def _parse_file():
    """Parse the config from a file.

    Note:
      Assumes any value that ``"$LOOKS_LIKE_THIS"`` in a service
      definition refers to an environment variable, and attempts to get
      it accordingly.

    """
    file_name = path.join(
        path.abspath(path.dirname(path.dirname(__file__))), 'config.json'
    )
    logger.info('loading configuration from file: %r', file_name)
    try:
        data = _read_file(file_name)
    except FileNotFoundError:
        logger.error('no configuration available, set FLASH_CONFIG or '
                     'provide config.json')
        exit()
    for service in data.get('services', []):
        for key, val in service.items():
            if isinstance(val, str) and re.match(r'^\$[A-Z_]+$', val):
                env_val = getenv(val[1:])
                if env_val is None:
                    logger.warning('environment variable %r not found', val[1:])
                service[key] = env_val or val
    return data
Parse the config from a file.

    Note:
      Assumes any value that ``"$LOOKS_LIKE_THIS"`` in a service
      definition refers to an environment variable, and attempts to get
      it accordingly.