data' must be a string (or other buffer object), and len(data) must be equal to the 'data_size' value passed earlier to set_params(). This will return a Deferred that will fire with two lists. The first is a list of shares, each of which is a string (or other buffer object) such that len(share) is the same as what get_share_size() returned earlier. The second is a list of shareids, in which each is an integer. The lengths of the two lists will always be equal to each other. The user should take care to keep each share closely associated with its shareid, as one is useless without the other. The length of this output list will normally be the same as the value provided to the 'max_shares' parameter of set_params(). This may be different if 'desired_share_ids' is provided. 'desired_share_ids', if provided, is required to be a sequence of ints, each of which is required to be >= 0 and < max_shares. If not provided, encode() will produce 'max_shares' shares, as if 'desired_share_ids' were set to range(max_shares). You might use this if you initially thought you were going to use 10 peers, started encoding, and then two of the peers dropped out: you could use desired_share_ids= to skip the work (both memory and CPU) of producing shares for the peers which are no longer available. """ def encode(inshares, desired_share_ids=None): """Encode some data. This may be called multiple times. Each call is independent. inshares is a sequence of length required_shares, containing buffers (i.e. strings), where each buffer contains the next contiguous non-overlapping segment of the input data. Each buffer is required to be the same length, and the sum of the lengths of the buffers is required to be exactly the data_size promised by set_params(). (This implies that the data has to be padded before being passed to encode(), unless of course it already happens to be an even multiple of required_shares in length.) ALSO: the requirement to break up your data into 'required_shares' chunks before calling encode() feels a bit surprising, at least from the point of view of a user who doesn't know how FEC works. It feels like an implementation detail that has leaked outside the abstraction barrier. Can you imagine a use case in which the data to be encoded might already be available in pre-segmented chunks, such that it is faster or less work to make encode() take a list rather than splitting a single string? ALSO ALSO: I think 'inshares' is a misleading term, since encode() is supposed to *produce* shares, so what it *accepts* should be something other than shares. Other places in this interface use the word 'data' for that-which-is-not-shares.. maybe we should use that term? 'desired_share_ids', if provided, is required to be a sequence of ints, each of which is required to be >= 0 and < max_shares. If not provided, encode() will produce 'max_shares' shares, as if 'desired_share_ids' were set to range(max_shares). You might use this if you initially thought you were going to use 10 peers, started encoding, and then two of the peers dropped out: you could use desired_share_ids= to skip the work (both memory and CPU) of producing shares for the peers which are no longer available. For each call, encode() will return a Deferred that fires with two lists, one containing shares and the other containing the shareids. The get_share_size() method can be used to determine the length of the share strings returned by encode(). Each shareid is a small integer, exactly as passed into 'desired_share_ids' (or range(max_shares), if desired_share_ids was not provided). The shares and their corresponding shareids are required to be kept together during storage and retrieval. Specifically, the share data is useless by itself: the decoder needs to be told which share is which by providing it with both the shareid and the actual share data. This function will allocate an amount of memory roughly equal to:: (max_shares - required_shares) * get_share_size() When combined with the memory that the caller must allocate to provide the input data, this leads to a memory footprint roughly equal to the size of the resulting encoded shares (i.e. the expansion factor times the size of the input segment). """ # rejected ideas: # # returning a list of (shareidN,shareN) tuples instead of a pair of # lists (shareids..,shares..). Brian thought the tuples would # encourage users to keep the share and shareid together throughout # later processing, Zooko pointed out that the code to iterate # through two lists is not really more complicated than using a list # of tuples and there's also a performance improvement # # having 'data_size' not required to be an integral multiple of # 'required_shares'. Doing this would require encode() to perform # padding internally, and we'd prefer to have any padding be done # explicitly by the caller. Yes, it is an abstraction leak, but # hopefully not an onerous one. class ICodecDecoder(Interface): def set_params(data_size, required_shares, max_shares): """Set the params. They have to be exactly the same ones that were used for encoding. """ def get_needed_shares(): """Return the number of shares needed to reconstruct the data. set_params() is required to be called before this.""" def decode(some_shares, their_shareids): """Decode a partial list of shares into data. 'some_shares' is required to be a sequence of buffers of sharedata, a subset of the shares returned by ICodecEncode.encode(). Each share is required to be of the same length. The i'th element of their_shareids is required to be the shareid of the i'th buffer in some_shares. This returns a Deferred which fires with a sequence of buffers. This sequence will contain all of the segments of the original data, in order. The sum of the lengths of all of the buffers will be the 'data_size' value passed into the original ICodecEncode.set_params() call. To get back the single original input block of data, use ''.join(output_buffers), or you may wish to simply write them in order to an output file. Note that some of the elements in the result sequence may be references to the elements of the some_shares input sequence. In particular, this means that if those share objects are mutable (e.g. arrays) and if they are changed, then both the input (the 'some_shares' parameter) and the output (the value given when the deferred is triggered) will change. The length of 'some_shares' is required to be exactly the value of 'required_shares' passed into the original ICodecEncode.set_params() call. """ class IEncoder(Interface): """I take an object that provides IEncryptedUploadable, which provides encrypted data, and a list of shareholders. I then encode, hash, and deliver shares to those shareholders. I will compute all the necessary Merkle hash trees that are necessary to validate the crypttext that eventually comes back from the shareholders. I provide the URI Extension Block Hash, and the encoding parameters, both of which must be included in the URI. I do not choose shareholders, that is left to the IUploader. I must be given a dict of RemoteReferences to storage buckets that are ready and willing to receive data. """ def set_size(size): """Specify the number of bytes that will be encoded. This must be peformed before get_serialized_params() can be called. """ def set_params(params): """Override the default encoding parameters. 'params' is a tuple of (k,d,n), where 'k' is the number of required shares, 'd' is the shares_of_happiness, and 'n' is the total number of shares that will be created. Encoding parameters can be set in three ways. 1: The Encoder class provides defaults (3/7/10). 2: the Encoder can be constructed with an 'options' dictionary, in which the needed_and_happy_and_total_shares' key can be a (k,d,n) tuple. 3: set_params((k,d,n)) can be called. If you intend to use set_params(), you must call it before get_share_size or get_param are called. """ def set_encrypted_uploadable(u): """Provide a source of encrypted upload data. 'u' must implement IEncryptedUploadable. When this is called, the IEncryptedUploadable will be queried for its length and the storage_index that should be used. This returns a Deferred that fires with this Encoder instance. This must be performed before start() can be called. """ def get_param(name): """Return an encoding parameter, by name. 'storage_index': return a string with the (16-byte truncated SHA-256 hash) storage index to which these shares should be pushed. 'share_counts': return a tuple describing how many shares are used: (needed_shares, shares_of_happiness, total_shares) 'num_segments': return an int with the number of segments that will be encoded. 'segment_size': return an int with the size of each segment. 'block_size': return the size of the individual blocks that will be delivered to a shareholder's put_block() method. By knowing this, the shareholder will be able to keep all blocks in a single file and still provide random access when reading them. # TODO: can we avoid exposing this? 'share_size': an int with the size of the data that will be stored on each shareholder. This is aggregate amount of data that will be sent to the shareholder, summed over all the put_block() calls I will ever make. It is useful to determine this size before asking potential shareholders whether they will grant a lease or not, since their answers will depend upon how much space we need. TODO: this might also include some amount of overhead, like the size of all the hashes. We need to decide whether this is useful or not. 'serialized_params': a string with a concise description of the codec name and its parameters. This may be passed into the IUploadable to let it make sure that the same file encoded with different parameters will result in different storage indexes. Once this is called, set_size() and set_params() may not be called. """ def set_shareholders(shareholders): """Tell the encoder where to put the encoded shares. 'shareholders' must be a dictionary that maps share number (an integer ranging from 0 to n-1) to an instance that provides IStorageBucketWriter. This must be performed before start() can be called.""" def start(): """Begin the encode/upload process. This involves reading encrypted data from the IEncryptedUploadable, encoding it, uploading the shares to the shareholders, then sending the hash trees. set_encrypted_uploadable() and set_shareholders() must be called before this can be invoked. This returns a Deferred that fires with a verify cap when the upload process is complete. The verifycap, plus the encryption key, is sufficient to construct the read cap. """ class IDecoder(Interface): """I take a list of shareholders and some setup information, then download, validate, decode, and decrypt data from them, writing the results to an output file. I do not locate the shareholders, that is left to the IDownloader. I must be given a dict of RemoteReferences to storage buckets that are ready to send data. """ def setup(outfile): """I take a file-like object (providing write and close) to which all the plaintext data will be written. TODO: producer/consumer . Maybe write() should return a Deferred that indicates when it will accept more data? But probably having the IDecoder be a producer is easier to glue to IConsumer pieces. """ def set_shareholders(shareholders): """I take a dictionary that maps share identifiers (small integers) to RemoteReferences that provide RIBucketReader. This must be called before start().""" def start(): """I start the download. This process involves retrieving data and hash chains from the shareholders, using the hashes to validate the data, decoding the shares into segments, decrypting the segments, then writing the resulting plaintext to the output file. I return a Deferred that will fire (with self) when the download is complete. """ class IDownloadTarget(Interface): # Note that if the IDownloadTarget is also an IConsumer, the downloader # will register itself as a producer. This allows the target to invoke # downloader.pauseProducing, resumeProducing, and stopProducing. def open(size): """Called before any calls to write() or close(). If an error occurs before any data is available, fail() may be called without a previous call to open(). 'size' is the length of the file being downloaded, in bytes.""" def write(data): """Output some data to the target.""" def close(): """Inform the target that there is no more data to be written.""" def fail(why): """fail() is called to indicate that the download has failed. 'why' is a Failure object indicating what went wrong. No further methods will be invoked on the IDownloadTarget after fail().""" def register_canceller(cb): """The CiphertextDownloader uses this to register a no-argument function that the target can call to cancel the download. Once this canceller is invoked, no further calls to write() or close() will be made.""" def finish(): """When the CiphertextDownloader is done, this finish() function will be called. Whatever it returns will be returned to the invoker of Downloader.download. """ # The following methods are just because that target might be a repairer.DownUpConnector, # and just because the current CHKUpload object expects to find the storage index and # encoding parameters in its Uploadable. def set_storageindex(storageindex): """ Set the storage index. """ def set_encodingparams(encodingparams): """ Set the encoding parameters. """ class IDownloader(Interface): def download(uri, target): """Perform a CHK download, sending the data to the given target. 'target' must provide IDownloadTarget. Returns a Deferred that fires (with the results of target.finish) when the download is finished, or errbacks if something went wrong.""" class IEncryptedUploadable(Interface): def set_upload_status(upload_status): """Provide an IUploadStatus object that should be filled with status information. The IEncryptedUploadable is responsible for setting key-determination progress ('chk'), size, storage_index, and ciphertext-fetch progress. It may delegate some of this responsibility to others, in particular to the IUploadable.""" def get_size(): """This behaves just like IUploadable.get_size().""" def get_all_encoding_parameters(): """Return a Deferred that fires with a tuple of (k,happy,n,segment_size). The segment_size will be used as-is, and must match the following constraints: it must be a multiple of k, and it shouldn't be unreasonably larger than the file size (if segment_size is larger than filesize, the difference must be stored as padding). This usually passes through to the IUploadable method of the same name. The encoder strictly obeys the values returned by this method. To make an upload use non-default encoding parameters, you must arrange to control the values that this method returns. """ def get_storage_index(): """Return a Deferred that fires with a 16-byte storage index. """ def read_encrypted(length, hash_only): """This behaves just like IUploadable.read(), but returns crypttext instead of plaintext. If hash_only is True, then this discards the data (and returns an empty list); this improves efficiency when resuming an interrupted upload (where we need to compute the plaintext hashes, but don't need the redundant encrypted data).""" def get_plaintext_hashtree_leaves(first, last, num_segments): """OBSOLETE; Get the leaf nodes of a merkle hash tree over the plaintext segments, i.e. get the tagged hashes of the given segments. The segment size is expected to be generated by the IEncryptedUploadable before any plaintext is read or ciphertext produced, so that the segment hashes can be generated with only a single pass. This returns a Deferred which fires with a sequence of hashes, using: tuple(segment_hashes[first:last]) 'num_segments' is used to assert that the number of segments that the IEncryptedUploadable handled matches the number of segments that the encoder was expecting. This method must not be called until the final byte has been read from read_encrypted(). Once this method is called, read_encrypted() can never be called again. """ def get_plaintext_hash(): """OBSOLETE; Get the hash of the whole plaintext. This returns a Deferred which fires with a tagged SHA-256 hash of the whole plaintext, obtained from hashutil.plaintext_hash(data). """ def close(): """Just like IUploadable.close().""" class IUploadable(Interface): def set_upload_status(upload_status): """Provide an IUploadStatus object that should be filled with status information. The IUploadable is responsible for setting key-determination progress ('chk').""" def set_default_encoding_parameters(params): """Set the default encoding parameters, which must be a dict mapping strings to ints. The meaningful keys are 'k', 'happy', 'n', and 'max_segment_size'. These might have an influence on the final encoding parameters returned by get_all_encoding_parameters(), if the Uploadable doesn't have more specific preferences. This call is optional: if it is not used, the Uploadable will use some built-in defaults. If used, this method must be called before any other IUploadable methods to have any effect. """ def get_size(): """Return a Deferred that will fire with the length of the data to be uploaded, in bytes. This will be called before the data is actually used, to compute encoding parameters. """ def get_all_encoding_parameters(): """Return a Deferred that fires with a tuple of (k,happy,n,segment_size). The segment_size will be used as-is, and must match the following constraints: it must be a multiple of k, and it shouldn't be unreasonably larger than the file size (if segment_size is larger than filesize, the difference must be stored as padding). The relative values of k and n allow some IUploadables to request better redundancy than others (in exchange for consuming more space in the grid). Larger values of segment_size reduce hash overhead, while smaller values reduce memory footprint and cause data to be delivered in smaller pieces (which may provide a smoother and more predictable download experience). The encoder strictly obeys the values returned by this method. To make an upload use non-default encoding parameters, you must arrange to control the values that this method returns. One way to influence them may be to call set_encoding_parameters() before calling get_all_encoding_parameters(). """ def get_encryption_key(): """Return a Deferred that fires with a 16-byte AES key. This key will be used to encrypt the data. The key will also be hashed to derive the StorageIndex. Uploadables which want to achieve convergence should hash their file contents and the serialized_encoding_parameters to form the key (which of course requires a full pass over the data). Uploadables can use the upload.ConvergentUploadMixin class to achieve this automatically. Uploadables which do not care about convergence (or do not wish to make multiple passes over the data) can simply return a strongly-random 16 byte string. get_encryption_key() may be called multiple times: the IUploadable is required to return the same value each time. """ def read(length): """Return a Deferred that fires with a list of strings (perhaps with only a single element) which, when concatenated together, contain the next 'length' bytes of data. If EOF is near, this may provide fewer than 'length' bytes. The total number of bytes provided by read() before it signals EOF must equal the size provided by get_size(). If the data must be acquired through multiple internal read operations, returning a list instead of a single string may help to reduce string copies. 'length' will typically be equal to (min(get_size(),1MB)/req_shares), so a 10kB file means length=3kB, 100kB file means length=30kB, and >=1MB file means length=300kB. This method provides for a single full pass through the data. Later use cases may desire multiple passes or access to only parts of the data (such as a mutable file making small edits-in-place). This API will be expanded once those use cases are better understood. """ def close(): """The upload is finished, and whatever filehandle was in use may be closed.""" class IUploadResults(Interface): """I am returned by upload() methods. I contain a number of public attributes which can be read to determine the results of the upload. Some of these are functional, some are timing information. All of these may be None. .file_size : the size of the file, in bytes .uri : the CHK read-cap for the file .ciphertext_fetched : how many bytes were fetched by the helper .sharemap: dict mapping share identifier to set of serverids (binary strings). This indicates which servers were given which shares. For immutable files, the shareid is an integer (the share number, from 0 to N-1). For mutable files, it is a string of the form 'seq%d-%s-sh%d', containing the sequence number, the roothash, and the share number. .servermap : dict mapping server peerid to a set of share numbers .timings : dict of timing information, mapping name to seconds (float) total : total upload time, start to finish storage_index : time to compute the storage index peer_selection : time to decide which peers will be used contacting_helper : initial helper query to upload/no-upload decision existence_check : helper pre-upload existence check helper_total : initial helper query to helper finished pushing cumulative_fetch : helper waiting for ciphertext requests total_fetch : helper start to last ciphertext response cumulative_encoding : just time spent in zfec cumulative_sending : just time spent waiting for storage servers hashes_and_close : last segment push to shareholder close total_encode_and_push : first encode to shareholder close """ class IDownloadResults(Interface): """I am created internally by download() methods. I contain a number of public attributes which contain details about the download process.:: .file_size : the size of the file, in bytes .servers_used : set of server peerids that were used during download .server_problems : dict mapping server peerid to a problem string. Only servers that had problems (bad hashes, disconnects) are listed here. .servermap : dict mapping server peerid to a set of share numbers. Only servers that had any shares are listed here. .timings : dict of timing information, mapping name to seconds (float) peer_selection : time to ask servers about shares servers_peer_selection : dict of peerid to DYHB-query time uri_extension : time to fetch a copy of the URI extension block hashtrees : time to fetch the hash trees segments : time to fetch, decode, and deliver segments cumulative_fetch : time spent waiting for storage servers cumulative_decode : just time spent in zfec cumulative_decrypt : just time spent in decryption total : total download time, start to finish fetch_per_server : dict of peerid to list of per-segment fetch times """ class IUploader(Interface): def upload(uploadable): """Upload the file. 'uploadable' must impement IUploadable. This returns a Deferred which fires with an UploadResults instance, from which the URI of the file can be obtained as results.uri .""" def upload_ssk(write_capability, new_version, uploadable): """TODO: how should this work?""" class ICheckable(Interface): def check(monitor, verify=False, add_lease=False): """Check upon my health, optionally repairing any problems. This returns a Deferred that fires with an instance that provides ICheckResults, or None if the object is non-distributed (i.e. LIT files). The monitor will be checked periodically to see if the operation has been cancelled. If so, no new queries will be sent, and the Deferred will fire (with a OperationCancelledError) immediately. Filenodes and dirnodes (which provide IFilesystemNode) are also checkable. Instances that represent verifier-caps will be checkable but not downloadable. Some objects (like LIT files) do not actually live in the grid, and their checkers return None (non-distributed files are always healthy). If verify=False, a relatively lightweight check will be performed: I will ask all servers if they have a share for me, and I will believe whatever they say. If there are at least N distinct shares on the grid, my results will indicate r.is_healthy()==True. This requires a roundtrip to each server, but does not transfer very much data, so the network bandwidth is fairly low. If verify=True, a more resource-intensive check will be performed: every share will be downloaded, and the hashes will be validated on every bit. I will ignore any shares that failed their hash checks. If there are at least N distinct valid shares on the grid, my results will indicate r.is_healthy()==True. This requires N/k times as much download bandwidth (and server disk IO) as a regular download. If a storage server is holding a corrupt share, or is experiencing memory failures during retrieval, or is malicious or buggy, then verification will detect the problem, but checking will not. If add_lease=True, I will ensure that an up-to-date lease is present on each share. The lease secrets will be derived from by node secret (in BASEDIR/private/secret), so either I will add a new lease to the share, or I will merely renew the lease that I already had. In a future version of the storage-server protocol (once Accounting has been implemented), there may be additional options here to define the kind of lease that is obtained (which account number to claim, etc). TODO: any problems seen during checking will be reported to the health-manager.furl, a centralized object which is responsible for figuring out why files are unhealthy so corrective action can be taken. """ def check_and_repair(monitor, verify=False, add_lease=False): """Like check(), but if the file/directory is not healthy, attempt to repair the damage. Any non-healthy result will cause an immediate repair operation, to generate and upload new shares. After repair, the file will be as healthy as we can make it. Details about what sort of repair is done will be put in the check-and-repair results. The Deferred will not fire until the repair is complete. This returns a Deferred which fires with an instance of ICheckAndRepairResults.""" class IDeepCheckable(Interface): def start_deep_check(verify=False, add_lease=False): """Check upon the health of me and everything I can reach. This is a recursive form of check(), useable only on dirnodes. I return a Monitor, with results that are an IDeepCheckResults object. TODO: If any of the directories I traverse are unrecoverable, the Monitor will report failure. If any of the files I check upon are unrecoverable, those problems will be reported in the IDeepCheckResults as usual, and the Monitor will not report a failure. """ def start_deep_check_and_repair(verify=False, add_lease=False): """Check upon the health of me and everything I can reach. Repair anything that isn't healthy. This is a recursive form of check_and_repair(), useable only on dirnodes. I return a Monitor, with results that are an IDeepCheckAndRepairResults object. TODO: If any of the directories I traverse are unrecoverable, the Monitor will report failure. If any of the files I check upon are unrecoverable, those problems will be reported in the IDeepCheckResults as usual, and the Monitor will not report a failure. """ class ICheckResults(Interface): """I contain the detailed results of a check/verify operation. """ def get_storage_index(): """Return a string with the (binary) storage index.""" def get_storage_index_string(): """Return a string with the (printable) abbreviated storage index.""" def get_uri(): """Return the (string) URI of the object that was checked.""" def is_healthy(): """Return a boolean, True if the file/dir is fully healthy, False if it is damaged in any way. Non-distributed LIT files always return True.""" def is_recoverable(): """Return a boolean, True if the file/dir can be recovered, False if not. Unrecoverable files are obviously unhealthy. Non-distributed LIT files always return True.""" def needs_rebalancing(): """Return a boolean, True if the file/dir's reliability could be improved by moving shares to new servers. Non-distributed LIT files always return False.""" def get_data(): """Return a dictionary that describes the state of the file/dir. LIT files always return an empty dictionary. Normal files and directories return a dictionary with the following keys (note that these use binary strings rather than base32-encoded ones) (also note that for mutable files, these counts are for the 'best' version): count-shares-good: the number of distinct good shares that were found count-shares-needed: 'k', the number of shares required for recovery count-shares-expected: 'N', the number of total shares generated count-good-share-hosts: the number of distinct storage servers with good shares. If this number is less than count-shares-good, then some shares are doubled up, increasing the correlation of failures. This indicates that one or more shares should be moved to an otherwise unused server, if one is available. count-corrupt-shares: the number of shares with integrity failures list-corrupt-shares: a list of 'share locators', one for each share that was found to be corrupt. Each share locator is a list of (serverid, storage_index, sharenum). count-incompatible-shares: the number of shares which are of a share format unknown to this checker list-incompatible-shares: a list of 'share locators', one for each share that was found to be of an unknown format. Each share locator is a list of (serverid, storage_index, sharenum). servers-responding: list of (binary) storage server identifiers, one for each server which responded to the share query (even if they said they didn't have shares, and even if they said they did have shares but then didn't send them when asked, or dropped the connection, or returned a Failure, and even if they said they did have shares and sent incorrect ones when asked) sharemap: dict mapping share identifier to list of serverids (binary strings). This indicates which servers are holding which shares. For immutable files, the shareid is an integer (the share number, from 0 to N-1). For mutable files, it is a string of the form 'seq%d-%s-sh%d', containing the sequence number, the roothash, and the share number. The following keys are most relevant for mutable files, but immutable files will provide sensible values too:: count-wrong-shares: the number of shares for versions other than the 'best' one (which is defined as being the recoverable version with the highest sequence number, then the highest roothash). These are either leftover shares from an older version (perhaps on a server that was offline when an update occurred), shares from an unrecoverable newer version, or shares from an alternate current version that results from an uncoordinated write collision. For a healthy file, this will equal 0. count-recoverable-versions: the number of recoverable versions of the file. For a healthy file, this will equal 1. count-unrecoverable-versions: the number of unrecoverable versions of the file. For a healthy file, this will be 0. """ def get_summary(): """Return a string with a brief (one-line) summary of the results.""" def get_report(): """Return a list of strings with more detailed results.""" class ICheckAndRepairResults(Interface): """I contain the detailed results of a check/verify/repair operation. The IFilesystemNode.check()/verify()/repair() methods all return instances that provide ICheckAndRepairResults. """ def get_storage_index(): """Return a string with the (binary) storage index.""" def get_storage_index_string(): """Return a string with the (printable) abbreviated storage index.""" def get_repair_attempted(): """Return a boolean, True if a repair was attempted.""" def get_repair_successful(): """Return a boolean, True if repair was attempted and the file/dir was fully healthy afterwards. False if no repair was attempted or if a repair attempt failed.""" def get_pre_repair_results(): """Return an ICheckResults instance that describes the state of the file/dir before any repair was attempted.""" def get_post_repair_results(): """Return an ICheckResults instance that describes the state of the file/dir after any repair was attempted. If no repair was attempted, the pre-repair and post-repair results will be identical.""" class IDeepCheckResults(Interface): """I contain the results of a deep-check operation. This is returned by a call to ICheckable.deep_check(). """ def get_root_storage_index_string(): """Return the storage index (abbreviated human-readable string) of the first object checked.""" def get_counters(): """Return a dictionary with the following keys:: count-objects-checked: count of how many objects were checked count-objects-healthy: how many of those objects were completely healthy count-objects-unhealthy: how many were damaged in some way count-objects-unrecoverable: how many were unrecoverable count-corrupt-shares: how many shares were found to have corruption, summed over all objects examined """ def get_corrupt_shares(): """Return a set of (serverid, storage_index, sharenum) for all shares that were found to be corrupt. Both serverid and storage_index are binary. """ def get_all_results(): """Return a dictionary mapping pathname (a tuple of strings, ready to be slash-joined) to an ICheckResults instance, one for each object that was checked.""" def get_results_for_storage_index(storage_index): """Retrive the ICheckResults instance for the given (binary) storage index. Raises KeyError if there are no results for that storage index.""" def get_stats(): """Return a dictionary with the same keys as IDirectoryNode.deep_stats().""" class IDeepCheckAndRepairResults(Interface): """I contain the results of a deep-check-and-repair operation. This is returned by a call to ICheckable.deep_check_and_repair(). """ def get_root_storage_index_string(): """Return the storage index (abbreviated human-readable string) of the first object checked.""" def get_counters(): """Return a dictionary with the following keys:: count-objects-checked: count of how many objects were checked count-objects-healthy-pre-repair: how many of those objects were completely healthy (before any repair) count-objects-unhealthy-pre-repair: how many were damaged in some way count-objects-unrecoverable-pre-repair: how many were unrecoverable count-objects-healthy-post-repair: how many of those objects were completely healthy (after any repair) count-objects-unhealthy-post-repair: how many were damaged in some way count-objects-unrecoverable-post-repair: how many were unrecoverable count-repairs-attempted: repairs were attempted on this many objects. The count-repairs- keys will always be provided, however unless repair=true is present, they will all be zero. count-repairs-successful: how many repairs resulted in healthy objects count-repairs-unsuccessful: how many repairs resulted did not results in completely healthy objects count-corrupt-shares-pre-repair: how many shares were found to have corruption, summed over all objects examined (before any repair) count-corrupt-shares-post-repair: how many shares were found to have corruption, summed over all objects examined (after any repair) """ def get_stats(): """Return a dictionary with the same keys as IDirectoryNode.deep_stats().""" def get_corrupt_shares(): """Return a set of (serverid, storage_index, sharenum) for all shares that were found to be corrupt before any repair was attempted. Both serverid and storage_index are binary. """ def get_remaining_corrupt_shares(): """Return a set of (serverid, storage_index, sharenum) for all shares that were found to be corrupt after any repair was completed. Both serverid and storage_index are binary. These are shares that need manual inspection and probably deletion. """ def get_all_results(): """Return a dictionary mapping pathname (a tuple of strings, ready to be slash-joined) to an ICheckAndRepairResults instance, one for each object that was checked.""" def get_results_for_storage_index(storage_index): """Retrive the ICheckAndRepairResults instance for the given (binary) storage index. Raises KeyError if there are no results for that storage index.""" class IRepairable(Interface): def repair(check_results): """Attempt to repair the given object. Returns a Deferred that fires with a IRepairResults object. I must be called with an object that implements ICheckResults, as proof that you have actually discovered a problem with this file. I will use the data in the checker results to guide the repair process, such as which servers provided bad data and should therefore be avoided. The ICheckResults object is inside the ICheckAndRepairResults object, which is returned by the ICheckable.check() method:: d = filenode.check(repair=False) def _got_results(check_and_repair_results): check_results = check_and_repair_results.get_pre_repair_results() return filenode.repair(check_results) d.addCallback(_got_results) return d """ class IRepairResults(Interface): """I contain the results of a repair operation.""" class IClient(Interface): def upload(uploadable): """Upload some data into a CHK, get back the UploadResults for it. @param uploadable: something that implements IUploadable @return: a Deferred that fires with the UploadResults instance. To get the URI for this file, use results.uri . """ def create_mutable_file(contents=""): """Create a new mutable file with contents, get back the URI string. @param contents: the initial contents to place in the file. @return: a Deferred that fires with tne (string) SSK URI for the new file. """ def create_empty_dirnode(): """Create a new dirnode, empty and unattached. @return: a Deferred that fires with the new IDirectoryNode instance. """ def create_node_from_uri(uri): """Create a new IFilesystemNode instance from the uri, synchronously. @param uri: a string or IURI-providing instance. This could be for a LiteralFileNode, a CHK file node, a mutable file node, or a directory node @return: an instance that provides IFilesystemNode (or more usefully one of its subclasses). File-specifying URIs will result in IFileNode or IMutableFileNode -providing instances, like FileNode, LiteralFileNode, or MutableFileNode. Directory-specifying URIs will result in IDirectoryNode-providing instances, like NewDirectoryNode. """ class IClientStatus(Interface): def list_all_uploads(): """Return a list of uploader objects, one for each upload which currently has an object available (tracked with weakrefs). This is intended for debugging purposes.""" def list_active_uploads(): """Return a list of active IUploadStatus objects.""" def list_recent_uploads(): """Return a list of IUploadStatus objects for the most recently started uploads.""" def list_all_downloads(): """Return a list of downloader objects, one for each download which currently has an object available (tracked with weakrefs). This is intended for debugging purposes.""" def list_active_downloads(): """Return a list of active IDownloadStatus objects.""" def list_recent_downloads(): """Return a list of IDownloadStatus objects for the most recently started downloads.""" class IUploadStatus(Interface): def get_started(): """Return a timestamp (float with seconds since epoch) indicating when the operation was started.""" def get_storage_index(): """Return a string with the (binary) storage index in use on this upload. Returns None if the storage index has not yet been calculated.""" def get_size(): """Return an integer with the number of bytes that will eventually be uploaded for this file. Returns None if the size is not yet known. """ def using_helper(): """Return True if this upload is using a Helper, False if not.""" def get_status(): """Return a string describing the current state of the upload process.""" def get_progress(): """Returns a tuple of floats, (chk, ciphertext, encode_and_push), each from 0.0 to 1.0 . 'chk' describes how much progress has been made towards hashing the file to determine a CHK encryption key: if non-convergent encryption is in use, this will be trivial, otherwise the whole file must be hashed. 'ciphertext' describes how much of the ciphertext has been pushed to the helper, and is '1.0' for non-helper uploads. 'encode_and_push' describes how much of the encode-and-push process has finished: for helper uploads this is dependent upon the helper providing progress reports. It might be reasonable to add all three numbers and report the sum to the user.""" def get_active(): """Return True if the upload is currently active, False if not.""" def get_results(): """Return an instance of UploadResults (which contains timing and sharemap information). Might return None if the upload is not yet finished.""" def get_counter(): """Each upload status gets a unique number: this method returns that number. This provides a handle to this particular upload, so a web page can generate a suitable hyperlink.""" class IDownloadStatus(Interface): def get_started(): """Return a timestamp (float with seconds since epoch) indicating when the operation was started.""" def get_storage_index(): """Return a string with the (binary) storage index in use on this download. This may be None if there is no storage index (i.e. LIT files).""" def get_size(): """Return an integer with the number of bytes that will eventually be retrieved for this file. Returns None if the size is not yet known. """ def using_helper(): """Return True if this download is using a Helper, False if not.""" def get_status(): """Return a string describing the current state of the download process.""" def get_progress(): """Returns a float (from 0.0 to 1.0) describing the amount of the download that has completed. This value will remain at 0.0 until the first byte of plaintext is pushed to the download target.""" def get_active(): """Return True if the download is currently active, False if not.""" def get_counter(): """Each download status gets a unique number: this method returns that number. This provides a handle to this particular download, so a web page can generate a suitable hyperlink.""" class IServermapUpdaterStatus(Interface): pass class IPublishStatus(Interface): pass class IRetrieveStatus(Interface): pass class NotCapableError(Exception): """You have tried to write to a read-only node.""" class BadWriteEnablerError(Exception): pass class RIControlClient(RemoteInterface): def wait_for_client_connections(num_clients=int): """Do not return until we have connections to at least NUM_CLIENTS storage servers. """ def upload_from_file_to_uri(filename=str, convergence=ChoiceOf(None, StringConstraint(2**20))): """Upload a file to the grid. This accepts a filename (which must be absolute) that points to a file on the node's local disk. The node will read the contents of this file, upload it to the grid, then return the URI at which it was uploaded. If convergence is None then a random encryption key will be used, else the plaintext will be hashed, then that hash will be mixed together with the "convergence" string to form the encryption key. """ return URI def download_from_uri_to_file(uri=URI, filename=str): """Download a file from the grid, placing it on the node's local disk at the given filename (which must be absolute[?]). Returns the absolute filename where the file was written.""" return str # debug stuff def get_memory_usage(): """Return a dict describes the amount of memory currently in use. The keys are 'VmPeak', 'VmSize', and 'VmData'. The values are integers, measuring memory consupmtion in bytes.""" return DictOf(str, int) def speed_test(count=int, size=int, mutable=Any()): """Write 'count' tempfiles to disk, all of the given size. Measure how long (in seconds) it takes to upload them all to the servers. Then measure how long it takes to download all of them. If 'mutable' is 'create', time creation of mutable files. If 'mutable' is 'upload', then time access to the same mutable file instead of creating one. Returns a tuple of (upload_time, download_time). """ return (float, float) def measure_peer_response_time(): """Send a short message to each connected peer, and measure the time it takes for them to respond to it. This is a rough measure of the application-level round trip time. @return: a dictionary mapping peerid to a float (RTT time in seconds) """ return DictOf(Nodeid, float) UploadResults = Any() #DictOf(str, str) class RIEncryptedUploadable(RemoteInterface): __remote_name__ = "RIEncryptedUploadable.tahoe.allmydata.com" def get_size(): return Offset def get_all_encoding_parameters(): return (int, int, int, long) def read_encrypted(offset=Offset, length=ReadSize): return ListOf(str) def get_plaintext_hashtree_leaves(first=int, last=int, num_segments=int): return ListOf(Hash) def get_plaintext_hash(): return Hash def close(): return None class RICHKUploadHelper(RemoteInterface): __remote_name__ = "RIUploadHelper.tahoe.allmydata.com" def get_version(): """ Return a dictionary of version information. """ return DictOf(str, Any()) def upload(reader=RIEncryptedUploadable): return UploadResults class RIHelper(RemoteInterface): __remote_name__ = "RIHelper.tahoe.allmydata.com" def get_version(): """ Return a dictionary of version information. """ return DictOf(str, Any()) def upload_chk(si=StorageIndex): """See if a file with a given storage index needs uploading. The helper will ask the appropriate storage servers to see if the file has already been uploaded. If so, the helper will return a set of 'upload results' that includes whatever hashes are needed to build the read-cap, and perhaps a truncated sharemap. If the file has not yet been uploaded (or if it was only partially uploaded), the helper will return an empty upload-results dictionary and also an RICHKUploadHelper object that will take care of the upload process. The client should call upload() on this object and pass it a reference to an RIEncryptedUploadable object that will provide ciphertext. When the upload is finished, the upload() method will finish and return the upload results. """ return (UploadResults, ChoiceOf(RICHKUploadHelper, None)) class RIStatsProvider(RemoteInterface): __remote_name__ = "RIStatsProvider.tahoe.allmydata.com" """ Provides access to statistics and monitoring information. """ def get_stats(): """ returns a dictionary containing 'counters' and 'stats', each a dictionary with string counter/stat name keys, and numeric values. counters are monotonically increasing measures of work done, and stats are instantaneous measures (potentially time averaged internally) """ return DictOf(str, DictOf(str, ChoiceOf(float, int, long))) class RIStatsGatherer(RemoteInterface): __remote_name__ = "RIStatsGatherer.tahoe.allmydata.com" """ Provides a monitoring service for centralised collection of stats """ def provide(provider=RIStatsProvider, nickname=str): """ @param provider: a stats collector instance which should be polled periodically by the gatherer to collect stats. @param nickname: a name useful to identify the provided client """ return None class IStatsProducer(Interface): def get_stats(): """ returns a dictionary, with str keys representing the names of stats to be monitored, and numeric values. """ class RIKeyGenerator(RemoteInterface): __remote_name__ = "RIKeyGenerator.tahoe.allmydata.com" """ Provides a service offering to make RSA key pairs. """ def get_rsa_key_pair(key_size=int): """ @param key_size: the size of the signature key. @return: tuple(verifying_key, signing_key) """ return TupleOf(str, str) class FileTooLargeError(Exception): pass class IValidatedThingProxy(Interface): def start(): """ Acquire a thing and validate it. Return a deferred which is eventually fired with self if the thing is valid or errbacked if it can't be acquired or validated. """ class InsufficientVersionError(Exception): def __init__(self, needed, got): self.needed = needed self.got = got def __repr__(self): return "InsufficientVersionError(need '%s', got %s)" % (self.needed, self.got)