need a real argparser for the bin/nova-manage commands

[Trey Morris]

take "bin/nova-manager network create" as an example. With multi-nic it has the following parameters
label, fixed_range, num_networks, network_size, vlan_start, vpn_start, fixed_range_v6, gateway_v6, flat_network_bridge, bridge_interface
There will be times you want to create v4 networks specifying flat_network_bridge or bridge_interface, there is not way to skip over the args in between, and no way to use keyword args on the command line so you end up having to do something like
nova-manage network create public 10.0.0.0/8 1 15 0 0 0 0 xenbr1 eth1
where you fill the gaps with zeros.
nova-manage network create public 10.0.0.0/8 1 15 --flat-network_bridge xenbr1 --bridge_interface eth1
would be much more readable

[Brian Waldon (bcwaldon)]

I would love to see this same idea applied to all of our command line utilities

[Kevin L. Mitchell (klmitch)]

You know, it should be easy if you're willing to drop the '--': simply take any command-line arguments containing '=' and turn them into keyword arguments, then pass them in. So for instance:

  nova-manage network create public 10.0.0.0/8 1 15 flat_network_bridge=xenbr1 bridge_interface=eth1

Then you'd have something like:

def parse_args(argv):
    args = {}

[Kevin L. Mitchell (klmitch)]

(I hate launchpad. To continue:)

    args = ()
    kwargs = {}
    for arg in argv:
        if '=' in arg:
            k, v = arg.split('=', 1)
            kwargs[k] = v
        else:
            args.append(arg)
    return args, kwargs

Then, in main():

    args, kwargs = parse_args(argv)
    try:
        fn(*args, **kwargs)
        sys.exit(0)
    [...]

There are more subtleties we could try to take account of, too, like either prohibiting non-'=' arguments after encountering '=' arguments, or making such arguments be assigned to the parameters after the key.

[Jay Pipes (jaypipes)]

Incidentally, glance's CLI tool (bin/glance) uses exactly the same approach that Kevin takes above...