[openstack-dev] [Keystone] [Horizon] Pagination support for Identity dashboard entities

Morgan Fainberg morgan.fainberg at gmail.com
Fri Aug 14 21:52:50 UTC 2015



> On Aug 14, 2015, at 14:22, Adam Young <ayoung at redhat.com> wrote:
> 
>> On 08/14/2015 02:31 PM, David Lyle wrote:
>> I understand the reasoning, but there are use cases for indexing (re: searchlight) and auditing that are completely unsupported in keystone v3. As from keystone, I have no way to exhaustively list who has accounts in my cloud using OpenStack APIs. That seems like a hole that should be filled.
> 
> Not possible.  Federation is a mapping from a remote service.
> 
> We don't have the data.
> 
> The only place where Keystone is likely to be holding on to users is for service users.
> 
> 
> This is not the Keystone team being stubborn.  These are technical and practical limitations based on how OpenStack is being deployed in the wild.
> 
> 
> LDAP does not provide sufficient tools to do pagination in a practical manner.  LDAP does not guarantee ordering for query results, and there is no limit and offset.  Holding a cursor open is not allowed by corporate IT.  
> 
> 

It also looks to be forward paging only, going back a page requires starting the query over. An error will require starting the query over. LDAP paging is meant to allow gathering of more data than server max not offset based. Order is not guaranteed on any restart, so it is likely to be major inconsistencies in what is on a page instead of minor. 

> 
> 
> 
> 
>> 
>> Not to mention API consistency, which others have already brought up.
>> 
>> David
>> 
>> 
>> 
>> On Fri, Aug 14, 2015 at 9:02 AM, Morgan Fainberg <morgan.fainberg at gmail.com> wrote:
>>> For the identity (users and groups) backend as long as we support LDAP (and as side note federated users never show up in this list anyway) and with the drive towards pushing all user management out of keystone itself to ldap or other tools that do it better, I don't see pagination as something we should be providing. Providing an inconsistent user experience based on leaking underlying implementation details is something I am very against. This stance ensures that horizon and other tools like it will not need to know underlying implementation details to provide a consistent user experience. Unfortunately here we do need to cater to the lowest common denominator and filtering/searching/limiting is the clear common mechanism
>>> 
>>> With regards to resources (projects, domains, etc) since we no longer support using LDAP (deprecated with removal in mitaka) I have less strong feelings towards and wouldn't block efforts to implement if it is not already available (if not available this is likely a mitaka goal).
>>> 
>>> --Morgan
>>> 
>>> Sent via mobile
>>> 
>>> > On Aug 14, 2015, at 07:39, Jay Pipes <jaypipes at gmail.com> wrote:
>>> >
>>> >> On 08/14/2015 09:14 AM, Morgan Fainberg wrote:
>>> >> As a quick note the api-ref you are linking to has some gaps/has not
>>> >> been kept in sync with the official api specifications.
>>> >>
>>> >> The official API specification is located at
>>> >> http://specs.openstack.org/openstack/keystone-specs/ (v2 and v3 sections
>>> >> at the top) and there is a known open bug to work with the docs team to
>>> >> get this in sync (somehow).
>>> >>
>>> >> Unfortunately there are a number of cases                 especially with the identity
>>> >> backend where pagination just does not work (or works completely
>>> >> unreliably) such as utilizing the ldap driver.                 Either a cursor must be
>>> >> maintained (problematic in REST) or the results could be wildly
>>> >> different every single request meaning each page is not really
>>> >> guaranteed to be the "next page" it could be the same/show inconsistent
>>> >> results. The second issue is that the pagination is not a good UX even
>>> >> where it works - the simple question is: if you can filter the results
>>> >> how many pages deep do you go before refining the query; think of your
>>> >> use of search engines.
>>> >>
>>> >> In light of these issues Keystone has opted for a filter / limit
>>> >> (config). If the results exceed the limit there is a truncation that
>>> >> occurs and it is recommended extra filtering be applied to reduce the
>>> >> total number of results.
>>> >>
>>> >> This discussion has gone around a few times, pagination in keystone is
>>> >> not currently on the roadmap. In addition to the above doc bug, we
>>> >> should work to better socialize this filter-over-paginate methodology.
>>> >
>>> > I understand all the things you write above about the problems that Keystone's underlying architecture (driver-based, not always able to do pagination in the individual drivers). However, it really does mean that Keystone is the only project in OpenStack that behaves this way. All other services provide limit/marker paginations, AFAIK, which is efficient and, while not the same UX as a filtering methodology, is entirely compatible and complementary to filtering.
>>> >
>>> > Best,
>>> > -jay
>>> >
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>> 
>> 
>> 
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