[Kimchi-devel] [RFC] ISO pool: Support to download ISO from URL

[Aline Manera]

On 08/19/2014 04:03 PM, Crístian Viana wrote:
> On 19-08-2014 13:53, Crístian Viana wrote:
>> On 19-08-2014 10:49, Aline Manera wrote:
>>> Just one more comment along the others made by Royce.
>>>
>>> Yes - download and upload functionality will be available to all pools.
>>
>> Ok! So I'll update the RFC to support multiple storage pools and to 
>> use the Tasks API to handle the pause/resume/cancel operations.
>
> Well, Aline and I found a problem with this proposal. Currently, the 
> REST API always redirects "POST" requests in a Collection to the 
> function "<colletion-name>_create". In our case, if we send "POST 
> /storagepools/<pool-name>/storagevolumes/download", that would be 
> redirected to the backend function "storagevolumes_create". There is 
> no way to redirect those requests to different functions (like, 
> ideally, "storagevolumes_download" and "storagevolumes_upload").
>
> So I see two options from here:
>
>     1) Use the first API proposed by Aline: "POST 
> /storagepools/<pool-name>/storagevolumes". By looking at the 
> parameters (i.e. whether 'url' starts with "file://" or 
> "[http|ftp]://") we can tell if the operation is download or upload.

We can use "url" for download and "file" for upload.

if "url" in params.keys():
     self.download()
elif "file" in params.keys():
     self.upload()

>
>     2) Remodel the control code to support multiple actions when 
> POST'ing to a Collection.

It will not be possible as we expect to have an resource id instead of 
an action name.
To be able to do it we should treat the action name as a reserved name 
to avoid having a id and action with the same name

# This is a resource named "upload"
/storagepools/upload

# This is an action upload on storagepools collection
/storagepools/upload

I strongly suggest to adopt option 1.
The if/else will not be a big deal as we can do the functions self 
contained for easy maintenance.