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.sdk 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 (None) if the variable is not set
baz = Variable.get("baz", default=None)

You can also access variables through the Task Context using get_current_context():

from airflow.sdk import get_current_context


def my_task():
    context = get_current_context()
    var = context["var"]
    my_variable = var["value"].get("my_variable_name")
    return my_variable

The context["var"] dictionary provides two ways to access variables:

var["value"]: returns the variable as a raw string value.
var["json"]: returns the variable as a JSON value. This is useful when the variable stores a dictionary, list, or other structured data.

You can also use them from templates:

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

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

Variables are global unless created for a specific Airflow Team (if your environment is configured to use Multi-Team). Global Variables should only be used for overall configuration that covers the entire installation. Team based Variables should be used for overall configuration related to one specific Team. To pass data from one Task/Operator to another, you should use 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 Managing Variables.