'swift-ring-builder <builder_file> write_ring
Just rewrites the distributable ring file. This is done automatically after
a successful rebalance, so really this is only useful after one or more
\'set_info\' calls when no rebalance is needed but you want to send out the
new device information.'

@staticmethod
def write_ring():

    ring_data = builder.get_ring()
    if (not ring_data._replica2part2dev_id):
        if ring_data.devs:
            print('Warning:    Writing    a    ring    with    no    partition    assignments    but    with    devices;    did    you    forget    to    run    "rebalance"?')
        else:
            print('Warning:    Writing    an    empty    ring')
    ring_data.save(pathjoin(backup_dir, (('%d.' % time()) + basename(ring_file))))
    ring_data.save(ring_file)
    exit(EXIT_SUCCESS)
