Principle:Apache Airflow Hook Connection Implementation
| Knowledge Sources | |
|---|---|
| Domains | Integration, Connection_Management |
| Last Updated | 2026-02-08 00:00 GMT |
Overview
An abstraction layer for managing authenticated connections to external systems through reusable hook classes.
Description
Hook and Connection Implementation defines the pattern for creating reusable connection handlers to external services. The BaseHook abstract class provides the interface for connection management, while the Connection model stores credentials in the metadata database. Hooks encapsulate authentication, connection pooling, and API interaction logic. Connection types are registered via provider.yaml, enabling custom UI forms in the Airflow web interface.
Usage
Create a hook class extending BaseHook when integrating with a new external service. Define connection types for UI support. Use get_connection() to retrieve stored credentials and get_conn() to establish the actual connection.
Theoretical Basis
Hook Pattern:
- Connection Model: Stores credentials (host, port, login, password, extra JSON)
- Hook Class: Wraps Connection with service-specific logic
- UI Integration: Custom form widgets and field behaviors for the connections UI
Connection Resolution:
# Pseudo-code for connection resolution
def get_connection(conn_id):
# 1. Check secrets backends (Vault, AWS SM, etc.)
# 2. Check environment variables (AIRFLOW_CONN_{conn_id})
# 3. Check metadata database
return connection