[Pulp-dev] let's rename RepositoryVersion to Snapshot

Wed Mar 28 14:05:02 UTC 2018

Thanks for bringing up this topic. I feel like it’s been worthwhile to
explore it as RepositoryVersion isn’t a perfect name for the concept.

David

On Wed, Mar 28, 2018 at 9:57 AM, Dennis Kliban <dkliban at redhat.com> wrote:

> Thank you everyone for your feedback. I agree that snapshot carries some
> connotations that are not congruent with the mental model we want to
> present to our users. -1 from me also :)
>
> On Wed, Mar 28, 2018 at 9:35 AM, David Davis <daviddavis at redhat.com>
> wrote:
>
>> I concur with @dalley. I read through the wikipedia article on snapshots
>> in computer storage again and it just doesn’t seem to fit our model.
>> Snapshots typically mean backups or archives and using them to describe the
>> current state of the repository doesn’t make sense. As Ina says, a user
>> should instead trigger a snapshot to create a copy/backup/archive of a
>> repository’s content. Creating a new snapshot automatically by modifying
>> the current state of the repo doesn’t make sense.
>>
>>
>> David
>>
>> On Wed, Mar 28, 2018 at 9:24 AM, Daniel Alley <dalley at redhat.com> wrote:
>>
>>> -0 to changing the name.  Shorter is good, but I do think the name is
>>> misleading, and I disagree with the reasoning provided in the meeting the
>>> other day that "snapshot is more self-explanatory" - which I don't believe
>>> that it is.
>>>
>>> this term is not unique to Pulp so it is easier to explain to the user
>>>
>>>
>>> I think Ina's point from the other day about what meaning other
>>> developers - not affiliated with pulp - associate with the name "snapshot"
>>> shouldn't be dismissed.  If we're reusing a term but attaching a meaning to
>>> it that is not quite the same as what the average person would guess it
>>> was, the information won't "stick" as well.
>>>
>>> Sure, there are Pulp concepts that have to be explained to the user in
>>> any event, but we should still try to match their expectations as closely
>>> as possible.
>>>
>>> And while I'd welcome data to the contrary, I don't think a user would
>>> have a harder time understanding the concept of a "RepositoryVersion" than
>>> they would a "Snapshot".  It's pure composition.  People are familiar with
>>> repositories, people are familiar with versions.. I don't see a problem
>>> there.
>>>
>>> On Wed, Mar 21, 2018 at 8:00 AM, Ina Panova <ipanova at redhat.com> wrote:
>>>
>>>> +1 to keep RepositoryVersion.
>>>>
>>>> I also do not like the fact that it is quite long, that's why i do like
>>>> the Snapshot, but thinking more of what snapshot is - is something that
>>>> *you* need to trigger and it is not triggered automatically.
>>>> I'd say, we are working with repository versioning and not snapshots.
>>>>
>>>> Back to aptly, they use the term shapshot, which you need to manually
>>>> create https://www.aptly.info/doc/aptly/snapshot/create/
>>>>
>>>>
>>>>
>>>> --------
>>>> Regards,
>>>>
>>>> Ina Panova
>>>> Software Engineer| Pulp| Red Hat Inc.
>>>>
>>>> "Do not go where the path may lead,
>>>>  go instead where there is no path and leave a trail."
>>>>
>>>> On Tue, Mar 20, 2018 at 5:14 PM, Matthias Dellweg <dellweg at atix.de>
>>>> wrote:
>>>>
>>>>> I guess, you meant 'RepositoryVersions' there. Maybe it is just a typo,
>>>>> or maybe your subconciousness already adepted to this change. ;)
>>>>>
>>>>> I'm +1, because from the REST API or model view, you do not ask what
>>>>> changed, but rather what is in that snapshot|version.
>>>>> And since you are renaming all models of pulp3 atm, you are giving a
>>>>> plugin maintainer a hard time, anyway. I think, it's now or never.
>>>>>
>>>>> Matthias
>>>>>
>>>>> On Tue, 20 Mar 2018 11:55:14 -0400
>>>>> David Davis <daviddavis at redhat.com> wrote:
>>>>>
>>>>> > I’m not too worried about the change being too large. However, I
>>>>> > agree with @dalley though about snapshot not fitting my mental model
>>>>> > of how I view snapshots so any work seems like a loss to me.
>>>>> >
>>>>> > I’m at -1 but am happy to talk more about it.
>>>>> >
>>>>> >
>>>>> > David
>>>>> >
>>>>> > On Tue, Mar 20, 2018 at 11:08 AM, Daniel Alley <dalley at redhat.com>
>>>>> > wrote:
>>>>> >
>>>>> > > I think of a "snapshot" like a VM snapshot or a Windows restore
>>>>> > > point - an archival copy of a very fluid and non-discrete system at
>>>>> > > one point in time.  By that understanding, the term
>>>>> > > RepositoryVersion probably fits better.
>>>>> > >
>>>>> > > I acknowledge the other benefits though.  -/+0?
>>>>> > >
>>>>> > > On Tue, Mar 20, 2018 at 10:51 AM, Dennis Kliban <
>>>>> dkliban at redhat.com>
>>>>> > > wrote:
>>>>> > >
>>>>> > >> The article you link to just says that "a snapshot is the state of
>>>>> > >> a system at a particular point in time". The point in time can be
>>>>> > >> now or in the past.
>>>>> > >>
>>>>> > >> The current state of a repository's content would be described as
>>>>> > >> the latest or most recent snapshot of a repository.
>>>>> > >>
>>>>> > >> I am not too worried about the pain of doing the refactoring
>>>>> across
>>>>> > >> multiple repos.
>>>>> > >>
>>>>> > >> On Tue, Mar 20, 2018 at 10:20 AM, David Davis
>>>>> > >> <daviddavis at redhat.com> wrote:
>>>>> > >>
>>>>> > >>> I have some reservations about using the name Snapshot.
>>>>> > >>> Specifically, I don’t think the snapshot term is a good fit. As
>>>>> > >>> wikipedia says [0], in CS a snapshot represents a state of
>>>>> > >>> something "in the past.” How would we describe the current state
>>>>> > >>> of the repository’s content then? I think "current version" would
>>>>> > >>> make sense but not "current snapshot.”
>>>>> > >>>
>>>>> > >>> Also, changing the code in pulpcore and plugins is going to be a
>>>>> > >>> pain. Especially with the other things we have planned like
>>>>> > >>> renaming Importers to Remotes. I think this should factor into
>>>>> > >>> our decision as well.
>>>>> > >>>
>>>>> > >>> [0] https://en.wikipedia.org/wiki/Snapshot
>>>>> > >>>
>>>>> > >>>
>>>>> > >>> David
>>>>> > >>>
>>>>> > >>> On Tue, Mar 20, 2018 at 10:05 AM, Austin Macdonald
>>>>> > >>> <austin at redhat.com> wrote:
>>>>> > >>>
>>>>> > >>>> "Snapshot" is a nice way to explain what a RepositoryVersion is,
>>>>> > >>>> especially in the context of Publications. "Publish a
>>>>> > >>>> snapshot."  I like the idea, and I informally floated it around
>>>>> > >>>> PulpCon but decided not to propose it because:
>>>>> > >>>>
>>>>> > >>>>    - Snapshot is a little misleading about the actual data we
>>>>> > >>>> store. Specifically, since RepositoryVersions are stored as
>>>>> > >>>> diffs, when a user views the "content in a version", this is
>>>>> > >>>> calculated. This is a subtle point, and hopefully not user
>>>>> > >>>> facing at all, but I think snapshot implies a little bit more
>>>>> > >>>> certainty than we can offer.
>>>>> > >>>>    - A snapshot also implies a slightly different workflow to
>>>>> > >>>> me. The workflow I expect with snapshots is to change
>>>>> > >>>> Repositories "willy nilly", and when you are satisfied, you
>>>>> > >>>> "take" an snapshot. Versions imply the workflow we have, which
>>>>> > >>>> is that any time the content set of a Repository is changed, a
>>>>> > >>>> new version is created.
>>>>> > >>>>
>>>>> > >>>> However, I think those concerns are minor and are overshadowed
>>>>> > >>>> by the potential benefits. Also, I see a direct connection to
>>>>> > >>>> the thread "Plugin relationship to tasks". The name
>>>>> > >>>> Snapshot/RepositoryVersion is part of the choice of how we
>>>>> > >>>> portray the changing of content set of a repo.
>>>>> > >>>>
>>>>> > >>>>    1. We can "change a repo" which creates a new version.
>>>>> > >>>>    2. We can "create a new version" which has different content.
>>>>> > >>>>
>>>>> > >>>> To me (1) implies "dispatching a task that has the side effect
>>>>> of
>>>>> > >>>> creating a new repository version. It would lend itself well to
>>>>> > >>>> the concept of "managing repositories" rather than "managing
>>>>> > >>>> versions/snapshots". If we choose this way, I think the name
>>>>> > >>>> Snapshot conceptually makes sense.
>>>>> > >>>>
>>>>> > >>>> (2) implies a POST to create a new RepositoryVersion. As
>>>>> > >>>> explained in the plugin tasks thread, there are some problems
>>>>> > >>>> with this, but it is similar to the concept of creating a git
>>>>> > >>>> commit. I think we wouldn't think of "creating a new Snapshot"
>>>>> > >>>> to change the content.
>>>>> > >>>>
>>>>> > >>>> On Tue, Mar 20, 2018 at 9:33 AM, Dennis Kliban
>>>>> > >>>> <dkliban at redhat.com> wrote:
>>>>> > >>>>
>>>>> > >>>>> I propose that we rename the RepositoryVersion model in Pulp 3
>>>>> > >>>>> to Snapshot. The REST API would also change to use
>>>>> > >>>>> /api/v3/repositories/<uuid>/snapshot/
>>>>> > >>>>>
>>>>> > >>>>> The Snapshot name is a better description of what a repository
>>>>> > >>>>> version is and it is also much shorter in length.
>>>>> > >>>>>
>>>>> > >>>>> Thoughts?
>>>>> > >>>>>
>>>>> > >>>>>
>>>>> > >>>>> -Dennis
>>>>> > >>>>>
>>>>> > >>>>> _______________________________________________
>>>>> > >>>>> Pulp-dev mailing list
>>>>> > >>>>> Pulp-dev at redhat.com
>>>>> > >>>>> https://www.redhat.com/mailman/listinfo/pulp-dev
>>>>> > >>>>>
>>>>> > >>>>>
>>>>> > >>>>
>>>>> > >>>> _______________________________________________
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>>>>> > >>>> Pulp-dev at redhat.com
>>>>> > >>>> https://www.redhat.com/mailman/listinfo/pulp-dev
>>>>> > >>>>
>>>>> > >>>>
>>>>> > >>>
>>>>> > >>
>>>>> > >> _______________________________________________
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>>>>> > >> https://www.redhat.com/mailman/listinfo/pulp-dev
>>>>> > >>
>>>>> > >>
>>>>> > >
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Herzliche Grüße aus München
>>>>>
>>>>> Matthias Dellweg
>>>>> ______________________________________________________
>>>>> Dr. Matthias M. Dellweg
>>>>>
>>>>> (Open Source Software Engineer)
>>>>>
>>>>> Tel: +49 (0)89 452 35 38-12
>>>>> Fax: +49 (0)89 452 35 38-290
>>>>> E-Mail: dellweg at atix.de
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>>>>>
>>>>
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>>>>
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>>
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