example of opening and editing a .tar.gz (change permissions in this case)

editTarfile.py

import tarfile
import tempfile
import stat
import os

tar_file = "input.tar.gz"
tar = tarfile.open(tar_file, "r:gz")
members = tar.getmembers()

file_permission = stat.S_IRUSR | stat.S_IWUSR
folder_permission = stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR

# Let's pretend we want to edit, and write to new tar
if len(members) > 0:
    fd, tmp_tar = tempfile.mkstemp(prefix=("%s.fixed." % tar_file))
    os.close(fd)
    fixed_tar = tarfile.open(tmp_tar, "w:gz")

    # Then process members
    for member in members:

        # add o+rwx for directories
        if member.isdir() and not member.issym():
            member.mode = folder_permission | member.mode
            extracted = tar.extractfile(member)
            fixed_tar.addfile(member, extracted)

        # add o+rw for plain files
        elif member.isfile() and not member.issym():
            member.mode = file_permission | member.mode
            extracted = tar.extractfile(member)
            fixed_tar.addfile(member, extracted)
        else:
            fixed_tar.addfile(member)
            
    fixed_tar.close()
    tar.close()

    # Rename the fixed tar to be the old name
    os.rename(tmp_tar, tar_file)
else:
    tar.close()