baseimage-tutorial-framework/tfw/config/lazy_environment.py

from collections import namedtuple
from os import environ

from tfw.internals.lazy import lazy_property


class LazyEnvironment:
    def __init__(self, prefix, tuple_name):
        self._prefix = prefix
        self._tuple_name = tuple_name

    @lazy_property
    def environment(self):
        return self.prefixed_envvars_to_namedtuple()

    def prefixed_envvars_to_namedtuple(self):
        envvars = {
            envvar.replace(self._prefix, '', 1): environ.get(envvar)
            for envvar in environ.keys()
            if envvar.startswith(self._prefix)
        }
        return namedtuple(self._tuple_name, envvars)(**envvars)