from leap import * from u1db import errors from u1db.backends import CommonBackend from u1db.remote.http_target import HTTPSyncTarget from swiftclient import client class OpenStackDatabase(CommonBackend): """A U1DB implementation that uses OpenStack as its persistence layer.""" def __init__(self, auth_url, user, auth_key, container): """Create a new OpenStack data container.""" self._auth_url = auth_url self._user = user self._auth_key = auth_key self._container = container self.set_document_factory(LeapDocument) self._connection = swiftclient.Connection(self._auth_url, self._user, self._auth_key) self._get_auth() #------------------------------------------------------------------------- # implemented methods from Database #------------------------------------------------------------------------- def set_document_factory(self, factory): self._factory = factory def set_document_size_limit(self, limit): raise NotImplementedError(self.set_document_size_limit) def whats_changed(self, old_generation=0): raise NotImplementedError(self.whats_changed) def get_doc(self, doc_id, include_deleted=False): # TODO: support deleted docs? headers = self._connection.head_object(self._container, doc_id) rev = headers['x-object-meta-rev'] response, contents = self._connection.get_object(self._container, doc_id) return self._factory(doc_id, rev, contents) def get_all_docs(self, include_deleted=False): """Get all documents from the database.""" raise NotImplementedError(self.get_all_docs) def put_doc(self, doc): if doc.doc_id is None: raise errors.InvalidDocId() self._check_doc_id(doc.doc_id) self._check_doc_size(doc) # TODO: check for conflicts? new_rev = self._allocate_doc_rev(doc.rev) headers = { 'X-Object-Meta-Rev' : new_rev } self._connection.put_object(self._container, doc_id, doc.get_json(), headers=headers) return new_rev def delete_doc(self, doc): raise NotImplementedError(self.delete_doc) # start of index-related methods: these are not supported by this backend. def create_index(self, index_name, *index_expressions): return False def delete_index(self, index_name): return False def list_indexes(self): return [] def get_from_index(self, index_name, *key_values): return [] def get_range_from_index(self, index_name, start_value=None, end_value=None): return [] def get_index_keys(self, index_name): return [] # end of index-related methods: these are not supported by this backend. def get_doc_conflicts(self, doc_id): return [] def resolve_doc(self, doc, conflicted_doc_revs): raise NotImplementedError(self.resolve_doc) def get_sync_target(self): return OpenStackSyncTarget(self) def close(self): raise NotImplementedError(self.close) def sync(self, url, creds=None, autocreate=True): raise NotImplementedError(self.close) def _get_replica_gen_and_trans_id(self, other_replica_uid): self._update_u1db_data() return self._sync_log.get_replica_gen_and_trans_id(other_replica_uid) def _set_replica_gen_and_trans_id(self, other_replica_uid, other_generation, other_transaction_id): self._update_u1db_data() return self._sync_log.set_replica_gen_and_trans_id(other_replica_uid, other_generation, other_transaction_id) #------------------------------------------------------------------------- # implemented methods from CommonBackend #------------------------------------------------------------------------- def _get_generation(self): self._update_u1db_data() return self._transaction_log.get_generation() def _get_generation_info(self): self._update_u1db_data() return self._transaction_log.get_generation_info() def _get_doc(self, doc_id, check_for_conflicts=False): """Get just the document content, without fancy handling.""" raise NotImplementedError(self._get_doc) def _has_conflicts(self, doc_id): raise NotImplementedError(self._has_conflicts) def _put_and_update_indexes(self, doc_id, old_doc, new_rev, content): raise NotImplementedError(self._put_and_update_indexes) def _get_trans_id_for_gen(self, generation): self._update_u1db_data() trans_id = self._transaction_log.get_trans_id_for_gen(generation) if trans_id is None: raise errors.InvalidGeneration return trans_id #------------------------------------------------------------------------- # OpenStack specific methods #------------------------------------------------------------------------- def _is_initialized(self, c): raise NotImplementedError(self._is_initialized) def _initialize(self, c): raise NotImplementedError(self._initialize) def _get_auth(self): self._url, self._auth_token = self._connection.get_auth() return self._url, self.auth_token def _update_u1db_data(self): data = self.get_doc('u1db_data').content self._transaction_log = data['transaction_log'] self._sync_log = data['sync_log'] class OpenStackSyncTarget(HTTPSyncTarget): def get_sync_info(self, source_replica_uid): raise NotImplementedError(self.get_sync_info) def record_sync_info(self, source_replica_uid, source_replica_generation, source_replica_transaction_id): raise NotImplementedError(self.record_sync_info) class SimpleLog(object): def __init__(self, log=None): self._log = [] if log: self._log = log def append(self, msg): self._log.append(msg) def reduce(self, func, initializer=None): return reduce(func, self._log, initializer) def map(self, func): return map(func, self._log) class TransactionLog(SimpleLog): """ A list of (generation, doc_id, transaction_id) tuples. """ def get_generation(self): """ Return the current generation. """ gens = self.map(lambda x: x[0]) if not gens: return 0 return max(gens) def get_generation_info(self): """ Return the current generation and transaction id. """ if not self._log: return(0, '') info = self.map(lambda x: (x[0], x[2])) return reduce(lambda x, y: x if (x[0] > y[0]) else y, info) def get_trans_id_for_gen(self, gen): """ Get the transaction id corresponding to a particular generation. """ log = self.reduce(lambda x, y: y if y[0] == gen else x) if log is None: return None return log[2] class SyncLog(SimpleLog): """ A list of (replica_id, generation, transaction_id) tuples. """ def find_by_replica_uid(self, replica_uid): if not self._log: return () return self.reduce(lambda x, y: y if y[0] == replica_uid else x) def get_replica_gen_and_trans_id(self, other_replica_uid): """ Return the last known generation and transaction id for the other db replica. """ info = self.find_by_replica_uid(other_replica_uid) if not info: return (0, '') return (info[1], info[2]) def set_replica_gen_and_trans_id(self, other_replica_uid, other_generation, other_transaction_id): """ Set the last-known generation and transaction id for the other database replica. """ old_log = self._log self._log = [] for log in old_log: if log[0] != other_replica_uid: self.append(log) self.append((other_replica_uid, other_generation, other_transaction_id))