bundles/zfs: import bundle from work repository

bundles/zfs/files/zfs-auto-snapshot

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+
+
+import re
+
+from datetime import datetime
+from json import loads
+from subprocess import check_call, check_output
+from sys import argv
+
+
+def create_snap_and_rotate(ds, label, retain, now, all_snapshots):
+    new_snap = '{}@zfs-auto-snap_{}-{}'.format(ds, label, now)
+    check_call(['zfs', 'snapshot', new_snap])
+
+    prefix = '{}@zfs-auto-snap_{}-'.format(ds, label)
+    my_candidates = []
+    for i in sorted(all_snapshots):
+        if i.startswith(prefix):
+            my_candidates.append(i)
+
+    my_candidates.append(new_snap)
+
+    for i in my_candidates[:-retain]:
+        assert '@' in i, 'BUG! Dataset "{}" has no @!'.format(i)
+        check_call(['zfs', 'destroy', i])
+
+
+label = argv[1]
+
+with open('/etc/zfs-snapshot-config.json', 'r') as fp:
+    metadata = loads(fp.read())
+
+if 'snapshot_only' in metadata:
+    datasets = set(metadata['snapshot_only'])
+else:
+    output = check_output(['zfs', 'list', '-H', '-o', 'name']).decode('UTF-8')
+    datasets = set(output.splitlines())
+
+for pattern in metadata.get('snapshot_never', set()):
+    datasets = set(filter(lambda x: not re.search(pattern, x), datasets))
+
+default_retain = metadata['retain_defaults'][label]
+now = datetime.now().strftime('%F-%H%M')
+snapshots_created = False
+
+if datasets:
+    all_snapshots = check_output(['zfs', 'list', '-H', '-o', 'name', '-t', 'snap']).decode('UTF-8').splitlines()
+
+    for ds in datasets:
+        retain = int(metadata.get('retain_per_dataset', {}).get(ds, {}).get(label, default_retain))
+        if retain > 0:
+            create_snap_and_rotate(ds, label, retain, now, all_snapshots)
+            snapshots_created = True
+
+with open('/var/tmp/zfs-auto-snapshot.status', 'w') as fp:
+    fp.write('{}\n'.format(datetime.now().strftime('%s') if snapshots_created else 0))