GitHub user aeroyorch created a discussion: Configure Flask app settings via prefixed environment variables in FAB provider
During the review of #58293, a discussion came up around how the Airflow webserver Flask application is configured. At the moment, Flask-specific settings/behaviour are mainly provided through `webserver_config.py`. This discussion is intended as a follow-up to explore whether Airflow should optionally support a second way of configuring some Flask app settings, using prefixed environment variables via [app.config.from_prefixed_env()](https://flask.palletsprojects.com/en/stable/config/#configuring-from-environment-variables) (Flask-Limiter also [honors Flask’s configuration values](https://flask-limiter.readthedocs.io/en/stable/configuration.html#using-flask-config).). # Motivation Using `app.config.from_prefixed_env()` would allow selected Flask configuration options to be provided via environment variables, for example: ```text AIRFLOW__FLASK__RATELIMITER_STORAGE_URI=${AIRFLOW__CELERY__BROKER_URL} ``` This approach can be useful not only in the Airflow Helm chart, but more generally in declarative deployments where configuration is defined via environment variables and overridden per environment without changing Python files. It can also help avoid introducing imperative logic or environment-specific conditionals in code, which can make it harder to understand which configuration applies in a given setup. In addition, sensitive parts of the configuration can be managed separately using secrets. At the same time, this is a proposal, and some users may not see additional value if their current setup already meets their needs. # Proposal Allow the webserver to optionally load some Flask configuration values from environment variables using `app.config.from_prefixed_env()`, with a clear prefix such as `AIRFLOW__FAB__`, or even a more specific namespace (e.g. `AIRFLOW__FAB__FLASK_SETTINGS`, `AIRFLOW__FAB__FLASK_CONFIG`, `AIRFLOW__FAB__CONFIG`). This mechanism would not replace `webserver_config.py`, which would continue to be the primary configuration mechanism. When both approaches are used, `webserver_config.py` would have precedence over environment-based configuration. GitHub link: https://github.com/apache/airflow/discussions/60048 ---- This is an automatically sent email for [email protected]. To unsubscribe, please send an email to: [email protected]
