[Pulp-dev] problems with publishers in Pulp 3

[Dennis Kliban]

The docker plugin is going to get rid of Publishers and Publications[0]. We
are planning to update the DockerDistribution with a 'RepositoryVersion'
field. If any other plugins want to do the same thing, we will need to make
a change in pulpcore to the Distribution model.

[0] https://pulp.plan.io/issues/4669

On Mon, Apr 8, 2019 at 4:44 PM Brian Bouterse <bbouters at redhat.com> wrote:

> Thank you for writing this out. The most significant issue I read in this
> is that 3 of the 9 plugins are having their users take steps that aren't
> adding any value in their workflow. They want to (and have an opportunity
> to) take repository version content and expose it directly. They don't need
> Publications or Publishers. If they need no metadata, instead of a
> "pass-through" publication it would be easier to have a Distribution refer
> to a RepositoryVersion directly and remove the "pass-through" feature. They
> the user could skip this step (
> https://github.com/pulp/pulp_ansible#create-a-publication ) and instead
> post the RepositoryVersion reference as part of the Distributor itself (
> https://github.com/pulp/pulp_ansible#create-a-distribution-for-the-publication
> ).
>
> The second issue I read here is that having users CRUD a publisher and
> then call that publisher is not as helpful/useful as CRUDing the resulting
> Publication directly. One practical issue related to this is the saving of
> the "publish" parameters. How do we store those over time? Our modeling
> choices have made this a bit challenging because Publication's aren't
> plugin controlled. A simple remedy is to have plugins provide various
> Publication objects instead of Publishers. These Publications would be
> managed by Master/Detail and when created it would run the task that
> creates the Publication and return the 202. This simplifies Pulp in that
> the options that were used to create the publication can be saved on the
> Publication as provided by various plugins. It also allows users to take
> one less step (they don't need to make a publisher to then make a
> publication). Instead users that need metadata generated can do so with one
> step, making the publication. So my main question is, can anyone remember
> why we didn't use Master/Detail in this area originally?
>
> I believe these are changes we should explore. The top one is a pretty
> simple add on and mostly not a breaking change. The bottom one would be a
> larger change, but one that I believe we could make and should seriously
> consider pre 3.0 GA.
>
>
>
> On Mon, Apr 8, 2019 at 7:42 AM Dennis Kliban <dkliban at redhat.com> wrote:
>
>> TLDR:
>>
>> Auto-distribution of publications is performed implicitly instead of
>> explicitly.
>> Plugins that don't generate metadata during publish have to provide a
>> generic publisher.
>> Users have to keep track of publishers to make sure auto-distribution of
>> new publications works.
>>
>> More background:
>>
>> Publishers in Pulp 3 serve three distinct functions:
>>   - store configuration for how a publication should be created
>>   - create publications using the configuration
>>   - update any distributions that are supposed to be auto updated with
>> new publications of a repository (auto distribution).
>>
>> Ansible, Docker, and Maven plugins do not generate any metadata when
>> creating a publication. So their publishers don't need to store any
>> configuration. Users of these plugins only get two benefits from publishers:
>>   - create publications using the configuration
>>   - update any distributions that are supposed to be auto updated with
>> new publications of a repository (auto distribution).
>>
>> The publications created by the publishers of these plugins could be
>> created using a single generic publish task. So the only remaining benefit
>> of a publisher for these plugins is the auto-distiribution that occurs when
>> a Distribution has a repository and a pubisher configured. The only way
>> this feature is documented right now is with the help text on the
>> 'repository' and 'publisher' fields of Distributions.
>>
>> Does anyone else see these as problems with the Publishers?
>> _______________________________________________
>> Pulp-dev mailing list
>> Pulp-dev at redhat.com
>> https://www.redhat.com/mailman/listinfo/pulp-dev
>>
>
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