Apply configuration defined in webserver_config.py to Flask config

[vincbeck]

In AF2 you can extend the Flask application configuration in $AIRFLOW_HOME/webserver_config.py. We must keep this mechanism in FAB provider in AF3 because many users rely on it (and some features as well). The documentation refers to this file as well. This is an issue reported by @zachliu on Slack.

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[potiuk]

nice!

[zachliu]

Here’s a summary of the issue (Slack messages only have a 90-day lifespan):

• Airflow version: 3.0.0rc1.post2, providers-fab version: 2.0.0rc3

• airflow.cfg contains:

  [core]auth_manager = airflow.providers.fab.auth_manager.fab_auth_manager.FabAuthManager
  [fab]auth_backends = airflow.providers.fab.auth_manager.api.auth.backend.basic_auth,airflow.providers.fab.auth_manager.api.auth.backend.session

• symptom: the OAuth login page does not load
  

• webserver_config.py is set up following FAB documentation:

  from __future__ importannotationsimportosfromairflow.providers.fab.auth_manager.security_manager.overrideimport (
  FabAirflowSecurityManagerOverride,
  )
  fromflask_appbuilder.constimportAUTH_OAUTH# Flask-WTF flag for CSRFWTF_CSRF_ENABLED=TrueWTF_CSRF_TIME_LIMIT=NoneAUTH_TYPE=AUTH_OAUTHAUTH_USER_REGISTRATION=TrueAUTH_USER_REGISTRATION_ROLE=NoneAUTH_ROLES_SYNC_AT_LOGIN=TrueOAUTH_PROVIDERS= [
  {
  'name': 'auth0',
  ...
  },
  ]
  classCustomSecurityManager(FabAirflowSecurityManagerOverride):
  """Custom Security Manager"""SECURITY_MANAGER_CLASS=CustomSecurityManager

• Confusing log entry observed:

  webserver-1 | [2025-04-07T20:07:23.995+0000] {override.py:824} DEBUG - OAuth providers init auth0
  

Solution:

• Fixed in this PR - thanks to @vincbeck 🎉
• That log entry showed up because we had all run airflow users create ... at some point, which invokes

  airflow/providers/fab/src/airflow/providers/fab/auth_manager/cli_commands/utils.py

  Line 57 in adbb062

  flask_app.config.from_pyfile(webserver_config, silent=True)

  
  but it doesn’t actually use the "flask_app" object in the ways that matter for OAuth.