backupScript

#!/usr/bin/env python3

import datetime
import os
import socket
import subprocess
import sys
import tempfile

from config import *

DATE = datetime.datetime.now().strftime("%Y-%m-%d")
TIME = datetime.datetime.now().strftime("%H:%M:%S")
HOSTNAME = socket.gethostname()

os.environ["BORG_PASSPHRASE"] = PASSPHRASE

# Set up logging
logging.basicConfig(filename=LOGFILE_PATH, level=LOGGING_LEVEL,
                    format="%(asctime)s - %(levelname)s - %(message)s")

def borg_repository_exists():
    if not os.path.exists(REPOSITORY_LOCATION):
        return False
    elif os.listdir(REPOSITORY_LOCATION) == []:
        return False
    else:
        return True

def init_borg_repository():
    process_init = subprocess.run(["borg", "init", "--encryption=repokey-blake2", REPOSITORY_LOCATION],
                                   stdout=subprocess.PIPE,
                                   stderr=subprocess.PIPE)

    if process_init.returncode == 0:
        logging.info("Initialized BorgBackup repository.")
    elif process_init.returncode == 1:
        logging.warning("Initialized BorgBackup, however there is a warning. " + process_init.stderr.decode("utf-8"))
    else:
        logging.critical("Could not initialize BorgBackup repository. " + process_init.stderr.decode("utf-8"))
        sys.exit(1)

def get_file_with_excluded_dicts():
    temp_file = tempfile.NamedTemporaryFile(mode="r+")
    for excluded_directory in EXCLUDED_DIRECTORIES:
        temp_file.write(excluded_directory + "\n")
    temp_file.flush()
    return temp_file

def create_backup(temp_file=get_file_with_excluded_dicts()):
    process_create = subprocess.run(["borg", "create",
                                     REPOSITORY_LOCATION + "::" + HOSTNAME + "-" + DATE,
                                     DIRECTORY_TO_BACKUP,
                                     "--exclude-from", temp_file.name,
                                     "--compression", "lz4"],
                                     stdout=subprocess.PIPE,
                                     stderr=subprocess.PIPE)

    if process_create.returncode == 0:
        update_datefile()
        logging.info("Backup successful.")
        #TODO: Optional more precise output (e.g. backup size)?
    elif process_create.returncode == 1:
        logging.warning("Backup reached its normal end, but there were "
                        "warnings. The backup date in the file " + LOGFILE_PATH +
                        " has not been updated. "
                        + process_create.stderr.decode("utf-8"))
    else:
        logging.error("Could not create backup." + process_create.stderr.decode("utf-8"))


def update_datefile():
    try:
        with open(BACKUP_DATE_FILE_PATH, "w") as date_file:
            date_file.seek(0)
            date_file.write(DATE)
    except PermissionError:
        logging.warning("Could not update date of latest backup because of missing permissions.")

def prune_backups():
    process_prune = subprocess.run(["borg", "prune", REPOSITORY_LOCATION, "--prefix",
                                    HOSTNAME + "-",
                                    "--keep-daily=" + KEEP_DAILY,
                                    "--keep-weekly=" + KEEP_WEEKLY,
                                    "--keep-monthly=" + KEEP_MONTHLY],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.PIPE)

    if process_prune.returncode == 0:
        logging.info("Prune successful.")
    elif process_prune.returncode == 1:
        logging.warning("Warning for prune command. " + process_prune.stderr.decode("utf-8"))
    else:
        logging.warning("Error while executing 'prune' command." + process_prune.stderr.decode("utf-8"))

def mount():
    # Note here that 'vers=1.0' is required because FRITZ!Box only supports SMB 1.0
    process_mount = subprocess.run(["mount", "-t", "cifs", "-o", "credentials=" + SMB_CREDENTIALS_FILE + "," + \
                                    "vers=1.0", "//" + SHARE_ADDRESS, MOUNT_POINT],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.PIPE)
    if process_mount.returncode == 0:
        logging.info(SHARE_ADDRESS + " has been mounted.")
    else:
        logging.critical("Could not mount Samba share. " + process_mount.stderr.decode("utf-8"))
        sys.exit(1)

def umount():
    process_umount = subprocess.run(["umount", MOUNT_POINT],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.PIPE)
    if process_umount.returncode == 0:
        logging.info("Umount successful.")
    else:
        logging.warning("Umount returncode is not 0. " + process_umount.stderr.decode("utf-8"))


if __name__ == "__main__":
    logging.info("Script started ...")

    if not os.path.isdir(REPOSITORY_LOCATION):
        mount()
    else:
        logging.warning(SHARE_ADDRESS + " already mounted!")

    if not borg_repository_exists():
        init_borg_repository()

    create_backup()

    prune_backups()

    umount()

    logging.info("Script has been completed." + "\n" + \
                 "=====================================")