mailman/backup: Use a python script, with which is easier to implement backup rotation

- name: Backup script

  template:

    src: backup.sh

    dest: /srv/mailman/backup.sh

    src: backup.py

    dest: /srv/mailman/backup.py

    owner: root

    group: root

    mode: 0755

      job: root

    - env: false

      name: backup

      job: chronic /srv/mailman/backup.sh

      job: chronic /srv/mailman/backup.py

#!/usr/bin/python3

#

# {{ ansible_managed }}

#

import os

import re

import sys

import datetime

import tempfile

import subprocess

from pathlib import Path

time_str = '%Y%m%dT%H%M%SZ'

reg = re.compile(r'^backup-rb-lists_(\d{8}T\d{6}Z)\.tar\.xz$')

now = datetime.datetime.now()

now_str = now.strftime(time_str)

backupdir = Path('/srv/mailman/backups/')

if not backupdir.exists():

    backupdir.mkdir()

if not backupdir.is_dir():

    print('backupdir exists but it is not a directory', file=sys.stderr)

bakfile = backupdir / 'backup-rb-lists_{}.tar.xz'.format(now_str)

with tempfile.NamedTemporaryFile(dir=backupdir, delete=False) as f:

    print('Creating the tarball…')

    try:

        subprocess.run(

            ('tar', 'cJf', f.name, '.'),

            cwd='/var/lib/mailman/',

            stdout=subprocess.PIPE,

            stderr=subprocess.STDOUT,

            check=True,

        )

    except subprocess.CalledProcessError as e:

        print('tar call failed ({}):'.format(e.returncode), file=sys.stderr)

        print(e.stdout.decode('utf-8'), file=sys.stderr)

        os.remove(f.name)

        sys.exit(1)

    try:

        print('Moving backup tarball in place…')

        os.rename(f.name, bakfile)

    except OSError as e:

        print('Failed to rename file in place', file=sys.stderr)

        os.remove(f.name)

        raise e

print('Backup completed!')

print()

# find old backup files

to_keep = []

to_remove = []

for f in backupdir.iterdir():

    if not f.is_file():

        continue

    r = re.match(reg, f.name)

    if not r:

        print(f'Not recognized: {f.name}')

        continue

    old_date = datetime.datetime.strptime(r.group(1), time_str)

    if now - old_date < datetime.timedelta(days=30):

        to_keep.append(f)

        continue

    if old_date.day == 1:

        to_keep.append(f)

        continue

    to_remove.append(f)

# TODO: actually implement removal.

print("rsync to Mattia's place:")

try:

    p = subprocess.check_output(

        ('rsync', '-vr', f'{backupdir}{os.sep}',

         'mattia@savidlin.mapreri.org:/home/mattia/backup-rb-lists/'),

        stderr=subprocess.STDOUT,

    )

except subprocess.CalledProcessError as e:

    print('rsync to mattia failed:', file=sys.stderr)

    print(e.stdout.decode('utf-8'))

    sys.exit(1)

#!/bin/sh

#

# {{ ansible_managed }}

#

set -eux

d=$(date +%Y%m%dT%H%M%SZ)

backupdir=/srv/mailman/backups

mkdir -pv "$backupdir"

f="$backupdir/backup-rb-lists_${d}.tar.xz"

trap 'rm -fv ${f}.tmp' EXIT

cd /var/lib/mailman

tar cJf "${f}.tmp" .

mv "${f}.tmp" "$f"

trap - EXIT

rsync -v "$f" mattia@savidlin.mapreri.org:/home/mattia/backup-rb-lists/