nrmig

#!/usr/bin/env python3

"""New Relic Account Migration Utility

This script can be used to run account migration tasks.
"""

import argparse
import configparser
import os
import library.migrationlogger as m_logger
import library.utils as m_utils
import migratepolicies
import migrateconditions

logger = m_logger.get_logger(os.path.basename(__file__))

def create_argument_parser() -> argparse.ArgumentParser:
    """Create and configure the nrmig argument parser

    :returns: a configured argument parser
    :rtype: argparse.ArgumentParser
    """

    # Create the global options group parser
    global_options_parser = argparse.ArgumentParser(add_help=False)
    global_options_parser.add_argument(
        '-c',
        '--config',
        type=str, 
        default='config.ini',
        help='the config file to use'
    )
    global_options_parser.add_argument(
        '-d',
        '--debug',
        default=False,
        action='store_true',
        help='debug mode'
    )

    # Create the top-level parser
    parser = argparse.ArgumentParser(
        prog='nrmig',
        parents=[global_options_parser],
        formatter_class=argparse.ArgumentDefaultsHelpFormatter
    )
    subparsers = parser.add_subparsers(
        required=True,
        dest='command',
        title='commands',
        metavar='<command>'
    )

    # Create the parser for the "migrate" command
    migrate_parser = subparsers.add_parser(
        'migrate',
        help='perform a migration',
        parents=[global_options_parser],
        formatter_class=argparse.ArgumentDefaultsHelpFormatter
    )
    migrate_subparsers = migrate_parser.add_subparsers(
        required=True,
        dest='migrate_command',
        title='sub-commands',
        metavar='<migrate-command>'
    )

    # Let each of the commands configure their parsing rules
    for clazz in [
        migratepolicies.MigratePoliciesCommand,
        migrateconditions.MigrateConditionsCommand,
    ]:
        command = clazz()
        command.configure_parser(migrate_subparsers, global_options_parser)

    return parser


def parse_config(config_file_path: str) -> configparser.ConfigParser:
    """Parse the configuration file

    :param config_file_path: the configuraiton file
    :type config_file_path: str
    :returns: an initialized configuration parser
    :rtype: configparser.ConfigParser
    """

    logger.info('Parsing configuration from file %s...' % config_file_path)
    config = configparser.ConfigParser()

    try:
        with open(config_file_path, 'r') as config_file:
            config.read_file(config_file)
    except OSError as err:
        m_utils.error_message_and_exit(
            'The file %s could not be opened: %s' % (
                config_file_path,
                err.strerror
            )
        )

    return config


def main():
    """Parse the CLI arguments and run the appropriate commands.
    """

    logger.info('Starting migration...')

    # Create the argument parser
    parser = create_argument_parser()

    # Parse the command line
    args = parser.parse_args()

    # Configure logger
    m_utils.configure_loglevel(args)

    # Parse the configuration file
    config = parse_config(args.config)

    # Run the appropriate command function
    args.func(config, args)

    logger.info('Done.')


if __name__ == "__main__":
    main()