feature(backups): batched removals of snapshots

selfprivacy_api/backup/__init__.py

@@ -397,9 +397,8 @@ class Backups:
 
         # TODO: Can be optimized since there is forgetting of an array in one restic op
         # but most of the time this will be only one snap to forget.
-        for snap in auto_snaps:
-            if snap not in new_snaplist:
-                Backups.forget_snapshot(snap)
+        deletable_snaps = [snap for snap in auto_snaps if snap not in new_snaplist]
+        Backups.forget_snapshots(deletable_snaps)
 
     @staticmethod
     def _standardize_quotas(i: int) -> int:
@@ -606,6 +605,19 @@ class Backups:
 
         return snap
 
+    @staticmethod
+    def forget_snapshots(snapshots: List[Snapshot]) -> None:
+        """
+        Deletes a batch of snapshots from the repo and from cache
+        Optimized
+        """
+        ids = [snapshot.id for snapshot in snapshots]
+        Backups.provider().backupper.forget_snapshots(ids)
+
+        # less critical
+        for snapshot in snapshots:
+            Storage.delete_cached_snapshot(snapshot)
+
     @staticmethod
     def forget_snapshot(snapshot: Snapshot) -> None:
         """Deletes a snapshot from the repo and from cache"""

selfprivacy_api/backup/backuppers/__init__.py

@@ -66,3 +66,8 @@ class AbstractBackupper(ABC):
     def forget_snapshot(self, snapshot_id) -> None:
         """Forget a snapshot"""
         raise NotImplementedError
+
+    @abstractmethod
+    def forget_snapshots(self, snapshot_ids: List[str]) -> None:
+        """Maybe optimized deletion of a batch of snapshots, just cycling if unsupported"""
+        raise NotImplementedError

selfprivacy_api/backup/backuppers/none_backupper.py

@@ -39,4 +39,7 @@ class NoneBackupper(AbstractBackupper):
         raise NotImplementedError
 
     def forget_snapshot(self, snapshot_id):
-        raise NotImplementedError
+        raise NotImplementedError("forget_snapshot")
+
+    def forget_snapshots(self, snapshots):
+        raise NotImplementedError("forget_snapshots")

selfprivacy_api/backup/backuppers/restic_backupper.py

@@ -86,6 +86,10 @@ class ResticBackupper(AbstractBackupper):
         return f"echo {LocalBackupSecret.get()}"
 
     def restic_command(self, *args, tags: Optional[List[str]] = None) -> List[str]:
+        """
+        Construct a restic command against the currently configured repo
+        Can support [nested] arrays as arguments, will flatten them into the final commmand
+        """
         if tags is None:
             tags = []
 
@@ -384,15 +388,15 @@ class ResticBackupper(AbstractBackupper):
                     output,
                 )
 
+    def forget_snapshot(self, snapshot_id: str) -> None:
+        self.forget_snapshots([snapshot_id])
+
     @unlocked_repo
-    def forget_snapshot(self, snapshot_id) -> None:
-        """
-        Either removes snapshot or marks it for deletion later,
-        depending on server settings
-        """
+    def forget_snapshots(self, snapshot_ids: List[str]) -> None:
+        # in case the backupper program supports batching, otherwise implement it by cycling
         forget_command = self.restic_command(
             "forget",
-            snapshot_id,
+            [snapshot_ids],
             # TODO: prune should be done in a separate process
             "--prune",
         )
@@ -414,7 +418,7 @@ class ResticBackupper(AbstractBackupper):
 
             if "no matching ID found" in err:
                 raise ValueError(
-                    "trying to delete, but no such snapshot: ", snapshot_id
+                    "trying to delete, but no such snapshot(s): ", snapshot_ids
                 )
 
             assert (