lbry-sdk/lbrynet/core/HashBlob.py

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from StringIO import StringIO
import logging
import os
import tempfile
import threading
import shutil
from twisted.internet import interfaces, defer, threads
from twisted.protocols.basic import FileSender
from twisted.python.failure import Failure
from zope.interface import implements
from lbrynet import conf
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from lbrynet.core.Error import DownloadCanceledError, InvalidDataError
from lbrynet.core.cryptoutils import get_lbry_hash_obj
from lbrynet.core.utils import is_valid_blobhash
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log = logging.getLogger(__name__)
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class HashBlobReader(object):
implements(interfaces.IConsumer)
def __init__(self, write_func):
self.write_func = write_func
def registerProducer(self, producer, streaming):
from twisted.internet import reactor
self.producer = producer
self.streaming = streaming
if self.streaming is False:
reactor.callLater(0, self.producer.resumeProducing)
def unregisterProducer(self):
pass
def write(self, data):
from twisted.internet import reactor
self.write_func(data)
if self.streaming is False:
reactor.callLater(0, self.producer.resumeProducing)
class HashBlobWriter(object):
def __init__(self, write_handle, length_getter, finished_cb):
self.write_handle = write_handle
self.length_getter = length_getter
self.finished_cb = finished_cb
self._hashsum = get_lbry_hash_obj()
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self.len_so_far = 0
@property
def blob_hash(self):
return self._hashsum.hexdigest()
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def write(self, data):
self._hashsum.update(data)
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self.len_so_far += len(data)
if self.len_so_far > self.length_getter():
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self.finished_cb(
self,
Failure(InvalidDataError("Length so far is greater than the expected length."
" %s to %s" % (self.len_so_far,
self.length_getter()))))
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else:
if self.write_handle is None:
log.debug("Tried to write to a write_handle that was None.")
return
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self.write_handle.write(data)
if self.len_so_far == self.length_getter():
self.finished_cb(self)
def cancel(self, reason=None):
if reason is None:
reason = Failure(DownloadCanceledError())
self.finished_cb(self, reason)
class HashBlob(object):
"""A chunk of data available on the network which is specified by a hashsum"""
def __init__(self, blob_hash, length=None):
assert is_valid_blobhash(blob_hash)
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self.blob_hash = blob_hash
self.length = length
self.writers = {} # {Peer: writer, finished_deferred}
self.finished_deferred = None
self._verified = False
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self.readers = 0
@property
def verified(self):
# protect verified from being modified by other classes
return self._verified
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def set_length(self, length):
if self.length is not None and length == self.length:
return True
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if self.length is None and 0 <= length <= conf.settings['BLOB_SIZE']:
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self.length = length
return True
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log.warning("Got an invalid length. Previous length: %s, Invalid length: %s",
self.length, length)
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return False
def get_length(self):
return self.length
def is_validated(self):
return bool(self._verified)
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def is_downloading(self):
if self.writers:
return True
return False
def read(self, write_func):
def close_self(*args):
self.close_read_handle(file_handle)
return args[0]
file_sender = FileSender()
reader = HashBlobReader(write_func)
file_handle = self.open_for_reading()
if file_handle is not None:
d = file_sender.beginFileTransfer(file_handle, reader)
d.addCallback(close_self)
else:
d = defer.fail(ValueError("Could not read the blob"))
return d
def writer_finished(self, writer, err=None):
def fire_finished_deferred():
self._verified = True
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for p, (w, finished_deferred) in self.writers.items():
if w == writer:
finished_deferred.callback(self)
del self.writers[p]
return True
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log.warning(
"Somehow, the writer that was accepted as being valid was already removed: %s",
writer)
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return False
def errback_finished_deferred(err):
for p, (w, finished_deferred) in self.writers.items():
if w == writer:
finished_deferred.errback(err)
del self.writers[p]
def cancel_other_downloads():
for p, (w, finished_deferred) in self.writers.items():
w.cancel()
if err is None:
if writer.len_so_far == self.length and writer.blob_hash == self.blob_hash:
if self._verified is False:
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d = self._save_verified_blob(writer)
d.addCallbacks(lambda _: fire_finished_deferred(), errback_finished_deferred)
d.addCallback(lambda _: cancel_other_downloads())
else:
errback_finished_deferred(Failure(DownloadCanceledError()))
d = defer.succeed(True)
else:
err_string = "length vs expected: {0}, {1}, hash vs expected: {2}, {3}"
err_string = err_string.format(self.length, writer.len_so_far, self.blob_hash,
writer.blob_hash)
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errback_finished_deferred(Failure(InvalidDataError(err_string)))
d = defer.succeed(True)
else:
errback_finished_deferred(err)
d = defer.succeed(True)
d.addBoth(lambda _: self._close_writer(writer))
return d
def open_for_writing(self, peer):
pass
def open_for_reading(self):
pass
def delete(self):
pass
def close_read_handle(self, file_handle):
pass
def _close_writer(self, writer):
pass
def _save_verified_blob(self, writer):
pass
def __str__(self):
return self.blob_hash[:16]
def __repr__(self):
return '<{}({})>'.format(self.__class__.__name__, str(self))
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class BlobFile(HashBlob):
"""A HashBlob which will be saved to the hard disk of the downloader"""
def __init__(self, blob_dir, *args):
HashBlob.__init__(self, *args)
self.blob_dir = blob_dir
self.file_path = os.path.join(blob_dir, self.blob_hash)
self.setting_verified_blob_lock = threading.Lock()
self.moved_verified_blob = False
if os.path.isfile(self.file_path):
self.set_length(os.path.getsize(self.file_path))
# This assumes that the hash of the blob has already been
# checked as part of the blob creation process. It might
# be worth having a function that checks the actual hash;
# its probably too expensive to have that check be part of
# this call.
self._verified = True
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def open_for_writing(self, peer):
if not peer in self.writers:
log.debug("Opening %s to be written by %s", str(self), str(peer))
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write_file = tempfile.NamedTemporaryFile(delete=False, dir=self.blob_dir)
finished_deferred = defer.Deferred()
writer = HashBlobWriter(write_file, self.get_length, self.writer_finished)
self.writers[peer] = (writer, finished_deferred)
return finished_deferred, writer.write, writer.cancel
log.warning("Tried to download the same file twice simultaneously from the same peer")
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return None, None, None
def open_for_reading(self):
if self._verified is True:
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file_handle = None
try:
file_handle = open(self.file_path, 'rb')
self.readers += 1
return file_handle
except IOError:
self.close_read_handle(file_handle)
return None
def delete(self):
if not self.writers and not self.readers:
self._verified = False
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self.moved_verified_blob = False
def delete_from_file_system():
if os.path.isfile(self.file_path):
os.remove(self.file_path)
d = threads.deferToThread(delete_from_file_system)
def log_error(err):
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log.warning("An error occurred deleting %s: %s",
str(self.file_path), err.getErrorMessage())
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return err
d.addErrback(log_error)
return d
else:
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return defer.fail(Failure(
ValueError("File is currently being read or written and cannot be deleted")))
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def close_read_handle(self, file_handle):
if file_handle is not None:
file_handle.close()
self.readers -= 1
def _close_writer(self, writer):
if writer.write_handle is not None:
log.debug("Closing %s", str(self))
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name = writer.write_handle.name
writer.write_handle.close()
threads.deferToThread(os.remove, name)
writer.write_handle = None
def _save_verified_blob(self, writer):
def move_file():
with self.setting_verified_blob_lock:
if self.moved_verified_blob is False:
temp_file_name = writer.write_handle.name
writer.write_handle.close()
shutil.move(temp_file_name, self.file_path)
writer.write_handle = None
self.moved_verified_blob = True
return True
else:
raise DownloadCanceledError()
return threads.deferToThread(move_file)
class TempBlob(HashBlob):
"""A HashBlob which will only exist in memory"""
def __init__(self, *args):
HashBlob.__init__(self, *args)
self.data_buffer = ""
def open_for_writing(self, peer):
if not peer in self.writers:
temp_buffer = StringIO()
finished_deferred = defer.Deferred()
writer = HashBlobWriter(temp_buffer, self.get_length, self.writer_finished)
self.writers[peer] = (writer, finished_deferred)
return finished_deferred, writer.write, writer.cancel
return None, None, None
def open_for_reading(self):
if self._verified is True:
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return StringIO(self.data_buffer)
return None
def delete(self):
if not self.writers and not self.readers:
self._verified = False
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self.data_buffer = ''
return defer.succeed(True)
else:
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return defer.fail(Failure(
ValueError("Blob is currently being read or written and cannot be deleted")))
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def close_read_handle(self, file_handle):
file_handle.close()
def _close_writer(self, writer):
if writer.write_handle is not None:
writer.write_handle.close()
writer.write_handle = None
def _save_verified_blob(self, writer):
if not self.data_buffer:
self.data_buffer = writer.write_handle.getvalue()
writer.write_handle.close()
writer.write_handle = None
return defer.succeed(True)
else:
return defer.fail(Failure(DownloadCanceledError()))
class HashBlobCreator(object):
def __init__(self, blob_manager):
self.blob_manager = blob_manager
self._hashsum = get_lbry_hash_obj()
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self.len_so_far = 0
self.blob_hash = None
self.length = None
def open(self):
pass
def close(self):
self.length = self.len_so_far
if self.length == 0:
self.blob_hash = None
else:
self.blob_hash = self._hashsum.hexdigest()
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d = self._close()
if self.blob_hash is not None:
d.addCallback(lambda _: self.blob_manager.creator_finished(self))
d.addCallback(lambda _: self.blob_hash)
else:
d.addCallback(lambda _: None)
return d
def write(self, data):
self._hashsum.update(data)
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self.len_so_far += len(data)
self._write(data)
def _close(self):
pass
def _write(self, data):
pass
class BlobFileCreator(HashBlobCreator):
def __init__(self, blob_manager, blob_dir):
HashBlobCreator.__init__(self, blob_manager)
self.blob_dir = blob_dir
self.out_file = tempfile.NamedTemporaryFile(delete=False, dir=self.blob_dir)
def _close(self):
temp_file_name = self.out_file.name
self.out_file.close()
if self.blob_hash is not None:
shutil.move(temp_file_name, os.path.join(self.blob_dir, self.blob_hash))
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else:
os.remove(temp_file_name)
return defer.succeed(True)
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def _write(self, data):
self.out_file.write(data)
class TempBlobCreator(HashBlobCreator):
def __init__(self, blob_manager):
HashBlobCreator.__init__(self, blob_manager)
# TODO: use StringIO
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self.data_buffer = ''
def _close(self):
return defer.succeed(True)
def _write(self, data):
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self.data_buffer += data