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OpenStack Study: diskfile.py**** CubicPower OpenStack Study ****
# 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. """ 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 random import shuffle 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, listdir, split_path, ismount, remove_file from swift.common.exceptions import DiskFileQuarantined, DiskFileNotExist, \ DiskFileCollision, DiskFileNoSpace, DiskFileDeviceUnavailable, \ DiskFileDeleted, DiskFileError, DiskFileNotOpen, PathNotDir, \ ReplicationLockTimeout, DiskFileExpired 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'
**** CubicPower OpenStack Study **** def read_metadata(fd): """ Helper function to read the pickled metadata from an object file. :param fd: file descriptor or filename 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)
**** CubicPower OpenStack Study **** def write_metadata(fd, metadata): """ Helper function to write pickled metadata for an object file. :param fd: file descriptor or filename 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
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** def get_ondisk_files(files, datadir): """ Given a simple list of files names, determine the files to use. :params files: simple set of files as a python list :params datadir: directory name files are from for convenience :returns: a tuple of data, meta and ts (tombstone) files, in one of two states: * 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 """ files.sort(reverse=True) data_file = meta_file = ts_file = None 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(datadir, afile) break if afile.endswith('.meta') and not meta_file: meta_file = join(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(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
**** CubicPower OpenStack Study **** 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 = 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: remove_file(join(hsh_path, files[0])) files.remove(files[0]) elif files: files.sort(reverse=True) data_file, meta_file, ts_file = get_ondisk_files(files, '') newest_file = data_file or ts_file for filename in list(files): if ((filename < newest_file) or (meta_file and filename.endswith('.meta') and filename < meta_file)): remove_file(join(hsh_path, filename)) files.remove(filename) return files
**** CubicPower OpenStack Study **** 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: try: os.rmdir(hsh_path) except OSError: pass for filename in files: md5.update(filename) try: os.rmdir(path) except OSError: pass return md5.hexdigest()
**** CubicPower OpenStack Study **** 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)
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** class AuditLocation(object): """ Represents an object location to be audited. Other than being a bucket of data, the only useful thing this does is stringify to a filesystem path so the auditor's logs look okay. """
**** CubicPower OpenStack Study **** def __init__(self, path, device, partition): self.path, self.device, self.partition = path, device, partition
**** CubicPower OpenStack Study **** def __str__(self): return str(self.path) def object_audit_location_generator(devices, mount_check=True, logger=None, device_dirs=None): """ Given a devices path (e.g. "/srv/node"), yield an AuditLocation for all objects stored under that directory if device_dirs isn't set. If device_dirs is set, only yield AuditLocation for the objects under the entries in device_dirs. The AuditLocation only knows the path to the hash directory, not to the .data file therein (if any). This is to avoid a double listdir(hash_dir); the DiskFile object will always do one, so we don't. :param devices: parent directory of the devices to be audited :param mount_check: flag to check if a mount check should be performed on devices :param logger: a logger object :device_dirs: a list of directories under devices to traverse """ if not device_dirs: device_dirs = listdir(devices) else: # remove bogus devices and duplicates from device_dirs device_dirs = list( set(listdir(devices)).intersection(set(device_dirs))) # randomize devices in case of process restart before sweep completed shuffle(device_dirs) for device in device_dirs: if mount_check and not \ ismount(os.path.join(devices, device)): if logger: logger.debug( _('Skipping %s as it is not mounted'), device) continue datadir_path = os.path.join(devices, device, DATADIR) partitions = listdir(datadir_path) for partition in partitions: part_path = os.path.join(datadir_path, partition) try: suffixes = listdir(part_path) except OSError as e: if e.errno != errno.ENOTDIR: raise continue for asuffix in suffixes: suff_path = os.path.join(part_path, asuffix) try: hashes = listdir(suff_path) except OSError as e: if e.errno != errno.ENOTDIR: raise continue for hsh in hashes: hsh_path = os.path.join(suff_path, hsh) yield AuditLocation(hsh_path, device, partition)
**** CubicPower OpenStack Study **** def object_audit_location_generator(devices, mount_check=True, logger=None, device_dirs=None): """ Given a devices path (e.g. "/srv/node"), yield an AuditLocation for all objects stored under that directory if device_dirs isn't set. If device_dirs is set, only yield AuditLocation for the objects under the entries in device_dirs. The AuditLocation only knows the path to the hash directory, not to the .data file therein (if any). This is to avoid a double listdir(hash_dir); the DiskFile object will always do one, so we don't. :param devices: parent directory of the devices to be audited :param mount_check: flag to check if a mount check should be performed on devices :param logger: a logger object :device_dirs: a list of directories under devices to traverse """ if not device_dirs: device_dirs = listdir(devices) else: # remove bogus devices and duplicates from device_dirs device_dirs = list( set(listdir(devices)).intersection(set(device_dirs))) # randomize devices in case of process restart before sweep completed shuffle(device_dirs) for device in device_dirs: if mount_check and not \ ismount(os.path.join(devices, device)): if logger: logger.debug( _('Skipping %s as it is not mounted'), device) continue datadir_path = os.path.join(devices, device, DATADIR) partitions = listdir(datadir_path) for partition in partitions: part_path = os.path.join(datadir_path, partition) try: suffixes = listdir(part_path) except OSError as e: if e.errno != errno.ENOTDIR: raise continue for asuffix in suffixes: suff_path = os.path.join(part_path, asuffix) try: hashes = listdir(suff_path) except OSError as e: if e.errno != errno.ENOTDIR: raise continue for hsh in hashes: hsh_path = os.path.join(suff_path, hsh) yield AuditLocation(hsh_path, device, partition)
**** CubicPower OpenStack Study **** 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 """
**** CubicPower OpenStack Study **** 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')) self.reclaim_age = int(conf.get('reclaim_age', ONE_WEEK)) self.replication_one_per_device = config_true_value( conf.get('replication_one_per_device', 'true')) self.replication_lock_timeout = int(conf.get( 'replication_lock_timeout', 15)) threads_per_disk = int(conf.get('threads_per_disk', '0')) self.threadpools = defaultdict( lambda: ThreadPool(nthreads=threads_per_disk))
**** CubicPower OpenStack Study **** 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)
**** CubicPower OpenStack Study **** def get_dev_path(self, device, mount_check=None): """ 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 :param mount_check: whether or not to check mountedness of device. Defaults to bool(self.mount_check). :returns: full path to the device, None if the path to the device is not a proper mount point. """ should_check = self.mount_check if mount_check is None else mount_check if should_check and not check_mount(self.devices, device): dev_path = None else: dev_path = os.path.join(self.devices, device) return dev_path @contextmanager
**** CubicPower OpenStack Study **** def replication_lock(self, device): """ A context manager that will lock on the device given, if configured to do so. :raises ReplicationLockTimeout: If the lock on the device cannot be granted within the configured timeout. """ if self.replication_one_per_device: dev_path = self.get_dev_path(device) with lock_path( dev_path, timeout=self.replication_lock_timeout, timeout_class=ReplicationLockTimeout): yield True else: yield True
**** CubicPower OpenStack Study **** 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')
**** CubicPower OpenStack Study **** 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)
**** CubicPower OpenStack Study **** def object_audit_location_generator(self, device_dirs=None): return object_audit_location_generator(self.devices, self.mount_check, self.logger, device_dirs)
**** CubicPower OpenStack Study **** def get_diskfile_from_audit_location(self, audit_location): dev_path = self.get_dev_path(audit_location.device, mount_check=False) return DiskFile.from_hash_dir( self, audit_location.path, dev_path, audit_location.partition)
**** CubicPower OpenStack Study **** def get_diskfile_from_hash(self, device, partition, object_hash, **kwargs): """ Returns a DiskFile instance for an object at the given object_hash. Just in case someone thinks of refactoring, be sure DiskFileDeleted is *not* raised, but the DiskFile instance representing the tombstoned object is returned instead. :raises DiskFileNotExist: if the object does not exist """ dev_path = self.get_dev_path(device) if not dev_path: raise DiskFileDeviceUnavailable() object_path = os.path.join( dev_path, DATADIR, partition, object_hash[-3:], object_hash) try: filenames = hash_cleanup_listdir(object_path, self.reclaim_age) except OSError as err: if err.errno == errno.ENOTDIR: quar_path = quarantine_renamer(dev_path, object_path) logging.exception( _('Quarantined %s to %s because it is not a ' 'directory') % (object_path, quar_path)) raise DiskFileNotExist() if err.errno != errno.ENOENT: raise raise DiskFileNotExist() if not filenames: raise DiskFileNotExist() try: metadata = read_metadata(os.path.join(object_path, filenames[-1])) except EOFError: raise DiskFileNotExist() try: account, container, obj = split_path( metadata.get('name', ''), 3, 3, True) except ValueError: raise DiskFileNotExist() return DiskFile(self, dev_path, self.threadpools[device], partition, account, container, obj, **kwargs)
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** def _listdir(self, path): try: return os.listdir(path) except OSError as err: if err.errno != errno.ENOENT: self.logger.error( 'ERROR: Skipping %r due to error with listdir attempt: %s', path, err) return []
**** CubicPower OpenStack Study **** def yield_suffixes(self, device, partition): """ Yields tuples of (full_path, suffix_only) for suffixes stored on the given device and partition. """ dev_path = self.get_dev_path(device) if not dev_path: raise DiskFileDeviceUnavailable() partition_path = os.path.join(dev_path, DATADIR, partition) for suffix in self._listdir(partition_path): if len(suffix) != 3: continue try: int(suffix, 16) except ValueError: continue yield (os.path.join(partition_path, suffix), suffix)
**** CubicPower OpenStack Study **** def yield_hashes(self, device, partition, suffixes=None): """ Yields tuples of (full_path, hash_only, timestamp) for object information stored for the given device, partition, and (optionally) suffixes. If suffixes is None, all stored suffixes will be searched for object hashes. Note that if suffixes is not None but empty, such as [], then nothing will be yielded. """ dev_path = self.get_dev_path(device) if not dev_path: raise DiskFileDeviceUnavailable() if suffixes is None: suffixes = self.yield_suffixes(device, partition) else: partition_path = os.path.join(dev_path, DATADIR, partition) suffixes = ( (os.path.join(partition_path, suffix), suffix) for suffix in suffixes) for suffix_path, suffix in suffixes: for object_hash in self._listdir(suffix_path): object_path = os.path.join(suffix_path, object_hash) for name in hash_cleanup_listdir( object_path, self.reclaim_age): ts, ext = name.rsplit('.', 1) yield (object_path, object_hash, ts) break
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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'
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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) try: hash_cleanup_listdir(self._datadir) except OSError: logging.exception(_('Problem cleaning up %s'), self._datadir)
**** CubicPower OpenStack Study **** 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 """ 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)
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** def __init__(self, fp, data_file, obj_size, etag, threadpool, disk_chunk_size, keep_cache_size, device_path, logger, quarantine_hook, 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._quarantine_hook = quarantine_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
**** CubicPower OpenStack Study **** 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 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()
**** CubicPower OpenStack Study **** 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()
**** CubicPower OpenStack Study **** 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 self.close()
**** CubicPower OpenStack Study **** 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)
**** CubicPower OpenStack Study **** def _quarantine(self, msg): self._quarantined_dir = self._threadpool.run_in_thread( quarantine_renamer, self._device_path, self._data_file) self._logger.warn("Quarantined object %s: %s" % ( self._data_file, msg)) self._logger.increment('quarantines') self._quarantine_hook(msg)
**** CubicPower OpenStack Study **** 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()))
**** CubicPower OpenStack Study **** 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 DiskFileQuarantined: raise 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()
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** def __init__(self, mgr, device_path, threadpool, partition, account=None, container=None, obj=None, _datadir=None): 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 if account and container and obj: self._name = '/' + '/'.join((account, container, obj)) self._account = account self._container = container self._obj = obj name_hash = hash_path(account, container, obj) self._datadir = join( device_path, storage_directory(DATADIR, partition, name_hash)) else: # gets populated when we read the metadata self._name = None self._account = None self._container = None self._obj = None self._datadir = None self._tmpdir = join(device_path, 'tmp') self._metadata = None self._data_file = None self._fp = None self._quarantined_dir = None self._content_length = None if _datadir: self._datadir = _datadir else: name_hash = hash_path(account, container, obj) self._datadir = join( device_path, storage_directory(DATADIR, partition, name_hash)) @property
**** CubicPower OpenStack Study **** def account(self): return self._account @property
**** CubicPower OpenStack Study **** def container(self): return self._container @property
**** CubicPower OpenStack Study **** def obj(self): return self._obj @property
**** CubicPower OpenStack Study **** def content_length(self): if self._metadata is None: raise DiskFileNotOpen() return self._content_length @property
**** CubicPower OpenStack Study **** def timestamp(self): if self._metadata is None: raise DiskFileNotOpen() return self._metadata.get('X-Timestamp') @classmethod
**** CubicPower OpenStack Study **** def from_hash_dir(cls, mgr, hash_dir_path, device_path, partition): return cls(mgr, device_path, None, partition, _datadir=hash_dir_path)
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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()
**** CubicPower OpenStack Study **** def _quarantine(self, data_file, msg): """ Quarantine a file; responsible for incrementing the associated logger's count of quarantines. :param data_file: full path of data file to quarantine :param msg: reason for quarantining to be included in the exception :returns: DiskFileQuarantined exception object """ self._quarantined_dir = self._threadpool.run_in_thread( quarantine_renamer, self._device_path, data_file) self._logger.warn("Quarantined object %s: %s" % ( data_file, msg)) self._logger.increment('quarantines') return DiskFileQuarantined(msg)
**** CubicPower OpenStack Study **** 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 """ try: files = os.listdir(self._datadir) except OSError as err: if err.errno == errno.ENOTDIR: # If there's a file here instead of a directory, quarantine # it; something's gone wrong somewhere. raise self._quarantine( # hack: quarantine_renamer actually renames the directory # enclosing the filename you give it, but here we just # want this one file and not its parent. os.path.join(self._datadir, "made-up-filename"), "Expected directory, found file at %s" % self._datadir) elif err.errno != errno.ENOENT: raise DiskFileError( "Error listing directory %s: %s" % (self._datadir, err)) # The data directory does not exist, so the object cannot exist. fileset = (None, None, None) else: fileset = get_ondisk_files(files, self._datadir) return fileset
**** CubicPower OpenStack Study **** 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: try: metadata = self._failsafe_read_metadata(ts_file, ts_file) except DiskFileQuarantined: # If the tombstone's corrupted, quarantine it and pretend it # wasn't there exc = DiskFileNotExist() else: # 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(metadata=metadata) return exc
**** CubicPower OpenStack Study **** def _verify_name_matches_hash(self, data_file): hash_from_fs = os.path.basename(self._datadir) hash_from_name = hash_path(self._name.lstrip('/')) if hash_from_fs != hash_from_name: raise self._quarantine( data_file, "Hash of name in metadata does not match directory name")
**** CubicPower OpenStack Study **** 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 DiskFileExpired: 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: raise 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. raise self._quarantine( data_file, "bad metadata x-delete-at value %s" % ( self._metadata['X-Delete-At'])) else: if x_delete_at <= time.time(): raise DiskFileExpired(metadata=self._metadata) try: metadata_size = int(self._metadata['Content-Length']) except KeyError: raise self._quarantine( data_file, "missing content-length in metadata") except ValueError: # Quarantine, the content-length key is present but not an # integer. raise 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. raise self._quarantine(data_file, "not stat-able: %s" % err) else: obj_size = statbuf.st_size if obj_size != metadata_size: raise self._quarantine( data_file, "metadata content-length %s does" " not match actual object size %s" % ( metadata_size, statbuf.st_size)) self._content_length = obj_size return obj_size
**** CubicPower OpenStack Study **** def _failsafe_read_metadata(self, source, quarantine_filename=None): # Takes source and filename separately so we can read from an open # file if we have one try: return read_metadata(source) except Exception as err: raise self._quarantine( quarantine_filename, "Exception reading metadata: %s" % err)
**** CubicPower OpenStack Study **** 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 = self._failsafe_read_metadata(fp, data_file) if meta_file: self._metadata = self._failsafe_read_metadata(meta_file, meta_file) 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 if self._name is None: # If we don't know our name, we were just given a hash dir at # instantiation, so we'd better validate that the name hashes back # to us self._name = self._metadata['name'] self._verify_name_matches_hash(data_file) self._verify_data_file(data_file, fp) return fp
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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()
**** CubicPower OpenStack Study **** def reader(self, keep_cache=False, _quarantine_hook=lambda m: None): """ 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 keep_cache: caller's preference for keeping data read in the OS buffer cache :param _quarantine_hook: 1-arg callable called when obj quarantined; the arg is the reason for quarantine. Default is to ignore it. Not needed by the REST layer. :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, quarantine_hook=_quarantine_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
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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)
**** CubicPower OpenStack Study **** 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})
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