import functools import os import zlib import bz2 import config import hashlib import threading import Queue import copy import errno import re import logging from .errors import KeepWriteError, AssertionError, ArgumentError from .keep import KeepLocator from ._normalize_stream import normalize_stream from ._ranges import locators_and_ranges, replace_range, Range from .retry import retry_method MOD = "mod" WRITE = "write" _logger = logging.getLogger('arvados.arvfile') def split(path): """split(path) -> streamname, filename Separate the stream name and file name in a /-separated stream path and return a tuple (stream_name, file_name). If no stream name is available, assume '.'. """ try: stream_name, file_name = path.rsplit('/', 1) except ValueError: # No / in string stream_name, file_name = '.', path return stream_name, file_name class _FileLikeObjectBase(object): def __init__(self, name, mode): self.name = name self.mode = mode self.closed = False @staticmethod def _before_close(orig_func): @functools.wraps(orig_func) def before_close_wrapper(self, *args, **kwargs): if self.closed: raise ValueError("I/O operation on closed stream file") return orig_func(self, *args, **kwargs) return before_close_wrapper def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): try: self.close() except Exception: if exc_type is None: raise def close(self): self.closed = True class ArvadosFileReaderBase(_FileLikeObjectBase): def __init__(self, name, mode, num_retries=None): super(ArvadosFileReaderBase, self).__init__(name, mode) self._filepos = 0L self.num_retries = num_retries self._readline_cache = (None, None) def __iter__(self): while True: data = self.readline() if not data: break yield data def decompressed_name(self): return re.sub('\.(bz2|gz)$', '', self.name) @_FileLikeObjectBase._before_close def seek(self, pos, whence=os.SEEK_SET): if whence == os.SEEK_CUR: pos += self._filepos elif whence == os.SEEK_END: pos += self.size() self._filepos = min(max(pos, 0L), self.size()) def tell(self): return self._filepos @_FileLikeObjectBase._before_close @retry_method def readall(self, size=2**20, num_retries=None): while True: data = self.read(size, num_retries=num_retries) if data == '': break yield data @_FileLikeObjectBase._before_close @retry_method def readline(self, size=float('inf'), num_retries=None): cache_pos, cache_data = self._readline_cache if self.tell() == cache_pos: data = [cache_data] else: data = [''] data_size = len(data[-1]) while (data_size < size) and ('\n' not in data[-1]): next_read = self.read(2 ** 20, num_retries=num_retries) if not next_read: break data.append(next_read) data_size += len(next_read) data = ''.join(data) try: nextline_index = data.index('\n') + 1 except ValueError: nextline_index = len(data) nextline_index = min(nextline_index, size) self._readline_cache = (self.tell(), data[nextline_index:]) return data[:nextline_index] @_FileLikeObjectBase._before_close @retry_method def decompress(self, decompress, size, num_retries=None): for segment in self.readall(size, num_retries): data = decompress(segment) if data: yield data @_FileLikeObjectBase._before_close @retry_method def readall_decompressed(self, size=2**20, num_retries=None): self.seek(0) if self.name.endswith('.bz2'): dc = bz2.BZ2Decompressor() return self.decompress(dc.decompress, size, num_retries=num_retries) elif self.name.endswith('.gz'): dc = zlib.decompressobj(16+zlib.MAX_WBITS) return self.decompress(lambda segment: dc.decompress(dc.unconsumed_tail + segment), size, num_retries=num_retries) else: return self.readall(size, num_retries=num_retries) @_FileLikeObjectBase._before_close @retry_method def readlines(self, sizehint=float('inf'), num_retries=None): data = [] data_size = 0 for s in self.readall(num_retries=num_retries): data.append(s) data_size += len(s) if data_size >= sizehint: break return ''.join(data).splitlines(True) def size(self): raise NotImplementedError() def read(self, size, num_retries=None): raise NotImplementedError() def readfrom(self, start, size, num_retries=None): raise NotImplementedError() class StreamFileReader(ArvadosFileReaderBase): class _NameAttribute(str): # The Python file API provides a plain .name attribute. # Older SDK provided a name() method. # This class provides both, for maximum compatibility. def __call__(self): return self def __init__(self, stream, segments, name): super(StreamFileReader, self).__init__(self._NameAttribute(name), 'rb', num_retries=stream.num_retries) self._stream = stream self.segments = segments def stream_name(self): return self._stream.name() def size(self): n = self.segments[-1] return n.range_start + n.range_size @_FileLikeObjectBase._before_close @retry_method def read(self, size, num_retries=None): """Read up to 'size' bytes from the stream, starting at the current file position""" if size == 0: return '' data = '' available_chunks = locators_and_ranges(self.segments, self._filepos, size) if available_chunks: lr = available_chunks[0] data = self._stream.readfrom(lr.locator+lr.segment_offset, lr.segment_size, num_retries=num_retries) self._filepos += len(data) return data @_FileLikeObjectBase._before_close @retry_method def readfrom(self, start, size, num_retries=None): """Read up to 'size' bytes from the stream, starting at 'start'""" if size == 0: return '' data = [] for lr in locators_and_ranges(self.segments, start, size): data.append(self._stream.readfrom(lr.locator+lr.segment_offset, lr.segment_size, num_retries=num_retries)) return ''.join(data) def as_manifest(self): segs = [] for r in self.segments: segs.extend(self._stream.locators_and_ranges(r.locator, r.range_size)) return " ".join(normalize_stream(".", {self.name: segs})) + "\n" def synchronized(orig_func): @functools.wraps(orig_func) def synchronized_wrapper(self, *args, **kwargs): with self.lock: return orig_func(self, *args, **kwargs) return synchronized_wrapper class StateChangeError(Exception): def __init__(self, message, state, nextstate): super(StateChangeError, self).__init__(message) self.state = state self.nextstate = nextstate class _BufferBlock(object): """A stand-in for a Keep block that is in the process of being written. Writers can append to it, get the size, and compute the Keep locator. There are three valid states: WRITABLE Can append to block. PENDING Block is in the process of being uploaded to Keep, append is an error. COMMITTED The block has been written to Keep, its internal buffer has been released, fetching the block will fetch it via keep client (since we discarded the internal copy), and identifiers referring to the BufferBlock can be replaced with the block locator. """ WRITABLE = 0 PENDING = 1 COMMITTED = 2 ERROR = 3 def __init__(self, blockid, starting_capacity, owner): """ :blockid: the identifier for this block :starting_capacity: the initial buffer capacity :owner: ArvadosFile that owns this block """ self.blockid = blockid self.buffer_block = bytearray(starting_capacity) self.buffer_view = memoryview(self.buffer_block) self.write_pointer = 0 self._state = _BufferBlock.WRITABLE self._locator = None self.owner = owner self.lock = threading.Lock() self.wait_for_commit = threading.Event() self.error = None @synchronized def append(self, data): """Append some data to the buffer. Only valid if the block is in WRITABLE state. Implements an expanding buffer, doubling capacity as needed to accomdate all the data. """ if self._state == _BufferBlock.WRITABLE: while (self.write_pointer+len(data)) > len(self.buffer_block): new_buffer_block = bytearray(len(self.buffer_block) * 2) new_buffer_block[0:self.write_pointer] = self.buffer_block[0:self.write_pointer] self.buffer_block = new_buffer_block self.buffer_view = memoryview(self.buffer_block) self.buffer_view[self.write_pointer:self.write_pointer+len(data)] = data self.write_pointer += len(data) self._locator = None else: raise AssertionError("Buffer block is not writable") STATE_TRANSITIONS = frozenset([ (WRITABLE, PENDING), (PENDING, COMMITTED), (PENDING, ERROR), (ERROR, PENDING)]) @synchronized def set_state(self, nextstate, val=None): if (self._state, nextstate) not in self.STATE_TRANSITIONS: raise StateChangeError("Invalid state change from %s to %s" % (self.state, nextstate), self.state, nextstate) self._state = nextstate if self._state == _BufferBlock.PENDING: self.wait_for_commit.clear() if self._state == _BufferBlock.COMMITTED: self._locator = val self.buffer_view = None self.buffer_block = None self.wait_for_commit.set() if self._state == _BufferBlock.ERROR: self.error = val self.wait_for_commit.set() @synchronized def state(self): return self._state def size(self): """The amount of data written to the buffer.""" return self.write_pointer @synchronized def locator(self): """The Keep locator for this buffer's contents.""" if self._locator is None: self._locator = "%s+%i" % (hashlib.md5(self.buffer_view[0:self.write_pointer]).hexdigest(), self.size()) return self._locator @synchronized def clone(self, new_blockid, owner): if self._state == _BufferBlock.COMMITTED: raise AssertionError("Cannot duplicate committed buffer block") bufferblock = _BufferBlock(new_blockid, self.size(), owner) bufferblock.append(self.buffer_view[0:self.size()]) return bufferblock @synchronized def clear(self): self.owner = None self.buffer_block = None self.buffer_view = None class NoopLock(object): def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): pass def acquire(self, blocking=False): pass def release(self): pass def must_be_writable(orig_func): @functools.wraps(orig_func) def must_be_writable_wrapper(self, *args, **kwargs): if not self.writable(): raise IOError(errno.EROFS, "Collection is read-only.") return orig_func(self, *args, **kwargs) return must_be_writable_wrapper class _BlockManager(object): """BlockManager handles buffer blocks. Also handles background block uploads, and background block prefetch for a Collection of ArvadosFiles. """ DEFAULT_PUT_THREADS = 2 DEFAULT_GET_THREADS = 2 def __init__(self, keep): """keep: KeepClient object to use""" self._keep = keep self._bufferblocks = {} self._put_queue = None self._put_threads = None self._prefetch_queue = None self._prefetch_threads = None self.lock = threading.Lock() self.prefetch_enabled = True self.num_put_threads = _BlockManager.DEFAULT_PUT_THREADS self.num_get_threads = _BlockManager.DEFAULT_GET_THREADS @synchronized def alloc_bufferblock(self, blockid=None, starting_capacity=2**14, owner=None): """Allocate a new, empty bufferblock in WRITABLE state and return it. :blockid: optional block identifier, otherwise one will be automatically assigned :starting_capacity: optional capacity, otherwise will use default capacity :owner: ArvadosFile that owns this block """ if blockid is None: blockid = "bufferblock%i" % len(self._bufferblocks) bufferblock = _BufferBlock(blockid, starting_capacity=starting_capacity, owner=owner) self._bufferblocks[bufferblock.blockid] = bufferblock return bufferblock @synchronized def dup_block(self, block, owner): """Create a new bufferblock initialized with the content of an existing bufferblock. :block: the buffer block to copy. :owner: ArvadosFile that owns the new block """ new_blockid = "bufferblock%i" % len(self._bufferblocks) bufferblock = block.clone(new_blockid, owner) self._bufferblocks[bufferblock.blockid] = bufferblock return bufferblock @synchronized def is_bufferblock(self, locator): return locator in self._bufferblocks def _commit_bufferblock_worker(self): """Background uploader thread.""" while True: try: bufferblock = self._put_queue.get() if bufferblock is None: return loc = self._keep.put(bufferblock.buffer_view[0:bufferblock.write_pointer].tobytes()) bufferblock.set_state(_BufferBlock.COMMITTED, loc) except Exception as e: bufferblock.set_state(_BufferBlock.ERROR, e) finally: if self._put_queue is not None: self._put_queue.task_done() @synchronized def start_put_threads(self): if self._put_threads is None: # Start uploader threads. # If we don't limit the Queue size, the upload queue can quickly # grow to take up gigabytes of RAM if the writing process is # generating data more quickly than it can be send to the Keep # servers. # # With two upload threads and a queue size of 2, this means up to 4 # blocks pending. If they are full 64 MiB blocks, that means up to # 256 MiB of internal buffering, which is the same size as the # default download block cache in KeepClient. self._put_queue = Queue.Queue(maxsize=2) self._put_threads = [] for i in xrange(0, self.num_put_threads): thread = threading.Thread(target=self._commit_bufferblock_worker) self._put_threads.append(thread) thread.daemon = False thread.start() def _block_prefetch_worker(self): """The background downloader thread.""" while True: try: b = self._prefetch_queue.get() if b is None: return self._keep.get(b) except Exception: pass @synchronized def start_get_threads(self): if self._prefetch_threads is None: self._prefetch_queue = Queue.Queue() self._prefetch_threads = [] for i in xrange(0, self.num_get_threads): thread = threading.Thread(target=self._block_prefetch_worker) self._prefetch_threads.append(thread) thread.daemon = True thread.start() @synchronized def stop_threads(self): """Shut down and wait for background upload and download threads to finish.""" if self._put_threads is not None: for t in self._put_threads: self._put_queue.put(None) for t in self._put_threads: t.join() self._put_threads = None self._put_queue = None if self._prefetch_threads is not None: for t in self._prefetch_threads: self._prefetch_queue.put(None) for t in self._prefetch_threads: t.join() self._prefetch_threads = None self._prefetch_queue = None def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): self.stop_threads() def __del__(self): self.stop_threads() def commit_bufferblock(self, block, sync): """Initiate a background upload of a bufferblock. :block: The block object to upload :sync: If `sync` is True, upload the block synchronously. If `sync` is False, upload the block asynchronously. This will return immediately unless the upload queue is at capacity, in which case it will wait on an upload queue slot. """ try: # Mark the block as PENDING so to disallow any more appends. block.set_state(_BufferBlock.PENDING) except StateChangeError as e: if e.state == _BufferBlock.PENDING and sync: block.wait_for_commit.wait() if block.state() == _BufferBlock.ERROR: raise block.error return if sync: try: loc = self._keep.put(block.buffer_view[0:block.write_pointer].tobytes()) block.set_state(_BufferBlock.COMMITTED, loc) except Exception as e: block.set_state(_BufferBlock.ERROR, e) raise else: self.start_put_threads() self._put_queue.put(block) @synchronized def get_bufferblock(self, locator): return self._bufferblocks.get(locator) @synchronized def delete_bufferblock(self, locator): bb = self._bufferblocks[locator] bb.clear() del self._bufferblocks[locator] def get_block_contents(self, locator, num_retries, cache_only=False): """Fetch a block. First checks to see if the locator is a BufferBlock and return that, if not, passes the request through to KeepClient.get(). """ with self.lock: if locator in self._bufferblocks: bufferblock = self._bufferblocks[locator] if bufferblock.state() != _BufferBlock.COMMITTED: return bufferblock.buffer_view[0:bufferblock.write_pointer].tobytes() else: locator = bufferblock._locator if cache_only: return self._keep.get_from_cache(locator) else: return self._keep.get(locator, num_retries=num_retries) def commit_all(self): """Commit all outstanding buffer blocks. This is a synchronous call, and will not return until all buffer blocks are uploaded. Raises KeepWriteError() if any blocks failed to upload. """ with self.lock: items = self._bufferblocks.items() for k,v in items: if v.state() != _BufferBlock.COMMITTED: v.owner.flush(sync=False) with self.lock: if self._put_queue is not None: self._put_queue.join() err = [] for k,v in items: if v.state() == _BufferBlock.ERROR: err.append((v.locator(), v.error)) if err: raise KeepWriteError("Error writing some blocks", err, label="block") for k,v in items: # flush again with sync=True to remove committed bufferblocks from # the segments. if v.owner: v.owner.flush(sync=True) def block_prefetch(self, locator): """Initiate a background download of a block. This assumes that the underlying KeepClient implements a block cache, so repeated requests for the same block will not result in repeated downloads (unless the block is evicted from the cache.) This method does not block. """ if not self.prefetch_enabled: return if self._keep.get_from_cache(locator) is not None: return with self.lock: if locator in self._bufferblocks: return self.start_get_threads() self._prefetch_queue.put(locator) class ArvadosFile(object): """Represent a file in a Collection. ArvadosFile manages the underlying representation of a file in Keep as a sequence of segments spanning a set of blocks, and implements random read/write access. This object may be accessed from multiple threads. """ def __init__(self, parent, name, stream=[], segments=[]): """ ArvadosFile constructor. :stream: a list of Range objects representing a block stream :segments: a list of Range objects representing segments """ self.parent = parent self.name = name self._committed = False self._segments = [] self.lock = parent.root_collection().lock for s in segments: self._add_segment(stream, s.locator, s.range_size) self._current_bblock = None def writable(self): return self.parent.writable() @synchronized def segments(self): return copy.copy(self._segments) @synchronized def clone(self, new_parent, new_name): """Make a copy of this file.""" cp = ArvadosFile(new_parent, new_name) cp.replace_contents(self) return cp @must_be_writable @synchronized def replace_contents(self, other): """Replace segments of this file with segments from another `ArvadosFile` object.""" map_loc = {} self._segments = [] for other_segment in other.segments(): new_loc = other_segment.locator if other.parent._my_block_manager().is_bufferblock(other_segment.locator): if other_segment.locator not in map_loc: bufferblock = other.parent._my_block_manager().get_bufferblock(other_segment.locator) if bufferblock.state() != _BufferBlock.WRITABLE: map_loc[other_segment.locator] = bufferblock.locator() else: map_loc[other_segment.locator] = self.parent._my_block_manager().dup_block(bufferblock, self).blockid new_loc = map_loc[other_segment.locator] self._segments.append(Range(new_loc, other_segment.range_start, other_segment.range_size, other_segment.segment_offset)) self._committed = False def __eq__(self, other): if other is self: return True if not isinstance(other, ArvadosFile): return False othersegs = other.segments() with self.lock: if len(self._segments) != len(othersegs): return False for i in xrange(0, len(othersegs)): seg1 = self._segments[i] seg2 = othersegs[i] loc1 = seg1.locator loc2 = seg2.locator if self.parent._my_block_manager().is_bufferblock(loc1): loc1 = self.parent._my_block_manager().get_bufferblock(loc1).locator() if other.parent._my_block_manager().is_bufferblock(loc2): loc2 = other.parent._my_block_manager().get_bufferblock(loc2).locator() if (KeepLocator(loc1).stripped() != KeepLocator(loc2).stripped() or seg1.range_start != seg2.range_start or seg1.range_size != seg2.range_size or seg1.segment_offset != seg2.segment_offset): return False return True def __ne__(self, other): return not self.__eq__(other) @synchronized def set_committed(self): """Set committed flag to False""" self._committed = True @synchronized def committed(self): """Get whether this is committed or not.""" return self._committed @must_be_writable @synchronized def truncate(self, size): """Shrink the size of the file. If `size` is less than the size of the file, the file contents after `size` will be discarded. If `size` is greater than the current size of the file, an IOError will be raised. """ if size < self.size(): new_segs = [] for r in self._segments: range_end = r.range_start+r.range_size if r.range_start >= size: # segment is past the trucate size, all done break elif size < range_end: nr = Range(r.locator, r.range_start, size - r.range_start, 0) nr.segment_offset = r.segment_offset new_segs.append(nr) break else: new_segs.append(r) self._segments = new_segs self._committed = False elif size > self.size(): raise IOError(errno.EINVAL, "truncate() does not support extending the file size") def readfrom(self, offset, size, num_retries, exact=False): """Read up to `size` bytes from the file starting at `offset`. :exact: If False (default), return less data than requested if the read crosses a block boundary and the next block isn't cached. If True, only return less data than requested when hitting EOF. """ with self.lock: if size == 0 or offset >= self.size(): return '' readsegs = locators_and_ranges(self._segments, offset, size) prefetch = locators_and_ranges(self._segments, offset + size, config.KEEP_BLOCK_SIZE, limit=32) locs = set() data = [] for lr in readsegs: block = self.parent._my_block_manager().get_block_contents(lr.locator, num_retries=num_retries, cache_only=(bool(data) and not exact)) if block: blockview = memoryview(block) data.append(blockview[lr.segment_offset:lr.segment_offset+lr.segment_size].tobytes()) locs.add(lr.locator) else: break for lr in prefetch: if lr.locator not in locs: self.parent._my_block_manager().block_prefetch(lr.locator) locs.add(lr.locator) return ''.join(data) def _repack_writes(self, num_retries): """Test if the buffer block has more data than actual segments. This happens when a buffered write over-writes a file range written in a previous buffered write. Re-pack the buffer block for efficiency and to avoid leaking information. """ segs = self._segments # Sum up the segments to get the total bytes of the file referencing # into the buffer block. bufferblock_segs = [s for s in segs if s.locator == self._current_bblock.blockid] write_total = sum([s.range_size for s in bufferblock_segs]) if write_total < self._current_bblock.size(): # There is more data in the buffer block than is actually accounted for by segments, so # re-pack into a new buffer by copying over to a new buffer block. contents = self.parent._my_block_manager().get_block_contents(self._current_bblock.blockid, num_retries) new_bb = self.parent._my_block_manager().alloc_bufferblock(self._current_bblock.blockid, starting_capacity=write_total, owner=self) for t in bufferblock_segs: new_bb.append(contents[t.segment_offset:t.segment_offset+t.range_size]) t.segment_offset = new_bb.size() - t.range_size self._current_bblock = new_bb @must_be_writable @synchronized def writeto(self, offset, data, num_retries): """Write `data` to the file starting at `offset`. This will update existing bytes and/or extend the size of the file as necessary. """ if len(data) == 0: return if offset > self.size(): raise ArgumentError("Offset is past the end of the file") if len(data) > config.KEEP_BLOCK_SIZE: # Chunk it up into smaller writes n = 0 dataview = memoryview(data) while n < len(data): self.writeto(offset+n, dataview[n:n + config.KEEP_BLOCK_SIZE].tobytes(), num_retries) n += config.KEEP_BLOCK_SIZE return self._committed = False if self._current_bblock is None or self._current_bblock.state() != _BufferBlock.WRITABLE: self._current_bblock = self.parent._my_block_manager().alloc_bufferblock(owner=self) if (self._current_bblock.size() + len(data)) > config.KEEP_BLOCK_SIZE: self._repack_writes(num_retries) if (self._current_bblock.size() + len(data)) > config.KEEP_BLOCK_SIZE: self.parent._my_block_manager().commit_bufferblock(self._current_bblock, sync=False) self._current_bblock = self.parent._my_block_manager().alloc_bufferblock(owner=self) self._current_bblock.append(data) replace_range(self._segments, offset, len(data), self._current_bblock.blockid, self._current_bblock.write_pointer - len(data)) self.parent.notify(WRITE, self.parent, self.name, (self, self)) return len(data) @synchronized def flush(self, sync=True, num_retries=0): """Flush the current bufferblock to Keep. :sync: If True, commit block synchronously, wait until buffer block has been written. If False, commit block asynchronously, return immediately after putting block into the keep put queue. """ if self.committed(): return if self._current_bblock and self._current_bblock.state() != _BufferBlock.COMMITTED: if self._current_bblock.state() == _BufferBlock.WRITABLE: self._repack_writes(num_retries) self.parent._my_block_manager().commit_bufferblock(self._current_bblock, sync=sync) if sync: to_delete = set() for s in self._segments: bb = self.parent._my_block_manager().get_bufferblock(s.locator) if bb: if bb.state() != _BufferBlock.COMMITTED: self.parent._my_block_manager().commit_bufferblock(self._current_bblock, sync=True) to_delete.add(s.locator) s.locator = bb.locator() for s in to_delete: self.parent._my_block_manager().delete_bufferblock(s) self.parent.notify(MOD, self.parent, self.name, (self, self)) @must_be_writable @synchronized def add_segment(self, blocks, pos, size): """Add a segment to the end of the file. `pos` and `offset` reference a section of the stream described by `blocks` (a list of Range objects) """ self._add_segment(blocks, pos, size) def _add_segment(self, blocks, pos, size): """Internal implementation of add_segment.""" self._committed = False for lr in locators_and_ranges(blocks, pos, size): last = self._segments[-1] if self._segments else Range(0, 0, 0, 0) r = Range(lr.locator, last.range_start+last.range_size, lr.segment_size, lr.segment_offset) self._segments.append(r) @synchronized def size(self): """Get the file size.""" if self._segments: n = self._segments[-1] return n.range_start + n.range_size else: return 0 @synchronized def manifest_text(self, stream_name=".", portable_locators=False, normalize=False): buf = "" filestream = [] for segment in self.segments: loc = segment.locator if loc.startswith("bufferblock"): loc = self._bufferblocks[loc].calculate_locator() if portable_locators: loc = KeepLocator(loc).stripped() filestream.append(LocatorAndRange(loc, locator_block_size(loc), segment.segment_offset, segment.range_size)) buf += ' '.join(normalize_stream(stream_name, {stream_name: filestream})) buf += "\n" return buf @must_be_writable @synchronized def _reparent(self, newparent, newname): self._committed = False self.flush(sync=True) self.parent.remove(self.name) self.parent = newparent self.name = newname self.lock = self.parent.root_collection().lock class ArvadosFileReader(ArvadosFileReaderBase): """Wraps ArvadosFile in a file-like object supporting reading only. Be aware that this class is NOT thread safe as there is no locking around updating file pointer. """ def __init__(self, arvadosfile, num_retries=None): super(ArvadosFileReader, self).__init__(arvadosfile.name, "r", num_retries=num_retries) self.arvadosfile = arvadosfile def size(self): return self.arvadosfile.size() def stream_name(self): return self.arvadosfile.parent.stream_name() @_FileLikeObjectBase._before_close @retry_method def read(self, size=None, num_retries=None): """Read up to `size` bytes from the file and return the result. Starts at the current file position. If `size` is None, read the entire remainder of the file. """ if size is None: data = [] rd = self.arvadosfile.readfrom(self._filepos, config.KEEP_BLOCK_SIZE, num_retries) while rd: data.append(rd) self._filepos += len(rd) rd = self.arvadosfile.readfrom(self._filepos, config.KEEP_BLOCK_SIZE, num_retries) return ''.join(data) else: data = self.arvadosfile.readfrom(self._filepos, size, num_retries, exact=True) self._filepos += len(data) return data @_FileLikeObjectBase._before_close @retry_method def readfrom(self, offset, size, num_retries=None): """Read up to `size` bytes from the stream, starting at the specified file offset. This method does not change the file position. """ return self.arvadosfile.readfrom(offset, size, num_retries) def flush(self): pass class ArvadosFileWriter(ArvadosFileReader): """Wraps ArvadosFile in a file-like object supporting both reading and writing. Be aware that this class is NOT thread safe as there is no locking around updating file pointer. """ def __init__(self, arvadosfile, mode, num_retries=None): super(ArvadosFileWriter, self).__init__(arvadosfile, num_retries=num_retries) self.mode = mode @_FileLikeObjectBase._before_close @retry_method def write(self, data, num_retries=None): if self.mode[0] == "a": self.arvadosfile.writeto(self.size(), data, num_retries) else: self.arvadosfile.writeto(self._filepos, data, num_retries) self._filepos += len(data) return len(data) @_FileLikeObjectBase._before_close @retry_method def writelines(self, seq, num_retries=None): for s in seq: self.write(s, num_retries) @_FileLikeObjectBase._before_close def truncate(self, size=None): if size is None: size = self._filepos self.arvadosfile.truncate(size) if self._filepos > self.size(): self._filepos = self.size() @_FileLikeObjectBase._before_close def flush(self): self.arvadosfile.flush() def close(self): if not self.closed: self.flush() super(ArvadosFileWriter, self).close()