sla_miss_callback not triggered when SLA is missed

[sam-gen-cop]

Apache Airflow version

Other Airflow 2 version (please specify below)

If "Other Airflow 2 version" selected, which one?

2.10.1

What happened?

I have added a custom SLA callback function to the DAG script, which is supposed to trigger when the task breaches the SLA defined. However, the callback function is not getting triggered. Please tell me where I'm going wrong.

What you think should happen instead?

No response

How to reproduce

Script used to test the callback,

import time
from datetime import datetime, timedelta
from airflow import DAG
from airflow.operators.python_operator import PythonOperator
from airflow.utils.log.logging_mixin import LoggingMixin

def sla_miss_callback(dag, task_list, blocking_task_list, slas, blocking_tis):
    logger = LoggingMixin().log
    logger.info("SLA MISS CALLBACK TRIGGERED!")
    logger.info(f"Dag: {dag.dag_id}")
    logger.info(f"Task List: {task_list}")
    logger.info(f"Blocking Task List: {blocking_task_list}")
    logger.info(f"SLAs: {slas}")
    logger.info(f"Blocking TIs: {blocking_tis}")

def sleep_task():
    time.sleep(15)

default_args = {
    'owner': 'airflow',
    'start_date': datetime(2025, 1, 1),
}

with DAG(
    dag_id='test_sla_callback',
    default_args=default_args,
    schedule_interval="*/5 * * * *", 
    sla_miss_callback=sla_miss_callback, 
    catchup=False
) as dag:

    sleeper = PythonOperator(
        task_id='sleep_long_time',
        python_callable=sleep_task,
        sla=timedelta(seconds=10),
    )

Operating System

NA

Versions of Apache Airflow Providers

apache-airflow-providers-amazon - 8.28.0
apache-airflow-providers-celery - 3.8.1
apache-airflow-providers-common-compat - 1.2.0
apache-airflow-providers-common-io - 1.4.0
apache-airflow-providers-common-sql - 1.16.0
apache-airflow-providers-fab - 1.3.0
apache-airflow-providers-ftp - 3.11.0
apache-airflow-providers-http - 4.13.0
apache-airflow-providers-imap - 3.7.0
apache-airflow-providers-postgres - 5.12.0
apache-airflow-providers-smtp - 1.8.0
apache-airflow-providers-sqlite - 3.9.0

Deployment

Amazon (AWS) MWAA

Deployment details

No response

Anything else?

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[potiuk]

Hard to help you - looks good, but not sure where you look for logs. Possibly the log appars in scheduler/dag processor logs.

Left it for discussion but I think that's your probem. Also SLA MISS is generated AFTER task completes - which is a known problems with SLAs. Airflow 3 is dropping SLAs conmpletely and there will be a new "deadline" feature. https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=323488182

[sam-gen-cop]

I'm using AWS MWAA. Here is the screenshot of the logs for the above DAG.

The SLA callback didn't trigger even after the task missed SLA and succeeded.

[prasathp]

@sam-gen-cop Are you still facing this issue? I’m experiencing the same problem where sla_miss_callback is not triggered when an SLA is missed in Airflow 2.10.1 as we recently migrated to 2.10.1 from 2.4.3.

[sam-gen-cop]

Yes it does @prasathp