# Copyright (c) 2010-2013 OpenStack Foundation # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or # implied. # See the License for the specific language governing permissions and # limitations under the License. """ Disk File Interface for the Swift Object Server The `DiskFile`, `DiskFileWriter` and `DiskFileReader` classes combined define the on-disk abstraction layer for supporting the object server REST API interfaces (excluding `REPLICATE`). Other implementations wishing to provide an alternative backend for the object server must implement the three classes. An example alternative implementation can be found in the `mem_server.py` and `mem_diskfile.py` modules along size this one. The `DiskFileManager` is a reference implemenation specific class and is not part of the backend API. The remaining methods in this module are considered implementation specifc and are also not considered part of the backend API. """ from __future__ import with_statement import cPickle as pickle import errno import os import time import uuid import hashlib import logging import traceback from os.path import basename, dirname, exists, getmtime, join from tempfile import mkstemp from contextlib import contextmanager from collections import defaultdict from xattr import getxattr, setxattr from eventlet import Timeout from swift import gettext_ as _ from swift.common.constraints import check_mount from swift.common.utils import mkdirs, normalize_timestamp, \ storage_directory, hash_path, renamer, fallocate, fsync, \ fdatasync, drop_buffer_cache, ThreadPool, lock_path, write_pickle, \ config_true_value from swift.common.exceptions import DiskFileQuarantined, DiskFileNotExist, \ DiskFileCollision, DiskFileNoSpace, DiskFileDeviceUnavailable, \ DiskFileDeleted, DiskFileError, DiskFileNotOpen, PathNotDir from swift.common.swob import multi_range_iterator PICKLE_PROTOCOL = 2 ONE_WEEK = 604800 HASH_FILE = 'hashes.pkl' METADATA_KEY = 'user.swift.metadata' # These are system-set metadata keys that cannot be changed with a POST. # They should be lowercase. DATAFILE_SYSTEM_META = set('content-length content-type deleted etag'.split()) DATADIR = 'objects' ASYNCDIR = 'async_pending' def read_metadata(fd): """ Helper function to read the pickled metadata from an object file. :param fd: file descriptor to load the metadata from :returns: dictionary of metadata """ metadata = '' key = 0 try: while True: metadata += getxattr(fd, '%s%s' % (METADATA_KEY, (key or ''))) key += 1 except IOError: pass return pickle.loads(metadata) def write_metadata(fd, metadata): """ Helper function to write pickled metadata for an object file. :param fd: file descriptor to write the metadata :param metadata: metadata to write """ metastr = pickle.dumps(metadata, PICKLE_PROTOCOL) key = 0 while metastr: setxattr(fd, '%s%s' % (METADATA_KEY, key or ''), metastr[:254]) metastr = metastr[254:] key += 1 def quarantine_renamer(device_path, corrupted_file_path): """ In the case that a file is corrupted, move it to a quarantined area to allow replication to fix it. :params device_path: The path to the device the corrupted file is on. :params corrupted_file_path: The path to the file you want quarantined. :returns: path (str) of directory the file was moved to :raises OSError: re-raises non errno.EEXIST / errno.ENOTEMPTY exceptions from rename """ from_dir = dirname(corrupted_file_path) to_dir = join(device_path, 'quarantined', 'objects', basename(from_dir)) invalidate_hash(dirname(from_dir)) try: renamer(from_dir, to_dir) except OSError as e: if e.errno not in (errno.EEXIST, errno.ENOTEMPTY): raise to_dir = "%s-%s" % (to_dir, uuid.uuid4().hex) renamer(from_dir, to_dir) return to_dir def hash_cleanup_listdir(hsh_path, reclaim_age=ONE_WEEK): """ List contents of a hash directory and clean up any old files. :param hsh_path: object hash path :param reclaim_age: age in seconds at which to remove tombstones :returns: list of files remaining in the directory, reverse sorted """ files = os.listdir(hsh_path) if len(files) == 1: if files[0].endswith('.ts'): # remove tombstones older than reclaim_age ts = files[0].rsplit('.', 1)[0] if (time.time() - float(ts)) > reclaim_age: os.unlink(join(hsh_path, files[0])) files.remove(files[0]) elif files: files.sort(reverse=True) meta = data = tomb = None for filename in list(files): if not meta and filename.endswith('.meta'): meta = filename if not data and filename.endswith('.data'): data = filename if not tomb and filename.endswith('.ts'): tomb = filename if (filename < tomb or # any file older than tomb filename < data or # any file older than data (filename.endswith('.meta') and filename < meta)): # old meta os.unlink(join(hsh_path, filename)) files.remove(filename) return files def hash_suffix(path, reclaim_age): """ Performs reclamation and returns an md5 of all (remaining) files. :param reclaim_age: age in seconds at which to remove tombstones :raises PathNotDir: if given path is not a valid directory :raises OSError: for non-ENOTDIR errors """ md5 = hashlib.md5() try: path_contents = sorted(os.listdir(path)) except OSError as err: if err.errno in (errno.ENOTDIR, errno.ENOENT): raise PathNotDir() raise for hsh in path_contents: hsh_path = join(path, hsh) try: files = hash_cleanup_listdir(hsh_path, reclaim_age) except OSError as err: if err.errno == errno.ENOTDIR: partition_path = dirname(path) objects_path = dirname(partition_path) device_path = dirname(objects_path) quar_path = quarantine_renamer(device_path, hsh_path) logging.exception( _('Quarantined %s to %s because it is not a directory') % (hsh_path, quar_path)) continue raise if not files: os.rmdir(hsh_path) for filename in files: md5.update(filename) try: os.rmdir(path) except OSError: pass return md5.hexdigest() def invalidate_hash(suffix_dir): """ Invalidates the hash for a suffix_dir in the partition's hashes file. :param suffix_dir: absolute path to suffix dir whose hash needs invalidating """ suffix = basename(suffix_dir) partition_dir = dirname(suffix_dir) hashes_file = join(partition_dir, HASH_FILE) with lock_path(partition_dir): try: with open(hashes_file, 'rb') as fp: hashes = pickle.load(fp) if suffix in hashes and not hashes[suffix]: return except Exception: return hashes[suffix] = None write_pickle(hashes, hashes_file, partition_dir, PICKLE_PROTOCOL) def get_hashes(partition_dir, recalculate=None, do_listdir=False, reclaim_age=ONE_WEEK): """ Get a list of hashes for the suffix dir. do_listdir causes it to mistrust the hash cache for suffix existence at the (unexpectedly high) cost of a listdir. reclaim_age is just passed on to hash_suffix. :param partition_dir: absolute path of partition to get hashes for :param recalculate: list of suffixes which should be recalculated when got :param do_listdir: force existence check for all hashes in the partition :param reclaim_age: age at which to remove tombstones :returns: tuple of (number of suffix dirs hashed, dictionary of hashes) """ hashed = 0 hashes_file = join(partition_dir, HASH_FILE) modified = False force_rewrite = False hashes = {} mtime = -1 if recalculate is None: recalculate = [] try: with open(hashes_file, 'rb') as fp: hashes = pickle.load(fp) mtime = getmtime(hashes_file) except Exception: do_listdir = True force_rewrite = True if do_listdir: for suff in os.listdir(partition_dir): if len(suff) == 3: hashes.setdefault(suff, None) modified = True hashes.update((hash_, None) for hash_ in recalculate) for suffix, hash_ in hashes.items(): if not hash_: suffix_dir = join(partition_dir, suffix) try: hashes[suffix] = hash_suffix(suffix_dir, reclaim_age) hashed += 1 except PathNotDir: del hashes[suffix] except OSError: logging.exception(_('Error hashing suffix')) modified = True if modified: with lock_path(partition_dir): if force_rewrite or not exists(hashes_file) or \ getmtime(hashes_file) == mtime: write_pickle( hashes, hashes_file, partition_dir, PICKLE_PROTOCOL) return hashed, hashes return get_hashes(partition_dir, recalculate, do_listdir, reclaim_age) else: return hashed, hashes class DiskFileManager(object): """ Management class for devices, providing common place for shared parameters and methods not provided by the DiskFile class (which primarily services the object server REST API layer). The `get_diskfile()` method is how this implementation creates a `DiskFile` object. .. note:: This class is reference implementation specific and not part of the pluggable on-disk backend API. .. note:: TODO(portante): Not sure what the right name to recommend here, as "manager" seemed generic enough, though suggestions are welcome. :param conf: caller provided configuration object :param logger: caller provided logger """ def __init__(self, conf, logger): self.logger = logger self.devices = conf.get('devices', '/srv/node/') self.disk_chunk_size = int(conf.get('disk_chunk_size', 65536)) self.keep_cache_size = int(conf.get('keep_cache_size', 5242880)) self.bytes_per_sync = int(conf.get('mb_per_sync', 512)) * 1024 * 1024 self.mount_check = config_true_value(conf.get('mount_check', 'true')) threads_per_disk = int(conf.get('threads_per_disk', '0')) self.threadpools = defaultdict( lambda: ThreadPool(nthreads=threads_per_disk)) def construct_dev_path(self, device): """ Construct the path to a device without checking if it is mounted. :param device: name of target device :returns: full path to the device """ return os.path.join(self.devices, device) def get_dev_path(self, device): """ Return the path to a device, checking to see that it is a proper mount point based on a configuration parameter. :param device: name of target device :returns: full path to the device, None if the path to the device is not a proper mount point. """ if self.mount_check and not check_mount(self.devices, device): dev_path = None else: dev_path = os.path.join(self.devices, device) return dev_path def pickle_async_update(self, device, account, container, obj, data, timestamp): device_path = self.construct_dev_path(device) async_dir = os.path.join(device_path, ASYNCDIR) ohash = hash_path(account, container, obj) self.threadpools[device].run_in_thread( write_pickle, data, os.path.join(async_dir, ohash[-3:], ohash + '-' + normalize_timestamp(timestamp)), os.path.join(device_path, 'tmp')) self.logger.increment('async_pendings') def get_diskfile(self, device, partition, account, container, obj, **kwargs): dev_path = self.get_dev_path(device) if not dev_path: raise DiskFileDeviceUnavailable() return DiskFile(self, dev_path, self.threadpools[device], partition, account, container, obj, **kwargs) def get_hashes(self, device, partition, suffix): dev_path = self.get_dev_path(device) if not dev_path: raise DiskFileDeviceUnavailable() partition_path = os.path.join(dev_path, DATADIR, partition) if not os.path.exists(partition_path): mkdirs(partition_path) suffixes = suffix.split('-') if suffix else [] _junk, hashes = self.threadpools[device].force_run_in_thread( get_hashes, partition_path, recalculate=suffixes) return hashes class DiskFileWriter(object): """ Encapsulation of the write context for servicing PUT REST API requests. Serves as the context manager object for the :class:`swift.obj.diskfile.DiskFile` class's :func:`swift.obj.diskfile.DiskFile.create` method. .. note:: It is the responsibility of the :func:`swift.obj.diskfile.DiskFile.create` method context manager to close the open file descriptor. .. note:: The arguments to the constructor are considered implementation specific. The API does not define the constructor arguments. :param name: name of object from REST API :param datadir: on-disk directory object will end up in on :func:`swift.obj.diskfile.DiskFileWriter.put` :param fd: open file descriptor of temporary file to receive data :param tmppath: full path name of the opened file descriptor :param bytes_per_sync: number bytes written between sync calls :param threadpool: internal thread pool to use for disk operations """ def __init__(self, name, datadir, fd, tmppath, bytes_per_sync, threadpool): # Parameter tracking self._name = name self._datadir = datadir self._fd = fd self._tmppath = tmppath self._bytes_per_sync = bytes_per_sync self._threadpool = threadpool # Internal attributes self._upload_size = 0 self._last_sync = 0 self._extension = '.data' def write(self, chunk): """ Write a chunk of data to disk. All invocations of this method must come before invoking the :func: For this implementation, the data is written into a temporary file. :param chunk: the chunk of data to write as a string object :returns: the total number of bytes written to an object """ def _write_entire_chunk(chunk): while chunk: written = os.write(self._fd, chunk) self._upload_size += written chunk = chunk[written:] self._threadpool.run_in_thread(_write_entire_chunk, chunk) # For large files sync every 512MB (by default) written diff = self._upload_size - self._last_sync if diff >= self._bytes_per_sync: self._threadpool.force_run_in_thread(fdatasync, self._fd) drop_buffer_cache(self._fd, self._last_sync, diff) self._last_sync = self._upload_size return self._upload_size def _finalize_put(self, metadata, target_path): # Write the metadata before calling fsync() so that both data and # metadata are flushed to disk. write_metadata(self._fd, metadata) # We call fsync() before calling drop_cache() to lower the amount of # redundant work the drop cache code will perform on the pages (now # that after fsync the pages will be all clean). fsync(self._fd) # From the Department of the Redundancy Department, make sure we call # drop_cache() after fsync() to avoid redundant work (pages all # clean). drop_buffer_cache(self._fd, 0, self._upload_size) invalidate_hash(dirname(self._datadir)) # After the rename completes, this object will be available for other # requests to reference. renamer(self._tmppath, target_path) hash_cleanup_listdir(self._datadir) def put(self, metadata): """ Finalize writing the file on disk. For this implementation, this method is responsible for renaming the temporary file to the final name and directory location. This method should be called after the final call to :func:`swift.obj.diskfile.DiskFileWriter.write`. :param metadata: dictionary of metadata to be associated with the object """ if not self._tmppath: raise ValueError("tmppath is unusable.") timestamp = normalize_timestamp(metadata['X-Timestamp']) metadata['name'] = self._name target_path = join(self._datadir, timestamp + self._extension) self._threadpool.force_run_in_thread( self._finalize_put, metadata, target_path) class DiskFileReader(object): """ Encapsulation of the WSGI read context for servicing GET REST API requests. Serves as the context manager object for the :class:`swift.obj.diskfile.DiskFile` class's :func:`swift.obj.diskfile.DiskFile.reader` method. .. note:: The quarantining behavior of this method is considered implementation specific, and is not required of the API. .. note:: The arguments to the constructor are considered implementation specific. The API does not define the constructor arguments. :param fp: open file object pointer reference :param data_file: on-disk data file name for the object :param obj_size: verified on-disk size of the object :param etag: expected metadata etag value for entire file :param threadpool: thread pool to use for read operations :param disk_chunk_size: size of reads from disk in bytes :param keep_cache_size: maximum object size that will be kept in cache :param device_path: on-disk device path, used when quarantining an obj :param logger: logger caller wants this object to use :param iter_hook: called when __iter__ returns a chunk :param keep_cache: should resulting reads be kept in the buffer cache """ def __init__(self, fp, data_file, obj_size, etag, threadpool, disk_chunk_size, keep_cache_size, device_path, logger, iter_hook=None, keep_cache=False): # Parameter tracking self._fp = fp self._data_file = data_file self._obj_size = obj_size self._etag = etag self._threadpool = threadpool self._disk_chunk_size = disk_chunk_size self._device_path = device_path self._logger = logger self._iter_hook = iter_hook if keep_cache: # Caller suggests we keep this in cache, only do it if the # object's size is less than the maximum. self._keep_cache = obj_size < keep_cache_size else: self._keep_cache = False # Internal Attributes self._iter_etag = None self._bytes_read = 0 self._started_at_0 = False self._read_to_eof = False self._suppress_file_closing = False self._quarantined_dir = None # Currently referenced by the object Auditor only self.was_quarantined = '' def __iter__(self): """Returns an iterator over the data file.""" try: dropped_cache = 0 self._bytes_read = 0 self._started_at_0 = False self._read_to_eof = False if self._fp.tell() == 0: self._started_at_0 = True self._iter_etag = hashlib.md5() while True: chunk = self._threadpool.run_in_thread( self._fp.read, self._disk_chunk_size) if chunk: if self._iter_etag: self._iter_etag.update(chunk) self._bytes_read += len(chunk) if self._bytes_read - dropped_cache > (1024 * 1024): self._drop_cache(self._fp.fileno(), dropped_cache, self._bytes_read - dropped_cache) dropped_cache = self._bytes_read yield chunk if self._iter_hook: self._iter_hook() else: self._read_to_eof = True self._drop_cache(self._fp.fileno(), dropped_cache, self._bytes_read - dropped_cache) break finally: if not self._suppress_file_closing: self.close() def app_iter_range(self, start, stop): """Returns an iterator over the data file for range (start, stop)""" if start or start == 0: self._fp.seek(start) if stop is not None: length = stop - start else: length = None try: for chunk in self: if length is not None: length -= len(chunk) if length < 0: # Chop off the extra: yield chunk[:length] break yield chunk finally: if not self._suppress_file_closing: self.close() def app_iter_ranges(self, ranges, content_type, boundary, size): """Returns an iterator over the data file for a set of ranges""" if not ranges: yield '' else: try: self._suppress_file_closing = True for chunk in multi_range_iterator( ranges, content_type, boundary, size, self.app_iter_range): yield chunk finally: self._suppress_file_closing = False try: self.close() except DiskFileQuarantined: pass def _drop_cache(self, fd, offset, length): """Method for no-oping buffer cache drop method.""" if not self._keep_cache: drop_buffer_cache(fd, offset, length) def _quarantine(self, msg): self._quarantined_dir = self._threadpool.run_in_thread( quarantine_renamer, self._device_path, self._data_file) self._logger.increment('quarantines') self.was_quarantined = msg def _handle_close_quarantine(self): """Check if file needs to be quarantined""" if self._bytes_read != self._obj_size: self._quarantine( "Bytes read: %s, does not match metadata: %s" % ( self._bytes_read, self._obj_size)) elif self._iter_etag and \ self._etag != self._iter_etag.hexdigest(): self._quarantine( "ETag %s and file's md5 %s do not match" % ( self._etag, self._iter_etag.hexdigest())) def close(self): """ Close the open file handle if present. For this specific implementation, this method will handle quarantining the file if necessary. """ if self._fp: try: if self._started_at_0 and self._read_to_eof: self._handle_close_quarantine() except (Exception, Timeout) as e: self._logger.error(_( 'ERROR DiskFile %(data_file)s' ' close failure: %(exc)s : %(stack)s'), {'exc': e, 'stack': ''.join(traceback.format_stack()), 'data_file': self._data_file}) finally: fp, self._fp = self._fp, None fp.close() class DiskFile(object): """ Manage object files. This specific implementation manages object files on a disk formatted with a POSIX-compliant file system that supports extended attributes as metadata on a file or directory. .. note:: The arguments to the constructor are considered implementation specific. The API does not define the constructor arguments. :param mgr: associated DiskFileManager instance :param device_path: path to the target device or drive :param threadpool: thread pool to use for blocking operations :param partition: partition on the device in which the object lives :param account: account name for the object :param container: container name for the object :param obj: object name for the object """ def __init__(self, mgr, device_path, threadpool, partition, account, container, obj): self._mgr = mgr self._device_path = device_path self._threadpool = threadpool or ThreadPool(nthreads=0) self._logger = mgr.logger self._disk_chunk_size = mgr.disk_chunk_size self._bytes_per_sync = mgr.bytes_per_sync self._name = '/' + '/'.join((account, container, obj)) name_hash = hash_path(account, container, obj) self._datadir = join( device_path, storage_directory(DATADIR, partition, name_hash)) self._tmpdir = join(device_path, 'tmp') self._metadata = None self._data_file = None self._fp = None self._quarantined_dir = None def open(self): """ Open the object. This implementation opens the data file representing the object, reads the associated metadata in the extended attributes, additionally combining metadata from fast-POST `.meta` files. .. note:: An implementation is allowed to raise any of the following exceptions, but is only required to raise `DiskFileNotExist` when the object representation does not exist. :raises DiskFileCollision: on name mis-match with metadata :raises DiskFileNotExist: if the object does not exist :raises DiskFileDeleted: if the object was previously deleted :raises DiskFileQuarantined: if while reading metadata of the file some data did pass cross checks :returns: itself for use as a context manager """ data_file, meta_file, ts_file = self._get_ondisk_file() if not data_file: raise self._construct_exception_from_ts_file(ts_file) self._fp = self._construct_from_data_file( data_file, meta_file) # This method must populate the internal _metadata attribute. self._metadata = self._metadata or {} self._data_file = data_file return self def __enter__(self): """ Context enter. .. note:: An implemenation shall raise `DiskFileNotOpen` when has not previously invoked the :func:`swift.obj.diskfile.DiskFile.open` method. """ if self._metadata is None: raise DiskFileNotOpen() return self def __exit__(self, t, v, tb): """ Context exit. .. note:: This method will be invoked by the object server while servicing the REST API *before* the object has actually been read. It is the responsibility of the implementation to properly handle that. """ if self._fp is not None: fp, self._fp = self._fp, None fp.close() def _quarantine(self, data_file, msg): """ Quarantine a file; responsible for incrementing the associated loggers count of quarantines. :param data_file: full path of data file to quarantine :param msg: reason for quarantining to be included in the exception :raises DiskFileQuarantine: """ self._quarantined_dir = self._threadpool.run_in_thread( quarantine_renamer, self._device_path, data_file) self._logger.increment('quarantines') raise DiskFileQuarantined(msg) def _get_ondisk_file(self): """ Do the work to figure out if the data directory exists, and if so, determine the on-disk files to use. :returns: a tuple of data, meta and ts (tombstone) files, in one of three states: * all three are None data directory does not exist, or there are no files in that directory * ts_file is not None, data_file is None, meta_file is None object is considered deleted * data_file is not None, ts_file is None object exists, and optionally has fast-POST metadata """ data_file = meta_file = ts_file = None try: files = sorted(os.listdir(self._datadir), reverse=True) except OSError as err: if err.errno != errno.ENOENT: raise DiskFileError() # The data directory does not exist, so the object cannot exist. else: for afile in files: assert ts_file is None, "On-disk file search loop" \ " continuing after tombstone, %s, encountered" % ts_file assert data_file is None, "On-disk file search loop" \ " continuing after data file, %s, encountered" % data_file if afile.endswith('.ts'): meta_file = None ts_file = join(self._datadir, afile) break if afile.endswith('.meta') and not meta_file: meta_file = join(self._datadir, afile) # NOTE: this does not exit this loop, since a fast-POST # operation just updates metadata, writing one or more # .meta files, the data file will have an older timestamp, # so we keep looking. continue if afile.endswith('.data'): data_file = join(self._datadir, afile) break assert ((data_file is None and meta_file is None and ts_file is None) or (ts_file is not None and data_file is None and meta_file is None) or (data_file is not None and ts_file is None)), \ "On-disk file search algorithm contract is broken: data_file:" \ " %s, meta_file: %s, ts_file: %s" % (data_file, meta_file, ts_file) return data_file, meta_file, ts_file def _construct_exception_from_ts_file(self, ts_file): """ If a tombstone is present it means the object is considered deleted. We just need to pull the metadata from the tombstone file which has the timestamp to construct the deleted exception. If there was no tombstone, just report it does not exist. :param ts_file: the tombstone file name found on disk :returns: DiskFileDeleted if the ts_file was provided, else DiskFileNotExist """ if not ts_file: exc = DiskFileNotExist() else: with open(ts_file) as fp: metadata = read_metadata(fp) # All well and good that we have found a tombstone file, but # we don't have a data file so we are just going to raise an # exception that we could not find the object, providing the # tombstone's timestamp. exc = DiskFileDeleted() exc.timestamp = metadata['X-Timestamp'] return exc def _verify_data_file(self, data_file, fp): """ Verify the metadata's name value matches what we think the object is named. :param data_file: data file name being consider, used when quarantines occur :param fp: open file pointer so that we can `fstat()` the file to verify the on-disk size with Content-Length metadata value :raises DiskFileCollision: if the metadata stored name does not match the referenced name of the file :raises DiskFileNotExist: if the object has expired :raises DiskFileQuarantined: if data inconsistencies were detected between the metadata and the file-system metadata """ try: mname = self._metadata['name'] except KeyError: self._quarantine(data_file, "missing name metadata") else: if mname != self._name: self._logger.error( _('Client path %(client)s does not match ' 'path stored in object metadata %(meta)s'), {'client': self._name, 'meta': mname}) raise DiskFileCollision('Client path does not match path ' 'stored in object metadata') try: x_delete_at = int(self._metadata['X-Delete-At']) except KeyError: pass except ValueError: # Quarantine, the x-delete-at key is present but not an # integer. self._quarantine( data_file, "bad metadata x-delete-at value %s" % ( self._metadata['X-Delete-At'])) else: if x_delete_at <= time.time(): raise DiskFileNotExist('Expired') try: metadata_size = int(self._metadata['Content-Length']) except KeyError: self._quarantine( data_file, "missing content-length in metadata") except ValueError: # Quarantine, the content-length key is present but not an # integer. self._quarantine( data_file, "bad metadata content-length value %s" % ( self._metadata['Content-Length'])) fd = fp.fileno() try: statbuf = os.fstat(fd) except OSError as err: # Quarantine, we can't successfully stat the file. self._quarantine(data_file, "not stat-able: %s" % err) else: obj_size = statbuf.st_size if metadata_size is not None and obj_size != metadata_size: self._quarantine( data_file, "metadata content-length %s does" " not match actual object size %s" % ( metadata_size, statbuf.st_size)) return obj_size def _construct_from_data_file(self, data_file, meta_file): """ Open the `.data` file to fetch its metadata, and fetch the metadata from the fast-POST `.meta` file as well if it exists, merging them properly. :param data_file: on-disk `.data` file being considered :param meta_file: on-disk fast-POST `.meta` file being considered :returns: an opened data file pointer :raises DiskFileError: various exceptions from :func:`swift.obj.diskfile.DiskFile._verify_data_file` """ fp = open(data_file, 'rb') datafile_metadata = read_metadata(fp) if meta_file: with open(meta_file) as mfp: self._metadata = read_metadata(mfp) sys_metadata = dict( [(key, val) for key, val in datafile_metadata.iteritems() if key.lower() in DATAFILE_SYSTEM_META]) self._metadata.update(sys_metadata) else: self._metadata = datafile_metadata self._verify_data_file(data_file, fp) return fp def get_metadata(self): """ Provide the metadata for a previously opened object as a dictionary. :returns: object's metadata dictionary :raises DiskFileNotOpen: if the :func:`swift.obj.diskfile.DiskFile.open` method was not previously invoked """ if self._metadata is None: raise DiskFileNotOpen() return self._metadata def read_metadata(self): """ Return the metadata for an object without requiring the caller to open the object first. :returns: metadata dictionary for an object :raises DiskFileError: this implementation will raise the same errors as the `open()` method. """ with self.open(): return self.get_metadata() def reader(self, iter_hook=None, keep_cache=False): """ Return a :class:`swift.common.swob.Response` class compatible "`app_iter`" object as defined by :class:`swift.obj.diskfile.DiskFileReader`. For this implementation, the responsibility of closing the open file is passed to the :class:`swift.obj.diskfile.DiskFileReader` object. :param iter_hook: called when __iter__ returns a chunk :param keep_cache: caller's preference for keeping data read in the OS buffer cache :returns: a :class:`swift.obj.diskfile.DiskFileReader` object """ dr = DiskFileReader( self._fp, self._data_file, int(self._metadata['Content-Length']), self._metadata['ETag'], self._threadpool, self._disk_chunk_size, self._mgr.keep_cache_size, self._device_path, self._logger, iter_hook=iter_hook, keep_cache=keep_cache) # At this point the reader object is now responsible for closing # the file pointer. self._fp = None return dr @contextmanager def create(self, size=None): """ Context manager to create a file. We create a temporary file first, and then return a DiskFileWriter object to encapsulate the state. .. note:: An implementation is not required to perform on-disk preallocations even if the parameter is specified. But if it does and it fails, it must raise a `DiskFileNoSpace` exception. :param size: optional initial size of file to explicitly allocate on disk :raises DiskFileNoSpace: if a size is specified and allocation fails """ if not exists(self._tmpdir): mkdirs(self._tmpdir) fd, tmppath = mkstemp(dir=self._tmpdir) try: if size is not None and size > 0: try: fallocate(fd, size) except OSError: raise DiskFileNoSpace() yield DiskFileWriter(self._name, self._datadir, fd, tmppath, self._bytes_per_sync, self._threadpool) finally: try: os.close(fd) except OSError: pass try: os.unlink(tmppath) except OSError: pass def write_metadata(self, metadata): """ Write a block of metadata to an object without requiring the caller to create the object first. Supports fast-POST behavior semantics. :param metadata: dictionary of metadata to be associated with the object :raises DiskFileError: this implementation will raise the same errors as the `create()` method. """ with self.create() as writer: writer._extension = '.meta' writer.put(metadata) def delete(self, timestamp): """ Delete the object. This implementation creates a tombstone file using the given timestamp, and removes any older versions of the object file. Any file that has an older timestamp than timestamp will be deleted. .. note:: An implementation is free to use or ignore the timestamp parameter. :param timestamp: timestamp to compare with each file :raises DiskFileError: this implementation will raise the same errors as the `create()` method. """ timestamp = normalize_timestamp(timestamp) with self.create() as deleter: deleter._extension = '.ts' deleter.put({'X-Timestamp': timestamp})