Source code for kvalikirstu2.arg_parser

"""A module for the argument parser class in Kvalikirstu."""

import argparse
import codecs
import glob
import os
import configargparse

_CONF_ENCODING = 'utf-8'
DEFAULT_CONF_FILES = [os.path.join(os.path.dirname(os.path.abspath(__file__)), 'config.conf')]


class ConfigFileParsingException(Exception):
    """Raised when parsing args fails (during gui run)"""


class Kvalikirstu2ConfigArgParser(configargparse.ArgParser):
    """A class derived from configargparse.ArgumentParser for parsing arguments. Adds support for custom encoding.
    """
    def __init__(self, *args, config_files=[], encoding=_CONF_ENCODING, **kwargs):
        """

        :param encoding: The config file encoding.

        """
        self.encoding = encoding
        super().__init__(*args, **kwargs, default_config_files=config_files)

    def error(self, message):  # pylint: disable=E0202
        """ Overwrites argparse error method so that systemexit is not called within gui

        :param str message: The error message.

        """
        raise ConfigFileParsingException("\n%s\n\n%s" % ("Error while reading configuration file!", message))

    def _open_config_files(self, command_line_args):
        """Same functionality as super _open_config_files method, but uses codecs.open for opening config files.
        """
        config_files = []
        for files in map(glob.glob, map(os.path.expanduser, self._default_config_files)):
            for file in files:
                config_files.append(codecs.open(file, encoding=self.encoding))

        user_config_file_arg_actions = [a for a in self._actions if getattr(a, "is_config_file_arg", False)]

        if not user_config_file_arg_actions:
            return config_files

        for action in user_config_file_arg_actions:
            # try to parse out the config file path by using a clean new
            # ArgumentParser that only knows this one arg/action.
            arg_parser = argparse.ArgumentParser(
                prefix_chars=self.prefix_chars,
                add_help=False)
# pylint: disable=protected-access
            # calling protected method of argparse, don't see a way around this
            arg_parser._add_action(action)
# pylint: enable=protected-access

            # check whether the user provided a value
            parsed_arg = arg_parser.parse_known_args(args=command_line_args)
            if not parsed_arg:
                continue
            namespace, _ = parsed_arg
            user_config_file = getattr(namespace, action.dest, None)

            if not user_config_file:
                continue
            # validate the user-provided config file path
            user_config_file = os.path.expanduser(user_config_file)
            if not os.path.isfile(user_config_file):
                super().error('File not found: %s' % user_config_file)

            config_files += [codecs.open(user_config_file, encoding=self.encoding)]

        return config_files