swiftonfile/ufo/gluster/swift/common/utils.py

# Copyright (c) 2012 Red Hat, Inc.
#
# 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.

import logging
import os
import errno
import xattr
from hashlib import md5
import cPickle as pickle
from ConfigParser import ConfigParser, NoSectionError, NoOptionError
from swift.common.utils import normalize_timestamp, TRUE_VALUES
from gluster.swift.common.fs_utils import *
from gluster.swift.common import Glusterfs

X_CONTENT_TYPE = 'Content-Type'
X_CONTENT_LENGTH = 'Content-Length'
X_TIMESTAMP = 'X-Timestamp'
X_PUT_TIMESTAMP = 'X-PUT-Timestamp'
X_TYPE = 'X-Type'
X_ETAG = 'ETag'
X_OBJECTS_COUNT = 'X-Object-Count'
X_BYTES_USED = 'X-Bytes-Used'
X_CONTAINER_COUNT = 'X-Container-Count'
X_OBJECT_TYPE = 'X-Object-Type'
DIR_TYPE = 'application/directory'
ACCOUNT = 'Account'
METADATA_KEY = 'user.swift.metadata'
MAX_XATTR_SIZE = 65536
CONTAINER = 'container'
DIR = 'dir'
MARKER_DIR = 'marker_dir'
TEMP_DIR = 'tmp'
ASYNCDIR = 'async_pending'  # Keep in sync with swift.obj.server.ASYNCDIR
FILE = 'file'
FILE_TYPE = 'application/octet-stream'
OBJECT = 'Object'
OBJECT_TYPE = 'application/octet-stream'
DEFAULT_UID = -1
DEFAULT_GID = -1
PICKLE_PROTOCOL = 2
CHUNK_SIZE = 65536
MEMCACHE_KEY_PREFIX = 'gluster.swift.'
MEMCACHE_ACCOUNT_DETAILS_KEY_PREFIX = MEMCACHE_KEY_PREFIX + 'account.details.'
MEMCACHE_CONTAINER_DETAILS_KEY_PREFIX = MEMCACHE_KEY_PREFIX + 'container.details.'


def read_metadata(path):
    """
    Helper function to read the pickled metadata from a File/Directory.

    :param path: File/Directory to read metadata from.

    :returns: dictionary of metadata
    """
    metadata = None
    metadata_s = ''
    key = 0
    while metadata is None:
        try:
            metadata_s += xattr.get(path, '%s%s' % (METADATA_KEY, (key or '')))
        except IOError as err:
            if err.errno == errno.ENODATA:
                if key > 0:
                    # No errors reading the xattr keys, but since we have not
                    # been able to find enough chunks to get a successful
                    # unpickle operation, we consider the metadata lost, and
                    # drop the existing data so that the internal state can be
                    # recreated.
                    clean_metadata(path)
                # We either could not find any metadata key, or we could find
                # some keys, but were not successful in performing the
                # unpickling (missing keys perhaps)? Either way, just report
                # to the caller we have no metadata.
                metadata = {}
            else:
                logging.exception("xattr.get failed on %s key %s err: %s",
                                  path, key, str(err))
                # Note that we don't touch the keys on errors fetching the
                # data since it could be a transient state.
                raise
        else:
            try:
                # If this key provides all or the remaining part of the pickle
                # data, we don't need to keep searching for more keys. This
                # means if we only need to store data in N xattr key/value
                # pair, we only need to invoke xattr get N times. With large
                # keys sizes we are shooting for N = 1.
                metadata = pickle.loads(metadata_s)
                assert isinstance(metadata, dict)
            except EOFError, pickle.UnpicklingError:
                # We still are not able recognize this existing data collected
                # as a pickled object. Make sure we loop around to try to get
                # more from another xattr key.
                metadata = None
                key += 1
    return metadata

def write_metadata(path, metadata):
    """
    Helper function to write pickled metadata for a File/Directory.

    :param path: File/Directory path to write the metadata
    :param metadata: dictionary to metadata write
    """
    assert isinstance(metadata, dict)
    metastr = pickle.dumps(metadata, PICKLE_PROTOCOL)
    key = 0
    while metastr:
        try:
            xattr.set(path, '%s%s' % (METADATA_KEY, key or ''), metastr[:MAX_XATTR_SIZE])
        except IOError as err:
            logging.exception("xattr.set failed on %s key %s err: %s", path, key, str(err))
            raise
        metastr = metastr[MAX_XATTR_SIZE:]
        key += 1

def clean_metadata(path):
    key = 0
    while True:
        try:
            xattr.remove(path, '%s%s' % (METADATA_KEY, (key or '')))
        except IOError as err:
            if err.errno == errno.ENODATA:
                break
            raise
        key += 1

def check_user_xattr(path):
    if not os.path.exists(path):
        return False
    try:
        xattr.set(path, 'user.test.key1', 'value1')
    except IOError as err:
        logging.exception("check_user_xattr: set failed on %s err: %s", path, str(err))
        raise
    try:
        xattr.remove(path, 'user.test.key1')
    except IOError as err:
        logging.exception("check_user_xattr: remove failed on %s err: %s", path, str(err))
        #Remove xattr may fail in case of concurrent remove.
    return True

def validate_container(metadata):
    if not metadata:
        logging.warn('validate_container: No metadata')
        return False

    if X_TYPE not in metadata.keys() or \
       X_TIMESTAMP not in metadata.keys() or \
       X_PUT_TIMESTAMP not in metadata.keys() or \
       X_OBJECTS_COUNT not in metadata.keys() or \
       X_BYTES_USED not in metadata.keys():
        #logging.warn('validate_container: Metadata missing entries: %s' % metadata)
        return False

    (value, timestamp) = metadata[X_TYPE]
    if value == CONTAINER:
        return True

    logging.warn('validate_container: metadata type is not CONTAINER (%r)' % (value,))
    return False

def validate_account(metadata):
    if not metadata:
        logging.warn('validate_account: No metadata')
        return False

    if X_TYPE not in metadata.keys() or \
       X_TIMESTAMP not in metadata.keys() or \
       X_PUT_TIMESTAMP not in metadata.keys() or \
       X_OBJECTS_COUNT not in metadata.keys() or \
       X_BYTES_USED not in metadata.keys() or \
       X_CONTAINER_COUNT not in metadata.keys():
        #logging.warn('validate_account: Metadata missing entries: %s' % metadata)
        return False

    (value, timestamp) = metadata[X_TYPE]
    if value == ACCOUNT:
        return True

    logging.warn('validate_account: metadata type is not ACCOUNT (%r)' % (value,))
    return False

def validate_object(metadata):
    if not metadata:
        logging.warn('validate_object: No metadata')
        return False

    if X_TIMESTAMP not in metadata.keys() or \
       X_CONTENT_TYPE not in metadata.keys() or \
       X_ETAG not in metadata.keys() or \
       X_CONTENT_LENGTH not in metadata.keys() or \
       X_TYPE not in metadata.keys() or \
       X_OBJECT_TYPE not in metadata.keys():
        #logging.warn('validate_object: Metadata missing entries: %s' % metadata)
        return False

    if metadata[X_TYPE] == OBJECT:
        return True

    logging.warn('validate_object: metadata type is not OBJECT (%r)' % (metadata[X_TYPE],))
    return False

def is_marker(metadata):
    if not metadata:
        logging.warn('is_marker: No metadata')
        return False

    if X_OBJECT_TYPE not in metadata.keys():
        logging.warn('is_marker: X_OBJECT_TYPE missing from metadata: %s' % metadata)
        return False

    if metadata[X_OBJECT_TYPE] == MARKER_DIR:
        return True
    else:
        return False

def _update_list(path, cont_path, src_list, reg_file=True, object_count=0,
                 bytes_used=0, obj_list=[]):
    # strip the prefix off, also stripping the leading and trailing slashes
    obj_path = path.replace(cont_path, '').strip(os.path.sep)

    for i in src_list:
        if obj_path:
            obj_list.append(os.path.join(obj_path, i))
        else:
            obj_list.append(i)

        object_count += 1

        if reg_file:
            bytes_used += os.path.getsize(path + '/' + i)

    return object_count, bytes_used

def update_list(path, cont_path, dirs=[], files=[], object_count=0,
                bytes_used=0, obj_list=[]):
    object_count, bytes_used = _update_list(path, cont_path, files, True,
                                            object_count, bytes_used,
                                            obj_list)
    object_count, bytes_used = _update_list(path, cont_path, dirs, False,
                                            object_count, bytes_used,
                                            obj_list)
    return object_count, bytes_used


class ContainerDetails(object):
    def __init__(self, bytes_used, object_count, obj_list, dir_list):
        self.bytes_used = bytes_used
        self.object_count = object_count
        self.obj_list = obj_list
        self.dir_list = dir_list


def _get_container_details_from_fs(cont_path):
    """
    get container details by traversing the filesystem
    """
    bytes_used = 0
    object_count = 0
    obj_list = []
    dir_list = []

    if os.path.isdir(cont_path):
        for (path, dirs, files) in os.walk(cont_path):
            object_count, bytes_used = update_list(path, cont_path, dirs, files,
                                                   object_count, bytes_used,
                                                   obj_list)

            dir_list.append((path, do_stat(path).st_mtime))

    return ContainerDetails(bytes_used, object_count, obj_list, dir_list)

def get_container_details(cont_path, memcache=None):
    """
    Return object_list, object_count and bytes_used.
    """
    mkey = ''
    if memcache:
        mkey = MEMCACHE_CONTAINER_DETAILS_KEY_PREFIX + cont_path
        cd = memcache.get(mkey)
        if cd:
            if not cd.dir_list:
                cd = None
            else:
                for (path, mtime) in cd.dir_list:
                    if mtime != do_stat(path).st_mtime:
                        cd = None
    else:
        cd = None
    if not cd:
        cd = _get_container_details_from_fs(cont_path)
        if memcache:
            memcache.set(mkey, cd)
    return cd.obj_list, cd.object_count, cd.bytes_used


class AccountDetails(object):
    """ A simple class to store the three pieces of information associated
        with an account:

        1. The last known modification time
        2. The count of containers in the following list
        3. The list of containers
    """
    def __init__(self, mtime, container_count, container_list):
        self.mtime = mtime
        self.container_count = container_count
        self.container_list = container_list


def _get_account_details_from_fs(acc_path, acc_stats):
    container_list = []
    container_count = 0

    if not acc_stats:
        acc_stats = do_stat(acc_path)
    is_dir = (acc_stats.st_mode & 0040000) != 0
    if is_dir:
        for name in do_listdir(acc_path):
            if name.lower() == TEMP_DIR \
                    or name.lower() == ASYNCDIR \
                    or not os.path.isdir(os.path.join(acc_path, name)):
                continue
            container_count += 1
            container_list.append(name)

    return AccountDetails(acc_stats.st_mtime, container_count, container_list)

def get_account_details(acc_path, memcache=None):
    """
    Return container_list and container_count.
    """
    acc_stats = None
    mkey = ''
    if memcache:
        mkey = MEMCACHE_ACCOUNT_DETAILS_KEY_PREFIX + acc_path
        ad = memcache.get(mkey)
        if ad:
            # FIXME: Do we really need to stat the file? If we are object
            # only, then we can track the other Swift HTTP APIs that would
            # modify the account and invalidate the cached entry there. If we
            # are not object only, are we even called on this path?
            acc_stats = do_stat(acc_path)
            if ad.mtime != acc_stats.st_mtime:
                ad = None
    else:
        ad = None
    if not ad:
        ad = _get_account_details_from_fs(acc_path, acc_stats)
        if memcache:
            memcache.set(mkey, ad)
    return ad.container_list, ad.container_count

def _get_etag(path):
    etag = md5()
    with open(path, 'rb') as fp:
        while True:
            chunk = fp.read(CHUNK_SIZE)
            if chunk:
                etag.update(chunk)
            else:
                break
    return etag.hexdigest()

def get_object_metadata(obj_path):
    """
    Return metadata of object.
    """
    try:
        stats = os.stat(obj_path)
    except OSError as e:
        if e.errno != errno.ENOENT:
            raise
        metadata = {}
    else:
        is_dir = (stats.st_mode & 0040000) != 0
        metadata = {
            X_TYPE: OBJECT,
            X_TIMESTAMP: normalize_timestamp(stats.st_ctime),
            X_CONTENT_TYPE: DIR_TYPE if is_dir else FILE_TYPE,
            X_OBJECT_TYPE: DIR if is_dir else FILE,
            X_CONTENT_LENGTH: 0 if is_dir else stats.st_size,
            X_ETAG: md5().hexdigest() if is_dir else _get_etag(obj_path),
            }
    return metadata

def _add_timestamp(metadata_i):
    # At this point we have a simple key/value dictionary, turn it into
    # key/(value,timestamp) pairs.
    timestamp = 0
    metadata = {}
    for key, value_i in metadata_i.iteritems():
        if not isinstance(value_i, tuple):
            metadata[key] = (value_i, timestamp)
        else:
            metadata[key] = value_i
    return metadata

def get_container_metadata(cont_path, memcache=None):
    objects = []
    object_count = 0
    bytes_used = 0
    objects, object_count, bytes_used = get_container_details(cont_path, memcache)
    metadata = {X_TYPE: CONTAINER,
                X_TIMESTAMP: normalize_timestamp(os.path.getctime(cont_path)),
                X_PUT_TIMESTAMP: normalize_timestamp(os.path.getmtime(cont_path)),
                X_OBJECTS_COUNT: object_count,
                X_BYTES_USED: bytes_used}
    return _add_timestamp(metadata)

def get_account_metadata(acc_path, memcache=None):
    containers = []
    container_count = 0
    containers, container_count = get_account_details(acc_path, memcache)
    metadata = {X_TYPE: ACCOUNT,
                X_TIMESTAMP: normalize_timestamp(os.path.getctime(acc_path)),
                X_PUT_TIMESTAMP: normalize_timestamp(os.path.getmtime(acc_path)),
                X_OBJECTS_COUNT: 0,
                X_BYTES_USED: 0,
                X_CONTAINER_COUNT: container_count}
    return _add_timestamp(metadata)

def restore_metadata(path, metadata):
    meta_orig = read_metadata(path)
    if meta_orig:
        meta_new = meta_orig.copy()
        meta_new.update(metadata)
    else:
        meta_new = metadata
    if meta_orig != meta_new:
        write_metadata(path, meta_new)
    return meta_new

def create_object_metadata(obj_path):
    metadata = get_object_metadata(obj_path)
    return restore_metadata(obj_path, metadata)

def create_container_metadata(cont_path, memcache=None):
    metadata = get_container_metadata(cont_path, memcache)
    return restore_metadata(cont_path, metadata)

def create_account_metadata(acc_path, memcache=None):
    metadata = get_account_metadata(acc_path, memcache)
    return restore_metadata(acc_path, metadata)