Add basic repair tool

Fix #172

CHANGELOG.rst

@@ -21,6 +21,8 @@ Version 0.4.3
 - Removed some workarounds for Radicale. Upgrading to the latest Radicale will
   fix the issues.
 - Fixed issues with iCloud discovery.
+- Vdirsyncer now includes a simple ``repair`` command that seeks to fix some
+  broken items.
 
 Version 0.4.2
 =============

vdirsyncer/cli/__init__.py

@@ -3,7 +3,7 @@
 import functools
 import sys
 
-from .tasks import discover_collections, sync_pair
+from .tasks import discover_collections, repair_collection, sync_pair
 from .utils import CliError, WorkerQueue, cli_logger, handle_cli_error, \
     load_config, parse_pairs_args
 from .. import __version__, log
@@ -127,3 +127,21 @@ def discover(ctx, pairs, max_workers):
         ))
 
     wq.join()
+
+
+@app.command()
+@click.argument('collection')
+@click.pass_context
+@catch_errors
+def repair(ctx, collection):
+    '''
+    Repair a given collection: `storage/collection/storage`
+
+    `vdirsyncer repair calendars_local/foo` repairs the `foo` collection of the
+    `calendars_local` storage.
+
+    It will download all items and repair their properties if necessary.
+    Currently this only fixes absent or duplicate UIDs.
+    '''
+    general, all_pairs, all_storages = ctx.obj['config']
+    repair_collection(general, all_pairs, all_storages, collection)

vdirsyncer/cli/tasks.py

@@ -2,12 +2,14 @@
 
 import functools
 import json
+import uuid
 
 from .utils import CliError, JobFailed, cli_logger, collections_for_pair, \
     get_status_name, handle_cli_error, load_status, save_status, \
-    storage_instance_from_config
+    storage_class_from_config, storage_instance_from_config
 
 from ..sync import sync
+from ..utils.vobject import Item, to_unicode_lines
 
 
 def sync_pair(wq, pair_name, collections_to_sync, general, all_pairs,
@@ -84,3 +86,67 @@ def discover_collections(wq, pair_name, **kwargs):
         collections = None
     cli_logger.info('Saved for {}: collections = {}'
                     .format(pair_name, json.dumps(collections)))
+
+
+def repair_collection(general, all_pairs, all_storages, collection):
+    storage_name, collection = collection, None
+    if '/' in storage_name:
+        storage_name, collection = storage_name.split('/')
+
+    config = all_storages[storage_name]
+    storage_type = config['type']
+
+    if collection is not None:
+        cli_logger.info('Discovering collections (skipping cache).')
+        cls, config = storage_class_from_config(config)
+        for config in cls.discover(**config):
+            if config['collection'] == collection:
+                break
+        else:
+            raise CliError('Couldn\'t find collection {} for storage {}.'
+                           .format(collection, storage_name))
+
+    config['type'] = storage_type
+    storage = storage_instance_from_config(config)
+
+    cli_logger.info('Repairing {}/{}'.format(storage_name, collection))
+    cli_logger.warning('Make sure no other program is talking to the server.')
+    _repair_collection(storage)
+
+
+def _repair_collection(storage):
+    seen_uids = set()
+    all_hrefs = list(storage.list())
+    for i, (href, _) in enumerate(all_hrefs):
+        item, etag = storage.get(href)
+        cli_logger.info('[{}/{}] Processing {}'
+                        .format(i, len(all_hrefs), href))
+
+        parsed = item.parsed
+        changed = False
+        if parsed is None:
+            cli_logger.warning('Item {} can\'t be parsed, skipping.'
+                               .format(href))
+            continue
+
+        if item.uid is None or item.uid in seen_uids:
+            if item.uid is None:
+                cli_logger.warning('No UID, assigning random one.')
+            else:
+                cli_logger.warning('Duplicate UID, reassigning random one.')
+
+            new_uid = uuid.uuid4()
+            stack = [parsed]
+            while stack:
+                component = stack.pop()
+                if component.name in ('VEVENT', 'VTODO', 'VJOURNAL', 'VCARD'):
+                    component['UID'] = new_uid
+                    changed = True
+                else:
+                    stack.extend(component.subcomponents)
+
+        new_item = Item(u'\n'.join(to_unicode_lines(parsed)))
+        assert new_item.uid
+        seen_uids.add(new_item.uid)
+        if changed:
+            storage.update(href, new_item, etag)

vdirsyncer/cli/utils.py

@@ -45,7 +45,7 @@ class JobFailed(RuntimeError):
     pass
 
 
-def handle_cli_error(status_name='sync'):
+def handle_cli_error(status_name=None):
     '''
     Print a useful error message for the current exception.
 
@@ -80,20 +80,27 @@ def handle_cli_error(status_name='sync'):
         )
     except IdentConflict as e:
         cli_logger.error(
-            '{status_name}: Storage "{name}" contains multiple items with the '
-            'same UID or even content. Vdirsyncer will now abort the '
-            'synchronization of this collection, because the fix for this is '
-            'not clear; It could be the result of a badly behaving server.\n'
-            '\n{href_list}\n'
+            '{status_name}: Storage "{storage.instance_name}" contains '
+            'multiple items with the same UID or even content. Vdirsyncer '
+            'will now abort the synchronization of this collection, because '
+            'the fix for this is not clear; It could be the result of a badly '
+            'behaving server. You can try running:\n\n'
+            '    vdirsyncer repair {storage.instance_name}\n\n'
+            'But make sure to have a backup of your data in some form. The '
+            'offending hrefs are:\n\n{href_list}\n'
             .format(status_name=status_name,
-                    name=e.storage.instance_name,
+                    storage=e.storage,
                     href_list='\n'.join(map(repr, e.hrefs)))
         )
     except (click.Abort, KeyboardInterrupt, JobFailed):
         pass
     except Exception as e:
-        cli_logger.exception('Unhandled exception occured while syncing {}.'
-                             .format(status_name))
+        if status_name:
+            msg = 'Unhandled exception occured for {}.'.format(status_name)
+        else:
+            msg = 'Unhandled exception occured.'
+
+        cli_logger.exception(msg)
 
 
 def validate_section_name(name, section_type):