I'd be for deprecating it. It's too easy to use with too much too
loose and too little value. I see no real "business" value in it.
On Tue, Dec 28, 2021 at 5:27 PM Daniel Standish
<daniel.stand...@astronomer.io.invalid> wrote:
>
> Yeah that's correct. Sorry, I should have used `pendulum.today`. But yeah
> also equivalent to `pendulum.today('UTC').add(days=-N)` (while `days_ago`
> uses timedelta it's the same when there's no DST is involved)
>
>
> On Tue, Dec 28, 2021, 1:59 AM Ash Berlin-Taylor <a...@apache.org> wrote:
>>
>> days_ago is not just the same as utcnow minus N days, it is always
>> "truncated" to the start of the day, so it's closer to
>> "utcnow().replace(hour=0, minute=0, second=0) - timedelta(n)”
>>
>>
>> On 28 December 2021 00:08:53 GMT, Daniel Standish
>> <daniel.stand...@astronomer.io.INVALID> wrote:
>>>
>>> I recall some time ago we removed `days_ago` from all example dags. Not
>>> sure why we didn't also deprecate it.
>>>
>>> For reference, `days_ago(N)` returns utcnow minus N days.
>>>
>>> There's a PR to make it return a value in the default timezone, so that
>>> when you use it in an expression for dag `start_date`, the dag will be in
>>> the default timezone.
>>>
>>> I don't want to get into the merits of that here. But even assuming that
>>> this would be desirable, there's still some ambiguity we'd have to resolve.
>>> Namely, should we return `now minus N 24-hour periods` (as `now -
>>> timedelta(N)` would do) or should we return now minus N days (as
>>> pendulum.now().add(days=-N) would do)? Because of DST the two different
>>> approaches result in values that differ by 1 hour.
>>>
>>> What I do want to explore here is whether folks think we can / should just
>>> deprecate the function entirely. Personally this would be my preference.
>>> Using `days_ago(5)` is not much more convenient than `dttm.add(days=-N)`.
>>> And the latter has the benefit that it is unambiguous, doesn't make
>>> assumptions, and doesn't get in the way between user and library.
>>>
>>> So my proposal would be, don't change the behavior of `days_ago` and
>>> deprecate it with removal targeted in 3.0.
>>>
