[openstack-dev] [keystone] Pagination
jaypipes at gmail.com
Tue Aug 13 16:17:31 UTC 2013
On 08/13/2013 03:05 AM, Yee, Guang wrote:
> Passing the query parameters, whatever they are, into the driver if the
> given driver supports pagination and allowing the driver to override the
> manager default pagination functionality seem reasonable to me.
Please do use the standards that are supported in other OpenStack
services already: limit, marker, sort_key and sort_dir.
Pagination is meaningless without a sort key and direction, so picking a
sensible default for user/project records is good. I'd go with either
created_at (what Glance/Nova/Cinder use..) or with the user/project UUID.
The Glance DB API pagination is well-documented and clean . I highly
recommend it as a starting point.
Nova uses the same marker/limit/sort_key/sort_dir options for queries
that it allows pagination on. An example is the
instance_get_all_by_filters() call .
Cinder uses the same marker/limit/sort_key/sort_dir options for query
pagination as well. 
Finally, I'd consider supporting the standard change-since parameter for
listing operations. Both Nova  and Glance  support the parameter,
which is useful for tools that poll the APIs for "new" events/records.
In short, go with what is already a standard in the other projects...
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