mikes-backup-rotator/BackupRotator.py

252 lines
6.1 KiB
Python
Executable File

#!/usr/bin/env python3
"""
Mike's Backup Rotator
A simple script to help automatically rotate backup files
Copyright 2019 Mike Peralta; All rights reserved
Released under the GNU GENERAL PUBLIC LICENSE v3 (See LICENSE file for more)
"""
import datetime
import os
import shutil
import sys
import syslog
import yaml
class BackupRotator:
def __init__(self):
self.__dry_run = False
self.__configs = []
self.__config_paths = []
self.__calculated_actions = []
def run(self):
self.log("Begin")
self.consume_arguments()
self.consume_configs(self.__config_paths)
# Rotate once per config
for config_index in range(len(self.__configs)):
#
config = self.__configs[config_index]
#
self.log("Rotating for config " + str(config_index + 1) + " of " + str(len(self.__configs)), config["__path"])
self.do_rotate(config)
@staticmethod
def current_time():
now = datetime.datetime.now()
now_s = now.strftime("%b-%d-%Y %I:%M%p")
return str(now_s)
def log(self, s, o=None):
now = self.current_time()
to_log = "[" + now + "][Backup Rotator] " + str(s)
if o is not None:
to_log += " " + str(o)
syslog.syslog(to_log)
print(to_log)
def consume_arguments(self):
self.__config_paths = []
for i in range(1, len(sys.argv)):
arg = sys.argv[i]
if arg == "--config":
i, one_path = self.consume_argument_companion(i)
self.__config_paths.append(one_path)
self.log("Found config path argument:", one_path)
elif arg == "--dry-run":
self.__dry_run = True
self.log("Activating global dry-run mode")
@staticmethod
def consume_argument_companion(arg_index):
companion_index = arg_index + 1
if companion_index >= len(sys.argv):
raise Exception("Expected argument after", sys.argv[arg_index])
return companion_index, sys.argv[companion_index]
def consume_configs(self, paths: list=None):
if paths is None:
raise Exception("Auto-finding of config file not implemented")
# Use each config path
for path in paths:
# If this is a single path
if os.path.isfile(path):
self.consume_config(path)
# If this is a directory
elif os.path.isdir(path):
# Iterate over each file inside
for file_name in os.listdir(path):
self.consume_config(os.path.join(path, file_name))
def consume_config(self, path: str):
# Open the file
f = open(path)
if not f:
raise Exception("Unable to open config file: " + path)
# Parse
config = yaml.safe_load(f)
# Add its own path
config["__path"] = path
# Consume to internal
self.__configs.append(config)
self.log("Consumed config from path:", path)
def do_rotate(self, config):
self.rotate_paths(config)
def rotate_paths(self, config):
self.log("Begin rotating " + str(len(config["paths"])) + " paths")
for path in config["paths"]:
self.rotate_path(config, path)
def rotate_path(self, config, path):
self.log("Rotating path", path)
if "maximum-items" not in config:
raise Exception("Please provide config key: \"maximum-items\"")
max_items = config["maximum-items"]
if not os.path.isdir(path):
raise Exception("Path should be a directory:" + str(path))
children = self.gather_rotation_candidates(config, path)
# Do we need to rotate anything out?
if len(children) <= max_items:
self.log(
"Path only has " + str(len(children)) + " items,"
+ " but needs " + str(max_items) + " for rotation"
+ "; Won't rotate this path."
)
return
#
purge_count = len(children) - max_items
self.log(
"Need to purge " + str(purge_count) + " items"
)
for purge_index in range(purge_count):
#
item_to_purge = self.pick_item_to_purge(config, children)
children.remove(item_to_purge)
#
if os.path.isfile(item_to_purge):
self.remove_file(config, item_to_purge)
elif os.path.isdir(item_to_purge):
self.remove_directory(config, item_to_purge)
else:
raise Exception("Don't know how to remove this item: " + str(item_to_purge))
@staticmethod
def gather_rotation_candidates(config, path):
candidates = []
if "target-type" not in config.keys():
raise Exception("Please provide the configuration key: target-type")
for item_name in os.listdir(path):
item_path = os.path.join(path, item_name)
if config["target-type"] == "file":
if not os.path.isfile(item_path):
continue
elif config["target-type"] == "directory":
if not os.path.isdir(item_path):
continue
else:
raise Exception("Configuration key \"target-type\" must be \"file\" or \"directory\"")
candidates.append(item_path)
return candidates
@staticmethod
def pick_item_to_purge(config, items):
if "date-detection" not in config.keys():
raise Exception("Please provide config key: \"date-detection\"")
detection = config["date-detection"]
best_item = None
best_ctime = None
for item in items:
if detection == "file":
ctime = os.path.getctime(item)
if best_ctime is None or ctime < best_ctime:
best_ctime = ctime
best_item = item
else:
raise Exception("Invalid value for \"date-detection\": " + str(detection))
return best_item
def remove_file(self, config, file_path):
if not os.path.isfile(file_path):
raise Exception("Tried to remove a file, but this path isn't a file: " + str(file_path))
if self.__dry_run:
self.log("Won't purge file during global-level dry run: ", file_path)
elif "dry-run" in config.keys() and config["dry-run"] is True:
self.log("Won't purge file during config-level dry run: ", file_path)
else:
self.log("Purging file:", file_path)
os.remove(file_path)
def remove_directory(self, config, dir_path):
if not os.path.isdir(dir_path):
raise Exception("Tried to remove a directory, but this path isn't a directory: " + str(dir_path))
if self.__dry_run:
self.log("Won't purge directory during global-level dry run: ", dir_path)
elif "dry-run" in config.keys() and config["dry-run"] is True:
self.log("Won't purge directory during config-level dry run: ", dir_path)
else:
self.log("Purging directory:", dir_path)
shutil.rmtree(dir_path)