[jira] [Commented] (AIRFLOW-3581) Fix next_ds/prev_ds semantics for manual runs

["Menelaos Kokolios (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AIRFLOW-3581?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16937590#comment-16937590 ] 

Menelaos Kokolios commented on AIRFLOW-3581:
--------------------------------------------

[~aoen] I believe we need to be more careful when it comes to changes in the semantics of macros/functions.

Even though you categorized this as a bug, a lot of people might have relied in this functionality for their automated tests.

At least it shouldn't have been in a PATCH version update.

> Fix next_ds/prev_ds semantics for manual runs
> ---------------------------------------------
>
>                 Key: AIRFLOW-3581
>                 URL: https://issues.apache.org/jira/browse/AIRFLOW-3581
>             Project: Apache Airflow
>          Issue Type: Bug
>          Components: scheduler
>            Reporter: Dan Davydov
>            Assignee: Dan Davydov
>            Priority: Major
>             Fix For: 1.10.2
>
>
> {color:#222222}next_ds is useful when you need cron-style scheduling, e.g. a task that runs for date "X" uses that date for its logic, e.g. send an email to users saying the run that was supposed to run for date "X" has completed. The problem is it doesn't behave as expected when it comes to manually triggered runs as illustrated by the diagrams below.{color}
>   
>  Using execution_date in a task
>  *Scheduled Run (works as expected)*
>  execution_date1           start_date1
>  \/                                  \/
>   *|-----------------------------|*
>  /\                                  /\
>  \ _________________/
>     scheduling_interval
>   
>  *Manual Run* *(works as expected)*
> triggered_date + execution_date + start_date
>  \/
>  *|*
>   
>  Using next_ds in a Task
>  *Scheduled Run (works as expected)*
>  next_ds1 + start_date1           next_ds2 + start_date2
>  \/                                                         \/
>   *|------------------------------------------------|*
>  /\                                                         /\
>   \____________________________/
>               scheduling_interval
>   
>  *Manual Run* *(next_ds1 is expected to match triggered_date as in the case for the manually triggered run that uses the regular execution_date above)*
>  triggered_date                                    next_ds1 + start_date
>  \/                                                         \/
>  *|-------------------------------------------------|*
>  /\                                                         /\
>   ____________________________/
>               0 to scheduling_interval (depending on when the next execution date is)
>   
>  What should happen is that next_ds is always set to execution_date for manually triggered runs instead of the next schedule-interval aligned execution date.
>   
>  This _might_ break backwards compatibility for some users but it can be argued that the current functionality is a bug. If it's really desired we can create new aliases that behave logically although I am against this.
>   
>  prev_ds should probably also be made consistent with this logic.



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