Synnefo

# Copyright 2011 GRNET S.A. All rights reserved.

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"""

The Plankton attributes are the following:

  - checksum: the 'hash' meta

  - container_format: stored as a user meta

  - created_at: the 'modified' meta of the first version

  - deleted_at: the timestamp of the last version

  - disk_format: stored as a user meta

  - id: the 'uuid' meta

  - is_public: True if there is a * entry for the read permission

  - location: generated based on the file's path

  - name: stored as a user meta

  - owner: the file's account

  - properties: stored as user meta prefixed with PROPERTY_PREFIX

  - size: the 'bytes' meta

  - status: stored as a system meta

  - store: is always 'pithos'

  - updated_at: the 'modified' meta

"""

import json

import warnings

from operator import itemgetter

from time import gmtime, strftime

from functools import wraps, partial

from snf_django.lib.api import faults

from django.conf import settings

from pithos.backends.base import NotAllowedError as PithosNotAllowedError

import synnefo.lib.astakos as lib_astakos

import logging

from synnefo.settings import (CYCLADES_USE_QUOTAHOLDER,

                              CYCLADES_QUOTAHOLDER_URL,

                              CYCLADES_QUOTAHOLDER_TOKEN,

                              CYCLADES_QUOTAHOLDER_POOLSIZE)

logger = logging.getLogger(__name__)

PLANKTON_DOMAIN = 'plankton'

PLANKTON_PREFIX = 'plankton:'

PROPERTY_PREFIX = 'property:'

PLANKTON_META = ('container_format', 'disk_format', 'name', 'properties',

                 'status')

TRANSLATE_UUIDS = getattr(settings, 'TRANSLATE_UUIDS', False)

def get_displaynames(names):

    try:

        auth_url = settings.ASTAKOS_URL

        url = auth_url.replace('im/authenticate', 'service/api/user_catalogs')

        token = settings.CYCLADES_ASTAKOS_SERVICE_TOKEN

        uuids = lib_astakos.get_displaynames(token, names, url=url)

    except Exception, e:

        logger.exception(e)

        return {}

    return uuids

def get_location(account, container, object):

    assert '/' not in account, "Invalid account"

    assert '/' not in container, "Invalid container"

    return 'pithos://%s/%s/%s' % (account, container, object)

def split_location(location):

    """Returns (accout, container, object) from a location string"""

    t = location.split('/', 4)

    assert len(t) == 5, "Invalid location"

    return t[2:5]

class BackendException(Exception):

    pass

class NotAllowedError(BackendException):

    pass

from pithos.backends.util import PithosBackendPool

POOL_SIZE = 8

_pithos_backend_pool = \

    PithosBackendPool(

        POOL_SIZE,

        quotaholder_enabled=CYCLADES_USE_QUOTAHOLDER,

        quotaholder_url=CYCLADES_QUOTAHOLDER_URL,

        quotaholder_token=CYCLADES_QUOTAHOLDER_TOKEN,

        quotaholder_client_poolsize=CYCLADES_QUOTAHOLDER_POOLSIZE,

        db_connection=settings.BACKEND_DB_CONNECTION,

        block_path=settings.BACKEND_BLOCK_PATH)

def get_pithos_backend():

    return _pithos_backend_pool.pool_get()

def handle_backend_exceptions(func):

    @wraps(func)

    def wrapper(*args, **kwargs):

        try:

            return func(*args, **kwargs)

        except PithosNotAllowedError:

            raise NotAllowedError()

    return wrapper

class ImageBackend(object):

    """A wrapper arround the pithos backend to simplify image handling."""

    def __init__(self, user):

        self.user = user

        original_filters = warnings.filters

        warnings.simplefilter('ignore')         # Suppress SQLAlchemy warnings

        self.backend = get_pithos_backend()

        warnings.filters = original_filters     # Restore warnings

    @handle_backend_exceptions

    def _get_image(self, location):

        def format_timestamp(t):

            return strftime('%Y-%m-%d %H:%M:%S', gmtime(t))

        account, container, object = split_location(location)

        try:

            versions = self.backend.list_versions(self.user, account,

                                                  container, object)

        except NameError:

            return None

        image = {}

        meta = self._get_meta(location)

        if meta:

            image['deleted_at'] = ''

        else:

            # Object was deleted, use the latest version

            version, timestamp = versions[-1]

            meta = self._get_meta(location, version)

            image['deleted_at'] = format_timestamp(timestamp)

        if PLANKTON_PREFIX + 'name' not in meta:

            return None     # Not a Plankton image

        permissions = self._get_permissions(location)

        image['checksum'] = meta['hash']

        image['created_at'] = format_timestamp(versions[0][1])

        image['id'] = meta['uuid']

        image['is_public'] = '*' in permissions.get('read', [])

        image['location'] = location

        if TRANSLATE_UUIDS:

            displaynames = get_displaynames([account])

            if account in displaynames:

                display_account = displaynames[account]

            else:

                display_account = 'unknown'

            image['owner'] = display_account

        else:

            image['owner'] = account

        image['size'] = meta['bytes']

        image['store'] = 'pithos'

        image['updated_at'] = format_timestamp(meta['modified'])

        image['properties'] = {}

        for key, val in meta.items():

            if not key.startswith(PLANKTON_PREFIX):

                continue

            key = key[len(PLANKTON_PREFIX):]

            if key == 'properties':

                val = json.loads(val)

            if key in PLANKTON_META:

                image[key] = val

        return image

    @handle_backend_exceptions

    def _get_meta(self, location, version=None):

        account, container, object = split_location(location)

        try:

            return self.backend.get_object_meta(self.user, account, container,

                                                object, PLANKTON_DOMAIN,

                                                version)

        except NameError:

            return None

    @handle_backend_exceptions

    def _get_permissions(self, location):

        account, container, object = split_location(location)

        _a, _p, permissions = self.backend.get_object_permissions(self.user,

                                                                  account,

                                                                  container,

                                                                  object)

        return permissions

    @handle_backend_exceptions

    def _store(self, f, size=None):

        """Breaks data into blocks and stores them in the backend"""

        bytes = 0

        hashmap = []

        backend = self.backend

        blocksize = backend.block_size

        data = f.read(blocksize)

        while data:

            hash = backend.put_block(data)

            hashmap.append(hash)

            bytes += len(data)

            data = f.read(blocksize)

        if size and size != bytes:

            raise BackendException("Invalid size")

        return hashmap, bytes

    @handle_backend_exceptions

    def _update(self, location, size, hashmap, meta, permissions):

        account, container, object = split_location(location)

        self.backend.update_object_hashmap(self.user, account, container,

                                           object, size, hashmap, '',

                                           PLANKTON_DOMAIN,

                                           permissions=permissions)

        self._update_meta(location, meta, replace=True)

    @handle_backend_exceptions

    def _update_meta(self, location, meta, replace=False):

        account, container, object = split_location(location)

        prefixed = {}

        for key, val in meta.items():

            if key == 'properties':

                val = json.dumps(val)

            if key in PLANKTON_META:

                prefixed[PLANKTON_PREFIX + key] = val

        self.backend.update_object_meta(self.user, account, container, object,

                                        PLANKTON_DOMAIN, prefixed, replace)

    @handle_backend_exceptions

    def _update_permissions(self, location, permissions):

        account, container, object = split_location(location)

        self.backend.update_object_permissions(self.user, account, container,

                                               object, permissions)

    @handle_backend_exceptions

    def add_user(self, image_id, user):

        image = self.get_image(image_id)

        if not image:

            raise faults.ItemNotFound

        location = image['location']

        permissions = self._get_permissions(location)

        read = set(permissions.get('read', []))

        read.add(user)

        permissions['read'] = list(read)

        self._update_permissions(location, permissions)

    def close(self):

        self.backend.close()

    @handle_backend_exceptions

    def _delete(self, image_id):

        """Delete an Image.

        This method will delete the Image from the Storage backend.

        """

        image = self.get_image(image_id)

        account, container, object = split_location(image['location'])

        self.backend.delete_object(self.user, account, container, object)

    @handle_backend_exceptions

    def get_data(self, location):

        account, container, object = split_location(location)

        size, hashmap = self.backend.get_object_hashmap(self.user, account,

                                                        container, object)

        data = ''.join(self.backend.get_block(hash) for hash in hashmap)

        assert len(data) == size

        return data

    @handle_backend_exceptions

    def get_image(self, image_id):

        try:

            account, container, object = self.backend.get_uuid(self.user,

                                                               image_id)

        except NameError:

            return None

        location = get_location(account, container, object)

        return self._get_image(location)

    @handle_backend_exceptions

    def _iter(self, public=False, filters=None, shared_from=None):

        filters = filters or {}

        # Fix keys

        keys = [PLANKTON_PREFIX + 'name']

        size_range = (None, None)

        for key, val in filters.items():

            if key == 'size_min':

                size_range = (val, size_range[1])

            elif key == 'size_max':

                size_range = (size_range[0], val)

            else:

                keys.append('%s = %s' % (PLANKTON_PREFIX + key, val))

        backend = self.backend

        if shared_from:

            # To get shared images, we connect as shared_from member and

            # get the list shared by us

            user = shared_from

            accounts = [self.user]

        else:

            user = None if public else self.user

            accounts = backend.list_accounts(user)

        for account in accounts:

            for container in backend.list_containers(user, account,

                                                     shared=True):

                for path, _ in backend.list_objects(user, account, container,

                                                    domain=PLANKTON_DOMAIN,

                                                    keys=keys, shared=True,

                                                    size_range=size_range):

                    location = get_location(account, container, path)

                    image = self._get_image(location)

                    if image:

                        yield image

    def iter(self, filters=None):

        """Iter over all images available to the user"""

        return self._iter(filters=filters)

    def iter_public(self, filters=None):

        """Iter over public images"""

        return self._iter(public=True, filters=filters)

    def iter_shared(self, filters=None, member=None):

        """Iter over images shared to member"""

        return self._iter(filters=filters, shared_from=member)

    def list(self, filters=None, params={}):

        """Return all images available to the user"""

        images = list(self.iter(filters))

        key = itemgetter(params.get('sort_key', 'created_at'))

        reverse = params.get('sort_dir', 'desc') == 'desc'

        images.sort(key=key, reverse=reverse)

        return images

    def list_public(self, filters, params={}):

        """Return public images"""

        images = list(self.iter_public(filters))

        key = itemgetter(params.get('sort_key', 'created_at'))

        reverse = params.get('sort_dir', 'desc') == 'desc'

        images.sort(key=key, reverse=reverse)

        return images

    def list_users(self, image_id):

        image = self.get_image(image_id)

        if not image:

            raise faults.ItemNotFound

        permissions = self._get_permissions(image['location'])

        return [user for user in permissions.get('read', []) if user != '*']

    @handle_backend_exceptions

    def put(self, name, f, params):

        assert 'checksum' not in params, "Passing a checksum is not supported"

        assert 'id' not in params, "Passing an ID is not supported"

        assert params.pop('store', 'pithos') == 'pithos', "Invalid store"

        disk_format = params.setdefault('disk_format',

                                        settings.DEFAULT_DISK_FORMAT)

        assert disk_format in settings.ALLOWED_DISK_FORMATS,\

            "Invalid disk_format"

        assert params.setdefault('container_format',

                settings.DEFAULT_CONTAINER_FORMAT) in \

                settings.ALLOWED_CONTAINER_FORMATS, "Invalid container_format"

        container = settings.DEFAULT_PLANKTON_CONTAINER

        filename = params.pop('filename', name)

        location = 'pithos://%s/%s/%s' % (self.user, container, filename)

        is_public = params.pop('is_public', False)

        permissions = {'read': ['*']} if is_public else {}

        size = params.pop('size', None)

        hashmap, size = self._store(f, size)

        meta = {}

        meta['properties'] = params.pop('properties', {})

        meta.update(name=name, status='available', **params)

        self._update(location, size, hashmap, meta, permissions)

        return self._get_image(location)

    @handle_backend_exceptions

    def register(self, name, location, params):

        assert 'id' not in params, "Passing an ID is not supported"

        assert location.startswith('pithos://'), "Invalid location"

        assert params.pop('store', 'pithos') == 'pithos', "Invalid store"

        assert params.setdefault('disk_format',

                settings.DEFAULT_DISK_FORMAT) in \

                settings.ALLOWED_DISK_FORMATS, "Invalid disk_format"

        assert params.setdefault('container_format',

                settings.DEFAULT_CONTAINER_FORMAT) in \

                settings.ALLOWED_CONTAINER_FORMATS, "Invalid container_format"

        # user = self.user

        account, container, object = split_location(location)

        meta = self._get_meta(location)

        assert meta, "File not found"

        size = int(params.pop('size', meta['bytes']))

        if size != meta['bytes']:

            raise BackendException("Invalid size")

        checksum = params.pop('checksum', meta['hash'])

        if checksum != meta['hash']:

            raise BackendException("Invalid checksum")

        is_public = params.pop('is_public', False)

        if is_public:

            permissions = {'read': ['*']}

        else:

            permissions = {'read': [self.user]}

        meta = {}

        meta['properties'] = params.pop('properties', {})

        meta.update(name=name, status='available', **params)

        self._update_meta(location, meta)

        self._update_permissions(location, permissions)

        return self._get_image(location)

    @handle_backend_exceptions

    def remove_user(self, image_id, user):

        image = self.get_image(image_id)

        if not image:

            raise faults.ItemNotFound

        location = image['location']

        permissions = self._get_permissions(location)

        try:

            permissions.get('read', []).remove(user)

        except ValueError:

            return      # User did not have access anyway

        self._update_permissions(location, permissions)

    @handle_backend_exceptions

    def replace_users(self, image_id, users):

        image = self.get_image(image_id)

        if not image:

            raise faults.ItemNotFound

        location = image['location']

        permissions = self._get_permissions(location)

        permissions['read'] = users

        if image.get('is_public', False):

            permissions['read'].append('*')

        self._update_permissions(location, permissions)

    @handle_backend_exceptions

    def update(self, image_id, params):

        image = self.get_image(image_id)

        assert image, "Image not found"

        if not image:

            raise faults.ItemNotFound

        location = image['location']

        is_public = params.pop('is_public', None)

        if is_public is not None:

            permissions = self._get_permissions(location)

            read = set(permissions.get('read', []))

            if is_public:

                read.add('*')

            else:

                read.discard('*')

            permissions['read'] = list(read)

            self.backend._update_permissions(location, permissions)

        meta = {}

        meta['properties'] = params.pop('properties', {})

        meta.update(**params)

        self._update_meta(location, meta)

        return self.get_image(image_id)

    @handle_backend_exceptions

    def unregister(self, image_id):

        """Unregister an image."""

        image = self.get_image(image_id)

        if not image:

            raise faults.ItemNotFound

        location = image["location"]

        # Unregister the image by removing all metadata from domain

        # 'PLANKTON_DOMAIN'

        meta = self._get_meta(location)

        for k in meta.keys():

            meta[k] = ""

        self._update_meta(location, meta, False)