collect-files

#!/usr/bin/python3
# collect-files - a tar frontend that supports including subdirectories of excluded directories
# Benjamin Richter <br@waldteufel.eu>, Apr 2017

"""
Example:

$ cat backup-these
{"include": ["/home", "/home/my/.minecraft/saves", "/home/my/.minecraft/screenshots"],
"exclude": ["*/.minecraft"]}
$ collect-files backup-these -o /var/tmp/backup.tar

"""

import sys
import json
import os
import io
import os.path
import fnmatch
import tarfile
import itertools
import argparse

spin = itertools.cycle(('/', '-', '\\', '|'))
ctr = 0
def print_spinner():
    if sys.stderr.isatty():
        global ctr
        ctr += 1
        if ctr == 1000:
            ctr = 0
            print('\b', next(spin), sep='', end='', file=sys.stderr)
            sys.stderr.flush()

parser = argparse.ArgumentParser(description="Builds a tar archive from include/exlude lists. Supports including subdirectories of excluded directories.")
parser.add_argument('-v', '--verbose', action='count', help='print entries (once: top-level, twice: all)')
parser.add_argument('config', nargs='?', type=argparse.FileType('r'), default=sys.stdin, metavar="CONFIG", help="configuration file (default: stdin)")
parser.add_argument('-o', '--output', type=str, default='/dev/stdout', metavar="OUT", help="target tar file (default: stdout)")
args = parser.parse_args()

# cannot open '-' in binary mode via argparse.FileType
if args.output == '-':
    args.output = '/dev/stdout'

cfg = json.load(args.config)

def filter_tar(tarinfo):
    if os.path.ismount(tarinfo.name):
        return None
    for pat in cfg['exclude']:
        if fnmatch.fnmatch(tarinfo.name, pat):
            return None
    if args.verbose == 2:
        if tarinfo.isdir():
            print(tarinfo.name, "/", sep='', end='', file=sys.stderr)
        else:
            print(tarinfo.name, file=sys.stderr)
    elif args.verbose == 1:
        print_spinner()
    return tarinfo

with tarfile.open(args.output, mode='w|') as tar:
    for p in cfg['include']:
        if args.verbose == 1:
            print(p, end='', file=sys.stderr)
            if sys.stderr.isatty():
                print('  ', end='', file=sys.stderr)
            sys.stderr.flush()
        tar.add(p, filter=filter_tar)
        if args.verbose == 1:
            if sys.stderr.isatty():
                print('\b \b\b', end='', file=sys.stderr)
                sys.stderr.flush()
            print(file=sys.stderr)
            sys.stderr.flush()