add: docstrings in Manager

zfs-backup.py

@@ -48,6 +48,8 @@ def main():
 
 
 class Manager:
+    """Controls the overall backup process."""
+
     _map_type: dict[Dataset, Dataset | None]
 
     def __init__(self, local_pool: Pool, external_pool: ExternalPool):
@@ -55,6 +57,7 @@ class Manager:
         self._external_pool = external_pool
 
     def backup(self):
+        """Backup workflow."""
         self._external_pool.import_()
         try:
             self._external_pool.scrub(skip_if_recently_scrubbed=True)
@@ -65,18 +68,26 @@ class Manager:
             self._external_pool.export()
 
     def _backup_all_datasets(self):
+        """Send snapshots of local datasets to the backup pool."""
         print("Backing up datasets")
-        for local_dataset, remote_dataset in self._get_dataset_backup_map().items():
+        for (
+            local_dataset,
+            remote_dataset,
+        ) in self._get_user_filtered_dataset_backup_map().items():
             if remote_dataset is None:
                 stream = self._send_absolute(local_dataset)
             else:
                 stream = self._send_incremental(local_dataset, remote_dataset)
             ZFS.receive(stream, self._external_pool)
 
-    def _get_dataset_backup_map(self) -> _map_type:
+    def _get_user_filtered_dataset_backup_map(self) -> _map_type:
         return self._user_confirm_new_datasets(self._get_raw_dataset_map())
 
     def _user_confirm_new_datasets(self, dataset_map: _map_type) -> _map_type:
+        """For datasets that exist only locally, ask the user if he wants to back it up.
+
+        If he doesn't, remove it from the dict.
+        """
         return {
             local_dataset: remote_dataset
             for local_dataset, remote_dataset in dataset_map.items()
@@ -84,6 +95,10 @@ class Manager:
         }
 
     def _get_raw_dataset_map(self) -> _map_type:
+        """Return map from local to remote datasets.
+
+        If the local dataset has no remote match, set the remote dataset to None.
+        """
         return {
             local_dataset: self._search_matching_dataset_in_remote_pool(
                 local_dataset, self._external_pool
@@ -94,23 +109,29 @@ class Manager:
     def _send_incremental(
         self, local_dataset: Dataset, remote_dataset: Dataset
     ) -> Popen:
-        start_snapshot = self._get_last_common_snapshot(local_dataset, remote_dataset)
-        end_snapshot = self._get_last_snapshot_with_backup_tag(local_dataset)
+        """Send incremental stream between two datasets to remote."""
+        start_snapshot = self._get_newest_common_snapshot_with_backup_tags(
+            local_dataset, remote_dataset
+        )
+        end_snapshot = self._get_newest_snapshot_with_backup_tag(local_dataset)
         stream = ZFS.send_incremental(start_snapshot, end_snapshot)
         return stream
 
     def _send_absolute(self, local_dataset: Dataset) -> Popen:
-        snapshot = self._get_last_snapshot_with_backup_tag(local_dataset)
+        """Send absolute stream to remote."""
+        snapshot = self._get_newest_snapshot_with_backup_tag(local_dataset)
         return ZFS.send_absolute(snapshot)
 
-    def _get_last_snapshot_with_backup_tag(self, local_dataset):
-        snapshots = self._find_snapshots_with_backup_tag(local_dataset)
+    def _get_newest_snapshot_with_backup_tag(self, dataset: Dataset) -> Snapshot:
+        """From all snapshots in the dataset, get the newest one that matches the backup tags in the config."""
+        snapshots = self._find_snapshots_with_backup_tag(dataset)
         snapshots.sort()
         end_snapshot = snapshots[-1]
         return end_snapshot
 
     @property
     def _datasets_to_backup(self) -> list[Dataset]:
+        """Return local datasets to consider for a backup."""
         return [
             dataset
             for dataset in self._local_pool.datasets
@@ -119,6 +140,7 @@ class Manager:
 
     @staticmethod
     def _find_snapshots_with_backup_tag(dataset: Dataset) -> list[Snapshot]:
+        """Find snapshots of a dataset that carry the backup tags."""
         regex = _get_regex_matching_snapshots_with_tags(
             [config.snapshot_tag, config.snapshot_interval]
         )
@@ -130,15 +152,22 @@ class Manager:
     def _search_matching_dataset_in_remote_pool(
         dataset: Dataset, pool: Pool
     ) -> Dataset | None:
+        """For a dataset in the local pool, get the matching dataset in the remote pool.
+
+        If there is no match, return None.
+        """
         dataset_to_search = dataset.replace_pool(pool.name)
         for dataset in pool.datasets:
             if dataset == dataset_to_search:
                 return dataset
 
     @classmethod
-    def _get_last_common_snapshot(
+    def _get_newest_common_snapshot_with_backup_tags(
         cls, local_dataset: Dataset, remote_dataset: Dataset
     ) -> Snapshot:
+        """In a local and a remote dataset, find the newest snapshot with backup tags which exists in both datasets.
+
+        Return the local snapshot."""
         common_snapshots = [
             local_snap
             for local_snap in list(cls._find_snapshots_with_backup_tag(local_dataset))
@@ -287,7 +316,7 @@ class ZPool(CommandInterface):
         cls._scrub_if_necessary(pool, skip_if_recently_scrubbed)
         if wait_for_finish:
             cls._run_command(*cls._Subcommands.wait, pool.name)
-        if not cls._healthy(pool):
+        if not cls._is_healthy(pool):
             raise IOError(f"Pool {pool.name} is not healthy.")
 
     @classmethod
@@ -312,7 +341,7 @@ class ZPool(CommandInterface):
         return "scrub in progress" in cls._get_pool_status_output(pool)
 
     @classmethod
-    def _healthy(cls, pool: Pool) -> bool:
+    def _is_healthy(cls, pool: Pool) -> bool:
         return "ONLINE" in cls._get_pool_status_output(pool)
 
     @classmethod