start introducing modules

zfs_backup/dataset.py

@@ -0,0 +1,66 @@
+from __future__ import annotations
+
+import config
+from zfs import ZFS
+from zfs_backup.core import _get_regex_matching_snapshots_with_tags
+from snapshot import Snapshot
+from zfs_path import ZFSPath
+
+
+class Dataset:
+    def __init__(self, zfs_path: ZFSPath):
+        self._path = zfs_path
+
+    def __repr__(self):
+        return self.qualified_name
+
+    def __eq__(self, other: Dataset):
+        return self._path == other._path
+
+    def __hash__(self):
+        return self._path.__hash__()
+
+    @classmethod
+    def from_string(cls, qualified_name: str) -> Dataset:
+        return cls(ZFSPath.from_string(qualified_name))
+
+    @property
+    def qualified_name(self) -> str:
+        return str(self._path)
+
+    @property
+    def name_without_pool(self) -> str:
+        return self._path.name_without_pool
+
+    @property
+    def snapshots(self) -> list[Snapshot]:
+        """get qualified snapshots that are direct children of the dataset"""
+        return ZFS.get_snapshots(self)
+
+    def replace_pool(self, name: str) -> Dataset:
+        return Dataset(self._path.replace_pool(name))
+
+    def clean_old_snapshots(self) -> None:
+        for interval, number in config.keep_snapshots_per_interval.items():
+            self._clean_old_snapshots_for_interval(interval, number)
+
+    def _clean_old_snapshots_for_interval(self, interval: str, max_count: int) -> None:
+        regex = _get_regex_matching_snapshots_with_tags([config.snapshot_tag, interval])
+        snapshots = [
+            snapshot for snapshot in self.snapshots if snapshot.matches_regex(regex)
+        ]
+        old_snapshots = self._get_oldest_snapshots_exceeding_max_count(
+            snapshots, max_count
+        )
+        for snapshot in old_snapshots:
+            snapshot.destroy()
+
+    @staticmethod
+    def _get_oldest_snapshots_exceeding_max_count(
+        snapshots: list[Snapshot], max_count: int
+    ) -> list[Snapshot]:
+        snapshots.sort()
+        count = len(snapshots) - max_count
+        if count < 0:
+            count = 0
+        return snapshots[:count]