Hi all, a question regarding triggers and Prefect-specific best practices. I'm writing a dynamically-built flow that basically consists of three tasks: 1. Get the list of items to work with 2. Map a function to the items on that list. The task might raise a

SKIP

halfway if some condition is met 3. Map a function to the results of step 2 I'm coming from an airflow background and was expecting a

none_skipped

trigger to apply to step 3, with the expected behavior that it would run if and only if step 2 succeeded. But as far as I understood, all triggers in Prefect treat skipping as success, which is not what I want. So my question is, is this designed to defer people from not using Prefect in a non-Prefect way? Should I instead use branching logic? Or is it a known missing feature to be implemented later? This is easily workaround-able with some manual checking logic in step 3 but still. Thanks!

Unlike Airflows

skipped

state, Prefects

SKIP

signal is only raised manually. This implies that receiving an upstream

SKIP

signal is intentional by the developer, and is treated like a success. There doesn’t seem to be any built in triggers for your case, but I believe you can implement a custom trigger to suit your usage pretty easily. Check out the built in trigger implementations, they are pretty minimal: https://github.com/PrefectHQ/prefect/blob/master/src/prefect/triggers.py

Hi @Arsenii - I believe the trigger you are looking for we merged yesterday! https://github.com/PrefectHQ/prefect/pull/1787

Thank you @emre it's actually pretty easy to write a custom one, you're right

yup that is correct, we always mean immediately upstream