Re: [libvirt] [PATCH 0/2] Fix interface state transitions logic
On Thu, Dec 12, 2013 at 07:54:34AM -0700, Eric Blake wrote:
On 12/12/2013 07:41 AM, Daniel P. Berrange wrote:
>
> The usage you describe here is not within the scope of the
> virInterfaceCreate() API IMHO. If we want users to have the
> ability to "re start" an interface without taking it offline
> first, then we should add another API that explicitly supports
> that use case.
Or even a flag to the existing argument that says to restart if already
running, where the normal case of not having the flag is an error if
already running.
> Overloading a single virInterfaceCreate to support two different use
> cases puts applications in an impossible position if they *want* to
> see an error from attempting to start an already active interface.
Overloading without the use of a flag bit, that is.
In this scenario I'd prefer a separate API. Flags are good when they
are tweaking some aspect of behaviour but leaving the overall semantics
of the method intact.
A virInterfaceCreate API call is a lifecycle operation, which should
result in a lifecycle change (and event emission) upon success. Just
doing a refresh of the config isn't a lifecycle change and would not
be expected to trigger any lifecycle events either. This is different
enough that I think it would belong in a separate API.
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|