Airflow - Defining the key,value for a xcom_push function

Question

I am trying to pass a Python function in Airflow. I am not sure what the key and values should be for a xcom_push function. Could anyone assist on this. Thanks

def db_log(**context):
  db_con = psycopg2.connect(" dbname = 'name' user = 'user' password = 'pass' host = 'host' port = '5439' sslmode = 'require' ")
  task_instance = context['task_instance']
  task_instance.xcom_push(key=db_con, value = db_log)
  return (db_con)

Could anyone assist in getting the correct key and value for the xcom_push function. Thanks..

Answer 1

In examples the correct way of calling can be found, e.g.: https://github.com/apache/incubator-airflow/blob/master/airflow/example_dags/example_xcom.py

So here it should be

task_instance.xcom_push(key=<string identifier>, value=<actual value / object>)

In your case

task_instance.xcom_push(key="db_con", value=db_con)

Answer 2

This is a bit old, but from what I understand, if you are running db_log as a task, then returning db_con would automatically push it to the xcom.

You could then access it with {{ti.xcom_pull(task_ids='TASK_NAME_HERE')}}