#airflow

Design a production-grade Airflow DAG for daily ETL. Workflow: 1. Extract data from PostgreSQL and REST API. 2. Transform using pandas (clean, join, aggregate). 3. Load to data warehouse (Snowflake/BigQuery). 4. Send Slack notification on success/failure. 5. Implement retry logic and SLA monitoring. Use TaskGroups for organization, XComs for data passing, and proper error handling with callbacks.