Export dynamic environment variables available for operators to use

The key value pairs returned in get_airflow_context_vars defined in airflow_local_settings.py are injected to default airflow context environment variables, which are available as environment variables when running tasks. Note, both key and value are must be string.

dag_id, task_id, execution_date, dag_run_id, dag_owner, dag_email are reserved keys.

1. Create airflow_local_settings.py file and put in on $PYTHONPATH or to $AIRFLOW_HOME/config folder. (Airflow adds $AIRFLOW_HOME/config on PYTHONPATH when Airflow is initialized)

2. Define get_airflow_context_vars in airflow_local_settings.py file.

For example:

In your airflow_local_settings.py file.

def get_airflow_context_vars(context) -> dict[str, str]:
    """
    :param context: The context for the task_instance of interest.
    """
    # more env vars
    return {"airflow_cluster": "main"}