diff --git a/swh/objstorage/backends/libcloud.py b/swh/objstorage/backends/libcloud.py index 1a487d9..3630ec0 100644 --- a/swh/objstorage/backends/libcloud.py +++ b/swh/objstorage/backends/libcloud.py @@ -1,219 +1,227 @@ # Copyright (C) 2016-2017 The Software Heritage developers # See the AUTHORS file at the top-level directory of this distribution # License: GNU General Public License version 3, or any later version # See top-level LICENSE file for more information import abc import collections +from typing import Optional from urllib.parse import urlencode from swh.model import hashutil from swh.objstorage.objstorage import ObjStorage, compute_hash from swh.objstorage.objstorage import compressors, decompressors from swh.objstorage.exc import ObjNotFoundError, Error from libcloud.storage import providers import libcloud.storage.drivers.s3 from libcloud.storage.types import Provider, ObjectDoesNotExistError def patch_libcloud_s3_urlencode(): """Patches libcloud's S3 backend to properly sign queries. Recent versions of libcloud are not affected (they use signature V4), but 1.5.0 (the one in Debian 9) is.""" def s3_urlencode(params): """Like urllib.parse.urlencode, but sorts the parameters first. This is required to properly compute the request signature, see https://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement """ # noqa return urlencode(collections.OrderedDict(sorted(params.items()))) libcloud.storage.drivers.s3.urlencode = s3_urlencode patch_libcloud_s3_urlencode() class CloudObjStorage(ObjStorage, metaclass=abc.ABCMeta): """Abstract ObjStorage that connect to a cloud using Libcloud Implementations of this class must redefine the _get_provider method to make it return a driver provider (i.e. object that supports `get_driver` method) which return a LibCloud driver (see https://libcloud.readthedocs.io/en/latest/storage/api.html). + Args: + container_name: Name of the base container + compression: compression algorithm to use for objects + kwargs: extra arguments are passed through to the LibCloud driver """ - def __init__(self, container_name, compression=None, **kwargs): + def __init__(self, + container_name: str, + compression: Optional[str] = None, + **kwargs): super().__init__(**kwargs) self.driver = self._get_driver(**kwargs) self.container_name = container_name self.container = self.driver.get_container( container_name=container_name) self.compression = compression def _get_driver(self, **kwargs): """Initialize a driver to communicate with the cloud Kwargs: arguments passed to the StorageDriver class, typically key: key to connect to the API. secret: secret key for authentication. secure: (bool) support HTTPS host: (str) port: (int) api_version: (str) region: (str) Returns: a Libcloud driver to a cloud storage. """ # Get the driver class from its description. cls = providers.get_driver(self._get_provider()) # Initialize the driver. return cls(**kwargs) @abc.abstractmethod def _get_provider(self): """Get a libcloud driver provider This method must be overridden by subclasses to specify which of the native libcloud driver the current storage should connect to. Alternatively, provider for a custom driver may be returned, in which case the provider will have to support `get_driver` method. """ raise NotImplementedError('%s must implement `get_provider` method' % type(self)) def check_config(self, *, check_write): """Check the configuration for this object storage""" # FIXME: hopefully this blew up during instantiation return True def __contains__(self, obj_id): try: self._get_object(obj_id) except ObjNotFoundError: return False else: return True def __iter__(self): """ Iterate over the objects present in the storage Warning: Iteration over the contents of a cloud-based object storage may have bad efficiency: due to the very high amount of objects in it and the fact that it is remote, get all the contents of the current object storage may result in a lot of network requests. You almost certainly don't want to use this method in production. """ yield from (hashutil.bytehex_to_hash(obj.name.encode()) for obj in self.driver.iterate_container_objects(self.container)) def __len__(self): """Compute the number of objects in the current object storage. Warning: this currently uses `__iter__`, its warning about bad performance applies. Returns: number of objects contained in the storage. """ return sum(1 for i in self) def add(self, content, obj_id=None, check_presence=True): if obj_id is None: # Checksum is missing, compute it on the fly. obj_id = compute_hash(content) if check_presence and obj_id in self: return obj_id self._put_object(content, obj_id) return obj_id def restore(self, content, obj_id=None): return self.add(content, obj_id, check_presence=False) def get(self, obj_id): obj = b''.join(self._get_object(obj_id).as_stream()) d = decompressors[self.compression]() ret = d.decompress(obj) if d.unused_data: hex_obj_id = hashutil.hash_to_hex(obj_id) raise Error('Corrupt object %s: trailing data found' % hex_obj_id) return ret def check(self, obj_id): # Check that the file exists, as _get_object raises ObjNotFoundError self._get_object(obj_id) # Check the content integrity obj_content = self.get(obj_id) content_obj_id = compute_hash(obj_content) if content_obj_id != obj_id: raise Error(obj_id) def delete(self, obj_id): super().delete(obj_id) # Check delete permission obj = self._get_object(obj_id) return self.driver.delete_object(obj) def _get_object(self, obj_id): """Get a Libcloud wrapper for an object pointer. This wrapper does not retrieve the content of the object directly. """ hex_obj_id = hashutil.hash_to_hex(obj_id) try: return self.driver.get_object(self.container_name, hex_obj_id) except ObjectDoesNotExistError: raise ObjNotFoundError(obj_id) def _compressor(self, data): comp = compressors[self.compression]() for chunk in data: cchunk = comp.compress(chunk) if cchunk: yield cchunk trail = comp.flush() if trail: yield trail def _put_object(self, content, obj_id): """Create an object in the cloud storage. Created object will contain the content and be referenced by the given id. """ hex_obj_id = hashutil.hash_to_hex(obj_id) if not isinstance(content, collections.Iterator): content = (content,) self.driver.upload_object_via_stream( self._compressor(content), self.container, hex_obj_id) class AwsCloudObjStorage(CloudObjStorage): """ Amazon's S3 Cloud-based object storage """ def _get_provider(self): return Provider.S3 class OpenStackCloudObjStorage(CloudObjStorage): """ OpenStack Swift Cloud based object storage """ def _get_provider(self): return Provider.OPENSTACK_SWIFT