Re: [libvirt-users] Sys::Virt integration into other event loops
On Mar 14, 2014, at 9:32 AM, Daniel P. Berrange <berrange(a)redhat.com> wrote:
- Register and run your own event loop impl by calling the method
Sys::Virt::Event::register(), passing in a custom subclass of
the Sys::Virt::Event class. This is what you should do to integrate
with existing event loop impls like AnyEvent.
If you're set on using AnyEvent, then you want todo option 2 here. There's
no particularly good docs or example code here, but you can see how todo
this by looking at the Perl test suite. eg the t/800-events.t file. This
test suite does a pure perl event loop based on select().
Yes, I’ve used this file as a reference and implemented a Sys::Virt::Event subclass—works
fine. I had to make one little change to make it not block:
my $n = select($ro=$ri,$wo=$wi,$eo=$ei,
(defined $timeout ? ($timeout ? $timeout/1000 : 0) : undef));
should be:
my $n = select($ro=$ri,$wo=$wi,$eo=$ei,
(defined $timeout ? ($timeout ? $timeout/1000 : 0) : 0));
because the 'undef' will cause select() to block until there’s something readable.
On our systems, this seems to be every 4 seconds for some reason (is there a 4 second
timeout in libvirt itself?).
You’d probably want to adapt that and call into AnyEvent, instead of
select().
The add_handle/remove_handle/update_handle/add_timeout/update_timeout/
remove_timeout methods should all call into appropriate AnyEvent APIs.
Then you just need to run AnyEvent as normal.
Sounds good; if I can get something cleaner than this:
while (! $quit) {
EV::run EV::RUN_ONCE;
$ev->run_once(); ## $ev is an instance of Sys::Virt::Event subclass
}
I’ll be sure to share it. Thanks again.
Scott
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