[libvirt] [PATCH 03/13] Refactor domain events to handle multiple event types
Daniel P. Berrange
berrange at redhat.com
Thu Mar 25 16:26:18 UTC 2010
On Mon, Mar 22, 2010 at 03:36:34PM +0100, Daniel Veillard wrote:
> On Fri, Mar 19, 2010 at 03:38:51PM +0000, Daniel P. Berrange wrote:
> > The internal domain events APIs are designed to handle the lifecycle
> > events. This needs to be refactored to allow arbitrary new event
> > types to be handled.
> >
> > * The signature of virDomainEventDispatchFunc changes to use
> > virConnectDomainEventGenericCallback instead of the lifecycle
> > event specific virConnectDomainEventCallback
> > * Every registered callback gains a unique ID to allow its
> > removal based on ID, instead of function pointer
> > * Every registered callback gains an 'eventID' to allow callbacks
> > for different types of events to be distinguished
> > * virDomainEventDispatch is adapted to filter out callbacks
> > whose eventID does not match the eventID of the event being
> > dispatched
> > * virDomainEventDispatch is adapted to filter based on the
> > domain name and uuid, if this filter is set for a callback.
> > * virDomainEvent type/detail fields are moved into a union to
> > allow different data fields for other types of events to be
> > added later
> >
> > * src/conf/domain_event.h, src/conf/domain_event.c: Refactor
> > to allow handling of different types of events
> > * src/lxc/lxc_driver.c, src/qemu/qemu_driver.c,
> > src/remote/remote_driver.c, src/test/test_driver.c,
> > src/xen/xen_driver.c: Change dispatch function signature
> > to use virConnectDomainEventGenericCallback
> [...]
> > diff --git a/src/conf/domain_event.c b/src/conf/domain_event.c
> > index b520232..9d47eeb 100644
> > --- a/src/conf/domain_event.c
> > +++ b/src/conf/domain_event.c
> > @@ -35,20 +35,36 @@
> > virReportErrorHelper(conn, VIR_FROM_THIS, code, __FILE__, \
> > __FUNCTION__, __LINE__, __VA_ARGS__)
> >
> > +struct _virDomainMeta {
> > + int id;
> > + char *name;
> > + unsigned char uuid[VIR_UUID_BUFLEN];
> > +};
> > +typedef struct _virDomainMeta virDomainMeta;
> > +typedef virDomainMeta *virDomainMetaPtr;
> > +
> > struct _virDomainEventCallback {
> > + int callbackID;
> > + int eventID;
> > virConnectPtr conn;
> > - virConnectDomainEventCallback cb;
> > + virDomainMetaPtr dom;
> > + virConnectDomainEventGenericCallback cb;
> > void *opaque;
> > virFreeCallback freecb;
> > int deleted;
> > };
> >
> > struct _virDomainEvent {
> > - int id;
> > - char *name;
> > - unsigned char uuid[VIR_UUID_BUFLEN];
> > - int type;
> > - int detail;
> > + int eventID;
> > +
> > + virDomainMeta dom;
> > +
> > + union {
> > + struct {
> > + int type;
> > + int detail;
> > + } lifecycle;
> > + } data;
> > };
> >
> > /**
>
> Okay, that's logical, and most of the patch derives from that change,
>
> [...]
> > +static int virDomainEventDispatchMatchCallback(virDomainEventPtr event,
> > + virDomainEventCallbackPtr cb)
> > +{
> > + if (!cb)
> > + return 0;
> > + if (cb->deleted)
> > + return 0;
> > + if (cb->eventID != event->eventID)
> > + return 0;
> > +
> > + if (cb->dom) {
> > + /* Delibrately ignoring 'id' for matching, since that
> > + * will cause problems when a domain switches between
> > + * running & shutoff states */
> > +
> > + if (STREQ(event->dom.name, cb->dom->name) &&
> > + (memcmp(event->dom.uuid, cb->dom->uuid, VIR_UUID_BUFLEN) == 0))
> > + return 1;
>
> Do we really need to match for both ?
It might be better to check for just UUID actually, since you can get the
crazy situation where Xen renames a guest to 'migrating-XXXX' during
migration.
Daniel
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