YamlSettings Example with Null Validation

__init__.py

"""Example Module

Quick Example of a traverse funtion to verify all required values have been set by the user.

"""

__main__.py

"""Entrypoint

Attempt to use the configuration, and printout the super secret string

"""
from example.config import get_config


def main():
    print("https://{user}:{pass}@{host}".format(**get_config().service))


if __name__ == '__main__':
    main()

README.md

Failures:

python -m example
SERVICE_USER=foo python -m example

Valid:

SERVICE_USER=foo SERVICE_PASS=bar python -m example

Run directly from zip:

PYTHONPATH=example.zip SERVICE_USER=foo SERVICE_PASS=bar python -m example

config.py

import os
import yamlsettings


def validate(settings):
    """Asserts if a value in the required_keys paths is not defined

    """
    check_paths = [x.split('.') for x in settings.required_keys]

    def _null_travers(path, node):
        if node is None and any(path[:len(x)] == x for x in check_paths):
            raise RuntimeError("{} is not set".format(".".join(path)))
        return None

    settings.traverse(_null_travers)


def init():
    """The initialization of Configuration.
    """
    if _CONFIG['init']:
        return

    yaml_data = pkgutil.get_data("example", "settings.yaml")
    app_settings = yamlsettings.yamldict.load(yaml_data)
    yamlsettings.update_from_env(app_settings)
    validate(app_settings)

    _CONFIG['settings'] = app_settings
    _CONFIG['init'] = True


def get_config():
    """Get the current configuration.
    """
    if not _CONFIG['init']:
        init()
    return _CONFIG['settings']


_CONFIG = {
    'init': False,
    'settings': None,
}

settings.yaml

---
service:
  host: google.com
  user: null
  pass: null
foo_pass: bad example password

required_keys:
  - service
  - foo_pass