commit b8edec0076857728b998b895f59bd2f73b45f692
Author: Matthias Blankertz <matthias@blankertz.org>
Date:   Wed Sep 29 00:09:57 2021 +0200

    initial commit

diff --git a/LICENSE b/LICENSE
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+++ b/LICENSE
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+MIT License
+
+Copyright (c) 2021 Matthias Blankertz
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
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+++ b/requirements.txt
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+python-dateutil
diff --git a/setup.py b/setup.py
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+++ b/setup.py
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+from setuptools import setup, find_packages
+
+with open('LICENSE') as f:
+    license = f.read()
+
+setup(
+    name='zfs_smart_snapshot',
+    version='0.0.0',
+    description='Smart snapshoting for ZFS',
+    author='Matthias Blankertz',
+    author_email='matthias@blankertz.org',
+    license=license,
+    packages=find_packages(exclude=('tests', 'docs')),
+    entry_points={
+        'console_scripts': [
+            'zfs_smart_snapshot = zfs_smart_snapshot.main:main',
+        ],
+    },
+)
diff --git a/tests/context.py b/tests/context.py
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+++ b/tests/context.py
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+import os
+import sys
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+
+import zfs_smart_snapshot
diff --git a/tests/test_keep.py b/tests/test_keep.py
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+++ b/tests/test_keep.py
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+from datetime import datetime
+from zfs_smart_snapshot.main import keep_year, keep_month, keep_day, keep_hour, keep_frequent
+
+
+dates = [datetime(2018, 2, 3), datetime(2019, 3, 4), datetime(2020, 4, 5), datetime(2021, 1, 2),
+         datetime(2021, 2, 2), datetime(2021, 2, 3), datetime(2021, 3, 3), datetime(2021, 3, 4),
+         datetime(2021, 3, 5)]
+now = datetime(2021, 3, 5, 22, 45, 0)
+
+
+def test_keep_year():
+    assert keep_year(now, dates, 2) == {datetime(2020, 4, 5), datetime(2021, 1, 2)}
+    assert keep_year(now, dates, 0) == set()
+    dates_gap = [datetime(2018, 2, 3), datetime(2019, 3, 4), datetime(2021, 5, 6)]
+    assert keep_year(datetime(2021, 5, 6), dates_gap, 3) == {datetime(2019, 3, 4), datetime(2021, 5, 6)}
+    assert keep_year(datetime(2022, 2, 3), dates_gap, 1) == set()
+
+
+def test_keep_month():
+    assert keep_month(now, dates, 3) == {datetime(2021, 1, 2), datetime(2021, 2, 2), datetime(2021, 3, 3)}
+
+
+def test_keep_day():
+    assert keep_day(now, dates, 3) == {datetime(2021, 3, 3), datetime(2021, 3, 4), datetime(2021, 3, 5)}
+
+
+datetimes = [datetime(2021, 3, 5, 17, 0, 0), datetime(2021, 3, 5, 18, 0, 0), datetime(2021, 3, 5, 19, 0, 0),
+             datetime(2021, 3, 5, 20, 0, 0), datetime(2021, 3, 5, 21, 0, 0), datetime(2021, 3, 5, 22, 0, 0),
+             datetime(2021, 3, 5, 22, 15, 0), datetime(2021, 3, 5, 22, 30, 0), datetime(2021, 3, 5, 22, 45, 0)]
+
+
+def test_keep_hour():
+    assert keep_hour(now, datetimes, 3) == {datetime(2021, 3, 5, 20, 0, 0), datetime(2021, 3, 5, 21, 0, 0),
+                                            datetime(2021, 3, 5, 22, 0, 0)}
+
+
+def test_keep_frequent():
+    assert keep_frequent(now, datetimes, 3) == {datetime(2021, 3, 5, 22, 15, 0), datetime(2021, 3, 5, 22, 30, 0),
+                                                datetime(2021, 3, 5, 22, 45, 0)}
diff --git a/zfs_smart_snapshot/__init__.py b/zfs_smart_snapshot/__init__.py
new file mode 100644
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+++ b/zfs_smart_snapshot/__init__.py
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+
diff --git a/zfs_smart_snapshot/main.py b/zfs_smart_snapshot/main.py
new file mode 100644
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+++ b/zfs_smart_snapshot/main.py
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+from datetime import datetime
+from dateutil.relativedelta import relativedelta
+
+
+def keep_date(now, snapshots, date_convert, delta, count):
+    keep = set()
+    if count < 1:
+        return keep
+    start_date = date_convert(now) - delta*(count-1)
+    for snapshot in snapshots:
+        if snapshot.date() >= start_date:
+            keep.add(snapshot)
+            start_date = date_convert(snapshot) + delta
+        if start_date > now.date():
+            break
+    return keep
+
+
+def keep_year(now, snapshots, count):
+    return keep_date(now, snapshots, lambda d: d.date().replace(day=1, month=1), relativedelta(years=1), count)
+
+
+def keep_month(now, snapshots, count):
+    return keep_date(now, snapshots, lambda d: d.date().replace(day=1), relativedelta(months=1), count)
+
+
+def keep_day(now, snapshots, count):
+    return keep_date(now, snapshots, lambda d: d.date(), relativedelta(days=1), count)
+
+
+def keep_time(now, snapshots, convert, delta, count):
+    keep = set()
+    if count < 1:
+        return keep
+    start = convert(now) - delta*(count-1)
+    for snapshot in snapshots:
+        if snapshot >= start:
+            keep.add(snapshot)
+            start = convert(snapshot) + delta
+        if start > now:
+            break
+    return keep
+
+
+def keep_hour(now, snapshots, count):
+    return keep_time(now, snapshots, lambda d: d.replace(minute=0, second=0, microsecond=0), relativedelta(hours=1),
+                     count)
+
+
+def keep_frequent(now, snapshots, count):
+    return keep_time(now, snapshots, lambda d: d.replace(minute=d.minute//15*15, second=0, microsecond=0),
+                     relativedelta(minutes=15), count)
+
+
+def snapshots_to_keep(now, snapshots, yearly=0, monthly=0, weekly=0, daily=0, hourly=0, frequently=0):
+    snapshots.sort()
+    keep = set()
+    keep.union(keep_year(now, snapshots, yearly))
+    keep.union(keep_month(now, snapshots, monthly))
+    keep.union(keep_day(now, snapshots, daily))
+    return keep
+
+
+def main():
+    print("Hello, world!")