Replacement for prev_execution_date as it is deprecated in airflow 2

Question

I am migrating airflow 1 pipelines on airflow 2 and stumbled across the deprecated {{ prev_execution_date }}.

I am not sure what can be used instead.
I found prev_data_interval_start_success and prev_data_interval_end_success but not sure which one to pick from these or are they even correct replacement for prev_execution_date?

There were other template variables like execution_date whose replacement was logical_date.

Doc link : https://airflow.apache.org/docs/apache-airflow/stable/templates-ref.html

Answer 1

Just use TaskInstance or DagRun model. Here is an example:

import logging
from datetime import datetime

from airflow import DAG
from airflow.models import TaskInstance, DagRun
from airflow.operators.python import PythonOperator

dag = DAG(
    dag_id='test_dag',
    start_date=datetime(2024, 1, 1),
    schedule_interval='@daily',
    max_active_runs=1,
)


def first(ti: TaskInstance, **kwargs: dict):
    if ti.previous_ti:
        logging.info('ti.previous_ti.execution_date = %s', ti.previous_ti.execution_date)
    else:
        logging.info('previous_ti not found')

    dag_run = DagRun.get_previous_dagrun(dag_run=ti.dag_run)
    if dag_run:
        logging.info('dag_run = %s', dag_run.execution_date)
    else:
        logging.info('dag_run not found')


PythonOperator(dag=dag, task_id='first', python_callable=first)

Let's check logs:

# first dag_run
...
[2024-02-22, 09:44:39 UTC] {test_dag.py:20} INFO - previous_ti not found
[2024-02-22, 09:44:39 UTC] {test_dag.py:26} INFO - dag_run not found
...
# second dag_run
[2024-02-22, 09:44:41 UTC] {test_dag.py:18} INFO - ti.previous_ti.execution_date = 2024-01-01 00:00:00+00:00
[2024-02-22, 09:44:41 UTC] {test_dag.py:24} INFO - dag_run = 2024-01-01 00:00:00+00:00
...