Open Stack

This is a new concept to me in JSON, I've never heard of a wrapper 
element like that being called a namespace.

My first impression is that is looks like cruft. If there's nothing else 
at the root of the JSON document besides the namespace, all it means is 
that every time I go to access relevant data I have an extra layer of 
indirection. Something like:

volume_wrapper = get_volume(url)
volume = volume_wrapper['volume']

or

volume = get_volume(url)
name = volume['volume']['name']

If we ever forsee an aggregate API, I can see some value in it. For 
instance, a single call that aggregates a volume with some relevant 
metrics from ceilometer. In that case, I could see leaving both distinct 
data sets separate at the root with some form of namespace rather than 
attempting to merge the data.

Even in that case, I think it'd be up to the aggregate API to introduce 
that.

Looking at api.openstack.org, there doesn't appear to be any high level 
resource get that would aggregate the different subcollections.

For instance, {tenant_id}/volumes stuffs everything inside of an element 
called "volumes". {tenant_id}/types stuffs everything inside of an 
element called volume_types. If a call to {tenant_id} aggregated both of 
those, then I can see leaving the namespace in on the single ID look ups 
for consistency (even if it's redundant). However, the API doesn't 
appear to support that, so just looking at the examples given it looks 
like an added layer of depth that carries no extra information and makes 
using the returned result a bit awkward IMO.


On 02/26/2014 01:38 PM, Petr Blaho wrote:
> Hi,
>
> I am wondering what is the OpenStack way of returning json from
> apiclient.
>
> I have got 2 different JSON response examples from http://api.openstack.org/:
>
> json output with namespace:
> {
>    "volume":
>    {
>      "status":"available",
>      "availability_zone":"nova",
>      "id":"5aa119a8-d25b-45a7-8d1b-88e127885635",
>      "name":"vol-002",
>      "volume_type":"None",
>      "metadata":{
>        "contents":"not junk"
>      }
>    }
> }
> (example for GET 'v2/{tenant_id}/volumes/{volume_id}' of Block Storage API v2.0 taken from
> http://api.openstack.org/api-ref-blockstorage.html [most values ommited])
>
> json output without namespace:
> {
>    "alarm_actions": [
>        "http://site:8000/alarm"
>      ],
>      "alarm_id": null,
>      "combination_rule": null,
>      "description": "An alarm",
>      "enabled": true,
>      "type": "threshold",
>      "user_id": "c96c887c216949acbdfbd8b494863567"
> }
> (example for GET 'v2/alarms/{alarm_id}' of Telemetry API v2.0 taken from
> http://api.openstack.org/api-ref-telemetry.html [most values ommited])
>
> Tuskar API now uses "without namespace" variant.
>
> By looking at API docs at http://api.openstack.org/ I can say that
> projects use both ways, altought what I would describe as "nicer API"
> uses namespaced variant.
>
> So, returning to my question, does OpenStack have some rules what
> format of JSON (namespaced or not) should APIs return?
>