__main__.py

import argparse

from pkg_resources import iter_entry_points

from botoform.enriched import EnrichedVPC

from os import environ


def get_profile_names():
    """Return a list of profile names in ~/.aws/config"""
    import botocore.session

    return botocore.session.get_session().full_config.get("profiles", {}).keys()


def load_entry_points(group_name):
    """Return a dictionary of entry_points related to given group_name"""
    entry_points = {}
    for entry_point in iter_entry_points(group=group_name, name=None):
        entry_points[entry_point.name] = entry_point.load()
    return entry_points


def load_parsers_from_plugins(subparser, plugins):
    """iterate over all plugins and load their parser."""
    for plugin_name, plugin_class in plugins.items():
        # create a parser object for the plugin.
        plugin_parser = subparser.add_parser(
            plugin_name, description=plugin_class.__doc__
        )

        plugin_parser.add_argument("vpc_name", help="The VPC's Name tag.")

        try:
            # Assume class plugin with 'setup_parser' and 'main' staticmethods.
            plugin_class.setup_parser(plugin_parser)
            plugin_parser.set_defaults(func=plugin_class.main)
        except AttributeError:
            # Assume function plugin w/o 'setup_parser' or 'main' staticmethods.
            plugin_parser.set_defaults(func=plugin_class)


def build_parser(description, load_subparser_plugins=False):
    """build argparser and attach each plugin's parser to subparser."""
    parser = argparse.ArgumentParser(description=description)
    # requiredNamed = parser.add_argument_group('required named arguments')
    parser.add_argument(
        "-p",
        "--profile",
        choices=get_profile_names(),
        default=environ.get("AWS_DEFAULT_PROFILE", None),
        help="botocore profile name for AWS creds and other vars.",
    )
    parser.add_argument(
        "-r",
        "--region",
        default=environ.get("AWS_DEFAULT_REGION", None),
        help="AWS region to use",
    )
    # parser.add_argument('--search-regions', action='store_true', default=False,
    #  help='search regions for VPC with given vpc_name')
    # parser.add_argument('--quiet', action='store_true', default=False,
    #  help='prevent status messages to STDOUT')

    if load_subparser_plugins:
        # create a subparser for our plugins to attach to.
        subparser = parser.add_subparsers(
            title="subcommands",
            description="valid subcommands",
            help="--help for additional subcommand help",
        )
        plugins = load_entry_points("botoform.plugins")
        load_parsers_from_plugins(subparser, plugins)
    else:
        parser.add_argument("vpc_name", help="The VPC's Name tag.")

    return parser


def get_evpc_from_args(args):
    if "skip_evpc" not in args.__dict__:
        return EnrichedVPC(
            vpc_name=args.vpc_name, region_name=args.region, profile_name=args.profile
        )


def main():
    parser = build_parser("Manage infrastructure on AWS using YAML", True)
    args = parser.parse_args()
    evpc = get_evpc_from_args(args)
    # call the plugin main method.
    args.func(args, evpc)


if __name__ == "__main__":
    main()