> `schedule_interval=timedelta(days=14), start_date=...`. ash from what I've seen It doesn't give the same exact functionality This is what I observed: cron = schedule exactly on regardless of what happened with previous run (mostly) timedelta() = schedule after delta passed. However it's from end_date not from start_date. so schedule_interval=timedelta(days=14) means It will be scheduled 14 days from end_date or the previous run. If we consider for example that the dag takes 2 days to complete then the next one will be scheduled after 14 days from end_date (= 16 days from start_date).
This exact case is actually explained really well in the first issue listed https://github.com/apache/airflow/issues/8649 using daily example On Wed, Jan 20, 2021 at 9:17 PM Kaxil Naik <kaxiln...@gmail.com> wrote: > > `schedule_interval=timedelta(days=14), start_date=...`. > > > That won't support every second Thursday for example > > On Wed, Jan 20, 2021 at 6:54 PM Ash Berlin-Taylor <a...@apache.org> wrote: > >> Running exactly every two weeks can be done by setting >> `schedule_interval=timedelta(days=14), start_date=...`. >> >> Does this do what you need Elad? >> >> On 20 January 2021 18:12:36 GMT, Elad Kalif <elad...@gmail.com> wrote: >>> >>> >> In the example of a twice-a-month dag (not sure if it you have this >>> use case too?) what do you expect the "data interval" (i.e. execution_date) >>> to be? >>> Yes we have this use case too. The execution date does matter because I >>> want it to be bi-weekly for starting specific day and time >>> so with the current implementation I expect to provide >>> start_date=datetime(2021,1,19,20,5) & schedule_interval='2 weeks' >>> >>> Currently Airflow has 'hourly', 'daily' , 'weekly' - which doesn't allow >>> us to set it. >>> So a possible solution for this specific use case could be defining: >>> repeat_every - integer that represents the frequency (1,2,3,... n) >>> unit - str that provide the "gaps" (minutes, hours, days, weeks, months, >>> years) >>> Example: bi-weekly / twice a month can be: repeat_every = 2, unit = >>> 'weeks' >>> To get the 'hourly', 'daily' , 'weekly' functionality it >>> just needs to set unit=1. >>> >>> By the way this is exactly what google calendar allows to set if you >>> click on custom scheduling for a meeting. >>> >>> I'm still in favor of the python function approach as it should cover >>> all cases and provide full control for the users. >>> >>> On Wed, Jan 20, 2021 at 7:20 PM Deng Xiaodong <xd.den...@gmail.com> >>> wrote: >>> >>>> A quick thought (*maybe not making sense*): if *schedule_interval* accepts >>>> a list of values, we may support much higher complexity. >>>> >>>> For example, I may want to schedule my jobs at every days' 04:05 AND >>>> 02:31 , which cannot be expressed by single Cron pattern. Then I may want >>>> to have *schedule_interval = ["5 4 * * *", "31 2 * * *"]*. >>>> >>>> Maybe I missed something or the idea doesn't make sense. Please let me >>>> know. >>>> >>>> >>>> XD >>>> >>>> On Wed, Jan 20, 2021 at 6:09 PM Ash Berlin-Taylor <a...@apache.org> >>>> wrote: >>>> >>>>> Yes, we quite possibly could do this -- I'm trying to work out what >>>>> the needs are here. >>>>> >>>>> In the example of a twice-a-month dag (not sure if it you have this >>>>> use case too?) what do you expect the "data interval" (i.e. >>>>> execution_date) >>>>> to be? >>>>> >>>>> Or for this case does it not matter? >>>>> >>>>> -ash >>>>> >>>>> >>>>> On Wed, 20 Jan, 2021 at 19:06, Elad Kalif <elad...@gmail.com> wrote: >>>>> >>>>> Another case that is mentioned in one of the issues is the ability to >>>>> schedule a bi-weekly job (equivalent of bi-weekly meeting that you can set >>>>> in a calendar) which is very much needed. >>>>> >>>>> Maybe this is unrealistic but I think the game changer is if it would >>>>> be possible to let the users define their own logic and airflow will use >>>>> it >>>>> to schedule DAGs. >>>>> My thought here is - if I can define the logic in a python function >>>>> (regardless of what this logic is). Can't Airflow utilize it? >>>>> >>>>> On Wed, Jan 20, 2021 at 5:39 PM Ash Berlin-Taylor <a...@apache.org> >>>>> wrote: >>>>> >>>>>> Hi everyone, >>>>>> >>>>>> I'd like to (re)start the discussion about a new feature I'd like to >>>>>> add for Airflow 2.1, that I am loosely calling "improving >>>>>> schedule_interval" (catchy name I know!) >>>>>> >>>>>> I have two main high-level goals in mind here: >>>>>> >>>>>> 1. To reduce the confusion around execution_date (specifically the >>>>>> naming of the parameter!) - the whole start vs end discussion. >>>>>> 2. To support more complex schedules. >>>>>> >>>>>> Previous thread on this point 1 here: >>>>>> https://lists.apache.org/thread.html/2b12ae265795ff2e655a5161c972f5c7bbe60722a12849a0e2c5c55f%40%3Cdev.airflow.apache.org%3E, >>>>>> (but I'm taking a bit of a step back from that to think if there's a >>>>>> bigger >>>>>> change we could make that encompases this) >>>>>> >>>>>> >>>>>> I don't yet have a concrete plan, nor implementation in mind, but I'd >>>>>> like to start collecting peoples "wish list" when it comes to scheduling >>>>>> DAGS: >>>>>> >>>>>> - What do you wish you could express natively in terms of scheduling >>>>>> your DAGs? (I.e. without using "hacks" such as date sensor/skip tasks at >>>>>> start) >>>>>> - What schedules do you wish you could express now, that you just >>>>>> can't? >>>>>> - Do you have good example workflows that give a good example of >>>>>> where you want schedule at start? Follow up question: do you also want >>>>>> this >>>>>> to be different for different DAGs in your Airflow install? >>>>>> >>>>>> >>>>>> Existing issues: >>>>>> https://github.com/apache/airflow/issues/8649 "Add support for more >>>>>> than 1 cron exp per DAG" >>>>>> https://github.com/apache/airflow/issues/10194 "Ability to better >>>>>> support odd scheduling time" >>>>>> https://github.com/apache/airflow/issues/10449 "Dynamic Schedule >>>>>> Intervals" >>>>>> https://github.com/apache/airflow/issues/10123 "Job Schedule >>>>>> Interval on 2nd & 4th Tuesday" >>>>>> >>>>>> I'll start: >>>>>> >>>>>> Case1: >>>>>> >>>>>> One example that came up recently in slack was an actual astronomer >>>>>> wanting a DAG to run with a schedule of "@sunset"! This also brings up >>>>>> the >>>>>> subject of "running dags at interval start or end" >>>>>> >>>>>> Case2: >>>>>> >>>>>> I'd like to be able to run a daily process at the end of each week >>>>>> day. I.e. to process data for Monday..Friday. The naive way of expressing >>>>>> this would be "0 0 * * MON-FRI", but that means that the dags would run >>>>>> Tuesday, Wednesday ,Thursday ,Friday, Monday -- meaning Friday's data >>>>>> isn't processed until Monday! >>>>>> >>>>>> My thoughts on this is we need to separate schedule interval (when to >>>>>> run a task) from the period duration (i.e look at one days worth of >>>>>> data). >>>>>> >>>>>> Thanks, >>>>>> Ash >>>>>> >>>>>> >>>>>> >>>>>>
