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

@@ -29,6 +29,10 @@ Version 0.19.0
   you're validating certificate fingerprints, use `sha256` instead.
 - The ``google`` storage types no longer require ``requests-oauthlib``, but
   require ``python-aiohttp-oauthlib`` instead.
+- 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 0.18.0
 ==============

docs/config.rst

@@ -415,6 +415,8 @@ Local
       #encoding = "utf-8"
       #post_hook = null
       #fileignoreext = ".tmp"
+      #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.
@@ -437,6 +439,12 @@ Local
         new/updated file.
     :param fileeignoreext: The file extention to ignore. It is only useful
         if fileext is set to the empty string. The default is ``.tmp``.
+    :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
 

tests/system/cli/test_config.py

@@ -60,8 +60,13 @@ def test_read_config(read_config):
             "yesno": False,
             "number": 42,
             "instance_name": "bob_a",
+            "implicit": [],
+        },
+        "bob_b": {
+            "type": "carddav",
+            "instance_name": "bob_b",
+            "implicit": [],
         },
-        "bob_b": {"type": "carddav", "instance_name": "bob_b"},
     }
 
 

tests/system/utils/test_main.py

@@ -21,7 +21,7 @@ def test_get_storage_init_args():
     from vdirsyncer.storage.memory import MemoryStorage
 
     all, required = utils.get_storage_init_args(MemoryStorage)
-    assert all == {"fileext", "collection", "read_only", "instance_name"}
+    assert all == {"fileext", "collection", "read_only", "instance_name", "implicit"}
     assert not required
 
 

vdirsyncer/cli/config.py

@@ -115,6 +115,14 @@ def _parse_section(self, section_type, name, options):
                 raise ValueError("More than one general section.")
             self._general = options
         elif section_type == "storage":
+            if "implicit" not in options:
+                options["implicit"] = []
+            elif isinstance(options["implicit"], str):
+                options["implicit"] = [options["implicit"]]
+            elif not isinstance(options["implicit"], list):
+                raise ValueError(
+                    "`implicit` parameter must be a list, string or absent."
+                )
             self._storages[name] = options
         elif section_type == "pair":
             self._pairs[name] = options

vdirsyncer/cli/discover.py

@@ -8,7 +8,9 @@
 import aiostream
 
 from .. import exceptions
+from . import cli_logger
 from .utils import handle_collection_not_found
+from .utils import handle_collection_was_removed
 from .utils import handle_storage_init_error
 from .utils import load_status
 from .utils import save_status
@@ -118,6 +120,33 @@ async def collections_for_pair(
             "cache_key": cache_key,
         },
     )
+
+    if "from b" in (pair.collections or []):
+        only_in_a = set(a_discovered.get_self().keys()) - set(
+            b_discovered.get_self().keys()
+        )
+        if only_in_a and "delete" in pair.config_a["implicit"]:
+            for a in only_in_a:
+                try:
+                    handle_collection_was_removed(pair.config_a, a)
+                    save_status(status_path, pair.name, a, data_type="metadata")
+                    save_status(status_path, pair.name, a, data_type="items")
+                except NotImplementedError as e:
+                    cli_logger.error(e)
+
+    if "from a" in (pair.collections or []):
+        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["implicit"]:
+            for b in only_in_b:
+                try:
+                    handle_collection_was_removed(pair.config_b, b)
+                    save_status(status_path, pair.name, b, data_type="metadata")
+                    save_status(status_path, pair.name, b, data_type="items")
+                except NotImplementedError as e:
+                    cli_logger.error(e)
+
     return rv
 
 

vdirsyncer/cli/utils.py

@@ -231,10 +231,15 @@ 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:
+        try:
+            os.remove(path)
+        except OSError:  # the file has not existed
+            pass
+        return
 
     with atomic_write(path, mode="w", overwrite=True) as f:
         json.dump(data, f)
@@ -334,6 +339,19 @@ def assert_permissions(path, wanted):
         os.chmod(path, wanted)
 
 
+def handle_collection_was_removed(config, collection):
+    if "delete" in config["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)
+
+
 async def handle_collection_not_found(config, collection, e=None):
     storage_name = config.get("instance_name", None)
 
@@ -343,7 +361,9 @@ async def handle_collection_not_found(config, collection, e=None):
         )
     )
 
-    if click.confirm("Should vdirsyncer attempt to create it?"):
+    if "create" in config["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

@@ -42,6 +42,9 @@ 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.  Must
+        be a possibly empty list of strings.
     """
 
     fileext = ".txt"
@@ -65,9 +68,16 @@ 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
+        self.implicit = implicit  # unused from within the Storage classes
         if self.read_only and not read_only:
             raise exceptions.UserError("This storage can only be read-only.")
         self.read_only = bool(read_only)
@@ -109,6 +119,18 @@ async 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
@@ -62,9 +63,7 @@ async 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
     async def create_collection(cls, collection, **kwargs):
@@ -80,6 +79,19 @@ async 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)