Extending ConfZ

The modular structure of ConfZ with its different sources and loader allow to easily extend it. To do so, you can define and register your own sources and loaders. Lets assume, we want the current platform and python version in our config:

import sys
from dataclasses import dataclass

from confz import ConfigSource
from confz.loaders import Loader, register_loader


@dataclass
class CustomSource(ConfigSource):
    platform: str = None    # Write the current platform into a config variable with this name
    version: str = None     # Write the current python version into a config variable with this name


class CustomLoader(Loader):
    @classmethod
    def populate_config(cls, config: dict, config_source: CustomSource):
        config_update = {
            config_source.platform: sys.platform,
            config_source.version: f"{sys.version_info[0]}.{sys.version_info[1]}"
        }
        cls.update_dict_recursively(config, config_update)


register_loader(CustomSource, CustomLoader)

Now, any config class can use this new source:

>>> from confz import BaseConfig
>>> class MyConfig(BaseConfig):
...     attr1: str
...     attr2: str

>>> MyConfig(config_sources=CustomSource(
...     platform="attr1",
...     version="attr2"
... ))
MyConfig(attr1='win32' attr2='3.9')

See the documentation of Loader for helper functions to reuse common functionality while writing such a loader.