Is there any way to get config parameters in Bash operator, when we run dag manually (like we have for Python kwargs)

Question

Is there any way to get config parameters in Bash operator, when we run dag manually with config from airflow UI (like we have for Python kwargs and args using context)?

Answer 1

Yes, this can be done using templating. The Airflow docs show a few examples of templating + BashOperator: https://airflow.apache.org/docs/apache-airflow/stable/howto/operator/bash.html#templating. Since Bash isn't Python code where you can pass through Python variables, you have to define "placeholders" in the bash_command argument for Python variables/statements to evaluate at runtime. For example:

BashOperator(
    task_id="example",
    bash_command='echo "{{ params.foo }}"',
)

The curly braces {{ }} define a template and params is an object that holds user-defined variables, that you can set when triggering a DAG. For example, the following configuration when triggering a DAG and the code above, will make the BashOperator run echo "bar".