How to monitor Apache Airflow DAGs so you know when they silently fail

Your Airflow DAG ran last night. All tasks: green. All durations: normal. Export job completed at 02:14. Zero rows exported. Nobody knows. This is the silent failure Airflow's built-in alerting doesn't catch. on_failure_callback fires when a task crashes. It doesn't fire when a task exits 0 after connecting to a stale database replica and processing nothing. That's the failure mode that eats your Monday morning. This article shows you two ways to add external monitoring to Airflow DAGs — so you