options.py

import sys
import getopt


class Options(object):
    def __init__(self, mandatory, optional=[], switches=[]):
        self.opts = {}

        self.__mand = mandatory
        self.__optn = optional
        self.__swtc = switches

    def __getattr__(self, attribute):
        if attribute in self.opts:
            return self.opts[attribute]
        return None

    def usage(self, notes=""):
        msg = "usage: %s" % (sys.argv[0])
        for option in self.__mand:
            msg += " --%s <%sname>" % (option, option)
        for option in self.__optn:
            msg += " [--%s <%sname>]" % (option, option)
        for option in self.__swtc:
            msg += " [--%s]" % (option)
        if notes != "":
            msg += "\nnotes: "
            msg += notes
        print(msg)

    def parse(self):
        opts = []
        for option in self.__mand:
            opts.append(option + "=")
        for option in self.__optn:
            opts.append(option + "=")
        for option in self.__swtc:
            opts.append(option)
        results = getopt.getopt(sys.argv[1:], "", opts)
        if len(results[1]) > 0:
            raise RuntimeError("unknown argument(s) '%s'" % (results[1]))
        for opt in results[0]:
            self.opts[opt[0][2:]] = opt[1]
        for option in self.__mand:
            if option not in self.opts:
                raise RuntimeError("mandatory option '--%s' not found" % (option))