tahoe-lafs/src/allmydata/offloaded.py

646 lines
26 KiB
Python

import os, stat, time, weakref
from zope.interface import implements
from twisted.application import service
from twisted.internet import defer
from foolscap import Referenceable
from foolscap.eventual import eventually
from allmydata import upload, interfaces, storage, uri
from allmydata.util import idlib, log, observer, fileutil, hashutil
class NotEnoughWritersError(Exception):
pass
class CHKCheckerAndUEBFetcher:
"""I check to see if a file is already present in the grid. I also fetch
the URI Extension Block, which is useful for an uploading client who
wants to avoid the work of encryption and encoding.
I return False if the file is not completely healthy: i.e. if there are
less than 'N' shares present.
If the file is completely healthy, I return a tuple of (sharemap,
UEB_data, UEB_hash).
"""
def __init__(self, peer_getter, storage_index, logparent=None):
self._peer_getter = peer_getter
self._found_shares = set()
self._storage_index = storage_index
self._sharemap = {}
self._readers = set()
self._ueb_hash = None
self._ueb_data = None
self._logparent = logparent
def log(self, *args, **kwargs):
if 'facility' not in kwargs:
kwargs['facility'] = "tahoe.helper.chk.checkandUEBfetch"
if 'parent' not in kwargs:
kwargs['parent'] = self._logparent
return log.msg(*args, **kwargs)
def check(self):
d = self._get_all_shareholders(self._storage_index)
d.addCallback(self._get_uri_extension)
d.addCallback(self._done)
return d
def _get_all_shareholders(self, storage_index):
dl = []
for (peerid, ss) in self._peer_getter("storage", storage_index):
d = ss.callRemote("get_buckets", storage_index)
d.addCallbacks(self._got_response, self._got_error,
callbackArgs=(peerid,))
dl.append(d)
return defer.DeferredList(dl)
def _got_response(self, buckets, peerid):
# buckets is a dict: maps shum to an rref of the server who holds it
shnums_s = ",".join([str(shnum) for shnum in buckets])
self.log("got_response: [%s] has %d shares (%s)" %
(idlib.shortnodeid_b2a(peerid), len(buckets), shnums_s),
level=log.NOISY)
self._found_shares.update(buckets.keys())
for k in buckets:
if k not in self._sharemap:
self._sharemap[k] = []
self._sharemap[k].append(peerid)
self._readers.update( [ (bucket, peerid)
for bucket in buckets.values() ] )
def _got_error(self, f):
if f.check(KeyError):
pass
log.err(f, parent=self._logparent)
pass
def _get_uri_extension(self, res):
# assume that we can pull the UEB from any share. If we get an error,
# declare the whole file unavailable.
if not self._readers:
self.log("no readers, so no UEB", level=log.NOISY)
return
b,peerid = self._readers.pop()
rbp = storage.ReadBucketProxy(b, peerid,
storage.si_b2a(self._storage_index))
d = rbp.startIfNecessary()
d.addCallback(lambda res: rbp.get_uri_extension())
d.addCallback(self._got_uri_extension)
d.addErrback(self._ueb_error)
return d
def _got_uri_extension(self, ueb):
self.log("_got_uri_extension", level=log.NOISY)
self._ueb_hash = hashutil.uri_extension_hash(ueb)
self._ueb_data = uri.unpack_extension(ueb)
def _ueb_error(self, f):
# an error means the file is unavailable, but the overall check
# shouldn't fail.
self.log("UEB fetch failed", failure=f, level=log.WEIRD)
return None
def _done(self, res):
if self._ueb_data:
found = len(self._found_shares)
total = self._ueb_data['total_shares']
self.log(format="got %(found)d shares of %(total)d",
found=found, total=total, level=log.NOISY)
if found < total:
# not all shares are present in the grid
self.log("not enough to qualify, file not found in grid",
level=log.NOISY)
return False
# all shares are present
self.log("all shares present, file is found in grid",
level=log.NOISY)
return (self._sharemap, self._ueb_data, self._ueb_hash)
# no shares are present
self.log("unable to find UEB data, file not found in grid",
level=log.NOISY)
return False
class CHKUploadHelper(Referenceable, upload.CHKUploader):
"""I am the helper-server -side counterpart to AssistedUploader. I handle
peer selection, encoding, and share pushing. I read ciphertext from the
remote AssistedUploader.
"""
implements(interfaces.RICHKUploadHelper)
def __init__(self, storage_index, helper,
incoming_file, encoding_file,
results, log_number):
self._storage_index = storage_index
self._helper = helper
self._incoming_file = incoming_file
self._encoding_file = encoding_file
self._upload_id = storage.si_b2a(storage_index)[:5]
self._log_number = log_number
self._results = results
self._upload_status = upload.UploadStatus()
self._upload_status.set_helper(False)
self._upload_status.set_storage_index(storage_index)
self._upload_status.set_status("fetching ciphertext")
self._upload_status.set_progress(0, 1.0)
self._helper.log("CHKUploadHelper starting for SI %s" % self._upload_id,
parent=log_number)
self._client = helper.parent
self._fetcher = CHKCiphertextFetcher(self, incoming_file, encoding_file,
self._log_number)
self._reader = LocalCiphertextReader(self, storage_index, encoding_file)
self._finished_observers = observer.OneShotObserverList()
d = self._fetcher.when_done()
d.addCallback(lambda res: self._reader.start())
d.addCallback(lambda res: self.start_encrypted(self._reader))
d.addCallback(self._finished)
d.addErrback(self._failed)
def log(self, *args, **kwargs):
if 'facility' not in kwargs:
kwargs['facility'] = "tahoe.helper.chk"
return upload.CHKUploader.log(self, *args, **kwargs)
def start(self):
self._started = time.time()
# determine if we need to upload the file. If so, return ({},self) .
# If not, return (UploadResults,None) .
self.log("deciding whether to upload the file or not", level=log.NOISY)
if os.path.exists(self._encoding_file):
# we have the whole file, and we might be encoding it (or the
# encode/upload might have failed, and we need to restart it).
self.log("ciphertext already in place", level=log.UNUSUAL)
return (self._results, self)
if os.path.exists(self._incoming_file):
# we have some of the file, but not all of it (otherwise we'd be
# encoding). The caller might be useful.
self.log("partial ciphertext already present", level=log.UNUSUAL)
return (self._results, self)
# we don't remember uploading this file
self.log("no ciphertext yet", level=log.NOISY)
return (self._results, self)
def remote_upload(self, reader):
# reader is an RIEncryptedUploadable. I am specified to return an
# UploadResults dictionary.
# let our fetcher pull ciphertext from the reader.
self._fetcher.add_reader(reader)
# and also hashes
self._reader.add_reader(reader)
# and inform the client when the upload has finished
return self._finished_observers.when_fired()
def _finished(self, res):
(uri_extension_hash, needed_shares, total_shares, size) = res
r = self._results
r.uri_extension_hash = uri_extension_hash
f_times = self._fetcher.get_times()
r.timings["cumulative_fetch"] = f_times["cumulative_fetch"]
r.ciphertext_fetched = self._fetcher.get_ciphertext_fetched()
r.timings["total_fetch"] = f_times["total"]
self._reader.close()
os.unlink(self._encoding_file)
self._finished_observers.fire(r)
self._helper.upload_finished(self._storage_index, size)
del self._reader
def _failed(self, f):
self.log(format="CHKUploadHelper(%(si)s) failed",
si=storage.si_b2a(self._storage_index)[:5],
failure=f,
level=log.UNUSUAL)
self._finished_observers.fire(f)
self._helper.upload_finished(self._storage_index, 0)
del self._reader
class AskUntilSuccessMixin:
# create me with a _reader array
_last_failure = None
def add_reader(self, reader):
self._readers.append(reader)
def call(self, *args, **kwargs):
if not self._readers:
raise NotEnoughWritersError("ran out of assisted uploaders, last failure was %s" % self._last_failure)
rr = self._readers[0]
d = rr.callRemote(*args, **kwargs)
def _err(f):
self._last_failure = f
if rr in self._readers:
self._readers.remove(rr)
self._upload_helper.log("call to assisted uploader %s failed" % rr,
failure=f, level=log.UNUSUAL)
# we can try again with someone else who's left
return self.call(*args, **kwargs)
d.addErrback(_err)
return d
class CHKCiphertextFetcher(AskUntilSuccessMixin):
"""I use one or more remote RIEncryptedUploadable instances to gather
ciphertext on disk. When I'm done, the file I create can be used by a
LocalCiphertextReader to satisfy the ciphertext needs of a CHK upload
process.
I begin pulling ciphertext as soon as a reader is added. I remove readers
when they have any sort of error. If the last reader is removed, I fire
my when_done() Deferred with a failure.
I fire my when_done() Deferred (with None) immediately after I have moved
the ciphertext to 'encoded_file'.
"""
def __init__(self, helper, incoming_file, encoded_file, logparent):
self._upload_helper = helper
self._incoming_file = incoming_file
self._encoding_file = encoded_file
self._upload_id = helper._upload_id
self._log_parent = logparent
self._done_observers = observer.OneShotObserverList()
self._readers = []
self._started = False
self._f = None
self._times = {
"cumulative_fetch": 0.0,
"total": 0.0,
}
self._ciphertext_fetched = 0
def log(self, *args, **kwargs):
if "facility" not in kwargs:
kwargs["facility"] = "tahoe.helper.chkupload.fetch"
if "parent" not in kwargs:
kwargs["parent"] = self._log_parent
return log.msg(*args, **kwargs)
def add_reader(self, reader):
AskUntilSuccessMixin.add_reader(self, reader)
eventually(self._start)
def _start(self):
if self._started:
return
self._started = True
started = time.time()
if os.path.exists(self._encoding_file):
self.log("ciphertext already present, bypassing fetch",
level=log.UNUSUAL)
# we'll still need the plaintext hashes (when
# LocalCiphertextReader.get_plaintext_hashtree_leaves() is
# called), and currently the easiest way to get them is to ask
# the sender for the last byte of ciphertext. That will provoke
# them into reading and hashing (but not sending) everything
# else.
have = os.stat(self._encoding_file)[stat.ST_SIZE]
d = self.call("read_encrypted", have-1, 1)
d.addCallback(self._done2, started)
return
# first, find out how large the file is going to be
d = self.call("get_size")
d.addCallback(self._got_size)
d.addCallback(self._start_reading)
d.addCallback(self._done)
d.addCallback(self._done2, started)
d.addErrback(self._failed)
def _got_size(self, size):
self.log("total size is %d bytes" % size, level=log.NOISY)
self._upload_helper._upload_status.set_size(size)
self._expected_size = size
def _start_reading(self, res):
# then find out how much crypttext we have on disk
if os.path.exists(self._incoming_file):
self._have = os.stat(self._incoming_file)[stat.ST_SIZE]
self.log("we already have %d bytes" % self._have, level=log.NOISY)
else:
self._have = 0
self.log("we do not have any ciphertext yet", level=log.NOISY)
self.log("starting ciphertext fetch", level=log.NOISY)
self._f = open(self._incoming_file, "ab")
# now loop to pull the data from the readers
d = defer.Deferred()
self._loop(d)
# this Deferred will be fired once the last byte has been written to
# self._f
return d
# read data in 50kB chunks. We should choose a more considered number
# here, possibly letting the client specify it. The goal should be to
# keep the RTT*bandwidth to be less than 10% of the chunk size, to reduce
# the upload bandwidth lost because this protocol is non-windowing. Too
# large, however, means more memory consumption for both ends. Something
# that can be transferred in, say, 10 seconds sounds about right. On my
# home DSL line (50kBps upstream), that suggests 500kB. Most lines are
# slower, maybe 10kBps, which suggests 100kB, and that's a bit more
# memory than I want to hang on to, so I'm going to go with 50kB and see
# how that works.
CHUNK_SIZE = 50*1024
def _loop(self, fire_when_done):
# this slightly weird structure is needed because Deferreds don't do
# tail-recursion, so it is important to let each one retire promptly.
# Simply chaining them will cause a stack overflow at the end of a
# transfer that involves more than a few hundred chunks.
# 'fire_when_done' lives a long time, but the Deferreds returned by
# the inner _fetch() call do not.
start = time.time()
d = defer.maybeDeferred(self._fetch)
def _done(finished):
elapsed = time.time() - start
self._times["cumulative_fetch"] += elapsed
if finished:
self.log("finished reading ciphertext", level=log.NOISY)
fire_when_done.callback(None)
else:
self._loop(fire_when_done)
def _err(f):
self.log(format="[%(si)s] ciphertext read failed",
si=self._upload_id, failure=f, level=log.UNUSUAL)
fire_when_done.errback(f)
d.addCallbacks(_done, _err)
return None
def _fetch(self):
needed = self._expected_size - self._have
fetch_size = min(needed, self.CHUNK_SIZE)
if fetch_size == 0:
self._upload_helper._upload_status.set_progress(1, 1.0)
return True # all done
percent = 0.0
if self._expected_size:
percent = 1.0 * (self._have+fetch_size) / self._expected_size
self.log(format="fetching [%(si)s] %(start)d-%(end)d of %(total)d (%(percent)d%%)",
si=self._upload_id,
start=self._have,
end=self._have+fetch_size,
total=self._expected_size,
percent=int(100.0*percent),
level=log.NOISY)
d = self.call("read_encrypted", self._have, fetch_size)
def _got_data(ciphertext_v):
for data in ciphertext_v:
self._f.write(data)
self._have += len(data)
self._ciphertext_fetched += len(data)
self._upload_helper._helper.count("chk_upload_helper.fetched_bytes", len(data))
self._upload_helper._upload_status.set_progress(1, percent)
return False # not done
d.addCallback(_got_data)
return d
def _done(self, res):
self._f.close()
self._f = None
self.log(format="done fetching ciphertext, size=%(size)d",
size=os.stat(self._incoming_file)[stat.ST_SIZE],
level=log.NOISY)
os.rename(self._incoming_file, self._encoding_file)
def _done2(self, _ignored, started):
self.log("done2", level=log.NOISY)
elapsed = time.time() - started
self._times["total"] = elapsed
self._readers = []
self._done_observers.fire(None)
def _failed(self, f):
if self._f:
self._f.close()
self._readers = []
self._done_observers.fire(f)
def when_done(self):
return self._done_observers.when_fired()
def get_times(self):
return self._times
def get_ciphertext_fetched(self):
return self._ciphertext_fetched
class LocalCiphertextReader(AskUntilSuccessMixin):
implements(interfaces.IEncryptedUploadable)
def __init__(self, upload_helper, storage_index, encoding_file):
self._readers = []
self._upload_helper = upload_helper
self._storage_index = storage_index
self._encoding_file = encoding_file
self._status = None
def start(self):
self._upload_helper._upload_status.set_status("pushing")
self._size = os.stat(self._encoding_file)[stat.ST_SIZE]
self.f = open(self._encoding_file, "rb")
def get_size(self):
return defer.succeed(self._size)
def get_all_encoding_parameters(self):
return self.call("get_all_encoding_parameters")
def get_storage_index(self):
return defer.succeed(self._storage_index)
def read_encrypted(self, length, hash_only):
assert hash_only is False
d = defer.maybeDeferred(self.f.read, length)
d.addCallback(lambda data: [data])
return d
def get_plaintext_hashtree_leaves(self, first, last, num_segments):
return self.call("get_plaintext_hashtree_leaves", first, last,
num_segments)
def get_plaintext_hash(self):
return self.call("get_plaintext_hash")
def close(self):
self.f.close()
# ??. I'm not sure if it makes sense to forward the close message.
return self.call("close")
class Helper(Referenceable, service.MultiService):
implements(interfaces.RIHelper, interfaces.IStatsProducer)
# this is the non-distributed version. When we need to have multiple
# helpers, this object will become the HelperCoordinator, and will query
# the farm of Helpers to see if anyone has the storage_index of interest,
# and send the request off to them. If nobody has it, we'll choose a
# helper at random.
name = "helper"
chk_upload_helper_class = CHKUploadHelper
MAX_UPLOAD_STATUSES = 10
def __init__(self, basedir, stats_provider=None):
self._basedir = basedir
self._chk_incoming = os.path.join(basedir, "CHK_incoming")
self._chk_encoding = os.path.join(basedir, "CHK_encoding")
fileutil.make_dirs(self._chk_incoming)
fileutil.make_dirs(self._chk_encoding)
self._active_uploads = {}
self._all_uploads = weakref.WeakKeyDictionary() # for debugging
self._all_upload_statuses = weakref.WeakKeyDictionary()
self._recent_upload_statuses = []
self.stats_provider = stats_provider
if stats_provider:
stats_provider.register_producer(self)
self._counters = {"chk_upload_helper.upload_requests": 0,
"chk_upload_helper.upload_already_present": 0,
"chk_upload_helper.upload_need_upload": 0,
"chk_upload_helper.fetched_bytes": 0,
"chk_upload_helper.encoded_bytes": 0,
}
service.MultiService.__init__(self)
def setServiceParent(self, parent):
service.MultiService.setServiceParent(self, parent)
def log(self, *args, **kwargs):
if 'facility' not in kwargs:
kwargs['facility'] = "tahoe.helper"
return self.parent.log(*args, **kwargs)
def count(self, key, value=1):
if self.stats_provider:
self.stats_provider.count(key, value)
self._counters[key] += value
def get_stats(self):
OLD = 86400*2 # 48hours
now = time.time()
inc_count = inc_size = inc_size_old = 0
enc_count = enc_size = enc_size_old = 0
inc = os.listdir(self._chk_incoming)
enc = os.listdir(self._chk_encoding)
for f in inc:
s = os.stat(os.path.join(self._chk_incoming, f))
size = s[stat.ST_SIZE]
mtime = s[stat.ST_MTIME]
inc_count += 1
inc_size += size
if now - mtime > OLD:
inc_size_old += size
for f in enc:
s = os.stat(os.path.join(self._chk_encoding, f))
size = s[stat.ST_SIZE]
mtime = s[stat.ST_MTIME]
enc_count += 1
enc_size += size
if now - mtime > OLD:
enc_size_old += size
stats = { 'chk_upload_helper.active_uploads': len(self._active_uploads),
'chk_upload_helper.incoming_count': inc_count,
'chk_upload_helper.incoming_size': inc_size,
'chk_upload_helper.incoming_size_old': inc_size_old,
'chk_upload_helper.encoding_count': enc_count,
'chk_upload_helper.encoding_size': enc_size,
'chk_upload_helper.encoding_size_old': enc_size_old,
}
stats.update(self._counters)
return stats
def remote_upload_chk(self, storage_index):
self.count("chk_upload_helper.upload_requests")
r = upload.UploadResults()
started = time.time()
si_s = storage.si_b2a(storage_index)
lp = self.log(format="helper: upload_chk query for SI %(si)s", si=si_s)
incoming_file = os.path.join(self._chk_incoming, si_s)
encoding_file = os.path.join(self._chk_encoding, si_s)
if storage_index in self._active_uploads:
self.log("upload is currently active", parent=lp)
uh = self._active_uploads[storage_index]
return uh.start()
d = self._check_for_chk_already_in_grid(storage_index, r, lp)
def _checked(already_present):
elapsed = time.time() - started
r.timings['existence_check'] = elapsed
if already_present:
# the necessary results are placed in the UploadResults
self.count("chk_upload_helper.upload_already_present")
self.log("file already found in grid", parent=lp)
return (r, None)
self.count("chk_upload_helper.upload_need_upload")
# the file is not present in the grid, by which we mean there are
# less than 'N' shares available.
self.log("unable to find file in the grid", parent=lp,
level=log.NOISY)
# We need an upload helper. Check our active uploads again in
# case there was a race.
if storage_index in self._active_uploads:
self.log("upload is currently active", parent=lp)
uh = self._active_uploads[storage_index]
else:
self.log("creating new upload helper", parent=lp)
uh = self.chk_upload_helper_class(storage_index, self,
incoming_file, encoding_file,
r, lp)
self._active_uploads[storage_index] = uh
self._add_upload(uh)
return uh.start()
d.addCallback(_checked)
def _err(f):
self.log("error while checking for chk-already-in-grid",
failure=f, level=log.WEIRD, parent=lp)
return f
d.addErrback(_err)
return d
def _check_for_chk_already_in_grid(self, storage_index, results, lp):
# see if this file is already in the grid
lp2 = self.log("doing a quick check+UEBfetch",
parent=lp, level=log.NOISY)
c = CHKCheckerAndUEBFetcher(self.parent.get_permuted_peers,
storage_index, lp2)
d = c.check()
def _checked(res):
if res:
(sharemap, ueb_data, ueb_hash) = res
self.log("found file in grid", level=log.NOISY, parent=lp)
results.uri_extension_hash = ueb_hash
results.sharemap = {}
for shnum, peerids in sharemap.items():
peers_s = ",".join(["[%s]" % idlib.shortnodeid_b2a(peerid)
for peerid in peerids])
results.sharemap[shnum] = "Found on " + peers_s
results.uri_extension_data = ueb_data
results.preexisting_shares = len(sharemap)
results.pushed_shares = 0
return True
return False
d.addCallback(_checked)
return d
def _add_upload(self, uh):
self._all_uploads[uh] = None
s = uh.get_upload_status()
self._all_upload_statuses[s] = None
self._recent_upload_statuses.append(s)
while len(self._recent_upload_statuses) > self.MAX_UPLOAD_STATUSES:
self._recent_upload_statuses.pop(0)
def upload_finished(self, storage_index, size):
# this is called with size=0 if the upload failed
self.count("chk_upload_helper.encoded_bytes", size)
uh = self._active_uploads[storage_index]
del self._active_uploads[storage_index]
s = uh.get_upload_status()
s.set_active(False)
def get_all_upload_statuses(self):
return self._all_upload_statuses