How to Add Data Contracts to an Airflow Pipeline: A Technical Guide

Data contracts, as detailed in this guide, serve as a framework for ensuring data quality by defining explicit agreements between data producers and consumers, using YAML files for both documentation and active validation. These contracts act as executable quality gates in Airflow pipelines, conducting checks both in-memory before data is written and post-write to a production table, thereby preventing bad data from reaching production and ensuring visibility on data integrity. Soda's approach integrates with various data stack components like Postgres, Airflow, and Soda Cloud, enabling automated and continuous validation, while the use of YAML allows for version control and human readability, making it accessible to both technical and non-technical stakeholders. The guide underscores the importance of running data contracts at multiple points in the data pipeline, highlights common pitfalls such as maintaining duplicate contract files, and introduces tools like Soda's Contract Copilot and web UI to facilitate participation from data stewards and other non-engineering stakeholders.