[katello-devel] Modelling of environments, products, etc in Katello (related to renaming of environments)
Dmitri Dolguikh
dmitri at redhat.com
Thu Aug 9 15:43:04 UTC 2012
On 09/08/12 03:49 PM, James Bowes wrote:
> On Thu, Aug 09, 2012 at 01:39:56PM +0100, Dmitri Dolguikh wrote:
>> On 09/08/12 01:20 PM, James Bowes wrote:
>>> On Thu, Aug 09, 2012 at 12:34:57PM +0100, Dmitri Dolguikh wrote:
>>>> Please see https://bugzilla.redhat.com/show_bug.cgi?id=795928 for
>>>> description of an issue with environment renaming.
>>>>
>>>> The immediate problems around environments: using of environment
>>>> names and environment ids for identification of environments
>>>> interchangeably. Using db ids for environment identification when
>>>> not using environment names.
>>>>
>>>> To resolve these:
>>>> - introduce environment uuids
>>>> - update katello/katello cli to use uuids for environment identification
>>>> - update repository naming to use environment uuids
>>>> - update candlepin (this will include updates to schema, and
>>>> resource controller)
>>>>
>>> -1 to UUIDs, for the same reason as has been discussed wrt pulp
>>> repo labels. a url like:
>>>
>>> https://my-cdn.local/content/dev/rhel-server/i386/
>>>
>>> is way more useful than:
>>>
>>> https://my-cdn.local/content/abc123213-23423423-aaa123/rhel-server/i386/
>>>
>>> not to mention, far more handsome!
>>>
>>> I'd rather see either immutable labels, or supporting renaming labels,
>>> too.
>> The issue boils down to renaming of environments. If we are to use
>> environment names for environment identification, we have to provide
>> resolution for urls that are no longer valid (via 301). Doable, but
>> additional work.
>>
> label and name can be seperate. label could be my-env, name could be "My
> Environment". label is something that can be easily passed into a cli
> command, or put in a yum url for content downloads. name would just be
> something you view.
>
> I don't think it's necessary to support redirection.
I think it is. The resource has to be reachable under the
originally-issued url, unless it has been deleted.
>
>> The idea of labels is interesting, but I don't think it would work
>> out in the long-term: it would become stale after a rename or two
>>
> Unless you update the label at the same time.
Defeats the point of the whole exercise.
>> With uuid's we won't need to support url redirection, they won't go
>> stale. For user-friendliness we should provide querying by name with
>> environment resource, smt. like:
>>
>> GET http://localhost/katello/api/organizations/ACME_Corporation/environments?name=super-duper
>>
> That's effectively the same as using the label directly in the path of
> the url, isn't it?
The difference is that uri gives you the resource in question, or a 404.
A query can return none, one, or multiple resources. In other words, a
query doesn't uniquely identify a resource, only provides a way to find one.
>
>> Less convenient, but easier to implement and maintain (from both
>> user and developer perspective).
>>
>> -d
>>
>>> To clarify, UUIDs are fine imo as an internal canonical id for envs
>>> within katello as a whole, but once the env is exposed on the cli or in
>>> a url, label should be used.
>>>
>>>> The larger problem: Katello and Candlepin modelling of
>>>> products/product content/environments lost coherency.
>>>>
>>>> Candlepin's view of the above trifecta (use of a monospaced font is
>>>> encouraged for the content below):
>>>> +-------------+ +--------------------+
>>>> | Environment | 1 <--- * | EnvironmentContent |
>>>> +-------------+ +--------------------+
>>>> ^
>>>> | *
>>>> | 1
>>>> +---------+ +----------------+
>>>> | Product | 1 ---> * | ProductContent |
>>>> +---------+ +----------------+
>>>>
>>>>
>>>> same thing in Katello (with added pulp repositories):
>>>>
>>>> +-------------+
>>>> | Pulp::Repos |<-----------------------+
>>>> +-------------+ |
>>>> ^ |
>>>> | uses |
>>>> +----------------------------------+ | +-------------+
>>>> | Candlepin::Product | | | Environment |
>>>> | (uses Candlepin::ProductContent) | | +-------------+
>>>> +----------------------------------+ | ^
>>>> | ^ | | 1
>>>> |uses | uses | |
>>>> | | | | *
>>>> +---------+ +--------------------+
>>>> | Product | 1 ---------------> * | EnvironmentProduct |
>>>> +---------+ +--------------------+
>>>> | |1
>>>> | |*
>>>> | V
>>>> | uses +------------+
>>>> +------| Repository |
>>>> +------------+
>>>>
>>>>
>>>> I propose:
>>>> - Rename EnvironmentProduct to ProductContent
>>>> - make it use Candlepin::ProductContent
>>>> - remove use of Pulp::Repos from Product
>>>> - delegate responsibility of generation of environment uuids to
>>>> Candlepin (should cp folks agree on this)
>>>>
>>>> resulting in:
>>>>
>>>> +-------------+
>>>> | Environment |
>>>> +-------------+
>>>> ^
>>>> | 1
>>>> | *
>>>> +---------+ +----------------+
>>>> | Product | 1 ---> * | ProductContent |
>>>> +---------+ +----------------+
>>>> |1 | uses
>>>> | | +---------------------------+
>>>> |1 +-> | Candlepin::ProductContent |
>>>> V +---------------------------+
>>>> +-------------+ uses +------------+
>>>> | Pulp::Repos |<-----| Repository |
>>>> +-------------+ +------------+
>>>>
>>>> I don't think many-1 relation is required on
>>>> Repository-ProductContent, it's 1-1?
>>>>
>>>>
>>>> Thoughts, concerns, opinions?
>>>> -d
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> katello-devel mailing list
>>>> katello-devel at redhat.com
>>>> https://www.redhat.com/mailman/listinfo/katello-devel
>>> -James
>>
> -James
>
>
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