app_settings module

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  # at least one *.yml file required
    additional_settings.yml
    /settings  # use this only in case if you need different settings for your environments
      production.yml
      production.db.yml
      development.yml
      development.db.yml

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, if exist ./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.

If you have settings, which not depends on the environment, simply use ./config/{file name}.yml; In case, when you need settings, which depends on the environment, use ./config/settings/{ENV}.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')

Default Environment value

You can redefine default environment value (development).

from app_settings import AppSettings

cfg = AppSettings(default_env_value='autotest')

file ./config/settings/autotest.yml will be loaded (if exist).

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)

Suppress KeyError exception

In case, if you don't want to receive KeyError exception if key not defined in file, you can use raise_error flag. By default: True

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

key = cfg.this_value_not_exist  # key == None

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 auto --cov=app_settings --cov-config .coveragerc ./tests

Sample usage for tests

Run these commands to create sample files structure

$ cd <your project dir> 
$ mkdir -p config/settings && \ 
    touch config/settings.yml && \
    touch config/settings/{production.yml,testing.yml} && \
    echo "implicity_wait: 5" > config/settings.yml && \
    echo 'search_text: "production environment"' > config/settings/production.yml && \
    echo 'search_text: "testing environment"' > config/settings/testing.yml
$ touch test_with_app_settings.py

Install all python requirements:

pip install selenium pytest app_settings

Copy code to test_with_app_settings.py

### Example, don't use it in your code
import os
os.environ['TEST_ENV'] = 'production'
### example

import pytest
from app_settings import AppSettings
from selenium import webdriver


@pytest.fixture(scope='session')
def settings():
    cfg = AppSettings(env_name='TEST_ENV')
    return cfg


@pytest.fixture
def browser(settings):
    driver = webdriver.Chrome()
    driver.implicitly_wait(settings.implicity_wait)
    yield driver
    driver.close()


def test_example(browser, settings):
    browser.get("https://ya.ru")
    search_field = browser.find_element_by_id('text')
    search_field.send_keys(settings.search_text)  # depending on env
    search_button = browser.find_element_by_tag_name('button')
    search_button.click()
    browser.find_elements_by_css_selector("div ul li")

TODO

Add reload feature

ivdunin/app_settings