Python script that constructs tar archives from newline delimited JSON input.

nd-json-tar.py

#!/usr/bin/env python3

import os, sys
import json
import tarfile

# apply attributes
def modify(attrib, stat, info):
    if 'mtime' in attrib:
        info.mtime = attrib['mtime']
    if 'mode' in attrib:
        info.mode = int(str(attrib['mode']), 8)
    if 'linkname' in attrib:
        info.linkname = attrib['linkname']
    if 'uid' in attrib:
        info.uid = attrib['uid']
    if 'gid' in attrib:
        info.gid = attrib['gid']
    if 'uname' in attrib:
        # setting null in json will omit
        info.uname = '' if attrib['uname'] is None else attrib['uname']
    if 'gname' in attrib:
        # setting null in json will omit
        info.gname = '' if attrib['gname'] is None else attrib['gname']

    if 'atime' in attrib:
        if attrib['atime'] == 'stat':
            info.pax_headers['atime'] = str(stat.st_atime)
        else:
            info.pax_headers['atime'] = str(float(attrib['atime']))
    if 'ctime' in attrib:
        if attrib['ctime'] == 'stat':
            info.pax_headers['ctime'] = str(stat.st_ctime)
        else:
            info.pax_headers['ctime'] = str(float(attrib['ctime']))

    return info

with os.fdopen(sys.stdout.fileno(), "wb", closefd=False) as stdout:
    with tarfile.open(mode='w|', fileobj=stdout, format=tarfile.PAX_FORMAT) as tar:
        for line in sys.stdin:
            attrib = json.loads(line)
            source = attrib['source']
            tar.add(
                name=source,
                arcname=attrib['name'],
                recursive=False,
                filter=lambda info: modify(attrib, os.stat(source), info),
            )