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Implement conflict resolution

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Fix #4
This commit is contained in:
Markus Unterwaditzer 2014-03-01 00:51:29 +01:00
parent 6776c79743
commit 78065a4e1f
5 changed files with 93 additions and 21 deletions
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3
config.example
View file

@ -6,6 +6,9 @@ status_path=~/.vdirsyncer/status/
# This syncronizes only a single collection/calendar/addressbook
a = bob_local
b = bob_remote
# conflict_resolution = None # abort when collisions occur
# conflict_resolution = a wins # assume a's items to be more up-to-date
# conflict_resolution = b wins # assume b's items to be more up-to-date
[storage bob_local]
# This represents only a single collection/calendar/addressbook

10
vdirsyncer/cli.py
View file

@ -56,9 +56,8 @@ def load_config(fname):
elif section.startswith('pair '):
name = section[len('pair '):]
options = get_options(section)
pairs[name] = a, b = options.pop('a'), options.pop('b')
storages.setdefault(a, {}).update(options)
storages.setdefault(b, {}).update(options)
a, b = options.pop('a'), options.pop('b')
pairs[name] = a, b, options
elif section == 'general':
general = get_options(section)
else:
@ -146,7 +145,7 @@ def _main(env, file_cfg):
actions = []
for pair_name in pairs:
try:
a, b = all_pairs[pair_name]
a, b, pair_options = all_pairs[pair_name]
except KeyError:
cli_logger.critical('Pair not found: {}'.format(pair_name))
cli_logger.critical('These are the pairs found: ')
@ -158,7 +157,8 @@ def _main(env, file_cfg):
def x(a=a, b=b, pair_name=pair_name):
cli_logger.debug('Syncing {}'.format(pair_name))
status = load_status(general['status_path'], pair_name)
sync(a, b, status)
sync(a, b, status,
pair_options.get('conflict_resolution', None))
save_status(general['status_path'], pair_name, status)
actions.append(x)

8
vdirsyncer/exceptions.py
View file

@ -43,3 +43,11 @@ class WrongEtagError(PreconditionFailed):
class StorageError(Error):
'''Internal or initialization errors with storage.'''
class SyncError(Error):
pass
class SyncConflict(SyncError):
pass

66
vdirsyncer/sync.py
View file

@ -40,7 +40,7 @@ def prefetch(storage, item_list, hrefs):
item_list[href]['obj'] = obj
def sync(storage_a, storage_b, status):
def sync(storage_a, storage_b, status, conflict_resolution=None):
'''Syncronizes two storages.
:param storage_a: The first storage
@ -51,6 +51,9 @@ def sync(storage_a, storage_b, status):
metadata about the two storages for detection of changes. Will be
modified by the function and should be passed to it at the next sync.
If this is the first sync, an empty dictionary should be provided.
:param conflict_resolution: Either 'a wins' or 'b wins'. If none is
provided, the sync function will raise
:py:exc:`vdirsyncer.exceptions.SyncConflict`.
'''
a_href_to_uid = dict(
(href_a, uid)
@ -81,13 +84,16 @@ def sync(storage_a, storage_b, status):
}
for action in actions:
action(storages, status)
action(storages, status, conflict_resolution)
def action_upload(uid, source, dest):
def inner(storages, status):
def inner(storages, status, conflict_resolution):
source_storage, source_list, source_uid_to_href = storages[source]
dest_storage, dest_list, dest_uid_to_href = storages[dest]
sync_logger.debug('Copying (uploading) item {} to {}'
.format(uid, dest_storage))
source_href = source_uid_to_href[uid]
source_etag = source_list[source_href]['etag']
@ -103,9 +109,11 @@ def action_upload(uid, source, dest):
def action_update(uid, source, dest):
def inner(storages, status):
def inner(storages, status, conflict_resolution):
source_storage, source_list, source_uid_to_href = storages[source]
dest_storage, dest_list, dest_uid_to_href = storages[dest]
sync_logger.debug('Copying (updating) item {} to {}'
.format(uid, dest_storage))
source_href = source_uid_to_href[uid]
source_etag = source_list[source_href]['etag']
@ -123,17 +131,50 @@ def action_update(uid, source, dest):
def action_delete(uid, source, dest):
def inner(storages, status):
def inner(storages, status, conflict_resolution):
if dest is not None:
dest_storage, dest_list, dest_uid_to_href = storages[dest]
sync_logger.debug('Deleting item {} from {}'
.format(uid, dest_storage))
dest_href = dest_uid_to_href[uid]
dest_etag = dest_list[dest_href]['etag']
dest_storage.delete(dest_href, dest_etag)
else:
sync_logger.debug('Deleting status info for nonexisting item {}'
.format(uid))
del status[uid]
return inner
def action_conflict_resolve(uid):
def inner(storages, status, conflict_resolution):
sync_logger.debug('Doing conflict resolution for item {}...'
.format(uid))
a_storage, list_a, a_uid_to_href = storages['a']
b_storage, list_b, b_uid_to_href = storages['b']
a_href = a_uid_to_href[uid]
b_href = b_uid_to_href[uid]
a_meta = list_a[a_href]
b_meta = list_b[b_href]
if a_meta['obj'].raw == b_meta['obj'].raw:
sync_logger.debug('...same content on both sides.')
status[uid] = a_href, a_meta['etag'], b_href, b_meta['etag']
elif conflict_resolution is None:
raise exceptions.SyncConflict()
elif conflict_resolution == 'a wins':
sync_logger.debug('...{} wins.'.format(a_storage))
action_update(uid, 'a', 'b')(storages, status, conflict_resolution)
elif conflict_resolution == 'b wins':
sync_logger.debug('...{} wins.'.format(b_storage))
action_update(uid, 'b', 'a')(storages, status, conflict_resolution)
else:
raise ValueError('Invalid conflict resolution mode: {}'
.format(conflict_resolution))
return inner
def get_actions(list_a, list_b, status, a_uid_to_href, b_uid_to_href):
prefetch_from_a = []
prefetch_from_b = []
@ -148,14 +189,7 @@ def get_actions(list_a, list_b, status, a_uid_to_href, b_uid_to_href):
b = list_b.get(href_b, None)
if uid not in status:
if uid in uids_a and uid in uids_b: # missing status
assert type(a['obj'].raw) is unicode, repr(a['obj'].raw)
assert type(b['obj'].raw) is unicode, repr(b['obj'].raw)
if a['obj'].raw != b['obj'].raw:
raise NotImplementedError( # TODO
'Conflict. No status and '
'different content on both sides.'
)
status[uid] = (href_a, a['etag'], href_b, b['etag'])
actions.append(action_conflict_resolve(uid))
# new item was created in a
elif uid in uids_a and uid not in uids_b:
prefetch_from_a.append(href_a)
@ -168,9 +202,9 @@ def get_actions(list_a, list_b, status, a_uid_to_href, b_uid_to_href):
_, status_etag_a, _, status_etag_b = status[uid]
if uid in uids_a and uid in uids_b:
if a['etag'] != status_etag_a and b['etag'] != status_etag_b:
# conflict resolution TODO
raise NotImplementedError('Conflict. '
'New etags on both sides.')
prefetch_from_a.append(href_a)
prefetch_from_b.append(href_b)
actions.append(action_conflict_resolve(uid))
elif a['etag'] != status_etag_a: # item was updated in a
prefetch_from_a.append(href_a)
actions.append(action_update(uid, 'a', 'b'))

27
vdirsyncer/tests/test_sync.py
View file

@ -113,3 +113,30 @@ class SyncTests(TestCase):
sync(a, b, status)
assert status == old_status
assert a.has('1.txt') and b.has('1.txt')
def test_conflict_resolution_both_etags_new(self):
a = MemoryStorage()
b = MemoryStorage()
item = Item(u'UID:1')
href_a, etag_a = a.upload(item)
href_b, etag_b = b.upload(item)
status = {}
sync(a, b, status)
assert status
a.update(href_a, Item(u'UID:1\nASDASD'), etag_a)
b.update(href_b, Item(u'UID:1\nHUEHUE'), etag_b)
self.assertRaises(exceptions.SyncConflict, sync, a, b, status)
sync(a, b, status, conflict_resolution='a wins')
obj_a, _ = a.get(href_a)
obj_b, _ = b.get(href_b)
assert obj_a.raw == obj_b.raw == u'UID:1\nASDASD'
def tset_conflict_resolution_new_etags_without_changes(self):
a = MemoryStorage()
b = MemoryStorage()
item = Item(u'UID:1')
href_a, etag_a = a.upload(item)
href_b, etag_b = b.upload(item)
status = {'1': (href_a, 'BOGUS_a', href_b, 'BOGUS_b')}
sync(a, b, status)
assert status == {'1': (href_a, etag_a, href_b, etag_b)}