Selectively load Flask configuration values from environment variables at runtime; never store secrets in configuration files again.

Initialize Flask-Habitat before any other middleware that requires configuration from a habitat source (e.g. environment, filesystem, or some other user-defined source) in order for Flask config values to be replaced.

from flask import Flask
from flask_habitat import Habitat
from flask_sqlalchemy import SQLAlchemy


app = Flask(__name__)
# DATABASE is an environment variable expected to contain the dburi
app.config["SQLALCHEMY_DATABASE_URI"] = "$DATABASE"
app.config.from_envvar("APP_SETTINGS")
habitat = Habitat(app)
db = SQLAlchemy(app)

Bear in mind that Flask-Habitat only looks for configuration values which are strings, which makes it compatible with any configuration format used, which is particularly beneficial when using YAML. Below is an example YAML-formatted config file using Flask-Environments:

COMMON: &common
  SQLALCHEMY_URI: $DATABASE_URI
  SECRET_KEY: $SECRET_KEY
  TOKEN_SALT: $TOKEN_SALT

DEVELOPMENT:
  <<: *common
  DEBUG: True

PRODUCTION:
  <<: *common
  SERVER_NAME: $SERVER_NAME

• HABITAT_SOURCE defines where configuration values will be pulled from, e.g. the environment, a file, or in the future, some user-defined source. Currently, the only supported value is environment.
• HABITAT_QUALIFIER defaults to $, and is the prefix that will be expected when looking for placeholders in configuration values.