Trigger rules (all_success, one_success, none_failed) in Apache Airflow - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the trigger rule all_success mean in Airflow?

The all_success trigger rule means the task will run only if all of its upstream tasks have completed successfully.

beginner

Explain the one_success trigger rule in Airflow.

The one_success trigger rule means the task will run if at least one of its upstream tasks has succeeded, regardless of others' states.

intermediate

What does the none_failed trigger rule ensure before running a task?

The none_failed trigger rule ensures the task runs only if none of its upstream tasks have failed. It allows upstream tasks to be skipped but not failed.

intermediate

If a task has three upstream tasks: two succeeded and one failed, which trigger rule will allow the task to run?

Only the one_success trigger rule will allow the task to run because at least one upstream task succeeded. all_success and none_failed will not run the task.

intermediate

Why might you use none_failed instead of all_success?

Use none_failed when you want the task to run as long as no upstream task failed, even if some were skipped. This is useful when skips are acceptable but failures are not.

Which trigger rule runs a task only if all upstream tasks succeeded?

A all_done

B one_success

C none_failed

D all_success

The all_success trigger rule requires every upstream task to succeed before running.

If one upstream task succeeded and others failed, which trigger rule allows the task to run?

A one_success

B all_success

C none_failed

D dummy

one_success runs the task if at least one upstream task succeeded.

Which trigger rule allows running if no upstream task failed, even if some were skipped?

A one_success

B none_failed

C all_success

D all_failed

none_failed allows running if no upstream tasks failed, skips are allowed.

What happens if a task uses all_success but one upstream task is skipped?

A Task does not run

B Task skips

C Task runs

D Task fails

all_success requires all upstream tasks to succeed; skipped upstream tasks prevent running.

Which trigger rule is best when you want to run a task if any upstream task succeeded?

A none_failed

B all_success

C one_success

D all_done

one_success runs the task if at least one upstream task succeeded.

Describe the differences between the trigger rules all_success, one_success, and none_failed in Airflow.

Think about how many upstream tasks must succeed or fail for each rule.

Give an example scenario where using none_failed is better than all_success.

Consider situations where skipping is acceptable but failure is not.