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    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

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Variables
=========

Variables are Airflow's runtime configuration concept - a general key/value store that is global and can be queried from your tasks, and easily set via Airflow's user interface, or bulk-uploaded as a JSON file.

To use them, just import and call ``get`` on the Variable model::

    from airflow.models import Variable

    # Normal call style
    foo = Variable.get("foo")

    # Auto-deserializes a JSON value
    bar = Variable.get("bar", deserialize_json=True)

    # Returns the value of default_var (None) if the variable is not set
    baz = Variable.get("baz", default_var=None)

You can also use them from :ref:`templates <concepts:jinja-templating>`::

    # Raw value
    echo {{ var.value.<variable_name> }}

    # Auto-deserialize JSON value
    echo {{ var.json.<variable_name> }}

Variables are **global**, and should only be used for overall configuration that covers the entire installation; to pass data from one Task/Operator to another, you should use :doc:`xcoms` instead.

We also recommend that you try to keep most of your settings and configuration in your DAG files, so it can be versioned using source control; Variables are really only for values that are truly runtime-dependent.

For more information on setting and managing variables, see :doc:`/howto/variable`.