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# -*- coding: utf-8 -*-
# sync.py
# Copyright (C) 2014 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Soledad synchronization utilities.
"""
import os
from twisted.internet import defer
from leap.soledad.common.log import getLogger
from leap.soledad.common.l2db import errors
from leap.soledad.common.l2db.sync import Synchronizer
from leap.soledad.common.errors import BackendNotReadyError
logger = getLogger(__name__)
# we may want to collect statistics from the sync process
DO_STATS = False
if os.environ.get('SOLEDAD_STATS'):
DO_STATS = True
class SoledadSynchronizer(Synchronizer):
"""
Collect the state around synchronizing 2 U1DB replicas.
Synchronization is bi-directional, in that new items in the source are sent
to the target, and new items in the target are returned to the source.
However, it still recognizes that one side is initiating the request. Also,
at the moment, conflicts are only created in the source.
Also modified to allow for interrupting the synchronization process.
"""
received_docs = []
def __init__(self, *args, **kwargs):
Synchronizer.__init__(self, *args, **kwargs)
if DO_STATS:
self.sync_phase = [0]
self.sync_exchange_phase = None
@defer.inlineCallbacks
def sync(self):
"""
Synchronize documents between source and target.
:return: A deferred which will fire after the sync has finished with
the local generation before the synchronization was performed.
:rtype: twisted.internet.defer.Deferred
"""
sync_target = self.sync_target
self.received_docs = []
# ---------- phase 1: get sync info from server ----------------------
if DO_STATS:
self.sync_phase[0] += 1
self.sync_exchange_phase = self.sync_target.sync_exchange_phase
# --------------------------------------------------------------------
# get target identifier, its current generation,
# and its last-seen database generation for this source
ensure_callback = None
try:
(self.target_replica_uid, target_gen, target_trans_id,
target_my_gen, target_my_trans_id) = yield \
sync_target.get_sync_info(self.source._replica_uid)
except (errors.DatabaseDoesNotExist, BackendNotReadyError) as e:
logger.debug("Database isn't ready on server. Will be created.")
logger.debug("Reason: %s" % e.__class__)
self.target_replica_uid = None
target_gen, target_trans_id = 0, ''
target_my_gen, target_my_trans_id = 0, ''
logger.debug("target replica uid: %s" % self.target_replica_uid)
logger.debug("target generation: %d" % target_gen)
logger.debug("target trans id: %s" % target_trans_id)
logger.debug("target my gen: %d" % target_my_gen)
logger.debug("target my trans_id: %s" % target_my_trans_id)
logger.debug("source replica_uid: %s" % self.source._replica_uid)
# make sure we'll have access to target replica uid once it exists
if self.target_replica_uid is None:
def ensure_callback(replica_uid):
self.target_replica_uid = replica_uid
# make sure we're not syncing one replica with itself
if self.target_replica_uid == self.source._replica_uid:
raise errors.InvalidReplicaUID
# validate the info the target has about the source replica
self.source.validate_gen_and_trans_id(
target_my_gen, target_my_trans_id)
# ---------- phase 2: what's changed ---------------------------------
if DO_STATS:
self.sync_phase[0] += 1
# --------------------------------------------------------------------
# what's changed since that generation and this current gen
my_gen, _, changes = self.source.whats_changed(target_my_gen)
logger.debug("there are %d documents to send" % len(changes))
# get source last-seen database generation for the target
if self.target_replica_uid is None:
target_last_known_gen, target_last_known_trans_id = 0, ''
else:
target_last_known_gen, target_last_known_trans_id = \
self.source._get_replica_gen_and_trans_id(
self.target_replica_uid)
logger.debug(
"last known target gen: %d" % target_last_known_gen)
logger.debug(
"last known target trans_id: %s" % target_last_known_trans_id)
# validate transaction ids
if not changes and target_last_known_gen == target_gen:
if target_trans_id != target_last_known_trans_id:
raise errors.InvalidTransactionId
defer.returnValue(my_gen)
# ---------- phase 3: sync exchange ----------------------------------
if DO_STATS:
self.sync_phase[0] += 1
# --------------------------------------------------------------------
docs_by_generation = self._docs_by_gen_from_changes(changes)
# exchange documents and try to insert the returned ones with
# the target, return target synced-up-to gen.
new_gen, new_trans_id = yield sync_target.sync_exchange(
docs_by_generation, self.source._replica_uid,
target_last_known_gen, target_last_known_trans_id,
self._insert_doc_from_target, ensure_callback=ensure_callback)
ids_sent = [doc_id for doc_id, _, _ in changes]
logger.debug("target gen after sync: %d" % new_gen)
logger.debug("target trans_id after sync: %s" % new_trans_id)
if hasattr(self.source, 'commit'): # sqlcipher backend speed up
self.source.commit() # insert it all in a single transaction
info = {
"target_replica_uid": self.target_replica_uid,
"new_gen": new_gen,
"new_trans_id": new_trans_id,
"my_gen": my_gen
}
self._syncing_info = info
# ---------- phase 4: complete sync ----------------------------------
if DO_STATS:
self.sync_phase[0] += 1
# --------------------------------------------------------------------
yield self.complete_sync()
_, _, changes = self.source.whats_changed(target_my_gen)
changed_doc_ids = [doc_id for doc_id, _, _ in changes]
just_received = list(set(changed_doc_ids) - set(ids_sent))
self.received_docs = just_received
# ---------- phase 5: sync is over -----------------------------------
if DO_STATS:
self.sync_phase[0] += 1
# --------------------------------------------------------------------
defer.returnValue(my_gen)
def _docs_by_gen_from_changes(self, changes):
docs_by_generation = []
kwargs = {'include_deleted': True}
for doc_id, gen, trans in changes:
get_doc = (self.source.get_doc, (doc_id,), kwargs)
docs_by_generation.append((get_doc, gen, trans))
return docs_by_generation
def complete_sync(self):
"""
Last stage of the synchronization:
(a) record last known generation and transaction uid for the remote
replica, and
(b) make target aware of our current reached generation.
:return: A deferred which will fire when the sync has been completed.
:rtype: twisted.internet.defer.Deferred
"""
logger.debug("completing deferred last step in sync...")
# record target synced-up-to generation including applying what we
# sent
info = self._syncing_info
self.source._set_replica_gen_and_trans_id(
info["target_replica_uid"], info["new_gen"], info["new_trans_id"])
# if gapless record current reached generation with target
return self._record_sync_info_with_the_target(info["my_gen"])
def _record_sync_info_with_the_target(self, start_generation):
"""
Store local replica metadata in server.
:param start_generation: The local generation when the sync was
started.
:type start_generation: int
:return: A deferred which will fire when the operation has been
completed.
:rtype: twisted.internet.defer.Deferred
"""
cur_gen, trans_id = self.source._get_generation_info()
if (cur_gen == start_generation + self.num_inserted and
self.num_inserted > 0):
return self.sync_target.record_sync_info(
self.source._replica_uid, cur_gen, trans_id)
return defer.succeed(None)
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