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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()
self._ensure_u1db_data()
#-------------------------------------------------------------------------
# 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):
self._get_u1db_data()
return self._transaction_log.whats_changed(old_generation)
def _get_doc(self, doc_id, check_for_conflicts=False):
"""Get just the document content, without fancy handling.
Conflicts do not happen on server side, so there's no need to check
for them.
"""
try:
response, contents = self._connection.get_object(self._container, doc_id)
rev = response['x-object-meta-rev']
return self._factory(doc_id, rev, contents)
except swiftclient.ClientException:
return None
def get_doc(self, doc_id, include_deleted=False):
doc = self._get_doc(doc_id, check_for_conflicts=True)
if doc is None:
return None
if doc.is_tombstone() and not include_deleted:
return None
return doc
def get_all_docs(self, include_deleted=False):
"""Get all documents from the database."""
generation = self._get_generation()
results = []
_, doc_ids = self._connection.get_container(self._container,
full_listing=True)
for doc_id in doc_ids:
doc = self._get_doc(doc_id)
if doc.content is None and not include_deleted:
continue
results.append(doc)
return (generation, results)
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)
new_gen = self._get_generation() + 1
trans_id = self._allocate_transaction_id()
self._transaction_log.append((new_gen, doc.doc_id, trans_id))
self._set_u1db_data()
return new_rev
def delete_doc(self, doc):
old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
if old_doc is None:
raise errors.DocumentDoesNotExist
if old_doc.rev != doc.rev:
raise errors.RevisionConflict()
if old_doc.is_tombstone():
raise errors.DocumentAlreadyDeleted
if old_doc.has_conflicts:
raise errors.ConflictedDoc()
new_rev = self._allocate_doc_rev(doc.rev)
doc.rev = new_rev
doc.make_tombstone()
self._put_doc(olddoc)
return new_rev
# 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):
from u1db.sync import Synchronizer
from u1db.remote.http_target import OpenStackSyncTarget
return Synchronizer(self, OpenStackSyncTarget(url, creds=creds)).sync(
autocreate=autocreate)
def _get_replica_gen_and_trans_id(self, other_replica_uid):
self._get_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._get_u1db_data()
self._sync_log.set_replica_gen_and_trans_id(other_replica_uid,
other_generation,
other_transaction_id)
self._set_u1db_data()
#-------------------------------------------------------------------------
# implemented methods from CommonBackend
#-------------------------------------------------------------------------
def _get_generation(self):
self._get_u1db_data()
return self._transaction_log.get_generation()
def _get_generation_info(self):
self._get_u1db_data()
return self._transaction_log.get_generation_info()
def _has_conflicts(self, doc_id):
# Documents never have conflicts on server.
return False
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._get_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 _ensure_u1db_data(self):
"""
Guarantee that u1db data exists in store.
"""
if self._is_initialized():
return
self._initialize()
def _is_initialized(self):
"""
Verify if u1db data exists in store.
"""
if not self._get_doc('u1db_data'):
return False
return True
def _initialize(self):
"""
Create u1db data object in store.
"""
content = { 'transaction_log' : [],
'sync_log' : [] }
doc = self.create_doc('u1db_data', content)
def _get_auth(self):
self._url, self._auth_token = self._connection.get_auth()
return self._url, self.auth_token
def _get_u1db_data(self):
data = self.get_doc('u1db_data').content
self._transaction_log = data['transaction_log']
self._sync_log = data['sync_log']
def _set_u1db_data(self):
doc = self._factory('u1db_data')
doc.content = { 'transaction_log' : self._transaction_log,
'sync_log' : self._sync_log }
self.put_doc(doc)
class OpenStackSyncTarget(HTTPSyncTarget):
def get_sync_info(self, source_replica_uid):
source_gen, source_trans_id = self._db._get_replica_gen_and_trans_id(
source_replica_uid)
my_gen, my_trans_id = self._db._get_generation_info()
return (
self._db._replica_uid, my_gen, my_trans_id, source_gen,
source_trans_id)
def record_sync_info(self, source_replica_uid, source_replica_generation,
source_replica_transaction_id):
if self._trace_hook:
self._trace_hook('record_sync_info')
self._db._set_replica_gen_and_trans_id(
source_replica_uid, source_replica_generation,
source_replica_transaction_id)
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