Bidirectional sync

config.example

@@ -1,5 +1,8 @@
 # An example configuration for vdirsyncer.
-
+#
+# Move it to ~/.vdirsyncer/config or ~/.config/vdirsyncer/config and edit it.
+# Run `vdirsyncer --help` for CLI usage.
+#
 # Optional parameters are commented out.
 # This file doesn't document all available parameters, see
 # http://vdirsyncer.readthedocs.org/ for the rest of them.
@@ -27,6 +30,9 @@ b = bob_contacts_remote
 
 collections = ["from b"]
 
+# Synchronize the "display name" property into a local file (~/.contacts/displayname).
+metadata = ["displayname"]
+
 # To resolve a conflict the following values are possible:
 #   `null` - abort when collisions occur (default)
 #   `"a wins"` - assume a's items to be more up-to-date
@@ -54,6 +60,9 @@ a = bob_calendar_local
 b = bob_calendar_remote
 collections = ["private", "work"]
 
+# Calendars also have a color property
+metadata = ["displayname", "color"]
+
 [storage bob_calendar_local]
 type = filesystem
 path = ~/.calendars/

docs/config.rst

@@ -62,10 +62,11 @@ Pair Section
 
 - ``a`` and ``b`` reference the storages to sync by their names.
 
-- ``collections``: Optional, a list of collections to synchronize. If this
-  parameter is omitted, it is assumed the storages are already directly
-  pointing to one collection each. Specifying a collection multiple times won't
-  make vdirsyncer sync that collection more than once.
+- ``collections``: Optional, a list of collections to synchronize when
+  ``vdirsyncer sync`` is executed. If this parameter is omitted, it is assumed
+  the storages are already directly pointing to one collection each. Specifying
+  a collection multiple times won't make vdirsyncer sync that collection more
+  than once.
 
   Furthermore, there are the special values ``"from a"`` and ``"from b"``,
   which tell vdirsyncer to try autodiscovery on a specific storage.
@@ -88,6 +89,14 @@ Pair Section
     Vdirsyncer will not attempt to merge the two items.
   - ``null``, the default, where an error is shown and no changes are done.
 
+- ``metadata``: Metadata keys that should be synchronized when ``vdirsyncer
+  metasync`` is executed. Example::
+
+      metadata = ["color", "displayname"]
+
+   This synchronizes the ``color`` and the ``displayname`` properties. The
+   ``conflict_resolution`` parameter applies here as well.
+
 .. _storage_config:
 
 Storage Section

vdirsyncer/cli/__init__.py

@@ -105,14 +105,19 @@ def sync(pairs, force_delete, max_workers):
     Synchronize the given pairs. If no arguments are given, all will be
     synchronized.
 
+    This command will not synchronize metadata, use `vdirsyncer metasync` for
+    that.
+
+    Examples:
+
         `vdirsyncer sync` will sync everything configured.
 
         `vdirsyncer sync bob frank` will sync the pairs "bob" and "frank".
 
-    `vdirsyncer sync bob/first_collection` will sync "first_collection" from
-    the pair "bob".
+        `vdirsyncer sync bob/first_collection` will sync "first_collection"
+        from the pair "bob".
     '''
-    from .tasks import sync_pair
+    from .tasks import prepare_pair, sync_collection
     from .utils import parse_pairs_args, WorkerQueue
     general, all_pairs, all_storages = ctx.obj['config']
 
@@ -120,11 +125,39 @@ def sync(pairs, force_delete, max_workers):
 
     for pair_name, collections in parse_pairs_args(pairs, all_pairs):
         wq.spawn_worker()
-        wq.put(functools.partial(sync_pair, pair_name=pair_name,
-                                 collections_to_sync=collections,
+        wq.put(functools.partial(prepare_pair, pair_name=pair_name,
+                                 collections=collections,
                                  general=general, all_pairs=all_pairs,
                                  all_storages=all_storages,
-                                 force_delete=force_delete))
+                                 force_delete=force_delete,
+                                 callback=sync_collection))
+
+    wq.join()
+
+
+@app.command()
+@click.argument('pairs', nargs=-1)
+@max_workers_option
+@catch_errors
+def metasync(pairs, max_workers):
+    '''
+    Synchronize metadata of the given pairs.
+
+    See the `sync` command regarding the PAIRS argument.
+    '''
+    from .tasks import prepare_pair, metasync_collection
+    from .utils import parse_pairs_args, WorkerQueue
+    general, all_pairs, all_storages = ctx.obj['config']
+
+    wq = WorkerQueue(max_workers)
+
+    for pair_name, collections in parse_pairs_args(pairs, all_pairs):
+        wq.spawn_worker()
+        wq.put(functools.partial(prepare_pair, pair_name=pair_name,
+                                 collections=collections,
+                                 general=general, all_pairs=all_pairs,
+                                 all_storages=all_storages,
+                                 callback=metasync_collection))
 
     wq.join()
 

vdirsyncer/cli/tasks.py

@@ -10,8 +10,8 @@ from .utils import CliError, JobFailed, cli_logger, collections_for_pair, \
 from ..sync import sync
 
 
-def sync_pair(wq, pair_name, collections_to_sync, general, all_pairs,
-              all_storages, force_delete):
+def prepare_pair(wq, pair_name, collections, general, all_pairs, all_storages,
+                 callback, **kwargs):
     a_name, b_name, pair_options = all_pairs[pair_name]
 
     try:
@@ -28,7 +28,7 @@ def sync_pair(wq, pair_name, collections_to_sync, general, all_pairs,
 
     # spawn one worker less because we can reuse the current one
     new_workers = -1
-    for collection in (collections_to_sync or all_collections):
+    for collection in (collections or all_collections):
         try:
             config_a, config_b = all_collections[collection]
         except KeyError:
@@ -37,9 +37,9 @@ def sync_pair(wq, pair_name, collections_to_sync, general, all_pairs,
                                pair_name, collection, list(all_collections)))
         new_workers += 1
         wq.put(functools.partial(
-            sync_collection, pair_name=pair_name, collection=collection,
+            callback, pair_name=pair_name, collection=collection,
             config_a=config_a, config_b=config_b, pair_options=pair_options,
-            general=general, force_delete=force_delete
+            general=general, **kwargs
         ))
 
     for i in range(new_workers):
@@ -107,3 +107,30 @@ def repair_collection(general, all_pairs, all_storages, collection):
     cli_logger.info('Repairing {}/{}'.format(storage_name, collection))
     cli_logger.warning('Make sure no other program is talking to the server.')
     repair_storage(storage)
+
+
+def metasync_collection(wq, pair_name, collection, config_a, config_b,
+                        pair_options, general):
+    from ..metasync import metasync
+    status_name = get_status_name(pair_name, collection)
+
+    try:
+        cli_logger.info('Metasyncing {}'.format(status_name))
+
+        status = load_status(general['status_path'], pair_name,
+                             collection, data_type='metadata') or {}
+
+        a = storage_instance_from_config(config_a)
+        b = storage_instance_from_config(config_b)
+
+        metasync(
+            a, b, status,
+            conflict_resolution=pair_options.get('conflict_resolution', None),
+            keys=pair_options.get('metadata', None) or ()
+        )
+    except:
+        handle_cli_error(status_name)
+        raise JobFailed()
+
+    save_status(general['status_path'], pair_name, collection,
+                data_type='metadata', data=status)

vdirsyncer/metasync.py

@@ -0,0 +1,54 @@
+from . import exceptions, log
+
+logger = log.get(__name__)
+
+
+class MetaSyncError(exceptions.Error):
+    pass
+
+
+class MetaSyncConflict(MetaSyncError):
+    key = None
+
+
+def metasync(storage_a, storage_b, status, keys, conflict_resolution):
+    def _a_to_b():
+        logger.info(u'Copying {} to {}'.format(key, storage_b))
+        storage_b.set_meta(key, a)
+        status[key] = a
+
+    def _b_to_a():
+        logger.info(u'Copying {} to {}'.format(key, storage_a))
+        storage_a.set_meta(key, b)
+        status[key] = b
+
+    def _resolve_conflict():
+        if a == b:
+            pass
+        elif conflict_resolution is None:
+            raise MetaSyncConflict(key=key)
+        elif conflict_resolution == 'a wins':
+            _a_to_b()
+        elif conflict_resolution == 'b wins':
+            _b_to_a()
+
+    for key in keys:
+        a = storage_a.get_meta(key)
+        b = storage_b.get_meta(key)
+        s = status.get(key)
+        logger.debug(u'Key: {}'.format(key))
+        logger.debug(u'A: {}'.format(a))
+        logger.debug(u'B: {}'.format(b))
+        logger.debug(u'S: {}'.format(s))
+
+        if a != s and b != s:
+            _resolve_conflict()
+        elif a != s and b == s:
+            _a_to_b()
+        elif a == s and b != s:
+            _b_to_a()
+        else:
+            assert a == b
+
+    for key in set(status) - set(keys):
+        del status[key]

vdirsyncer/storage/dav.py

@@ -607,7 +607,11 @@ class DavStorage(Storage):
             data=data, headers=self.session.get_default_headers()
         )
 
-        # FIXME: Deal with response
+        # XXX: Response content is currently ignored. Though exceptions are
+        # raised for HTTP errors, a multistatus with errorcodes inside is not
+        # parsed yet. Not sure how common those are, or how they look like. It
+        # might be easier (and safer in case of a stupid server) to just issue
+        # a PROPFIND to see if the value got actually set.
 
 
 class CaldavStorage(DavStorage):