> Breaking changes could be maintained via deprecation warnings for a
number of releases to avoid deterring users, whilst pushing towards a
cleaner interface.
No one wants to go and alter hundreds of DAGs, thousands of operator calls.
I know for a fact that the task would be monumental at both Lyft and Airbnb
and could lead to upgrades never happening, or cause many incidents (change
causes incidents!). It also mean a maintainer committing to changing all
operators to support both, handing deprecation warning, and cleaning up
eventually, I don't think you'll find someone to sign up for that task.
There are also a lot of operators in the wild (living in pipeline repos)
that may just never conform.
For operators specifically, as mentioned earlier in the thread, the reason
why it is the way it is is for `default_args` to set all the conn_ids at
the top of the script. Personally I feel strongly about not breaking this.
It makes DAG scripts look nice, and changing would be hard and very
disruptive (all DAGs in existence would have to adapt and would end up
looking worse by repeating conn_ids for each task instead of a global
setting).
As for hooks, why not just formalizing the fact that the first argument of
the constructor is a `conn_id` and using positional arguments when
instantiating hooks? There are generic operators out there that built upon
this assumption already.
Max
On Fri, Jun 29, 2018 at 9:04 AM julianderui...@gmail.com <
julianderui...@gmail.com> wrote:
> I would be very much in favour of moving to the naming approach you
> propose (conn_id for hooks, src_conn_id and dest_conn_id for operators with
> multiple connections), which I think is much more consistent than the
> current naming conventions. The added advantage of this naming is also that
> it makes it much easier in the future to work towards more generic
> operators/hooks where we (for example) copy from one database or file
> system without caring which file systems are involved. This avoids the
> wildfire of the current Airflow codebase in which we end up with an
> operator for every different combination of file systems.
>
> Breaking changes could be maintained via deprecation warnings for a number
> of releases to avoid deterring users, whilst pushing towards a cleaner
> interface.
>
> On 2018/05/30 01:19:37, "Daniel (Daniel Lamblin) [BDP - Seoul]" <
> lamb...@coupang.com> wrote:
> > The short of this email is: can we please name all the connection id
> named parameters to all hooks and operators as similarly as possible. EG
> just `conn_id`?
> >
> > So, when we started using Airflow I _had_ thought that minor versions
> would be compatible for a user's DAG, assuming no use of anything marked
> beta or deprecated, such that v1.7.1, 1.8.0, 1.8.1, 1.8.2 and 1.9.0 etc
> would all run dags from prior versions in that linage, each with possible
> stability and feature improvements and each with possibly more operators,
> hooks, executors (even) etc.
> >
> > This is (now) obviously not the case, and it's the group's choice about
> what should and what should not break on a release-by-release basis. I
> think a clear policy would be appropriate for full Apache status, but then
> I may have missed where the policy is defined. Though, if defined as not
> giving stability to the user's dags for most version changes isn't in my
> opinion going to grow confidence for Airflow being something you can grow
> with.
> >
> > Not to be overly dramatic, but currently the tiny change that the
> `s3Hook(…)` takes `aws_conn_id='any_string'` vs
> `s3_conn_id='still_any_string'` means that basically I have to maintain a
> 1.8.2 setup in perpetuity, because no one (here) wants to briefly code
> freeze before during and after an update so that we can update all the uses
> and be ready to roll back the update if something else breaks (also some
> people access the not-actually-private `_a_key and _s_key` and would need
> to switch to still-not-private `_get_credentials()[…]`). Instead we'll just
> run a second airflow setup at 1.9.0 (in each and every staged environment)
> and move the 8k dags piecemeal whe[never] people get the spare time and
> inclination. I mean, we might. It looks like 1.10.0 changes some config
> around s3 logging one more time… so maybe it's better to skip it?
> >
> > I saw the couple of PRs where the project itself had to make the changes
> to usages of the named field. There was momentary and passing concern that
> users' dags would need to do the same. In the PRs, of the options discussed
> (shims, supporting the deprecated name as deprecated, doing a hard rename),
> it wasn't brought up if the rename to aws_conn_id was the best name. [Was
> this discussed elsewhere?]
> >
> > And so I wondered why is there this virtual Hungarian notation on all
> the `conn_id`s?
> > A hook generally takes one `conn_id`, most operators take only one. In
> these cases couldn't the named parameter have been `conn_id`? When an
> operator needs a couple conn_ids, could it not have `src_conn_id` and
> `dest_conn_id` instead of locking in either s3 or aws, mysql or maria,
> dataflow or beam etc? Those are hypotheticals, I believe.
> >
> > Could I propose to plan to break absolutely all uses of
> `{named}_conn_id`s, before or by version 2.0, with an eye towards never
> again having to break a named parameter for the rest of 2.x's life? There's
> probably more named parameters that should be fixed per major release, and
> if you agree, some work should be done to identify them all, but this just
> happens to be the one that seems most likely to change often, and has so
> recently.
> >
> > Thanks,
> > -Daniel
> >
> >
>
