vincbeck opened a new pull request, #44464: URL: https://github.com/apache/airflow/pull/44464
To support Airflow 2.x plugins in Airflow 3 the goal is to embed a minimal version of Airflow 2 in fast api using [WSGIMiddleware](https://fastapi.tiangolo.com/advanced/wsgi/). The Airflow 2.x plugins will run in this application as they are running today in Airflow 2. `WSGIMiddleware` allows running a WSGI in the fast api application. This Flask application will be accessible at the path `/pluginsv2`. The plan is to: 1. (This PR) Embed Airflow 2 in the fast api application so that Airflow 2.x plugins will be available in Airflow 3. The Flask application will then be available in Flask webserver and FastApi runner 2. When the new Airflow 3 UI becomes the default UI and no fallback to the old UI is possible, strip out the Flask application to everything besides core elements needed by the plugins (these core elements are not identified yet, this will need to be done) 3. Move what is remaining of the Flask code from core Airflow to fab provider. The idea is, if you do not have any Airflow 2.x plugin defined in your environment, you should not have Flask as dependency. On the opposite, if you do have some Airflow 2.x plugins in your environment, fab provider will have to be installed and all the code needed to run the Flask application will be in this provider. The experience for the user will not be ideal because these plugins use the Airflow 2 UI, therefore the UI experience will be inconsistent between the Airflow pages (Airflow 3 UI) and the plugins (Airflow 2 UI). A warning message will be added in the embedded Flask application to let the user knows about this weird experience but also to recommend them to migrate their plugins to Airflow 3 plugins. <!-- Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <!-- Thank you for contributing! Please make sure that your code changes are covered with tests. And in case of new features or big changes remember to adjust the documentation. Feel free to ping committers for the review! In case of an existing issue, reference it using one of the following: closes: #ISSUE related: #ISSUE How to write a good git commit message: http://chris.beams.io/posts/git-commit/ --> <!-- Please keep an empty line above the dashes. --> --- **^ Add meaningful description above** Read the **[Pull Request Guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#pull-request-guidelines)** for more information. In case of fundamental code changes, an Airflow Improvement Proposal ([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvement+Proposals)) is needed. In case of a new dependency, check compliance with the [ASF 3rd Party License Policy](https://www.apache.org/legal/resolved.html#category-x). In case of backwards incompatible changes please leave a note in a newsfragment file, named `{pr_number}.significant.rst` or `{issue_number}.significant.rst`, in [newsfragments](https://github.com/apache/airflow/tree/main/newsfragments). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
