app-settings 1.1

YAML for application configuration, lite version (inspired by Ruby gem "config")

Simplify usage of YAML files for application configuration.

Inspired by Ruby Gem “config” https://github.com/railsconfig/config But not all features implemented yet.

Usage example

Installation: pip install app_settings

Create sample app with following structure:

/my_app
  my_app.py
  /config
    settings.yml  # required file
    additional_settings.yml
    /settings
      production.yml
      stage.yml
      development.yml  # required file

AppSettings – singleton, so it is not possible to create more than one instance of config object.

By default, script will try to load all ./config/*.yml and ./config/settings/${APP_ENV}.yml configuration files.

Take note, that all variables defined in ./config/*.yml files will be overridden by variables from ./config/settings/${APP_ENV}.yml.

Also, ./config/*.yml loaded in alphabetical order, so if you will define variable VAR in additional_settings.yml it will be redefined by VAR from settings.yml.

Environment (development/stage/production etc)

If your application use more than one environment, for example development and production, you can specify what config file to load by setting env variable

# before your application starts
# export APP_ENV='production' or APP_ENV='production' python my_app.py

from app_settings import AppSettings

cfg = AppSettings()

By default, if no APP_ENV is given, file ./config/settings/development.yml will be loaded, that’s why this file is required.

Also it is possible to redefine name of variable.

# export TEST_ENV='production'

from app_settings import AppSettings

cfg = AppSettings(env_name='TEST_ENV')

Working with environment variables

It is possible to redefine or set settings from environment variables. AppSettings will read all env variables with SETTINGS prefix (by default).

# settings.yml
level1:
  redefined: 'redefined'
  not_redefined: 'not redefined'

# export SETTINGS__MY_VAR='test'
# export SETTINGS__LEVEL1__REDEFINED='val'

from app_settings import AppSettings

cfg = AppSettings()
print(cfg.my_var)  # 'test'
print(cfg.level1.redefined)  # 'val'
print(cfg.level1.not_redefined)  # 'not redefined'

You can setup your own prefix:

# export MYPREFIX__MY_VAR='test'
# export MYPREFIX__LEVEL1__REDEFINED='val'

from app_settings import AppSettings

cfg = AppSettings(prefix='myprefix')
print(cfg.my_var)  # 'test'
print(cfg.level1.redefined)  # 'val'

Also it is possible to setup environment variable splitter (default: __).

# export SETTINGS.MY_VAR='test'
# export SETTINGS.LEVEL1.REDEFINED='val'

from app_settings import AppSettings

cfg = AppSettings(splitter='.')
print(cfg.my_var)  # 'test'
print(cfg.level1.redefined)  # 'val'

If you don’t need to set/redefine settings from environment variables, use use_env flag.

from app_settings import AppSettings
cfg = AppSettings(use_env=False)

Config path

You can redefine default config path

from app_settings import AppSettings

cfg = AppSettings(configs_path='my_config_path')

Run tests

cd app_settings
python -m pytest -v --alluredir=./tests/results -n `nproc` --cov=app_settings --cov-config .coveragerc ./tests

TODO

1. Add reload feature

2. Do not raise error if setting not found in dictionary

3. Load all yml by mask ./config/settings/${APP_ENV}.*.yml