cli/discover: remove/add local collections if the remote collection i…

…s deleted/created

This works when the destination backend is 'filesystem'.

-- add a new parameter to storage section:
   implicit = ["create", "delete"]

Changes cli/utils.py:save_status(): when data is None, remove the
underlaying file.

CHANGELOG.rst

@@ -9,6 +9,13 @@ Package maintainers and users who have to manually update their installation
 may want to subscribe to `GitHub's tag feed
 <https://github.com/pimutils/vdirsyncer/tags.atom>`_.
 
+Unreleased 0.1
+==============
+- Add ``implicit`` option to storage section.  It creates/deletes implicitly
+  collections in the destinations, when new collections are created/deleted
+  in the source.  The deletion is implemented only for the "filesystem" storage.
+  See :ref:`storage_config`.
+
 Version 0.16.8
 ==============
 

docs/config.rst

@@ -408,6 +408,8 @@ Local
       fileext = "..."
       #encoding = "utf-8"
       #post_hook = null
+      #implicit = "create"
+      #implicit = ["create", "delete"]
 
     Can be used with `khal <http://lostpackets.de/khal/>`_. See :doc:`vdir` for
     a more formal description of the format.
@@ -426,6 +428,12 @@ Local
     :param post_hook: A command to call for each item creation and
         modification. The command will be called with the path of the
         new/updated file.
+    :param implicit: When a new collection is created on the source, and the
+        value is "create", create the collection in the destination without
+        asking questions.  When the value is "delete" and a collection
+        is removed on the source, remove it in the destination.  The value
+        can be a string or an array of strings.  The deletion is implemented
+        only for the "filesystem" storage.
 
 .. storage:: singlefile
 

vdirsyncer/cli/discover.py

@@ -5,7 +5,7 @@
 
 from .. import exceptions
 from ..utils import cached_property
-from .utils import handle_collection_not_found
+from .utils import handle_collection_not_found, handle_collection_was_removed
 from .utils import handle_storage_init_error
 from .utils import load_status
 from .utils import save_status
@@ -80,6 +80,21 @@ def collections_for_pair(status_path, pair, from_cache=True,
         get_b_discovered=b_discovered.get_self,
         _handle_collection_not_found=handle_collection_not_found
     ))
+    only_in_b = set(b_discovered.get_self().keys()) - set(a_discovered.get_self().keys())
+    if only_in_b and 'delete' in pair.config_b.get('implicit'):
+        for b in only_in_b:
+            try:
+                handle_collection_was_removed(pair.config_b, b)
+                try:
+                    save_status(status_path, pair.name, b, data_type='metadata', data=None)
+                except OSError: # the .metadata file has not existed
+                    pass
+                try:
+                    save_status(status_path, pair.name, b, data_type='items', data=None)
+                except OSError: # the .items file has not existed
+                    pass
+            except NotImplementedError as e:
+                cli_logger.error(e)
 
     _sanity_check_collections(rv)
 

vdirsyncer/cli/utils.py

@@ -231,10 +231,12 @@ def manage_sync_status(base_path, pair_name, collection_name):
 
 def save_status(base_path, pair, collection=None, data_type=None, data=None):
     assert data_type is not None
-    assert data is not None
     status_name = get_status_name(pair, collection)
     path = expand_path(os.path.join(base_path, status_name)) + '.' + data_type
     prepare_status_path(path)
+    if data is None:
+        os.remove(path)
+        return
 
     with atomic_write(path, mode='w', overwrite=True) as f:
         json.dump(data, f)
@@ -397,14 +399,27 @@ def assert_permissions(path, wanted):
         os.chmod(path, wanted)
 
 
+def handle_collection_was_removed(config, collection):
+    if 'delete' in config.get('implicit'):
+        storage_type = config['type']
+        cls, config = storage_class_from_config(config)
+        config['collection'] = collection
+        try:
+            args = cls.delete_collection(**config)
+            args['type'] = storage_type
+            return args
+        except NotImplementedError as e:
+            cli_logger.error(e)
+
+
 def handle_collection_not_found(config, collection, e=None):
     storage_name = config.get('instance_name', None)
 
     cli_logger.warning('{}No collection {} found for storage {}.'
                        .format(f'{e}\n' if e else '',
                                json.dumps(collection), storage_name))
 
-    if click.confirm('Should vdirsyncer attempt to create it?'):
+    if 'create' in config.get('implicit') or click.confirm('Should vdirsyncer attempt to create it?'):
         storage_type = config['type']
         cls, config = storage_class_from_config(config)
         config['collection'] = collection

vdirsyncer/storage/base.py

@@ -40,6 +40,9 @@ class Storage(metaclass=StorageMeta):
 
     :param read_only: Whether the synchronization algorithm should avoid writes
         to this storage. Some storages accept no value other than ``True``.
+    :param implicit: Whether the synchronization shall create/delete collections
+        in the destination, when these were created/removed from the source.  Can
+        be a string, an array of strings, or skipped.
     '''
 
     fileext = '.txt'
@@ -63,9 +66,15 @@ class Storage(metaclass=StorageMeta):
     # The attribute values to show in the representation of the storage.
     _repr_attributes = ()
 
-    def __init__(self, instance_name=None, read_only=None, collection=None):
+    def __init__(self, instance_name=None, read_only=None, collection=None, implicit=None):
         if read_only is None:
             read_only = self.read_only
+        if implicit is None:
+            self.implicit = []
+        elif isinstance(implicit, str):
+            self.implicit = [implicit]
+        else:
+            self.implicit = implicit
         if self.read_only and not read_only:
             raise exceptions.UserError('This storage can only be read-only.')
         self.read_only = bool(read_only)
@@ -105,6 +114,18 @@ def create_collection(cls, collection, **kwargs):
         '''
         raise NotImplementedError()
 
+    @classmethod
+    def delete_collection(cls, collection, **kwargs):
+        '''
+        Delete the specified collection and return the new arguments.
+
+        ``collection=None`` means the arguments are already pointing to a
+        possible collection location.
+
+        The returned args should contain the collection name, for UI purposes.
+        '''
+        raise NotImplementedError()
+
     def __repr__(self):
         try:
             if self.instance_name:

vdirsyncer/storage/filesystem.py

@@ -1,6 +1,7 @@
 import errno
 import logging
 import os
+import shutil
 import subprocess
 
 from atomicwrites import atomic_write
@@ -55,9 +56,7 @@ def discover(cls, path, **kwargs):
     def _validate_collection(cls, path):
         if not os.path.isdir(path):
             return False
-        if os.path.basename(path).startswith('.'):
-            return False
-        return True
+        return not os.path.basename(path).startswith('.')
 
     @classmethod
     def create_collection(cls, collection, **kwargs):
@@ -73,6 +72,19 @@ def create_collection(cls, collection, **kwargs):
         kwargs['collection'] = collection
         return kwargs
 
+    @classmethod
+    def delete_collection(cls, collection, **kwargs):
+        kwargs = dict(kwargs)
+        path = kwargs['path']
+
+        if collection is not None:
+            path = os.path.join(path, collection)
+        shutil.rmtree(path, ignore_errors=True)
+
+        kwargs['path'] = path
+        kwargs['collection'] = collection
+        return kwargs
+
     def _get_filepath(self, href):
         return os.path.join(self.path, href)