how to let the parser print help message rather than error and exit
- by fluter
Hi, I am using argparse to handle cmd args, I wanna if there is no args specified, then print the help message, but now the parse will output a error, and then exit.
my code is:
def main():
print "in abing/start/main"
parser = argparse.ArgumentParser(prog="abing")#, usage="%(prog)s <command> [args] [--help]")
parser.add_argument("-v", "--verbose", action="store_true", default=False, help="show verbose output")
subparsers = parser.add_subparsers(title="commands")
bkr_subparser = subparsers.add_parser("beaker", help="beaker inspection")
bkr_subparser.set_defaults(command=beaker_command)
bkr_subparser.add_argument("-m", "--max", action="store", default=3, type=int, help="max resubmit count")
bkr_subparser.add_argument("-g", "--grain", action="store", default="J", choices=["J", "RS", "R", "T", "job", "recipeset", "recipe", "task"], type=str, help="resubmit selection granularity")
bkr_subparser.add_argument("job_ids", nargs=1, action="store", help="list of job id to be monitored")
et_subparser = subparsers.add_parser("errata", help="errata inspection")
et_subparser.set_defaults(command=errata_command)
et_subparser.add_argument("-w", "--workflows", action="store_true", help="generate workflows for the erratum")
et_subparser.add_argument("-r", "--run", action="store_true", help="generate workflows, and run for the erratum")
et_subparser.add_argument("-s", "--start-monitor", action="store_true", help="start monitor the errata system")
et_subparser.add_argument("-d", "--daemon", action="store_true", help="run monitor into daemon mode")
et_subparser.add_argument("erratum", action="store", nargs=1, metavar="ERRATUM", help="erratum id")
if len(sys.argv) == 1:
parser.print_help()
return
args = parser.parse_args()
args.command(args)
return
how can I do that?
thanks.
