Re: [libvirt] [PATCH 7/7] storage: Add storage backend pool/vol API's to capability output

29 Jan 2019

      On 1/29/19 5:18 AM, Michal Privoznik wrote:
...
On 1/16/19 2:15 AM, John Ferlan wrote:
...
https://bugzilla.redhat.com/show_bug.cgi?id=1581670
Add the Storage Pool and Volume API's defined for each generated
capability output, such as:
  <pool>
     <type>dir</pool>
     <poolapis>
       <buildPool/>
       <refreshPool/>
       <deletePool/>
     </poolapis>
     <volapis>
       <buildVol/>
       <buildVolFrom/>
       <createVol/>
       <refreshVol/>
       <deleteVol/>
       <resizeVol/>
       <uploadVol/>
       <downloadVol/>
       <wipeVol/>
     </volapis>
   </pool>
...
   <pool>
     <type>iscsi</pool>
     <poolapis>
       <findPoolSources/>
       <startPool/>
       <refreshPool/>
       <stopPool/>
     </poolapis>
     <volapis>
       <uploadVol/>
       <downloadVol/>
       <wipeVol/>
     </volapis>
   </pool>
Frankly, I don't like this. Firstly, our users don't see 'uploadVol'
they see 'virStorageVolUpload'. Secondly, I am not sure if we want to be
introspectable this much. I mean, our users can just call the API and
deal with VIR_ERR_NO_SUPPORT. This looks like an overkill to me.
That's fine - hence the reason for separation. I guess I was thinking
that developers may like to know what API's are supported by each pool -
kind of a "features" list of sorts.  Using the backend naming scheme
is/was kind of a cheat. I'm not against being more creative - ideas are
welcome ;-).

I think most important is perhaps knowing what volume operations a pool
supports or at least the upload/download, wipe, and resize.

Without any kind of extra data, the output is kind of boring:

<capabilities>

  <pool>
    <type>dir</pool>
  </pool>

  <pool>
    <type>fs</pool>
  </pool>

  <pool>
    <type>netfs</pool>
  </pool>

....

  <pool>
    <type>zfs</pool>
  </pool>

</capabilities>

John