256 lines
9.2 KiB
Python
256 lines
9.2 KiB
Python
"""
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Module with backup functions.
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"""
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import logging
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import os
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import shutil
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from datetime import datetime, timedelta
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from typing import Optional, Iterable
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import curateipsum.fs as 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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_lg = logging.getLogger(__name__)
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def _is_backup_entity(backup_entry: os.DirEntry) -> bool:
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""" Check if entity_path is a single backup dir. """
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if not backup_entry.is_dir():
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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(backup_dir: str) -> Iterable[os.DirEntry]:
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b_iter = os.scandir(backup_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_entity(b_ent):
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continue
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if not os.listdir(b_ent.path):
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_lg.info("Removing empty backup entity: %s", b_ent.name)
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os.rmdir(b_ent.path)
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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(backup_dir: str) -> Optional[os.DirEntry]:
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""" Returns path to latest backup created in backup_dir or None. """
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all_backups = sorted(_iterate_backups(backup_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: os.DirEntry) -> datetime:
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return datetime.strptime(backup.name, BACKUP_ENT_FMT)
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def set_backups_lock(backup_dir: str, force: bool = False) -> bool:
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""" Return false if previous backup is still running. """
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lock_file_path = os.path.join(backup_dir, LOCK_FILE)
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if os.path.exists(lock_file_path):
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if not force:
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return False
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os.unlink(lock_file_path)
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open(lock_file_path, "a").close()
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return True
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def release_backups_lock(backup_dir: str):
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lock_file_path = os.path.join(backup_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 cleanup_old_backups(
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backup_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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min_free_space: int = 0
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):
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"""
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Delete old backups. Never deletes the only backup.
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:param backup_dir: full path to backup directory.
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:param dry_run: don't do anything actually.
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:param keep_all: the number of days that all backups must be kept.
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:param keep_daily: the number of days that all daily backups must be kept.
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:param keep_weekly: the number of weeks of which one weekly backup must be kept.
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:param keep_monthly: the number of months (1 month = 30 days) of which
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one monthly backup must be kept.
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:param keep_yearly: the number of years of which one yearly backup must be kept.
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:param min_free_space: not used right now
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:return:
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"""
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all_backups = sorted(_iterate_backups(backup_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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elif 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 not dry_run and do_delete:
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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, entry_relpath: str, action: fs.Actions):
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_lg.debug("%s %s", action, entry_relpath)
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if action is not 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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backup_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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""" Main backup function """
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start_time_fmt = datetime.now().strftime(BACKUP_ENT_FMT)
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cur_backup = fs.PseudoDirEntry(os.path.join(backup_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(backup_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 backup,"
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" 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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# clean up delta dir from copied backup
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shutil.rmtree(os.path.join(cur_backup.path, DELTA_DIR), 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 %s backup", src_abs, cur_backup.name)
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for entry_relpath, action in rsync_func(src_abs, dst_abs, dry_run=dry_run):
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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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)
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backup_changed = 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("Newly 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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_lg.info("Backup created: %s", cur_backup.name)
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