Damian is correct. We've observed that exact behavior and noticed the timedelta logic is dubiously broken for DST but works for CRON.
On Mon, May 13, 2019 at 12:38 PM Shaw, Damian P. < [email protected]> wrote: > Hi, > > I’m not part of the Airflow team but I came to the same conclusion, that > the behavior is the opposite of what the documentation specifies. When > using the cron notation then DST is properly honored, when using timedelta > it is not. I played around with the DAG.following_schedule method to > satisfy this was the case. > > I’ve had production instance of airflow based on this that successfully > respected the March/April DST changes in many timezones. > > Regards > Damian > > From: Jiahao Chen [mailto:[email protected]] > Sent: Monday, May 13, 2019 2:08 PM > To: [email protected] > Subject: Cron schedule with DST-aware timezone > > Hi team, > > I have a question about the expected behavior of Airflow scheduler when > the schedule_interval is a cron expression and the start_date is in a > timezone with DST. > > Based on the Airflow documentation > https://airflow.apache.org/timezone.html#cron-schedules, the DST change > will be ignored if schedule_interval is a cron expresion (e.g. '0 17 * * > *'). And it gives an example that the GMT offset will not change regardless > how DST changes. If I'm understanding it correctly, that means if I upload > a DAG with a schedule_interval of "0 17 * * *" and a start_date of > 2019-03-15 17:00 PST(GMT-8) which is before the DST change on March 10, the > Airflow scheduler will always start the DAG on 5 pm everyday GMT-8 even > after the DST change on March 10. > > However, that is not the behavior I've seen with my experimental code (see > attachments). It looks like the the Airflow is actually taking the DST into > account, since the execution time is always 17:00 locally, which is 1 hour > off on the GMT after the DST change. > > Could you please confirm the behavior of Airflow scheduler in this use > case? > > Thank you! > Jiahao > > > > > =============================================================================== > > Please access the attached hyperlink for an important electronic > communications disclaimer: > http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html > =============================================================================== > >
