docs-archive/apache-airflow/2.0.0/apache-airflow/stable/_sources/howto/set-config.rst.txt

 .. 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.



Setting Configuration Options
=============================

The first time you run Airflow, it will create a file called ``airflow.cfg`` in
your ``$AIRFLOW_HOME`` directory (``~/airflow`` by default). This file contains Airflow's configuration and you
can edit it to change any of the settings. You can also set options with environment variables by using this format:
:envvar:`AIRFLOW__{SECTION}__{KEY}` (note the double underscores).

For example, the metadata database connection string can either be set in ``airflow.cfg`` like this:

.. code-block:: ini

    [core]
    sql_alchemy_conn = my_conn_string

or by creating a corresponding environment variable:

.. code-block:: bash

    export AIRFLOW__CORE__SQL_ALCHEMY_CONN=my_conn_string

You can also derive the connection string at run time by appending ``_cmd`` to
the key like this:

.. code-block:: ini

    [core]
    sql_alchemy_conn_cmd = bash_command_to_run

You can also derive the connection string at run time by appending ``_secret`` to
the key like this:

.. code-block:: ini

    [core]
    sql_alchemy_conn_secret = sql_alchemy_conn
    # You can also add a nested path
    # example:
    # sql_alchemy_conn_secret = core/sql_alchemy_conn

This will retrieve config option from Secret Backends e.g Hashicorp Vault. See
:ref:`Secrets Backends<secrets_backend_configuration>` for more details.

The following config options support this ``_cmd`` and ``_secret`` version:

* ``sql_alchemy_conn`` in ``[core]`` section
* ``fernet_key`` in ``[core]`` section
* ``broker_url`` in ``[celery]`` section
* ``flower_basic_auth`` in ``[celery]`` section
* ``result_backend`` in ``[celery]`` section
* ``password`` in ``[atlas]`` section
* ``smtp_password`` in ``[smtp]`` section
* ``secret_key`` in ``[webserver]`` section

The ``_cmd`` config options can also be set using a corresponding environment variable
the same way the usual config options can. For example:

.. code-block:: bash

    export AIRFLOW__CORE__SQL_ALCHEMY_CONN_CMD=bash_command_to_run

Similarly, ``_secret`` config options can also be set using a corresponding environment variable.
For example:

.. code-block:: bash

    export AIRFLOW__CORE__SQL_ALCHEMY_CONN_SECRET=sql_alchemy_conn

The idea behind this is to not store passwords on boxes in plain text files.

The universal order of precedence for all configuration options is as follows:

#. set as an environment variable (``AIRFLOW__CORE__SQL_ALCHEMY_CONN``)
#. set as a command environment variable (``AIRFLOW__CORE__SQL_ALCHEMY_CONN_CMD``)
#. set as a secret environment variable (``AIRFLOW__CORE__SQL_ALCHEMY_CONN_SECRET``)
#. set in ``airflow.cfg``
#. command in ``airflow.cfg``
#. secret key in ``airflow.cfg``
#. Airflow's built in defaults

You can check the current configuration with the ``airflow config list`` command.

If you only want to see the value for one option, you can use ``airflow config get-value`` command as in
the example below.

.. code-block:: bash

    $ airflow config get-value core executor
    SequentialExecutor

.. note::
    For more information on configuration options, see :doc:`../configurations-ref`

.. note::
    See :doc:`../modules_management` for details on how Python and Airflow manage modules.