Exemple #1
0
    def mover_pass(self, **kwargs):
        start_time = report_time = time.time()

        total_errors = 0
        mover_time = 0

        pool = GreenPool(self.concurrency)

        paths = paths_gen(self.volume)

        for path in paths:
            loop_time = time.time()

            now = time.time()
            if now - self.last_usage_check >= self.usage_check_interval:
                free_ratio = statfs(self.volume)
                usage = (1 - float(free_ratio)) * 100
                if usage <= self.usage_target:
                    self.logger.info(
                        'current usage %.2f%%: target reached (%.2f%%)', usage,
                        self.usage_target)
                    break
                self.last_usage_check = now

            # Spawn a chunk move task.
            # The call will block if no green thread is available.
            pool.spawn_n(self.safe_chunk_move, path)

            self.chunks_run_time = ratelimit(self.chunks_run_time,
                                             self.max_chunks_per_second)
            self.total_chunks_processed += 1
            now = time.time()

            if now - self.last_reported >= self.report_interval:
                self.logger.info(
                    '%(start_time)s '
                    '%(passes)d '
                    '%(errors)d '
                    '%(c_rate).2f '
                    '%(b_rate).2f '
                    '%(total).2f '
                    '%(mover_time).2f'
                    '%(mover_rate).2f' % {
                        'start_time': time.ctime(report_time),
                        'passes': self.passes,
                        'errors': self.errors,
                        'c_rate': self.passes / (now - report_time),
                        'b_rate': self.bytes_processed / (now - report_time),
                        'total': (now - start_time),
                        'mover_time': mover_time,
                        'mover_rate': mover_time / (now - start_time)
                    })
                report_time = now
                total_errors += self.errors
                self.passes = 0
                self.bytes_processed = 0
                self.last_reported = now
            mover_time += (now - loop_time)
            if self.limit != 0 and self.total_chunks_processed >= self.limit:
                break
        pool.waitall()
        elapsed = (time.time() - start_time) or 0.000001
        self.logger.info(
            '%(elapsed).02f '
            '%(errors)d '
            '%(chunk_rate).2f '
            '%(bytes_rate).2f '
            '%(mover_time).2f '
            '%(mover_rate).2f' % {
                'elapsed': elapsed,
                'errors': total_errors + self.errors,
                'chunk_rate': self.total_chunks_processed / elapsed,
                'bytes_rate': self.total_bytes_processed / elapsed,
                'mover_time': mover_time,
                'mover_rate': mover_time / elapsed
            })
Exemple #2
0
class Checker(object):
    def __init__(self,
                 namespace,
                 concurrency=50,
                 error_file=None,
                 rebuild_file=None,
                 full=True,
                 limit_listings=0,
                 request_attempts=1,
                 logger=None,
                 verbose=False,
                 integrity=False):
        self.pool = GreenPool(concurrency)
        self.error_file = error_file
        self.full = bool(full)
        self.integrity = bool(integrity)
        # Optimisation for when we are only checking one object
        # or one container.
        # 0 -> do not limit
        # 1 -> limit account listings (list of containers)
        # 2 -> limit container listings (list of objects)
        self.limit_listings = limit_listings
        if self.error_file:
            outfile = open(self.error_file, 'a')
            self.error_writer = csv.writer(outfile, delimiter=' ')

        self.rebuild_file = rebuild_file
        if self.rebuild_file:
            fd = open(self.rebuild_file, 'a')
            self.rebuild_writer = csv.writer(fd, delimiter='|')

        self.logger = logger or get_logger(
            {'namespace': namespace}, name='integrity', verbose=verbose)
        self.api = ObjectStorageApi(namespace,
                                    logger=self.logger,
                                    max_retries=request_attempts - 1,
                                    request_attempts=request_attempts)

        self.accounts_checked = 0
        self.containers_checked = 0
        self.objects_checked = 0
        self.chunks_checked = 0
        self.account_not_found = 0
        self.container_not_found = 0
        self.object_not_found = 0
        self.chunk_not_found = 0
        self.account_exceptions = 0
        self.container_exceptions = 0
        self.object_exceptions = 0
        self.chunk_exceptions = 0

        self.list_cache = {}
        self.running = {}
        self.result_queue = Queue()

    def complete_target_from_chunk_metadata(self, target, xattr_meta):
        """
        Complete a Target object from metadata found in chunk's extended
        attributes. In case the "fullpath" is not available, try to read
        legacy metadata, and maybe ask meta1 to resolve the CID into
        account and container names.
        """
        # pylint: disable=unbalanced-tuple-unpacking
        try:
            acct, ct, path, vers, content_id = \
                decode_fullpath(xattr_meta['full_path'])
            target.account = acct
            target.container = ct
            target.obj = path
            target.content_id = content_id
            target.version = vers
        except KeyError:
            # No fullpath header, try legacy headers
            if 'content_path' in xattr_meta:
                target.obj = xattr_meta['content_path']
            if 'content_id' in xattr_meta:
                target.content_id = xattr_meta['content_id']
            if 'content_version' in xattr_meta:
                target.version = xattr_meta['content_version']
            cid = xattr_meta.get('container_id')
            if cid:
                try:
                    md = self.api.directory.show(cid=cid)
                    acct = md.get('account')
                    ct = md.get('name')
                    if acct:
                        target.account = acct
                    if ct:
                        target.container = ct
                except Exception as err:
                    self.logger.warn(
                        "Failed to resolve CID %s into account "
                        "and container names: %s", cid, err)

    def send_result(self, target, errors=None):
        """
        Put an item in the result queue.
        """
        # TODO(FVE): send to an external queue.
        self.result_queue.put(ItemResult(target, errors))

    def write_error(self, target, irreparable=False):
        if not self.error_file:
            return
        error = list()
        if irreparable:
            error.append('#IRREPARABLE')
        error.append(target.account)
        if target.container:
            error.append(target.container)
        if target.obj:
            error.append(target.obj)
        if target.chunk:
            error.append(target.chunk)
        self.error_writer.writerow(error)

    def write_rebuilder_input(self, target, irreparable=False):
        # FIXME(FVE): cid can be computed from account and container names
        ct_meta = self.list_cache[(target.account, target.container)][1]
        try:
            cid = ct_meta['system']['sys.name'].split('.', 1)[0]
        except KeyError:
            cid = ct_meta['properties']['sys.name'].split('.', 1)[0]
        error = list()
        if irreparable:
            error.append('#IRREPARABLE')
        error.append(cid)
        # FIXME(FVE): ensure we always resolve content_id,
        # or pass object version along with object name.
        error.append(target.content_id or target.obj)
        error.append(target.chunk)
        self.rebuild_writer.writerow(error)

    def write_chunk_error(self, target, chunk=None, irreparable=False):
        if chunk is not None:
            target = target.copy()
            target.chunk = chunk
        self.write_error(target, irreparable=irreparable)
        if self.rebuild_file:
            self.write_rebuilder_input(target, irreparable=irreparable)

    def _check_chunk_xattr(self, target, obj_meta, xattr_meta):
        """
        Check coherency of chunk extended attributes with object metadata.

        :returns: a list of errors
        """
        errors = list()
        # Composed position -> erasure coding
        attr_prefix = 'meta' if '.' in obj_meta['pos'] else ''

        attr_key = attr_prefix + 'chunk_size'
        if str(obj_meta['size']) != xattr_meta.get(attr_key):
            errors.append(
                "'%s' xattr (%s) differs from size in meta2 (%s)" %
                (attr_key, xattr_meta.get(attr_key), obj_meta['size']))

        attr_key = attr_prefix + 'chunk_hash'
        if obj_meta['hash'] != xattr_meta.get(attr_key):
            errors.append(
                "'%s' xattr (%s) differs from hash in meta2 (%s)" %
                (attr_key, xattr_meta.get(attr_key), obj_meta['hash']))
        return errors

    def _check_chunk(self, target):
        """
        Execute various checks on a chunk:
        - does it appear in object's chunk list?
        - is it reachable?
        - are its extended attributes coherent?

        :returns: the list of errors encountered,
            and the chunk's owner object metadata.
        """
        chunk = target.chunk
        errors = list()
        obj_meta = None
        xattr_meta = None

        try:
            xattr_meta = self.api.blob_client.chunk_head(
                chunk, xattr=self.full, check_hash=self.integrity)
        except exc.NotFound as err:
            self.chunk_not_found += 1
            errors.append('Not found: %s' % (err, ))
        except exc.FaultyChunk as err:
            self.chunk_exceptions += 1
            errors.append('Faulty: %r' % (err, ))
        except Exception as err:
            self.chunk_exceptions += 1
            errors.append('Check failed: %s' % (err, ))

        if not target.obj and xattr_meta:
            self.complete_target_from_chunk_metadata(target, xattr_meta)

        if target.obj:
            obj_listing, obj_meta = self.check_obj(target.copy_object())
            if chunk not in obj_listing:
                errors.append('Missing from object listing')
                db_meta = dict()
            else:
                db_meta = obj_listing[chunk]

            if db_meta and xattr_meta and self.full:
                errors.extend(
                    self._check_chunk_xattr(target, db_meta, xattr_meta))

        self.send_result(target, errors)
        self.chunks_checked += 1
        return errors, obj_meta

    def check_chunk(self, target):
        errors, _obj_meta = self._check_chunk(target)
        return errors

    def _check_metachunk(self, target, stg_met, pos, chunks, recurse=0):
        """
        Check that a metachunk has the right number of chunks.

        :returns: the list of errors
        """
        required = stg_met.expected_chunks
        errors = list()

        if len(chunks) < required:
            missing_chunks = required - len(chunks)
            if stg_met.ec:
                subs = {x['num'] for x in chunks}
                for sub in range(required):
                    if sub not in subs:
                        errors.append("Missing chunk at position %d.%d" %
                                      (pos, sub))
            else:
                for _ in range(missing_chunks):
                    errors.append("Missing chunk at position %d" % pos)

        if recurse > 0:
            for chunk in chunks:
                tcopy = target.copy()
                tcopy.chunk = chunk['url']
                chunk_errors, _ = self._check_chunk(tcopy)
                if chunk_errors:
                    # The errors have already been reported by _check_chunk,
                    # but we must count this chunk among the unusable chunks
                    # of the current metachunk.
                    errors.append("Unusable chunk %s at position %s" %
                                  (chunk['url'], chunk['pos']))

        irreparable = required - len(errors) < stg_met.min_chunks_to_read
        if irreparable:
            errors.append(
                "Unavailable metachunk at position %s (%d/%d chunks)" %
                (pos, required - len(errors), stg_met.expected_chunks))
        # Since the "metachunk" is not an official item type,
        # this method does not report errors itself. Errors will
        # be reported as object errors.
        return errors

    def _check_obj_policy(self, target, obj_meta, chunks, recurse=0):
        """
        Check that the list of chunks of an object matches
        the object's storage policy.

        :returns: the list of errors encountered
        """
        stg_met = STORAGE_METHODS.load(obj_meta['chunk_method'])
        chunks_by_pos = _sort_chunks(chunks, stg_met.ec)
        tasks = list()
        for pos, chunks in chunks_by_pos.iteritems():
            tasks.append((pos,
                          self.pool.spawn(self._check_metachunk,
                                          target.copy(),
                                          stg_met,
                                          pos,
                                          chunks,
                                          recurse=recurse)))
        errors = list()
        for pos, task in tasks:
            try:
                errors.extend(task.wait())
            except Exception as err:
                errors.append("Check failed: pos %d: %s" % (pos, err))
        return errors

    def check_obj_versions(self, target, versions, recurse=0):
        """
        Run checks of all versions of the targeted object in parallel.
        """
        tasks = list()
        for ov in versions:
            tcopy = target.copy_object()
            tcopy.content_id = ov['id']
            tcopy.version = str(ov['version'])
            tasks.append((tcopy.version,
                          self.pool.spawn(self.check_obj,
                                          tcopy,
                                          recurse=recurse)))
        errors = list()
        for version, task in tasks:
            try:
                task.wait()
            except Exception as err:
                errors.append("Check failed: version %s: %s" % (version, err))
        if errors:
            # Send a result with the target without version to tell
            # we were not able to check all versions of the object.
            self.send_result(target, errors)

    def _load_obj_meta(self, target, errors):
        """
        Load object metadata and chunks.

        :param target: which object to check.
        :param errors: list of errors that will be appended
            in case any error occurs.
        :returns: a tuple with object metadata and a list of chunks.
        """
        try:
            return self.api.object_locate(target.account,
                                          target.container,
                                          target.obj,
                                          version=target.version,
                                          properties=False)
        except exc.NoSuchObject as err:
            self.object_not_found += 1
            errors.append('Not found: %s' % (err, ))
        except Exception as err:
            self.object_exceptions += 1
            errors.append('Check failed: %s' % (err, ))
        return None, []

    def check_obj(self, target, recurse=0):
        """
        Check one object version.
        If no version is specified, all versions of the object will be checked.
        :returns: the result of the check of the most recent version,
            or the one that is explicitly targeted.
        """
        account = target.account
        container = target.container
        obj = target.obj
        vers = target.version  # can be None

        if (account, container, obj, vers) in self.running:
            self.running[(account, container, obj, vers)].wait()
        if (account, container, obj, vers) in self.list_cache:
            return self.list_cache[(account, container, obj, vers)]
        self.running[(account, container, obj, vers)] = Event()
        self.logger.info('Checking object "%s"', target)
        container_listing, _ = self.check_container(target.copy_container())
        errors = list()
        if obj not in container_listing:
            errors.append('Missing from container listing')
            # checksum = None
        else:
            versions = container_listing[obj]
            if vers is None:
                if target.content_id is None:
                    # No version specified, check all versions
                    self.check_obj_versions(target.copy_object(),
                                            versions,
                                            recurse=recurse)
                    # Now return the cached result of the most recent version
                    target.content_id = versions[0]['id']
                    target.version = str(versions[0]['version'])
                    res = self.check_obj(target, recurse=0)
                    self.running[(account, container, obj, vers)].send(True)
                    del self.running[(account, container, obj, vers)]
                    return res
                else:
                    for ov in versions:
                        if ov['id'] == target.content_id:
                            vers = str(ov['version'])
                            target.version = vers
                            break
                    else:
                        errors.append('Missing from container listing')

            # TODO check checksum match
            # checksum = container_listing[obj]['hash']
            pass

        meta, chunks = self._load_obj_meta(target, errors)

        chunk_listing = {c['url']: c for c in chunks}
        if meta:
            self.list_cache[(account, container, obj, vers)] = \
                (chunk_listing, meta)
        self.objects_checked += 1
        self.running[(account, container, obj, vers)].send(True)
        del self.running[(account, container, obj, vers)]

        # Skip the check if we could not locate the object
        if meta:
            errors.extend(
                self._check_obj_policy(target, meta, chunks, recurse=recurse))

        self.send_result(target, errors)
        return chunk_listing, meta

    def check_container(self, target, recurse=0):
        account = target.account
        container = target.container

        if (account, container) in self.running:
            self.running[(account, container)].wait()
        if (account, container) in self.list_cache:
            return self.list_cache[(account, container)]
        self.running[(account, container)] = Event()
        self.logger.info('Checking container "%s"', target)
        account_listing = self.check_account(target.copy_account())
        errors = list()
        if container not in account_listing:
            errors.append('Missing from account listing')

        marker = None
        results = []
        ct_meta = dict()
        extra_args = dict()
        if self.limit_listings > 1 and target.obj:
            # When we are explicitly checking one object, start the listing
            # where this object is supposed to be. Do not use a limit,
            # but an end marker, in order to fetch all versions of the object.
            extra_args['prefix'] = target.obj
            extra_args['end_marker'] = target.obj + '\x00'  # HACK
        while True:
            try:
                resp = self.api.object_list(account,
                                            container,
                                            marker=marker,
                                            versions=True,
                                            **extra_args)
            except exc.NoSuchContainer as err:
                self.container_not_found += 1
                errors.append('Not found: %s' % (err, ))
                break
            except Exception as err:
                self.container_exceptions += 1
                errors.append('Check failed: %s' % (err, ))
                break

            if resp.get('truncated', False):
                marker = resp['next_marker']

            if resp['objects']:
                # safeguard, probably useless
                if not marker:
                    marker = resp['objects'][-1]['name']
                results.extend(resp['objects'])
                if self.limit_listings > 1:
                    break
            else:
                ct_meta = resp
                ct_meta.pop('objects')
                break

        container_listing = dict()
        # Save all object versions, with the most recent first
        for obj in results:
            container_listing.setdefault(obj['name'], list()).append(obj)
        for versions in container_listing.values():
            versions.sort(key=lambda o: o['version'], reverse=True)

        if self.limit_listings <= 1:
            # We just listed the whole container, keep the result in a cache
            self.containers_checked += 1
            self.list_cache[(account, container)] = container_listing, ct_meta
        self.running[(account, container)].send(True)
        del self.running[(account, container)]

        if recurse > 0:
            for obj_vers in container_listing.values():
                for obj in obj_vers:
                    tcopy = target.copy_object()
                    tcopy.obj = obj['name']
                    tcopy.content_id = obj['id']
                    tcopy.version = str(obj['version'])
                    self.pool.spawn_n(self.check_obj, tcopy, recurse - 1)
        self.send_result(target, errors)
        return container_listing, ct_meta

    def check_account(self, target, recurse=0):
        account = target.account

        if account in self.running:
            self.running[account].wait()
        if account in self.list_cache:
            return self.list_cache[account]
        self.running[account] = Event()
        self.logger.info('Checking account "%s"', target)
        errors = list()
        marker = None
        results = []
        extra_args = dict()
        if self.limit_listings > 0 and target.container:
            # When we are explicitly checking one container, start the listing
            # where this container is supposed to be, and list only one
            # container.
            extra_args['prefix'] = target.container
            extra_args['limit'] = 1
        while True:
            try:
                resp = self.api.container_list(account,
                                               marker=marker,
                                               **extra_args)
            except Exception as err:
                self.account_exceptions += 1
                errors.append('Check failed: %s' % (err, ))
                break
            if resp:
                marker = resp[-1][0]
                results.extend(resp)
                if self.limit_listings > 0:
                    break
            else:
                break

        containers = dict()
        for container in results:
            # Name, number of objects, number of bytes
            containers[container[0]] = (container[1], container[2])

        if self.limit_listings <= 0:
            # We just listed the whole account, keep the result in a cache
            self.accounts_checked += 1
            self.list_cache[account] = containers
        self.running[account].send(True)
        del self.running[account]

        if recurse > 0:
            for container in containers:
                tcopy = target.copy_account()
                tcopy.container = container
                self.pool.spawn_n(self.check_container, tcopy, recurse - 1)

        self.send_result(target, errors)
        return containers

    def check(self, target, recurse=0):
        if target.type == 'chunk':
            self.pool.spawn_n(self.check_chunk, target)
        elif target.type == 'object':
            self.pool.spawn_n(self.check_obj, target, recurse)
        elif target.type == 'container':
            self.pool.spawn_n(self.check_container, target, recurse)
        else:
            self.pool.spawn_n(self.check_account, target, recurse)

    def fetch_results(self):
        while not self.result_queue.empty():
            res = self.result_queue.get(True)
            yield res

    def log_result(self, result):
        if result.errors:
            if result.target.type == 'chunk':
                # FIXME(FVE): check error criticity
                # and set the irreparable flag.
                self.write_chunk_error(result.target)
            else:
                self.write_error(result.target)
            self.logger.warn('%s:\n%s', result.target,
                             result.errors_to_str(err_format='  %s'))

    def run(self):
        """
        Fetch results and write logs until all jobs have finished.

        :returns: a generator yielding check results.
        """
        while self.pool.running() + self.pool.waiting():
            for result in self.fetch_results():
                self.log_result(result)
                yield result
            sleep(0.1)
        self.pool.waitall()
        for result in self.fetch_results():
            self.log_result(result)
            yield result

    def report(self):
        success = True

        def _report_stat(name, stat):
            print("{0:18}: {1}".format(name, stat))

        print()
        print('Report')
        _report_stat("Accounts checked", self.accounts_checked)
        if self.account_not_found:
            success = False
            _report_stat("Missing accounts", self.account_not_found)
        if self.account_exceptions:
            success = False
            _report_stat("Exceptions", self.account_exceptions)
        print()
        _report_stat("Containers checked", self.containers_checked)
        if self.container_not_found:
            success = False
            _report_stat("Missing containers", self.container_not_found)
        if self.container_exceptions:
            success = False
            _report_stat("Exceptions", self.container_exceptions)
        print()
        _report_stat("Objects checked", self.objects_checked)
        if self.object_not_found:
            success = False
            _report_stat("Missing objects", self.object_not_found)
        if self.object_exceptions:
            success = False
            _report_stat("Exceptions", self.object_exceptions)
        print()
        _report_stat("Chunks checked", self.chunks_checked)
        if self.chunk_not_found:
            success = False
            _report_stat("Missing chunks", self.chunk_not_found)
        if self.chunk_exceptions:
            success = False
            _report_stat("Exceptions", self.chunk_exceptions)
        return success
Exemple #3
0
class Checker(object):
    def __init__(self,
                 namespace,
                 concurrency=50,
                 error_file=None,
                 rebuild_file=None,
                 check_xattr=True,
                 limit_listings=0,
                 request_attempts=1,
                 logger=None,
                 verbose=False,
                 check_hash=False,
                 min_time_in_error=0.0,
                 required_confirmations=0,
                 beanstalkd_addr=None,
                 beanstalkd_tube=BlobRebuilder.DEFAULT_BEANSTALKD_WORKER_TUBE,
                 cache_size=2**24,
                 **_kwargs):
        self.pool = GreenPool(concurrency)
        self.error_file = error_file
        self.error_sender = None
        self.check_xattr = bool(check_xattr)
        self.check_hash = bool(check_hash)
        self.logger = logger or get_logger(
            {'namespace': namespace}, name='integrity', verbose=verbose)
        # Optimisation for when we are only checking one object
        # or one container.
        # 0 -> do not limit
        # 1 -> limit account listings (list of containers)
        # 2 -> limit container listings (list of objects)
        self.limit_listings = limit_listings
        if self.error_file:
            outfile = open(self.error_file, 'a')
            self.error_writer = csv.writer(outfile, delimiter=' ')

        self.rebuild_file = rebuild_file
        if self.rebuild_file:
            self.fd = open(self.rebuild_file, 'a')
            self.rebuild_writer = csv.writer(self.fd, delimiter='|')

        if beanstalkd_addr:
            self.error_sender = BeanstalkdSender(beanstalkd_addr,
                                                 beanstalkd_tube, self.logger)

        self.api = ObjectStorageApi(namespace,
                                    logger=self.logger,
                                    max_retries=request_attempts - 1,
                                    request_attempts=request_attempts)
        self.rdir_client = RdirClient({"namespace": namespace},
                                      logger=self.logger)

        self.accounts_checked = 0
        self.containers_checked = 0
        self.objects_checked = 0
        self.chunks_checked = 0
        self.account_not_found = 0
        self.container_not_found = 0
        self.object_not_found = 0
        self.chunk_not_found = 0
        self.account_exceptions = 0
        self.container_exceptions = 0
        self.object_exceptions = 0
        self.chunk_exceptions = 0

        self.list_cache = CacheDict(cache_size)
        self.running_tasks = {}
        self.running_lock = Semaphore(1)
        self.result_queue = LightQueue(concurrency)

        self.running = True
        self.run_time = 0

        # Set of targets which must be checked again, to confirm
        # or deny the issues reported by previous passes.
        self.delayed_targets = dict()
        # Minimum time in error and number of confirmations of the error
        # before triggering a reconstruction action.
        self.min_time_in_error = min_time_in_error
        self.required_confirmations = required_confirmations

    def reset_stats(self):
        self.accounts_checked = 0
        self.containers_checked = 0
        self.objects_checked = 0
        self.chunks_checked = 0
        self.account_not_found = 0
        self.container_not_found = 0
        self.object_not_found = 0
        self.chunk_not_found = 0
        self.account_exceptions = 0
        self.container_exceptions = 0
        self.object_exceptions = 0
        self.chunk_exceptions = 0

    def _spawn(self, func, target, *args, **kwargs):
        """
        Spawn a task on the internal GreenPool.
        Discards the task if the pool is no more running.
        """
        if self.running:
            return self.pool.spawn(func, target, *args, **kwargs)
        self.logger.info("Discarding %s", target)
        return None

    def _spawn_n(self, func, target, *args, **kwargs):
        """
        Spawn a task on the internal GreenPool, do not wait for the result.
        Discards the task if the pool is no more running.
        """
        if self.running:
            return self.pool.spawn_n(func, target, *args, **kwargs)
        self.logger.info("Discarding %s", target)
        return None

    def complete_target_from_chunk_metadata(self, target, xattr_meta):
        """
        Complete a Target object from metadata found in chunk's extended
        attributes. In case the "fullpath" is not available, try to read
        legacy metadata, and maybe ask meta1 to resolve the CID into
        account and container names.
        """
        # pylint: disable=unbalanced-tuple-unpacking
        try:
            acct, ct, path, vers, content_id = \
                decode_fullpath(xattr_meta['full_path'])
            target.account = acct
            target.container = ct
            target.obj = path
            target.content_id = content_id
            target.version = vers
        except KeyError:
            # No fullpath header, try legacy headers
            if 'content_path' in xattr_meta:
                target.obj = xattr_meta['content_path']
            if 'content_id' in xattr_meta:
                target.content_id = xattr_meta['content_id']
            if 'content_version' in xattr_meta:
                target.version = xattr_meta['content_version']
            cid = xattr_meta.get('container_id')
            if cid:
                try:
                    md = self.api.directory.show(cid=cid)
                    acct = md.get('account')
                    ct = md.get('name')
                    if acct:
                        target.account = acct
                    if ct:
                        target.container = ct
                except Exception as err:
                    self.logger.warn(
                        "Failed to resolve CID %s into account "
                        "and container names: %s", cid, err)

    def recover_and_complete_object_meta(self, target, chunk):
        _, rawx_service, chunk_id = chunk.rsplit('/', 2)
        # 1. Fetch chunk list from rdir (could be cached).
        # Unfortunately we cannot seek for a chunk ID.
        entries = [
            x for x in self.rdir_client.chunk_fetch(rawx_service, limit=-1)
            if x[2] == chunk_id
        ]
        if not entries:
            self.logger.warn('Chunk %s not found in rdir' % chunk_id)
            return
        elif len(entries) > 1:
            self.logger.info('Chunk %s appears in %d objects', chunk_id,
                             len(entries))
        # 2. Find content and container IDs
        target.cid, target.content_id = entries[0][0:2]
        meta = self.api.object_get_properties(None,
                                              None,
                                              None,
                                              cid=target.cid,
                                              content=target.content_id)
        target.obj = meta['name']
        target.version = meta['version']
        target.account, target.container = self.api.resolve_cid(target.cid)

    def send_result(self, target, errors=None, irreparable=False):
        """
        Put an item in the result queue.
        """
        # TODO(FVE): send to an external queue.
        target.append_result(ItemResult(errors, irreparable))
        self.result_queue.put(target)

    def send_chunk_job(self, target, irreparable=False):
        """
        Send a "content broken" event, to trigger the
        reconstruction of the chunk.
        """
        item = (self.api.namespace, target.cid, target.content_id,
                target.chunk)
        ev_dict = BlobRebuilder.task_event_from_item(item)
        if irreparable:
            ev_dict['data']['irreparable'] = irreparable
        job = json.dumps(ev_dict)
        self.error_sender.send_job(job)
        self.error_sender.job_done()  # Don't expect any response

    def write_error(self, target, irreparable=False):
        if not self.error_file:
            return
        error = list()
        if irreparable:
            error.append(IRREPARABLE_PREFIX)
        error.append(target.account)
        if target.container:
            error.append(target.container)
        if target.obj:
            error.append(target.obj)
        if target.chunk:
            error.append(target.chunk)
        self.error_writer.writerow(error)

    def write_rebuilder_input(self, target, irreparable=False):
        error = list()
        if irreparable:
            error.append(IRREPARABLE_PREFIX)
        error.append(target.cid)
        # FIXME(FVE): ensure we always resolve content_id,
        # or pass object version along with object name.
        error.append(target.content_id or target.obj)
        error.append(target.chunk)
        self.rebuild_writer.writerow(error)

    def write_chunk_error(self, target, chunk=None, irreparable=False):
        if chunk is not None:
            target = target.copy()
            target.chunk = chunk
        self.write_error(target, irreparable=irreparable)
        if self.rebuild_file:
            self.write_rebuilder_input(target, irreparable=irreparable)
        if self.error_sender:
            self.send_chunk_job(target, irreparable=irreparable)

    def _check_chunk_xattr(self, target, obj_meta, xattr_meta):
        """
        Check coherency of chunk extended attributes with object metadata.

        :returns: a list of errors
        """
        errors = list()
        # Composed position -> erasure coding
        attr_prefix = 'meta' if '.' in obj_meta['pos'] else ''

        attr_key = attr_prefix + 'chunk_size'
        if str(obj_meta['size']) != xattr_meta.get(attr_key):
            errors.append(
                "'%s' xattr (%s) differs from size in meta2 (%s)" %
                (attr_key, xattr_meta.get(attr_key), obj_meta['size']))

        attr_key = attr_prefix + 'chunk_hash'
        if obj_meta['hash'] != xattr_meta.get(attr_key):
            errors.append(
                "'%s' xattr (%s) differs from hash in meta2 (%s)" %
                (attr_key, xattr_meta.get(attr_key), obj_meta['hash']))
        return errors

    def _check_chunk(self, target):
        """
        Execute various checks on a chunk:
        - does it appear in object's chunk list?
        - is it reachable?
        - are its extended attributes coherent?

        :returns: the list of errors encountered,
            and the chunk's owner object metadata.
        """
        chunk = target.chunk
        errors = list()
        obj_meta = None
        xattr_meta = None

        cached = self._get_cached_or_lock(chunk)
        if cached is not None:
            return cached + (True, )

        self.logger.debug('Checking chunk "%s"', target)
        try:
            xattr_meta = self.api.blob_client.chunk_head(
                chunk, xattr=self.check_xattr, check_hash=self.check_hash)
        except exc.NotFound as err:
            self.chunk_not_found += 1
            errors.append('Not found: %s' % (err, ))
        except exc.FaultyChunk as err:
            self.chunk_exceptions += 1
            errors.append('Faulty: %r' % (err, ))
        except Exception as err:
            self.chunk_exceptions += 1
            errors.append('Check failed: %s' % (err, ))

        if not target.obj:
            if xattr_meta:
                self.complete_target_from_chunk_metadata(target, xattr_meta)
            else:
                self.recover_and_complete_object_meta(target, chunk)

        if target.obj:
            obj_listing, obj_meta = self.check_obj(target.copy_object())
            if chunk not in obj_listing:
                errors.append('Missing from object listing')
                db_meta = dict()
            else:
                db_meta = obj_listing[chunk]

            if db_meta and xattr_meta and self.check_xattr:
                errors.extend(
                    self._check_chunk_xattr(target, db_meta, xattr_meta))

        self.list_cache[chunk] = errors, obj_meta
        self._unlock(chunk)

        # Do not send errors directly, let the caller do it.
        # Indeed, it may want to check if the chunks can be repaired or not.
        self.chunks_checked += 1
        return errors, obj_meta, False

    def check_chunk(self, target):
        errors, _obj_meta, from_cache = self._check_chunk(target)
        # If the result comes from the cache, we already reported it.
        if not from_cache:
            self.send_result(target, errors, target.irreparable)
        return errors

    def _check_metachunk(self, target, stg_met, pos, chunks, recurse=0):
        """
        Check that a metachunk has the right number of chunks.

        :returns: the list of errors
        """
        required = stg_met.expected_chunks
        errors = list()
        chunk_results = list()

        if len(chunks) < required:
            missing_chunks = required - len(chunks)
            if stg_met.ec:
                subs = {x['num'] for x in chunks}
                for sub in range(required):
                    if sub not in subs:
                        chkt = target.copy()
                        chkt.chunk = '%d.%d' % (pos, sub)
                        err = "Missing chunk at position %s" % chkt.chunk
                        chunk_results.append((chkt, [err], False))
                        errors.append(err)
            else:
                for _ in range(missing_chunks):
                    chkt = target.copy()
                    chkt.chunk = '%d.%d' % (pos, sub)
                    err = "Missing chunk at position %d" % pos
                    chunk_results.append((chkt, [err], False))
                    errors.append(err)

        if recurse > 0:
            for chunk in chunks:
                tcopy = target.copy()
                tcopy.chunk = chunk['url']
                chunk_errors, _, from_cache = self._check_chunk(tcopy)
                chunk_results.append((tcopy, chunk_errors, from_cache))
                if chunk_errors:
                    errors.append("Unusable chunk %s at position %s" %
                                  (chunk['url'], chunk['pos']))

        irreparable = required - len(errors) < stg_met.min_chunks_to_read
        if irreparable:
            errors.append(
                "Unavailable metachunk at position %s "
                "(%d/%d chunks available, %d/%d required)" %
                (pos, required - len(errors), stg_met.expected_chunks,
                 stg_met.min_chunks_to_read, stg_met.expected_chunks))
        for tgt, errs, from_cache in chunk_results:
            # If the result comes from the cache, we already reported it.
            if not from_cache:
                self.send_result(tgt, errs, irreparable)
        # Since the "metachunk" is not an official item type,
        # this method does not report errors itself. Errors will
        # be reported as object errors.
        return errors

    def _check_obj_policy(self, target, obj_meta, chunks, recurse=0):
        """
        Check that the list of chunks of an object matches
        the object's storage policy.

        :returns: the list of errors encountered
        """
        stg_met = STORAGE_METHODS.load(obj_meta['chunk_method'])
        chunks_by_pos = _sort_chunks(chunks, stg_met.ec)
        tasks = list()
        for pos, pchunks in iteritems(chunks_by_pos):
            tasks.append((pos,
                          self._spawn(self._check_metachunk,
                                      target.copy(),
                                      stg_met,
                                      pos,
                                      pchunks,
                                      recurse=recurse)))
        errors = list()
        for pos, task in tasks:
            if not task and not self.running:
                errors.append("Pos %d skipped: checker is exiting" % pos)
                continue
            try:
                errors.extend(task.wait())
            except Exception as err:
                errors.append("Check failed: pos %d: %s" % (pos, err))
        return errors

    def check_obj_versions(self, target, versions, recurse=0):
        """
        Run checks of all versions of the targeted object in parallel.
        """
        tasks = list()
        for ov in versions:
            tcopy = target.copy_object()
            tcopy.content_id = ov['id']
            tcopy.version = str(ov['version'])
            tasks.append((tcopy.version,
                          self._spawn(self.check_obj, tcopy, recurse=recurse)))
        errors = list()
        for version, task in tasks:
            if not task and not self.running:
                errors.append("Version %s skipped: checker is exiting" %
                              version)
                continue
            try:
                task.wait()
            except Exception as err:
                errors.append("Check failed: version %s: %s" % (version, err))
        if errors:
            # Send a result with the target without version to tell
            # we were not able to check all versions of the object.
            self.send_result(target, errors)

    def _load_obj_meta(self, target, errors):
        """
        Load object metadata and chunks.

        :param target: which object to check.
        :param errors: list of errors that will be appended
            in case any error occurs.
        :returns: a tuple with object metadata and a list of chunks.
        """
        try:
            return self.api.object_locate(target.account,
                                          target.container,
                                          target.obj,
                                          version=target.version,
                                          properties=False)
        except exc.NoSuchObject as err:
            self.object_not_found += 1
            errors.append('Not found: %s' % (err, ))
        except Exception as err:
            self.object_exceptions += 1
            errors.append('Check failed: %s' % (err, ))
        return None, []

    def _get_cached_or_lock(self, lock_key):
        # If something is running, wait for it
        with self.running_lock:
            event = self.running_tasks.get(lock_key)
        if event:
            event.wait()
            event = None

        # Maybe get a cached result
        if lock_key in self.list_cache:
            return self.list_cache[lock_key]

        # No cached result, try to compute the thing ourselves
        while True:
            with self.running_lock:
                # Another check while locked
                if lock_key in self.list_cache:
                    return self.list_cache[lock_key]
                # Still nothing cached
                event = self.running_tasks.get(lock_key)
                if event is None:
                    self.running_tasks[lock_key] = Event()
                    return None
            event.wait()

    def _unlock(self, lock_key):
        with self.running_lock:
            event = self.running_tasks[lock_key]
            del self.running_tasks[lock_key]
            event.send(True)

    def check_obj(self, target, recurse=0):
        """
        Check one object version.
        If no version is specified, all versions of the object will be checked.
        :returns: the result of the check of the most recent version,
            or the one that is explicitly targeted.
        """
        account = target.account
        container = target.container
        obj = target.obj
        vers = target.version  # can be None

        cached = self._get_cached_or_lock((account, container, obj, vers))
        if cached is not None:
            return cached

        self.logger.info('Checking object "%s"', target)
        container_listing, _ = self.check_container(target.copy_container())
        errors = list()
        if obj not in container_listing:
            errors.append('Missing from container listing')
            # checksum = None
        else:
            versions = container_listing[obj]
            if vers is None:
                if target.content_id is None:
                    # No version specified, check all versions
                    self.check_obj_versions(target.copy_object(),
                                            versions,
                                            recurse=recurse)
                    # Now return the cached result of the most recent version
                    target.content_id = versions[0]['id']
                    target.version = str(versions[0]['version'])
                    res = self.check_obj(target, recurse=0)
                    self._unlock((account, container, obj, vers))
                    return res
                else:
                    for ov in versions:
                        if ov['id'] == target.content_id:
                            vers = str(ov['version'])
                            target.version = vers
                            break
                    else:
                        errors.append('Missing from container listing')

            # TODO check checksum match
            # checksum = container_listing[obj]['hash']
            pass

        meta, chunks = self._load_obj_meta(target, errors)

        chunk_listing = {c['url']: c for c in chunks}
        if meta:
            if target.content_id is None:
                target.content_id = meta['id']
            if target.version is None:
                target.version = str(meta['version'])
            self.list_cache[(account, container, obj, vers)] = \
                (chunk_listing, meta)
        self.objects_checked += 1
        self._unlock((account, container, obj, vers))

        # Skip the check if we could not locate the object
        if meta:
            errors.extend(
                self._check_obj_policy(target, meta, chunks, recurse=recurse))

        self.send_result(target, errors)
        return chunk_listing, meta

    def check_container(self, target, recurse=0):
        account = target.account
        container = target.container

        cached = self._get_cached_or_lock((account, container))
        if cached is not None:
            return cached

        self.logger.info('Checking container "%s"', target)
        account_listing = self.check_account(target.copy_account())
        errors = list()
        if container not in account_listing:
            errors.append('Missing from account listing')

        marker = None
        results = []
        ct_meta = dict()
        extra_args = dict()
        if self.limit_listings > 1 and target.obj:
            # When we are explicitly checking one object, start the listing
            # where this object is supposed to be. Do not use a limit,
            # but an end marker, in order to fetch all versions of the object.
            extra_args['prefix'] = target.obj
            extra_args['end_marker'] = target.obj + '\x00'  # HACK
        while True:
            try:
                resp = self.api.object_list(account,
                                            container,
                                            marker=marker,
                                            versions=True,
                                            **extra_args)
            except exc.NoSuchContainer as err:
                self.container_not_found += 1
                errors.append('Not found: %s' % (err, ))
                break
            except Exception as err:
                self.container_exceptions += 1
                errors.append('Check failed: %s' % (err, ))
                break

            truncated = resp.get('truncated', False)
            if truncated:
                marker = resp['next_marker']

            if resp['objects']:
                # safeguard, probably useless
                if not marker:
                    marker = resp['objects'][-1]['name']
                results.extend(resp['objects'])
                if not truncated or self.limit_listings > 1:
                    break
            else:
                ct_meta = resp
                ct_meta.pop('objects')
                break

        container_listing = dict()
        # Save all object versions, with the most recent first
        for obj in results:
            container_listing.setdefault(obj['name'], list()).append(obj)
        for versions in container_listing.values():
            versions.sort(key=lambda o: o['version'], reverse=True)

        if self.limit_listings <= 1:
            # We just listed the whole container, keep the result in a cache
            self.containers_checked += 1
            self.list_cache[(account, container)] = container_listing, ct_meta
        self._unlock((account, container))

        if recurse > 0:
            for obj_vers in container_listing.values():
                for obj in obj_vers:
                    tcopy = target.copy_object()
                    tcopy.obj = obj['name']
                    tcopy.content_id = obj['id']
                    tcopy.version = str(obj['version'])
                    self._spawn_n(self.check_obj, tcopy, recurse - 1)
        self.send_result(target, errors)
        return container_listing, ct_meta

    def check_account(self, target, recurse=0):
        account = target.account

        cached = self._get_cached_or_lock(account)
        if cached is not None:
            return cached

        self.logger.info('Checking account "%s"', target)
        errors = list()
        marker = None
        results = []
        extra_args = dict()
        if self.limit_listings > 0 and target.container:
            # When we are explicitly checking one container, start the listing
            # where this container is supposed to be, and list only one
            # container.
            extra_args['prefix'] = target.container
            extra_args['limit'] = 1
        while True:
            try:
                resp = self.api.container_list(account,
                                               marker=marker,
                                               **extra_args)
            except Exception as err:
                self.account_exceptions += 1
                errors.append('Check failed: %s' % (err, ))
                break
            if resp:
                marker = resp[-1][0]
                results.extend(resp)
                if self.limit_listings > 0:
                    break
            else:
                break

        containers = dict()
        for container in results:
            # Name, number of objects, number of bytes
            containers[container[0]] = (container[1], container[2])

        if self.limit_listings <= 0:
            # We just listed the whole account, keep the result in a cache
            self.accounts_checked += 1
            self.list_cache[account] = containers
        self._unlock(account)

        if recurse > 0:
            for container in containers:
                tcopy = target.copy_account()
                tcopy.container = container
                self._spawn_n(self.check_container, tcopy, recurse - 1)

        self.send_result(target, errors)
        return containers

    def check(self, target, recurse=0):
        if target.type == 'chunk':
            self._spawn_n(self.check_chunk, target)
        elif target.type == 'object':
            self._spawn_n(self.check_obj, target, recurse)
        elif target.type == 'container':
            self._spawn_n(self.check_container, target, recurse)
        else:
            self._spawn_n(self.check_account, target, recurse)

    def check_all_accounts(self, recurse=0):
        all_accounts = self.api.account_list()
        for acct in all_accounts:
            self.check(Target(acct), recurse=recurse)

    def fetch_results(self, rate_limiter=None):
        while self.running and not self.result_queue.empty():
            res = self.result_queue.get(True)
            yield res
            # Rate limiting is done on the result queue for now.
            # Someday we could implement a submission queue instead of
            # letting each worker submit tasks to the pool, and do
            # the rate limiting on this queue.
            if rate_limiter is not None:
                self.run_time = rate_limiter(self.run_time)

    def merge_with_delayed_target(self, target):
        """
        Merge the specified target with a delayed one.

        :returns: the delayed target, if there is one, with an error log
            including the errors of the new target. Return the new target
            otherwise.
        """
        tkey = repr(target)
        prev_target = self.delayed_targets.get(tkey, target)
        if prev_target is not target:
            errors = dict(prev_target.error_log)
            errors.update(target.error_log)
            prev_target.error_log = sorted(errors.items())
        return prev_target

    def log_result(self, target):
        """
        Log a check result, if it shows errors. Dispatch the errors to the
        appropriate destinations (log files, queues, etc.).
        """
        # The result may come from a new target, or from an old target
        # we checked another time, or both.
        target = self.merge_with_delayed_target(target)
        if target.has_errors:
            time_in_error, confirmations = target.time_in_error()
            if (time_in_error < self.min_time_in_error
                    or confirmations < self.required_confirmations):
                self.logger.info("Delaying check for %s, %d/%d confirmations",
                                 target, confirmations,
                                 self.required_confirmations)
                self.delayed_targets[repr(target)] = target
            else:
                if target.type == 'chunk':
                    self.logger.info(
                        "Writing error for %s, %d/%d confirmations", target,
                        confirmations, self.required_confirmations)
                    self.write_chunk_error(target,
                                           irreparable=target.irreparable)
                else:
                    self.write_error(target, irreparable=target.irreparable)
                self.delayed_targets.pop(repr(target), None)
            self.logger.warn(
                '%s:%s\n%s', target,
                ' irreparable' if target.irreparable else '',
                target.latest_error_result().errors_to_str(err_format='  %s'))

    def run(self, rate_limiter=None):
        """
        Fetch results and write logs until all jobs have finished.

        :returns: a generator yielding check results.
        """
        while self.running and (self.pool.running() + self.pool.waiting()):
            for result in self.fetch_results(rate_limiter):
                self.log_result(result)
                yield result
            sleep(0.1)
        if self.running:
            self.pool.waitall()
        # No rate limiting
        for result in self.fetch_results():
            self.log_result(result)
            yield result
        self.list_cache = CacheDict(self.list_cache.size)

    def stop(self):
        self.logger.info("Stopping")
        self.running = False

    def report(self):
        success = True

        def _report_stat(name, stat):
            print("{0:18}: {1}".format(name, stat))

        print()
        print('Report')
        _report_stat("Accounts checked", self.accounts_checked)
        if self.account_not_found:
            success = False
            _report_stat("Missing accounts", self.account_not_found)
        if self.account_exceptions:
            success = False
            _report_stat("Exceptions", self.account_exceptions)
        print()
        _report_stat("Containers checked", self.containers_checked)
        if self.container_not_found:
            success = False
            _report_stat("Missing containers", self.container_not_found)
        if self.container_exceptions:
            success = False
            _report_stat("Exceptions", self.container_exceptions)
        print()
        _report_stat("Objects checked", self.objects_checked)
        if self.object_not_found:
            success = False
            _report_stat("Missing objects", self.object_not_found)
        if self.object_exceptions:
            success = False
            _report_stat("Exceptions", self.object_exceptions)
        print()
        _report_stat("Chunks checked", self.chunks_checked)
        if self.chunk_not_found:
            success = False
            _report_stat("Missing chunks", self.chunk_not_found)
        if self.chunk_exceptions:
            success = False
            _report_stat("Exceptions", self.chunk_exceptions)
        return success
Exemple #4
0
class Checker(object):
    def __init__(self, namespace, concurrency=50,
                 error_file=None, rebuild_file=None, full=True,
                 limit_listings=0, request_attempts=1):
        self.pool = GreenPool(concurrency)
        self.error_file = error_file
        self.full = bool(full)
        # Optimisation for when we are only checking one object
        # or one container.
        # 0 -> do not limit
        # 1 -> limit account listings (list of containers)
        # 2 -> limit container listings (list of objects)
        self.limit_listings = limit_listings
        if self.error_file:
            f = open(self.error_file, 'a')
            self.error_writer = csv.writer(f, delimiter=' ')

        self.rebuild_file = rebuild_file
        if self.rebuild_file:
            fd = open(self.rebuild_file, 'a')
            self.rebuild_writer = csv.writer(fd, delimiter='|')

        conf = {'namespace': namespace}
        self.account_client = AccountClient(
            conf,
            max_retries=request_attempts - 1)
        self.container_client = ContainerClient(
            conf,
            max_retries=request_attempts - 1,
            request_attempts=request_attempts)
        self.blob_client = BlobClient(conf=conf)

        self.accounts_checked = 0
        self.containers_checked = 0
        self.objects_checked = 0
        self.chunks_checked = 0
        self.account_not_found = 0
        self.container_not_found = 0
        self.object_not_found = 0
        self.chunk_not_found = 0
        self.account_exceptions = 0
        self.container_exceptions = 0
        self.object_exceptions = 0
        self.chunk_exceptions = 0

        self.list_cache = {}
        self.running = {}

    def write_error(self, target):
        error = [target.account]
        if target.container:
            error.append(target.container)
        if target.obj:
            error.append(target.obj)
        if target.chunk:
            error.append(target.chunk)
        self.error_writer.writerow(error)

    def write_rebuilder_input(self, target, obj_meta, ct_meta):
        try:
            cid = ct_meta['system']['sys.name'].split('.', 1)[0]
        except KeyError:
            cid = ct_meta['properties']['sys.name'].split('.', 1)[0]
        self.rebuild_writer.writerow((cid, obj_meta['id'], target.chunk))

    def write_chunk_error(self, target, obj_meta, chunk=None):
        if chunk is not None:
            target = target.copy()
            target.chunk = chunk
        if self.error_file:
            self.write_error(target)
        if self.rebuild_file:
            self.write_rebuilder_input(
                target, obj_meta,
                self.list_cache[(target.account, target.container)][1])

    def _check_chunk_xattr(self, target, obj_meta, xattr_meta):
        error = False
        # Composed position -> erasure coding
        attr_prefix = 'meta' if '.' in obj_meta['pos'] else ''

        attr_key = attr_prefix + 'chunk_size'
        if str(obj_meta['size']) != xattr_meta.get(attr_key):
            print("  Chunk %s '%s' xattr (%s) "
                  "differs from size in meta2 (%s)" %
                  (target, attr_key, xattr_meta.get(attr_key),
                   obj_meta['size']))
            error = True

        attr_key = attr_prefix + 'chunk_hash'
        if obj_meta['hash'] != xattr_meta.get(attr_key):
            print("  Chunk %s '%s' xattr (%s) "
                  "differs from hash in meta2 (%s)" %
                  (target, attr_key, xattr_meta.get(attr_key),
                   obj_meta['hash']))
            error = True
        return error

    def check_chunk(self, target):
        chunk = target.chunk

        obj_listing, obj_meta = self.check_obj(target)
        error = False
        if chunk not in obj_listing:
            print('  Chunk %s missing from object listing' % target)
            error = True
            db_meta = dict()
        else:
            db_meta = obj_listing[chunk]

        try:
            xattr_meta = self.blob_client.chunk_head(chunk, xattr=self.full)
        except exc.NotFound as e:
            self.chunk_not_found += 1
            error = True
            print('  Not found chunk "%s": %s' % (target, str(e)))
        except Exception as e:
            self.chunk_exceptions += 1
            error = True
            print('  Exception chunk "%s": %s' % (target, str(e)))
        else:
            if db_meta and self.full:
                error = self._check_chunk_xattr(target, db_meta, xattr_meta)

        if error:
            self.write_chunk_error(target, obj_meta)

        self.chunks_checked += 1

    def check_obj_policy(self, target, obj_meta, chunks):
        """
        Check that the list of chunks of an object matches
        the object's storage policy.
        """
        stg_met = STORAGE_METHODS.load(obj_meta['chunk_method'])
        chunks_by_pos = _sort_chunks(chunks, stg_met.ec)
        if stg_met.ec:
            required = stg_met.ec_nb_data + stg_met.ec_nb_parity
        else:
            required = stg_met.nb_copy
        for pos, clist in chunks_by_pos.iteritems():
            if len(clist) < required:
                print('  Missing %d chunks at position %s of %s' % (
                    required - len(clist), pos, target))
                if stg_met.ec:
                    subs = {x['num'] for x in clist}
                    for sub in range(required):
                        if sub not in subs:
                            self.write_chunk_error(target, obj_meta,
                                                   '%d.%d' % (pos, sub))
                else:
                    self.write_chunk_error(target, obj_meta, str(pos))

    def check_obj(self, target, recurse=False):
        account = target.account
        container = target.container
        obj = target.obj

        if (account, container, obj) in self.running:
            self.running[(account, container, obj)].wait()
        if (account, container, obj) in self.list_cache:
            return self.list_cache[(account, container, obj)]
        self.running[(account, container, obj)] = Event()
        print('Checking object "%s"' % target)
        container_listing, ct_meta = self.check_container(target)
        error = False
        if obj not in container_listing:
            print('  Object %s missing from container listing' % target)
            error = True
            # checksum = None
        else:
            # TODO check checksum match
            # checksum = container_listing[obj]['hash']
            pass

        results = []
        meta = dict()
        try:
            meta, results = self.container_client.content_locate(
                account=account, reference=container, path=obj,
                properties=False)
        except exc.NotFound as e:
            self.object_not_found += 1
            error = True
            print('  Not found object "%s": %s' % (target, str(e)))
        except Exception as e:
            self.object_exceptions += 1
            error = True
            print(' Exception object "%s": %s' % (target, str(e)))

        chunk_listing = dict()
        for chunk in results:
            chunk_listing[chunk['url']] = chunk

        # Skip the check if we could not locate the object
        if meta:
            self.check_obj_policy(target.copy(), meta, results)
            self.list_cache[(account, container, obj)] = (chunk_listing, meta)

        self.objects_checked += 1
        self.running[(account, container, obj)].send(True)
        del self.running[(account, container, obj)]

        if recurse:
            for chunk in chunk_listing:
                t = target.copy()
                t.chunk = chunk
                self.pool.spawn_n(self.check_chunk, t)
        if error and self.error_file:
            self.write_error(target)
        return chunk_listing, meta

    def check_container(self, target, recurse=False):
        account = target.account
        container = target.container

        if (account, container) in self.running:
            self.running[(account, container)].wait()
        if (account, container) in self.list_cache:
            return self.list_cache[(account, container)]
        self.running[(account, container)] = Event()
        print('Checking container "%s"' % target)
        account_listing = self.check_account(target)
        error = False
        if container not in account_listing:
            error = True
            print('  Container %s missing from account listing' % target)

        marker = None
        results = []
        ct_meta = dict()
        extra_args = dict()
        if self.limit_listings > 1 and target.obj:
            # When we are explicitly checking one object, start the listing
            # where this object is supposed to be, and list only one object.
            extra_args['prefix'] = target.obj
            extra_args['limit'] = 1
        while True:
            try:
                _, resp = self.container_client.content_list(
                    account=account, reference=container, marker=marker,
                    **extra_args)
            except exc.NotFound as e:
                self.container_not_found += 1
                error = True
                print('  Not found container "%s": %s' % (target, str(e)))
                break
            except Exception as e:
                self.container_exceptions += 1
                error = True
                print('  Exception container "%s": %s' % (target, str(e)))
                break

            if resp['objects']:
                marker = resp['objects'][-1]['name']
                results.extend(resp['objects'])
                if self.limit_listings > 1:
                    break
            else:
                ct_meta = resp
                ct_meta.pop('objects')
                break

        container_listing = dict()
        for obj in results:
            container_listing[obj['name']] = obj

        if self.limit_listings <= 1:
            # We just listed the whole container, keep the result in a cache
            self.containers_checked += 1
            self.list_cache[(account, container)] = container_listing, ct_meta
        self.running[(account, container)].send(True)
        del self.running[(account, container)]

        if recurse:
            for obj in container_listing:
                t = target.copy()
                t.obj = obj
                self.pool.spawn_n(self.check_obj, t, True)
        if error and self.error_file:
            self.write_error(target)
        return container_listing, ct_meta

    def check_account(self, target, recurse=False):
        account = target.account

        if account in self.running:
            self.running[account].wait()
        if account in self.list_cache:
            return self.list_cache[account]
        self.running[account] = Event()
        print('Checking account "%s"' % target)
        error = False
        marker = None
        results = []
        extra_args = dict()
        if self.limit_listings > 0 and target.container:
            # When we are explicitly checking one container, start the listing
            # where this container is supposed to be, and list only one
            # container.
            extra_args['prefix'] = target.container
            extra_args['limit'] = 1
        while True:
            try:
                resp = self.account_client.container_list(
                    account, marker=marker, **extra_args)
            except Exception as e:
                self.account_exceptions += 1
                error = True
                print('  Exception account "%s": %s' % (target, str(e)))
                break
            if resp['listing']:
                marker = resp['listing'][-1][0]
                results.extend(resp['listing'])
                if self.limit_listings > 0:
                    break
            else:
                break

        containers = dict()
        for e in results:
            containers[e[0]] = (e[1], e[2])

        if self.limit_listings <= 0:
            # We just listed the whole account, keep the result in a cache
            self.accounts_checked += 1
            self.list_cache[account] = containers
        self.running[account].send(True)
        del self.running[account]

        if recurse:
            for container in containers:
                t = target.copy()
                t.container = container
                self.pool.spawn_n(self.check_container, t, True)

        if error and self.error_file:
            self.write_error(target)
        return containers

    def check(self, target):
        if target.chunk and target.obj and target.container:
            self.pool.spawn_n(self.check_chunk, target)
        elif target.obj and target.container:
            self.pool.spawn_n(self.check_obj, target, True)
        elif target.container:
            self.pool.spawn_n(self.check_container, target, True)
        else:
            self.pool.spawn_n(self.check_account, target, True)

    def wait(self):
        self.pool.waitall()

    def report(self):
        success = True

        def _report_stat(name, stat):
            print("{0:18}: {1}".format(name, stat))

        print()
        print('Report')
        _report_stat("Accounts checked", self.accounts_checked)
        if self.account_not_found:
            success = False
            _report_stat("Missing accounts", self.account_not_found)
        if self.account_exceptions:
            success = False
            _report_stat("Exceptions", self.account_exceptions)
        print()
        _report_stat("Containers checked", self.containers_checked)
        if self.container_not_found:
            success = False
            _report_stat("Missing containers", self.container_not_found)
        if self.container_exceptions:
            success = False
            _report_stat("Exceptions", self.container_exceptions)
        print()
        _report_stat("Objects checked", self.objects_checked)
        if self.object_not_found:
            success = False
            _report_stat("Missing objects", self.object_not_found)
        if self.object_exceptions:
            success = False
            _report_stat("Exceptions", self.object_exceptions)
        print()
        _report_stat("Chunks checked", self.chunks_checked)
        if self.chunk_not_found:
            success = False
            _report_stat("Missing chunks", self.chunk_not_found)
        if self.chunk_exceptions:
            success = False
            _report_stat("Exceptions", self.chunk_exceptions)
        return success