TimeDeltaSensor in Airflow: What It Is and How It Works

The TimeDeltaSensor in Airflow is a sensor that waits for a specific amount of time to pass before allowing a task to proceed. It pauses the workflow for a defined time interval, acting like a timer to delay downstream tasks.

How It Works

The TimeDeltaSensor works like a simple timer in your Airflow workflow. Imagine you want to wait for 10 minutes before starting the next task. Instead of running immediately, the sensor pauses the workflow until the set time has passed.

It checks the current time against the time when the sensor started plus the delay you set. Once the waiting period is over, it lets the workflow continue. This is useful when you want to add a fixed delay between tasks without relying on external events.

Example

This example shows how to use TimeDeltaSensor to wait for 5 minutes before running the next task.

python

from datetime import timedelta
from airflow import DAG
from airflow.sensors.time_delta_sensor import TimeDeltaSensor
from airflow.operators.dummy import DummyOperator
from airflow.utils.dates import days_ago

default_args = {
    'start_date': days_ago(1),
}

dag = DAG(
    'timedelta_sensor_example',
    default_args=default_args,
    schedule_interval=None,
)

start = DummyOperator(
    task_id='start',
    dag=dag
)

wait_5_minutes = TimeDeltaSensor(
    task_id='wait_5_minutes',
    delta=timedelta(minutes=5),
    dag=dag
)

end = DummyOperator(
    task_id='end',
    dag=dag
)

start >> wait_5_minutes >> end

Output

The DAG will start with the 'start' task, then pause for 5 minutes at 'wait_5_minutes' before running the 'end' task.

When to Use

Use TimeDeltaSensor when you need to delay a task for a fixed amount of time within your Airflow workflow. This is helpful if you want to wait for a system to stabilize, allow time for external processes to complete, or space out tasks to avoid overload.

For example, you might wait 10 minutes after a data load before starting data validation, or delay retries with a fixed wait time.

Key Points

• TimeDeltaSensor waits for a fixed time interval before continuing.
• It is a simple way to add delays without external triggers.
• Useful for pacing workflows or waiting for external systems.
• Configured by setting the delta parameter with a timedelta object.

Key Takeaways

TimeDeltaSensor pauses a workflow for a set time interval before continuing.

It is configured using the delta parameter with a timedelta value.

Use it to add fixed delays between tasks without external dependencies.

Ideal for pacing workflows or waiting for external processes to settle.