Add additional plugin parameter about brewtils

[hazmat345]

Possibly allowing an additional spec to be passed to brewtils.load_config that would be merged with brewtil's spec?

[hazmat345]

May be better to just allow plugin authors to pass in their own argparser. That way they aren't required to learn / use yapconf.

EDIT: So this isn't as straightforward as I hoped. Passing in a custom parser to load_config is no problem, and that's good because it allows for successful parsing of 'extra' cli args (like any positional args). The issue is getting access to the results - load_config turns the results of the cli parsing into a dictionary and passes that to yapconf as a source. But because the 'extra' arguments aren't in the brewtils spec yapconf just drops them on the floor.

# cli args are ["arg value", "--bg-host", "localhost"]

def main():
    parser = ArgumentParser()
    parser.add_argument('some_arg')

    # yay, this works now (doesn't barf on the positional arg)
    config = brewtils.load_config(cli_args=sys.argv[1:], arg_parser=parser)

    # Let's assume the client needs the thing
    # This breaks because config.some_arg doesn't exist and there's no way to get it
    RemotePlugin(Client(config.some_arg),
                 name='complex', ...,
                 **brewtils.get_connection_info(cli_args=sys.argv[1:])

In order to make this work we'd need some way to return the results of the argparser in addition to the yapconf Box. If we go this route, I don't see any way to avoid having some sort of separate config object, and that may be more confusing than just asking people to write a spec.

Another option: we provide a way to get an argparser that's already loaded with the brewtils spec. That way they could parse cli args themselves and the --help would look as expected.

# cli args are ["arg value", "--bg-host", "localhost"]

def main():
    parser = brewtils.argument_parser()
    parser.add_argument('some_arg')

    parsed_args = parser.parse_args(cli_args)

    # sweet, now I can get to some_arg...
    RemotePlugin(Client(parsed_args.some_arg),
                 name='complex', ...,
                 # BUT you can't use the cli args here, we can't deal with the extras
                 **brewtils.get_connection_info(**vars(parsed_args)))

This is still not great - if you're actually using get_config instead of get_connection_info you'll have two different config objects and you'll just have to know which has which things.

I think just adding some spec is easier, as long as you're ok giving up positional args:

# cli args are ["--some-arg", "arg value", "--bg-host", "localhost"]

def main():
    extra_spec = {
        "some_arg": {
            "type": "str",
        }
    }

    config = brewtils.load_config(cli_args=sys.argv[1:], merge_specification=extra_spec)

    RemotePlugin(Client(config.some_arg),
                 name='complex', ...,
                 **brewtils.get_connection_info(cli_args=sys.argv[1:]))

[hazmat345]

@loganasherjones ping