diff --git a/swh/objstorage/cloud/__init__.py b/swh/objstorage/cloud/__init__.py new file mode 100644 index 0000000..bee9658 --- /dev/null +++ b/swh/objstorage/cloud/__init__.py @@ -0,0 +1,3 @@ +from objstorage_cloud import AwsCloudObjStorage, OpenStackCloudObjStorage + +__all__ = ['AwsCloudObjStorage', 'OpenStackCloudObjStorage'] diff --git a/swh/objstorage/cloud/objstorage_cloud.py b/swh/objstorage/cloud/objstorage_cloud.py index 2e76ce2..e0eddeb 100644 --- a/swh/objstorage/cloud/objstorage_cloud.py +++ b/swh/objstorage/cloud/objstorage_cloud.py @@ -1,141 +1,155 @@ # Copyright (C) 2016 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 from ..objstorage import ObjStorage, ID_HASH_ALGO from ..exc import ObjNotFoundError, Error from swh.core import hashutil from libcloud.storage import providers -from libcloud.storage.types import ObjectDoesNotExistError +from libcloud.storage.types import Provider, ObjectDoesNotExistError class CloudObjStorage(ObjStorage, metaclass=abc.ABCMeta): """ Abstract ObjStorage that allows connection 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). """ def __init__(self, api_key, api_secret_key, container_name): self.driver = self._get_driver(api_key, api_secret_key) self.container_name = container_name self.container = self.driver.get_container( container_name=container_name) def _get_driver(self, api_key, api_secret_key): """ Initialize a driver to communicate with the cloud Args: api_key: key to connect to the API. api_secret_key: secret key for authentification. 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(api_key, api_secret_key) @abc.abstractmethod def _get_provider(self): """ Get a libcloud driver provider This method must be overriden 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 tu support `get_driver` method. """ raise NotImplementedError('%s must implement `get_provider` method' % type(self)) def __contains__(self, obj_id): try: self._get_object(obj_id) except ObjectDoesNotExistError: 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 map(lambda obj: obj.name, 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. h = hashutil._new_hash(ID_HASH_ALGO, len(bytes)) h.update(bytes) obj_id = h.digest() 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, chech_presence=False) def get(self, obj_id): return bytes(self._get_object(obj_id).as_stream()) 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) # TODO factorize the hash computation. h = hashutil._new_hash(ID_HASH_ALGO, len(obj_content)) h.update(obj_content) content_obj_id = h.digest() if content_obj_id != obj_id: raise Error(obj_id) def _get_object(self, obj_id): """ Get a Libcloud wrapper for an object pointer. This wrapper does not retrieve the content of the object direclty. """ hex_obj_id = hashutil.hash_to_hex(obj_id) try: return self.driver.get_object(self.container_name, hex_obj_id) except ObjectDoesNotExistError as e: raise ObjNotFoundError(e.object_name) def _put_object(self, content, obj_id): """ Create an object in the cloud storage. Created object will contains the content and be referenced by the given id. """ hex_obj_id = hashutil.hash_to_hex(obj_id) self.driver.upload_object_via_stream(iter(content), self.container, hex_obj_id) + + +def AwsCloudObjStorage(CloudObjStorage): + """ Cloud-based object storage that works with Amazon's S3 + """ + def _get_provider(self): + return Provider.S3 + + +def OpenStackCloudObjStorage(CloudObjStorage): + """ Cloud-based object storage based on OpenStack Swift + """ + def _get_provider(self): + return Provider.OPENSTACK_SWIFT