[libvirt] [PATCH v2 6/6] libvirtaio: add .drain() coroutine

[Daniel P. Berrange]

On Tue, Sep 26, 2017 at 12:47:00AM +0200, Wojtek Porczyk wrote:
> On Mon, Sep 25, 2017 at 02:53:01PM +0100, Daniel P. Berrange wrote:
> > On Thu, Sep 14, 2017 at 02:41:12AM +0200, Wojtek Porczyk wrote:
> > > The intended use is to ensure that the implementation is empty, which is
> > > one way to ensure that all connections were properly closed and file
> > > descriptors reclaimed.
> > > 
> > > Signed-off-by: Wojtek Porczyk <woju at invisiblethingslab.com>
> > > ---
> (snip)
> > > +    @asyncio.coroutine
> > > +    def drain(self):
> > > +        '''Wait for the implementation to become idle.
> > > +
> > > +        This is a coroutine.
> > > +        '''
> > > +        self.log.debug('drain()')
> > > +        if self._pending:
> > > +            yield from self._finished.wait()
> > > +        self.log.debug('drain ended')
> > 
> > What is responsible for calling 'drain'  ?
> 
> Users of the library, and they do it at their pleasure. This is to allow the
> loop to actually run the scheduled tasks. After calling virConnect.close() the
> handles/timeouts aren't actually closed until the loop run the scheduled
> callbacks. In practice a simple `yield` in a coroutine would be also
> sufficient since respective Tasks are in the _ready queue and all run during
> next loop cycle, but that's not guaranteed in asyncio specification.

Ah I see.

Reviewed-by: Daniel P. Berrange <berrange at redhat.com>



Regards,
Daniel
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