Use python script

k8s/pgsql_bkps_jobs/pg-delete-old-backups-cronJob.yaml

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+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: postgresql-delete-old-backups
+spec:
+  schedule: "0 1 * * *"
+  failedJobsHistoryLimit: 3
+  successfulJobsHistoryLimit: 3
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          restartPolicy: OnFailure
+          containers:
+          - name: delete-old-backups
+            image: pyar/delete_old_backups
+            imagePullPolicy: Always
+            volumeMounts:
+            - mountPath: "/pg_backup"
+              name: backup-volume
+          volumes:
+            - name: backup-volume
+              persistentVolumeClaim:
+                claimName: pg-backup-pvc

scripts/Dockerfile

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+FROM python:3.9 
+
+ADD delete_old_backups.py .
+CMD ["python", "./delete_old_backups.py"]

scripts/delete_old_backups.py

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+"""Script to delete old backups in Azure.
+
+Tests builtin, just run `pytest` on this file.
+"""
+
+import re
+import sys
+from pathlib import Path
+from datetime import date
+
+
+
+
+MAX_LIFE = 30  # days
+RE_BACKUP_FILENAME = r"backupOn(\d\d\d\d)-(\d\d)-(\d\d)-(\d\d)-00_.*\.dump"
+
+today = date.today()
+
+
+def remove_old_files(basedir):
+    """Remove (some) old files found in the indicated directory.
+
+    The rule to deletion is: all those files older than MAX_LIFE days except first month day.
+    """
+    allfiles = basedir.iterdir()
+    for fpath in allfiles:
+        if rematch := re.match(RE_BACKUP_FILENAME, str(fpath.name)):
+            year, month, day, hour = map(int, rematch.groups())
+            if day == 1 and hour == 0:
+                # do not remove backups from first day of month
+                continue
+            backup_date = date(year, month, day)
+            delta_days = (today - backup_date).days
+            if delta_days > MAX_LIFE:
+                # too old! remove it
+                fpath.unlink()
+
+if __name__ == "__main__":
+    remove_old_files(Path("/pg_backup/"))
+    sys.exit(0)
+else:
+    # import pytest only when this is used as a module (imported by pytest itself to run the tests)
+    import pytest
+
+
+def test_nothing(tmp_path):
+    """No files in the indicated directory."""
+    remove_old_files(tmp_path)
+
+
+@pytest.mark.parametrize("filedate", [
+    "2001-11-08",  # today
+    "2001-11-07",  # yesterday
+    "2002-11-07",  # next year ... impossible, but let's test it anyway
+    "2001-10-09",  # exactly MAX_LIFE ago
+])
+@pytest.mark.parametrize("descriptor", [
+    "eventol_prod",
+    "web_production",
+    "asoc_members",
+])
+def test_recent(tmp_path, filedate, descriptor, monkeypatch):
+    """Do not remove recent files."""
+    testfile = tmp_path / f"backupOn{filedate}-00-00_{descriptor}.dump"
+    testfile.touch()
+    monkeypatch.setitem(globals(), "today", date(2001, 11, 8))
+    remove_old_files(tmp_path)
+    assert testfile.exists()
+
+
+@pytest.mark.parametrize("filedate", [
+    "2001-10-08",  # a month ago... but it's actually 31 days!
+    "2001-10-02",  # little older than the limit
+    "2001-02-15",  # quite older
+])
+@pytest.mark.parametrize("descriptor", [
+    "eventol_prod",
+    "web_production",
+    "asoc_members",
+])
+def test_older_normal(tmp_path, filedate, descriptor, monkeypatch):
+    """Remove old files."""
+    testfile = tmp_path / f"backupOn{filedate}-00-00_{descriptor}.dump"
+    testfile.touch()
+    monkeypatch.setitem(globals(), "today", date(2001, 11, 8))
+    remove_old_files(tmp_path)
+    assert not testfile.exists()
+
+
+@pytest.mark.parametrize("filedate", [
+    "2001-11-01",  # day one same month
+    "2001-10-01",  # day one previous month
+    "2000-01-01",  # day one, really old
+])
+def test_older_firstday(tmp_path, filedate, monkeypatch):
+    """Keep files for day one no matter if old."""
+    testfile = tmp_path / f"backupOn{filedate}-00-00_eventol_prod.dump"
+    testfile.touch()
+    monkeypatch.setitem(globals(), "today", date(2001, 11, 8))
+    remove_old_files(tmp_path)
+    assert testfile.exists()
+
+
+def test_complete(tmp_path, monkeypatch):
+    """Normal case, lot of files, some to keep some to don't."""
+    # pairs date / should still exist
+    testpoints = [
+        ("2001-09-01", True),
+        ("2001-09-05", False),
+        ("2001-09-15", False),
+        ("2001-10-01", True),
+        ("2001-10-05", False),
+        ("2001-10-15", True),
+        ("2001-11-01", True),
+        ("2001-11-05", True),
+    ]
+
+    testfiles = []
+    for filedate, keep in testpoints:
+        tf = tmp_path / f"backupOn{filedate}-00-00_eventol_prod.dump"
+        tf.touch()
+        testfiles.append((tf, keep))
+    monkeypatch.setitem(globals(), "today", date(2001, 11, 8))
+    remove_old_files(tmp_path)
+
+    for tf, keep in testfiles:
+        assert tf.exists() == keep