_environ_config.py 文件源码

def to_config(config_cls, environ=os.environ):
    if config_cls._prefix:
        app_prefix = (config_cls._prefix,)
    else:
        app_prefix = ()

    def default_get(environ, metadata, prefix, name):
        ce = metadata[CNF_KEY]
        if ce.name is not None:
            var = ce.name
        else:
            var = ("_".join(app_prefix + prefix + (name,))).upper()

        log.debug("looking for env var '%s'." % (var,))
        val = environ.get(var, ce.default)
        if val is RAISE:
            raise MissingEnvValueError(var)
        return val

    return _to_config(config_cls, default_get, environ, ())