 .. 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.



Running Airflow behind a reverse proxy
======================================

Airflow can be set up behind a reverse proxy, with the ability to set its endpoint with great
flexibility.

For example, you can configure your reverse proxy to get:

::

    https://lab.mycompany.com/myorg/airflow/

To do so, you need to set the following setting in your ``airflow.cfg``::

    base_url = http://my_host/myorg/airflow

- Configure your reverse  proxy (e.g. nginx) to pass the url and http header as it for the Airflow webserver, without any rewrite, for example::

      server {
        listen 80;
        server_name lab.mycompany.com;

        location /myorg/airflow/ {
            proxy_pass http://localhost:8080;
            proxy_set_header Host $http_host;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
            proxy_redirect off;
            proxy_http_version 1.1;
        }
      }

- Some parts of the UI are rendered inside iframes (Auth managers security links for instance), you need to make sure that you are not setting a restricted CSP for iframe rendering
  such as ``frame-ancestors 'none'``. You can set the CSP header in your reverse proxy configuration, for example::

      add_header Content-Security-Policy "frame-ancestors 'self';";

- Use ``--proxy-headers`` CLI flag to tell Uvicorn to respect these headers: ``airflow api-server --proxy-headers``

- If your proxy server is not on the same host (or in the same docker container) as Airflow, then you will need to
  set the ``FORWARDED_ALLOW_IPS`` environment variable so Uvicorn knows who to trust this header from. See
  `Uvicorn's docs <https://www.uvicorn.org/deployment/#proxies-and-forwarded-headers>`_. For the full options you can pass here.
  (Please note the ``--forwarded-allow-ips`` CLI option does not exist in Airflow.)

- Please make sure your proxy does not enforce http-only status on the Set-Cookie headers.
  Airflow frontend needs to access the cookies through javascript, and a http-only flag would disturb this functionality.

Helm Chart Configuration
------------------------

When deploying Airflow using the Helm chart behind a reverse proxy (e.g., nginx ingress), you need to configure the API server to respect proxy headers.

Configure the API server arguments to include the ``--proxy-headers`` flag::

    apiServer:
      args: ["bash", "-c", "exec airflow api-server --proxy-headers"]

If your proxy server is not on the same host as Airflow, set the ``FORWARDED_ALLOW_IPS`` environment variable::

    apiServer:
      args: ["bash", "-c", "exec airflow api-server --proxy-headers"]
      env:
        - name: FORWARDED_ALLOW_IPS
          value: "*"  # Use "*" for trusted environments, or specify proxy IP ranges for production

Additionally, configure your ingress annotations to pass the necessary headers. For nginx ingress, add these annotations::

    ingress:
      apiServer:
        enabled: true
        annotations:
          nginx.ingress.kubernetes.io/proxy-http-version: "1.1"
          nginx.ingress.kubernetes.io/proxy-redirect-off: "true"
          nginx.ingress.kubernetes.io/configuration-snippet: |
            proxy_set_header Host $http_host;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
        hosts:
          - name: airflow.example.com
            tls:
              enabled: true
              secretName: airflow-tls

Make sure to also set the ``base_url`` in your Airflow configuration::

    config:
      api:
        base_url: https://airflow.example.com

.. spelling::

  Uvicorn
