AIP-84 Allow specifying an injectable path_prefix

[pierrejeambrun]

Body

Allow via a configuration parameter a way for user to specify a path_prefix on the fastapi application. (FastAPI app also serves the webapplication, both will be under that prefix).

We can leverage the root_path param of fastapi and can build something similar to what we had for the legacy_api here:

airflow/airflow/www/extensions/init_wsgi_middlewares.py

Lines 45 to 51 in 051e617

	# Apply DispatcherMiddleware
	base_url = urlsplit(webserver_base_url)[2]
	if not base_url or base_url == "/":
	base_url = ""
	if base_url:
	wsgi_app = DispatcherMiddleware(_root_app, mounts={base_url: flask_app.wsgi_app})
	flask_app.wsgi_app = wsgi_app # type: ignore[assignment]

This will also most likely require some adjustment in the front-end part. (vite build + redirection etc... to use the appropriate prefix, otherwise we might end-up with 404 responses there).

Committer

• I acknowledge that I am a maintainer/committer of the Apache Airflow project.

[kaxil]

For whoever picks this issue: To know about root_path, path_prefix and the use-case check https://fastapi.tiangolo.com/advanced/behind-a-proxy/