[libvirt] [PATCH 1/2] driver: Include source parameter to virDomainGetHostname

[Daniel P. Berrangé]

On Mon, Nov 25, 2019 at 05:06:31PM +0100, Michal Privoznik wrote:
> On 11/24/19 10:33 PM, Julio Faracco wrote:
> > Thanks for your explanation, Peter!
> > 
> > I will focus on LXC side then...
> > 
> 
> You may still implement the API for other drivers too. The way we addressed
> this problem in the past is to create new API and have the old one call the
> new one. That's why we have "virSomething WithFlags()" APIs - because simply
> when introducing virSomething() API we did not think of adding flags. But if
> you then look how virSomething is implemented at driver level (say qemu
> driver) then you will see virSomething() is a very thin wrapper that calls
> virSomethingWithFlags(..., 0);.
> 
> 
> For instance virDomainCreate() and virDomainCreateWithFlags() and
> qemuDomainCreate() and qemuDomainCreateWithFlags().
> 
> So you will need to add a new API and then have the old call the new one
> with sensible @source. Since the sensible value can differ among drivers I
> guess we can have VIR_DOMAIN_HOSTNAME_SRC_DEFAULT which would mean
> "hypervisor driver default as in the most sensible source chosen
> automatically by driver".

This API already has flags, so the alternative to adding a "source"
parameter is to reuse the flags parameter to express the desired
data source. This is what we do the virDomainReboot/Shutdown methods.

The separate source parameter is the approach for virDomainGetInterfaces.
While it is certainly nicer to have a separate source, I think reusing the
flags parameter is acceptable given the API design we have.

Regards,
Daniel
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