uranusjr opened a new issue #16731: URL: https://github.com/apache/airflow/issues/16731
**Description** Airflow should outline (in documentation) what cron expressions are supported, and perform appropriate additional validation cron expressions. **Use case / motivation** #16692 proposed displaying a short description about the cron expression in the web UI. This bring out the issue that currently the cron expression formats supported by Airflow are essentially defined by croniter implementation, which is non-standard (POSIX only allows five-segment formats) and sometimes buggy (see https://github.com/apache/airflow/issues/16107#issuecomment-869559200). Since croniter itself does not offer expression description, we need to do this with another tool, meaning that non-standard expressions can be incorrectly described and cause user confusion. It would be beneficial for Airflow to explicitly specify what cron expression formats are supported (only POSIX, or POSIX plus extensions like the optional year segment, or something else), and perform additional validation to ensure croniter does not receive formats not supported by Airflow, even if it can handle them. Personally I’m inclined to only do POSIX and reject the sixth segment entirely, at least until croniter fixes its handling to correctly interpret it (see taichino/croniter#76). **Are you willing to submit a PR?** Yeah **Related Issues** https://github.com/apache/airflow/issues/16107#issuecomment-869559200 #16692 taichino/croniter#76 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
