Do one-time initialization.
    Call this to set up global state.

def setup(working_dir, interactive=False):
    """
    Do one-time initialization.
    Call this to set up global state.
    """
    # set up our implementation
    log.debug("Working dir: {}".format(working_dir))
    if not os.path.exists( working_dir ):
        os.makedirs( working_dir, 0700 )

    node_config = load_configuration(working_dir)
    if node_config is None:
        sys.exit(1)

    log.debug("config\n{}".format(json.dumps(node_config, indent=4, sort_keys=True)))
    return node_config