diff options
| -rw-r--r-- | common/src/leap/soledad/common/couch/__init__.py | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/common/src/leap/soledad/common/couch/__init__.py b/common/src/leap/soledad/common/couch/__init__.py index ba3192a4..effb2be2 100644 --- a/common/src/leap/soledad/common/couch/__init__.py +++ b/common/src/leap/soledad/common/couch/__init__.py @@ -27,10 +27,12 @@ import time import functools +from collections import defaultdict from StringIO import StringIO from urlparse import urljoin from contextlib import contextmanager from multiprocessing.pool import ThreadPool +from threading import Lock from couchdb.client import Server, Database @@ -113,6 +115,8 @@ class CouchDatabase(object): CONFIG_DOC_ID = '_local/config' SYNC_DOC_ID_PREFIX = '_local/sync_' + _put_doc_lock = defaultdict(Lock) + @classmethod def open_database(cls, url, create, ensure_ddocs=False, replica_uid=None, database_security=None): @@ -675,6 +679,7 @@ class CouchDatabase(object): 'length': len(content), } parts.append(content) + # save conflicts as attachment if doc.has_conflicts is True: conflicts = json.dumps( @@ -686,21 +691,26 @@ class CouchDatabase(object): 'length': len(conflicts), } parts.append(conflicts) + # add the gen document - while True: # TODO: add a lock, remove this while - try: - gen, _ = self.get_generation_info() - new_gen = gen + 1 - gen_doc = { - '_id': _get_gen_doc_id(new_gen), - 'gen': new_gen, - 'doc_id': doc.doc_id, - 'trans_id': transaction_id, - } - self._database.save(gen_doc) - break - except ResourceConflict: - pass + + # TODO: in u1db protocol, the increment of database generation should + # be made in the same atomic transaction as the actual document save, + # otherwise the same document might be concurrently updated by + # concurrent syncs from other replicas. A simple lock based on the uuid + # and doc_id would be enough to prevent that, if all entry points to + # database update are made through the soledad api. + with self._put_doc_lock[self._database.name]: + gen, _ = self.get_generation_info() + new_gen = gen + 1 + gen_doc = { + '_id': _get_gen_doc_id(new_gen), + 'gen': new_gen, + 'doc_id': doc.doc_id, + 'trans_id': transaction_id, + } + self._database.save(gen_doc) + # build the couch document couch_doc = { '_id': doc.doc_id, |