[Pulp-dev] Repo version validation

Tatiana Tereshchenko ttereshc at redhat.com
Wed Oct 9 18:22:29 UTC 2019

On Wed, Oct 9, 2019 at 5:52 PM Brian Bouterse <bmbouter at redhat.com> wrote:

> On Wed, Oct 9, 2019 at 5:23 AM Tatiana Tereshchenko <ttereshc at redhat.com>
> wrote:
>> I think the main confusion I have is that we call it validation.
>> Semantically, I'd expect the validation operation to complain if something
>> is invalid and to pass if everything is fine.
> Yes let's have validation perform, just validation. Thank you for bringing
> us back to this. +1
>> The solution [0] also implies that I think:
>>         Raises:
>>             django.core.exceptions.ValidationError: if the repository is
>> invalid
>> As I mentioned below I think a plugin needs to have an ability to change
>> the content of a repo version, it sounds more than just validation to me.
>> Let me know if I misunderstand something or misuse any terms.
> I agree. What about if we add add_content, remove_content classmethod for
> plugin writers to override on their Content subclass, and these were called
> by RepositoryVersion.add_content and RepositoryVersion.remove_content?
> These would be hooks similar to the validation hook, only these are
> designed to "handle" changes. The queryset would be type-filtered in the
> RepositoryVersion.add_content and RepositoryVersion.remove_content, so each
> Content model's implementation only needs to handle it's own type and it
> can rely on that. I'm open to other pattern suggestions with a similar
> outcome.

+1 to this idea. Thank you!
As we discussed offline, let's additionally pass a repo version itself
to add_content/remove_content plugin classmethod because for some content
types it's necessary to have access to other types in a repo version. E.g.
modulemd and its RPMs.

> This would handle the Advisory-merge use case for pulp_rpm for example.
> The Advisory object would define these two hook implementations, and when
> adding it would provide the merge-with-existing-content feature.
> We may need to take care that references to content could be invalidated
> anytime a call to RepositoryVersion.add_content or
> RepositoryVersion.remove_content occurs. That sounds do-able but it becomes
> a somewhat subtle requirement.

+1 to the concern
Additionally, new content can be added during those calls. E.g. Advisory
merge = removal of old one, addition of newly created one.

> I don't think this would fully handle the dependency use case though. This
> type of pattern only can account for the content that is already in the
> repsitory_version being created. So it lacks a reference to for example
> where content is being copied from, and what source content set it should
> look into to even provide dependency resolution. Also at sync-time it
> couldn't know if the packages it's "going to bring in extra" are just
> coming in a later part of the pipeline. So while I think we should
> implement these hooks, it doesn't solve the dependency solving use case.
> I'm ok w/ that, but what do you think?

I think it's fine. Dependency solving is a pure copy case, in my opinion,
so I'm not concerned that we don't cover it in the generic way for every
repo version.


>> I keep thinking these use cases are for copy not sync, because only in
>>> the copy case is the plugin writer's code not already involved.
>> I think any use case that modifies repo version in some way is important
>> here - sync, copy, upload, removal of content.
>> It's just happened that for sync we already have a mechanism for plugins
>> to influence the result, however it can likely be simplified and reuse what
>> will be implemented for the story [0] under discussion.
>> Tanya
>> [0] https://pulp.plan.io/issues/3541#note-3
>> On Tue, Oct 8, 2019 at 11:01 PM Brian Bouterse <bmbouter at redhat.com>
>> wrote:
>>> On Tue, Oct 8, 2019 at 2:55 PM David Davis <daviddavis at redhat.com>
>>> wrote:
>>>> I think @bmbouter's solution could handle the first example of checking
>>>> RPMs against a specific key.
>>>> The second example is trickier though because the validation would have
>>>> to know which module is being removed in order to know which packages to
>>>> remove from the repo. This is because the packages could exist in the repo
>>>> independently of the module. I think it'd have to have the list of
>>>> additions/removals in order to handle that use case.
>>> It would have reference to the repo_version being created, so I think it
>>> would have the RepositoryVersion.removed queryset to inspect.  I think this
>>> is mainly useful for copy operations at which point the copy endpoint may
>>> be a better tool for features like plugin-provided dependency resolution
>>> versus the generic copy operations in core.
>>> I keep thinking these use cases are for copy not sync, because only in
>>> the copy case is the plugin writer's code not already involved.
>>>> David
>>>> On Tue, Oct 8, 2019 at 12:55 PM Tatiana Tereshchenko <
>>>> ttereshc at redhat.com> wrote:
>>>>> The solution proposed in #3541 looks good for validation purposes.
>>>>> My understanding of the problem is that a plugin needs to apply some
>>>>> logic and decide which content to keep and which content to remove at repo
>>>>> version creation time and perform these changes.
>>>>> Examples:
>>>>>  - add to a repo version only RPMs signed with a specific key
>>>>>  - removal of the moduled content should automagically remove related
>>>>> RPMs from a repo version.
>>>>> In theory, for the examples above, if we have validation only, user
>>>>> can be forced to prepare perfect add/remove requests, however I think it
>>>>> won't be a good user experience.
>>>>> Can it be done in the same way as the suggestion for validation? Just
>>>>> if it makes sense for plugin to "fix" repo version itself, they will do it,
>>>>> otherwise validation error can be raised. What do you think?
>>>>> Tanya
>>>>> On Tue, Oct 8, 2019 at 4:46 PM Dennis Kliban <dkliban at redhat.com>
>>>>> wrote:
>>>>>> The plan outlined in 3541 solves the problem in a way that gives
>>>>>> plugin writers a lot of control. +1 to implementing it.
>>>>>> On Thu, Oct 3, 2019 at 12:23 PM David Davis <daviddavis at redhat.com>
>>>>>> wrote:
>>>>>>> We have a blocker for Pulp 3.0 GA[0] that we need to address soon in
>>>>>>> order to let plugins leverage it in their upcoming GA releases. It involves
>>>>>>> allowing plugin writers to validate content in a repo version. It's
>>>>>>> somewhat related to validating uniqueness in a repo version[1] except there
>>>>>>> are cases other than uniqueness that plugins might want to handle. One
>>>>>>> example might be a case where we want to prevent a user from adding a
>>>>>>> docker tag that points to a manifest outside a repo from getting added to
>>>>>>> the repo. I'm not sure if this is an actual example but it gives you an
>>>>>>> idea that there might be other non-unique validation plugin writers might
>>>>>>> want to add.
>>>>>>> Brian proposed a solution on 3541 that I think solves the
>>>>>>> problem[2]. I was hoping to maybe get some feedback on it so we could
>>>>>>> proceed by October 9.
>>>>>>> [0] https://pulp.plan.io/issues/3541
>>>>>>> [1] https://pulp.plan.io/issues/5008
>>>>>>> [2] https://pulp.plan.io/issues/3541
>>>>>>> David
>>>>>>> _______________________________________________
>>>>>>> Pulp-dev mailing list
>>>>>>> Pulp-dev at redhat.com
>>>>>>> https://www.redhat.com/mailman/listinfo/pulp-dev
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