From: Christian Heller Date: Mon, 4 Dec 2023 14:16:31 +0000 (+0100) Subject: Improve backup algorithm. X-Git-Url: https://plomlompom.com/repos/?a=commitdiff_plain;h=e58262d6913522cf57d5317fbf0398e2d56b29a0;p=misc Improve backup algorithm. --- diff --git a/plomlib.py b/plomlib.py index 739b00f..d1b4c4c 100644 --- a/plomlib.py +++ b/plomlib.py @@ -31,46 +31,52 @@ class PlomDB: return # collect modification times of numbered .bak files + print('DEBUG BACKUP') bak_prefix = f'{self.db_file}.bak.' - backup_dates = [] - i = 0 - bak_as = f'{bak_prefix}{i}' - while os.path.exists(bak_as): - mod_time = os.path.getmtime(bak_as) - backup_dates += [str(datetime.fromtimestamp(mod_time))] - i += 1 - bak_as = f'{bak_prefix}{i}' + # backup_dates = [] + mtimes_to_paths = {} + for path in [path for path in os.listdir(os.path.dirname(bak_prefix)) + if path.startswith(os.path.basename(bak_prefix))]: + mod_time = os.path.getmtime(path) + print(f'DEBUG pre-exists: {path} {mod_time}') + mtimes_to_paths[str(datetime.fromtimestamp(mod_time))] = path + # backup_dates += [str(datetime.fromtimestamp(mod_time))] + + for mtime in sorted(mtimes_to_paths.keys()): + print(f'DEBUG mtimes_to_paths: {mtime}:{mtimes_to_paths[mtime]}') # collect what numbered .bak files to save: the older, the fewer; for each # timedelta, keep the newest file that's older ages_to_keep = [timedelta(minutes=4**i) for i in range(0, 8)] + print(f'DEBUG ages_to_keep: {ages_to_keep}') now = datetime.now() - to_save = [] + to_save = {} for age in ages_to_keep: limit = now - age - for i, date in enumerate(reversed(backup_dates)): - if datetime.strptime(date, '%Y-%m-%d %H:%M:%S.%f') < limit: - unreversed_i = len(backup_dates) - i - 1 - if unreversed_i not in to_save: - to_save += [unreversed_i] + for mtime in reversed(sorted(mtimes_to_paths.keys())): + print(f'DEBUG checking if {mtime} < {limit} ({now} - {age})') + if datetime.strptime(mtime, '%Y-%m-%d %H:%M:%S.%f') < limit: + print('DEBUG it is, adding!') + to_save[mtime] = mtimes_to_paths[mtime] break - # remove redundant backup files - j = 0 - for i in to_save: - if i != j: - source = f'{bak_prefix}{i}' - target = f'{bak_prefix}{j}' + for path in [path for path in mtimes_to_paths.values() + if path not in to_save.values()]: + print(f'DEBUG removing {path} cause not in to_save') + os.remove(path) + + i = 0 + for mtime in sorted(to_save.keys()): + source = to_save[mtime] + target = f'{bak_prefix}{i}' + print(f'DEBUG to_save {source} -> {target}') + if source != target: shutil.move(source, target) - j += 1 - for i in range(j, len(backup_dates)): - try: - os.remove(f'{bak_prefix}{i}') - except FileNotFoundError: - pass + i += 1 # put copy of current state at end of bak list - shutil.copy(self.db_file, f'{bak_prefix}{j}') + print(f'DEBUG saving current state to {bak_prefix}{i}') + shutil.copy(self.db_file, f'{bak_prefix}{i}') def write_text_to_db(self, text, mode='w'): self.lock()