Airflow Sensor

External

• https://airflow.apache.org/docs/apache-airflow/stable/concepts/sensors.html
• https://airflow.apache.org/docs/apache-airflow/stable/concepts/smart-sensors.html
• https://airflow.apache.org/docs/apache-airflow/2.0.0/concepts.html#sensors

Internal

• Airflow Concepts

Overview

A Sensor is a subclass of Operator. Sensors wait for an external event to happen. When the event they are waiting for occurs, the tasks succeeds, so their downstream tasks can run. The sensors are primarily idle, and because of that, they have primarily three modes of running, that allows executing them with various degrees of efficiency: poke, reschedule and smart sensors.

Also see Deferrable Operators and Triggers.

Sensor Types

Poke

This is default run mode. The Sensor takes up a worker slot for its entire runtime.

Reschedule

The sensor takes up a worker slot only when it's checking, and sleeps for a set duration between checks.

Smart Sensor

There is a single centralized version of this sensor that batches all executions of it.