1207ee2838
This commit addresses 8 high-priority issues identified in code analysis. Fixes #3, #4, #5, #7, #10, #19, #20, #21 ## Critical Bug Fixes 1. **Race condition in lock file creation (#3)** - Changed to atomic file creation using os.O_CREAT | os.O_EXCL - Prevents two processes from both acquiring the lock - Location: curateipsum/backup.py:110-115 2. **Invalid lock file error handling (#4)** - Added try/except for corrupted/empty lock files - Gracefully removes corrupted locks and retries - Location: curateipsum/backup.py:121-133 3. **SIGKILL vs SIGTERM issue (#5)** - Now sends SIGTERM first for graceful shutdown - Waits 5 seconds before escalating to SIGKILL - Allows previous process to clean up resources - Location: curateipsum/backup.py:146-156 4. **Wrong stat object for permissions (#7)** - Fixed bug where dst_stat was used instead of src_stat - Permissions are now correctly updated during rsync - Location: curateipsum/fs.py:371 5. **os.chown() fails for non-root users (#10)** - Wrapped all os.chown() calls in try/except blocks - Logs debug message instead of crashing - Allows backups to succeed for non-root users - Locations: curateipsum/fs.py:217-221, 228-231, 383-387, 469-472 ## Comprehensive Test Coverage 6. **Lock file tests (#19)** - Added TestBackupLock class with 7 test cases - Tests: creation, concurrent prevention, stale locks, corruption - Location: tests/test_backups.py:228-330 7. **Filesystem operation tests (#20)** - Added tests/test_fs_extended.py with 6 test classes - Tests: copy_file, copy_direntry, rsync, hardlink_dir, scantree, rm_direntry - 20+ test cases covering normal and edge cases - Location: tests/test_fs_extended.py 8. **Integration tests (#21)** - Added tests/test_integration.py with 2 test classes - Tests full backup workflow end-to-end - Tests: incremental backups, hardlinks, delta dirs, cleanup, recovery - 14 test cases covering complete backup lifecycle - Location: tests/test_integration.py ## Test Results All 68 tests pass successfully: - 11 original backup cleanup tests - 7 new lock file tests - 16 original fs tests - 20 new fs extended tests - 14 new integration tests ## Impact These fixes address critical bugs that could cause: - Data corruption from concurrent backups - Incomplete cleanup from forced process termination - Permission sync failures - Tool unusability for non-root users The comprehensive test coverage ensures these bugs are caught early and provides confidence for future refactoring.
411 lines
15 KiB
Python
411 lines
15 KiB
Python
"""
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Module with backup functions.
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"""
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import errno
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import logging
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import os
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import shutil
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import signal
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import time
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from datetime import datetime, timedelta
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from typing import Optional, Iterable, Union
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from curateipsum import fs
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BACKUP_ENT_FMT = "%Y%m%d_%H%M%S"
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LOCK_FILE = ".backups_lock"
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DELTA_DIR = ".backup_delta"
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BACKUP_MARKER = ".backup_finished"
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_lg = logging.getLogger(__name__)
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def _get_backup_marker(
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backup_entry: Union[os.DirEntry, fs.PseudoDirEntry]
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) -> fs.PseudoDirEntry:
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"""Return DirEntry for marker file of given backup."""
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marker_name = "%s_%s" % (BACKUP_MARKER, backup_entry.name)
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marker_path = os.path.join(backup_entry.path, marker_name)
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return fs.PseudoDirEntry(path=marker_path)
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def _is_backup(backup_entry: Union[os.DirEntry, fs.PseudoDirEntry]) -> bool:
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"""Guess if backup_entry is a real backup."""
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backup_marker = _get_backup_marker(backup_entry)
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# if there is no marker file in the backup dir, it's not a backup
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if not os.path.exists(backup_marker.path):
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return False
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# if there is only a marker file in the backup dir, it's not a backup
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if os.listdir(backup_entry.path) == [backup_marker.name]:
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return False
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try:
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datetime.strptime(backup_entry.name, BACKUP_ENT_FMT)
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return True
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except ValueError:
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return False
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def _iterate_backups(backups_dir: str) -> Iterable[os.DirEntry]:
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"""Iterate over backups in backups_dir."""
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b_iter = os.scandir(backups_dir)
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b_ent: os.DirEntry
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for b_ent in b_iter:
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if not _is_backup(b_ent):
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continue
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yield b_ent
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b_iter.close()
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def _get_latest_backup(backups_dir: str) -> Optional[os.DirEntry]:
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"""Returns path to latest backup created in backups_dir or None."""
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all_backups = sorted(_iterate_backups(backups_dir), key=lambda e: e.name)
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if all_backups:
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return all_backups[-1]
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return None
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def _date_from_backup(backup_entry: os.DirEntry) -> datetime:
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"""Returns datetime object from backup name."""
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return datetime.strptime(backup_entry.name, BACKUP_ENT_FMT)
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def _pid_exists(pid: int) -> bool:
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"""Check whether pid exists in the current process table."""
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if pid == 0:
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# According to "man 2 kill" PID 0 has a special meaning:
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# it refers to <<every process in the process group of the
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# calling process>> so we don't want to go any further.
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# If we get here it means this UNIX platform *does* have
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# a process with id 0.
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return True
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try:
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os.kill(pid, 0)
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except OSError as err:
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if err.errno == errno.ESRCH:
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# ESRCH == No such process
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return False
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elif err.errno == errno.EPERM:
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# EPERM clearly means there's a process to deny access to
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return True
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else:
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# According to "man 2 kill" possible error values are
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# (EINVAL, EPERM, ESRCH) therefore we should never get
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# here. If we do let's be explicit in considering this
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# an error.
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raise err
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else:
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return True
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def set_backups_lock(backups_dir: str,
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force: bool = False) -> bool:
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"""
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Set lock file to prevent multiple backups running at the same time.
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Lock file contains PID of the process that created it.
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Return false if previous backup is still running and force flag is not set.
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"""
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lock_file_path = os.path.join(backups_dir, LOCK_FILE)
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# Try to create lock file atomically
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try:
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fd = os.open(lock_file_path, os.O_CREAT | os.O_EXCL | os.O_WRONLY, 0o644)
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os.write(fd, str(os.getpid()).encode())
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os.close(fd)
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return True
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except FileExistsError:
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# Lock file already exists, check if process is still running
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pass
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# Read existing lock file
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try:
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with open(lock_file_path, "r") as f:
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content = f.read().strip()
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if not content:
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raise ValueError("Lock file is empty")
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pid = int(content)
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except (ValueError, IOError) as e:
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_lg.warning("Corrupted lock file (%s), removing and retrying", e)
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try:
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os.unlink(lock_file_path)
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except OSError:
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pass
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return set_backups_lock(backups_dir, force)
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if _pid_exists(pid):
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if not force:
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_lg.warning(
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"Previous backup is still in progress (PID: %d), exiting", pid
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)
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return False
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_lg.warning(
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"Previous backup is still in progress (PID: %d), "
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"but force flag is set, attempting graceful termination", pid
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)
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# Try SIGTERM first for graceful shutdown
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try:
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os.kill(pid, signal.SIGTERM)
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_lg.info("Sent SIGTERM to process %d, waiting 5 seconds", pid)
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time.sleep(5)
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# Check if process is still running
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if _pid_exists(pid):
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_lg.warning("Process %d did not terminate, sending SIGKILL", pid)
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os.kill(pid, signal.SIGKILL)
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time.sleep(1) # Brief wait for SIGKILL to take effect
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except OSError as e:
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_lg.error("Failed to kill process %d: %s", pid, e)
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return False
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# Remove stale lock file and retry
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try:
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os.unlink(lock_file_path)
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except OSError as e:
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_lg.error("Failed to remove lock file: %s", e)
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return False
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return set_backups_lock(backups_dir, force)
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def release_backups_lock(backups_dir: str):
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"""Remove lock file."""
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lock_file_path = os.path.join(backups_dir, LOCK_FILE)
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if os.path.exists(lock_file_path):
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os.unlink(lock_file_path)
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def set_backup_marker(backup_entry: Union[os.DirEntry, fs.PseudoDirEntry]):
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"""Create finished backup marker file in backup's directory."""
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backup_marker = _get_backup_marker(backup_entry)
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if not os.path.exists(backup_marker.path):
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open(backup_marker.path, "a").close()
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def cleanup_old_backups(backups_dir: str,
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dry_run: bool = False,
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keep_all: int = 7,
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keep_daily: int = 30,
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keep_weekly: int = 52,
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keep_monthly: int = 12,
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keep_yearly: int = 5):
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"""
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Delete old backups. Never deletes the only backup.
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For keep_* params threshold is inclusive, e.g.:
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keep_weekly=1 being run on Thursday will keep one backup from this week and
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one from the previous, even if the previous week's backup was created on
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Monday.
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keep_monthly=3 being run on any day of April will keep one backup from each
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of months of January, February and March.
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:param backups_dir: full path to backups directory.
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:param dry_run: don't do anything.
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:param keep_all:
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up to this amount of days in the past all backups must be kept.
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:param keep_daily:
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up to this amount of days in the past one daily backup must be kept.
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:param keep_weekly:
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up to this amount of weeks in the past one weekly backup must be kept.
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:param keep_monthly:
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up to this amount of months in the past one monthly backup must be kept.
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1 month is considered to be 30 days.
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:param keep_yearly:
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up to this amount of years in the past one yearly backup must be kept.
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1 year is considered to be 365 days.
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"""
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all_backups = sorted(_iterate_backups(backups_dir),
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key=lambda e: e.name, reverse=True)
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if dry_run:
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_lg.info("Dry-run, no backups will be actually removed")
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if not all_backups:
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_lg.debug("No backups, exiting")
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return
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if len(all_backups) == 1:
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_lg.debug("Only one backup (%s) exists, will not remove it",
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all_backups[0].name)
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return
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now = datetime.now()
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thresholds = {k: now.strftime(BACKUP_ENT_FMT)
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for k in ("all", "daily", "weekly", "monthly", "yearly")}
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if keep_all is not None:
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thresholds["all"] = ((now - timedelta(days=keep_all))
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.replace(hour=0, minute=0, second=0)
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.strftime(BACKUP_ENT_FMT))
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if keep_daily is not None:
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thresholds["daily"] = ((now - timedelta(days=keep_daily))
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.replace(hour=0, minute=0, second=0)
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.strftime(BACKUP_ENT_FMT))
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if keep_weekly is not None:
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thresholds["weekly"] = (
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(now - timedelta(weeks=keep_weekly, days=now.weekday()))
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.strftime(BACKUP_ENT_FMT)
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)
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if keep_monthly is not None:
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thresholds["monthly"] = ((now - timedelta(days=30*keep_monthly))
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.replace(day=1, hour=0, minute=0, second=0)
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.strftime(BACKUP_ENT_FMT))
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if keep_yearly is not None:
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thresholds["yearly"] = (
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(now - timedelta(days=365*keep_yearly))
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.replace(month=1, day=1, hour=0, minute=0, second=0)
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.strftime(BACKUP_ENT_FMT)
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)
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prev_backup = all_backups[0]
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to_remove = {b: False for b in all_backups}
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for backup in all_backups[1:]:
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# skip all backups made after threshold
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if backup.name > thresholds["all"]:
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prev_backup = backup
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continue
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# leave only one backup per day for backups made after threshold
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if backup.name > thresholds["daily"]:
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if (_date_from_backup(prev_backup).date()
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== _date_from_backup(backup).date()):
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to_remove[prev_backup] = True
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prev_backup = backup
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continue
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# leave only one backup per week for backups made after threshold
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if backup.name > thresholds["weekly"]:
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if (_date_from_backup(prev_backup).isocalendar()[1]
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== _date_from_backup(backup).isocalendar()[1]):
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to_remove[prev_backup] = True
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prev_backup = backup
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continue
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# leave only one backup per month for backups made after threshold
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if backup.name > thresholds["monthly"]:
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if (_date_from_backup(prev_backup).date().replace(day=1)
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== _date_from_backup(backup).date().replace(day=1)):
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to_remove[prev_backup] = True
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prev_backup = backup
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continue
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# leave only one backup per year for backups made after threshold
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if backup.name > thresholds["yearly"]:
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if (_date_from_backup(prev_backup).date().replace(month=1, day=1)
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== _date_from_backup(backup).date().replace(month=1, day=1)):
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to_remove[prev_backup] = True
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prev_backup = backup
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continue
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to_remove[backup] = True
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for backup, do_delete in to_remove.items():
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if do_delete:
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if dry_run:
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_lg.info("Would remove old backup %s", backup.name)
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else:
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_lg.info("Removing old backup %s", backup.name)
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shutil.rmtree(backup.path)
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def process_backed_entry(backup_dir: str,
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entry_relpath: str,
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action: fs.Actions,
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msg: str):
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"""
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Additional processing of backed up DirEntry (file/dir/symlink).
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Actions:
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- if DirEntry was not deleted, hardlink it to DELTA_DIR.
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"""
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_lg.debug("%s %s %s", action, entry_relpath, msg)
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if action not in (fs.Actions.ERROR, fs.Actions.DELETE):
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fs.nest_hardlink(src_dir=backup_dir, src_relpath=entry_relpath,
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dst_dir=os.path.join(backup_dir, DELTA_DIR))
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def initiate_backup(sources,
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backups_dir: str,
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dry_run: bool = False,
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external_rsync: bool = False,
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external_hardlink: bool = False):
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"""
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Main backup function.
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Creates a new backup directory, copies data from the latest backup,
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and then syncs data from sources.
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:param sources: list of directories to backup (relative paths ok)
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:param backups_dir: directory where all backups are stored
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:param dry_run: if True, no actual changes will be made
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:param external_rsync: if True, use external rsync instead of python
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:param external_hardlink: if True, use external hardlink instead of python
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"""
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start_time_fmt = datetime.now().strftime(BACKUP_ENT_FMT)
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cur_backup = fs.PseudoDirEntry(os.path.join(backups_dir, start_time_fmt))
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_lg.debug("Current backup dir: %s", cur_backup.path)
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latest_backup = _get_latest_backup(backups_dir)
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if latest_backup is None:
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_lg.info("Creating empty directory for current backup: %s",
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cur_backup.name)
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os.mkdir(cur_backup.path)
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else:
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_lg.info("Copying data from latest backup %s to current backup %s",
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latest_backup.name, cur_backup.name)
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hl_res = fs.hardlink_dir(src_dir=latest_backup.path,
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dst_dir=cur_backup.path,
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use_external=external_hardlink)
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if not hl_res:
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_lg.error("Something went wrong during copying data from latest"
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" backup, removing created %s", cur_backup.name)
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shutil.rmtree(cur_backup.path, ignore_errors=True)
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return
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# remove backup markers from copied backup
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for fname in os.listdir(cur_backup.path):
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if fname.startswith(BACKUP_MARKER):
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os.remove(os.path.join(cur_backup.path, fname))
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# clean up delta dir from copied backup
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shutil.rmtree(os.path.join(cur_backup.path, DELTA_DIR),
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ignore_errors=True)
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rsync_func = fs.rsync_ext if external_rsync else fs.rsync
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backup_changed = False
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for src in sources:
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src_abs = os.path.abspath(src)
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src_name = os.path.basename(src_abs)
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dst_abs = os.path.join(cur_backup.path, src_name)
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_lg.info("Backing up directory %s to backup %s",
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src_abs, cur_backup.name)
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try:
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for entry_relpath, action, msg in rsync_func(
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src_abs, dst_abs, dry_run=dry_run
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):
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# TODO maybe should be run if first backup too?
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if latest_backup is not None:
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process_backed_entry(
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backup_dir=cur_backup.path,
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entry_relpath=os.path.join(src_name, entry_relpath),
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action=action,
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msg=msg,
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)
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# raise flag if something was changed since last backup
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backup_changed = True
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except fs.BackupCreationError as err:
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_lg.error("Error during backup creation: %s", err)
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_lg.error("Failed to create backup %s, removing", cur_backup.name)
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shutil.rmtree(cur_backup.path, ignore_errors=True)
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# do not create backup on dry-run
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if dry_run:
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_lg.info("Dry-run, removing created backup: %s", cur_backup.name)
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shutil.rmtree(cur_backup.path, ignore_errors=True)
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# do not create backup if no change from previous one
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elif latest_backup is not None and not backup_changed:
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_lg.info("Created backup %s is the same as previous one %s, removing",
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cur_backup.name, latest_backup.name)
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shutil.rmtree(cur_backup.path, ignore_errors=True)
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else:
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set_backup_marker(cur_backup)
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_lg.info("Backup created: %s", cur_backup.name)
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