* Add support for Selector in tracker.Reference.
`tracker.Reference` may now optionally replace `Name` with `Selector` to track zero or multiple resources of a particular `apiVersion`, `kind` and `namespace`.
Fixes: https://github.com/knative/pkg/issues/859
* Address code review comments
To use this with a typical informer, e.g. the way `Route` would monitor `Configurations` and `Revisions`, you'd do something like:
```go
c := &Reconciler{
Base: reconciler.NewBase(opt, controllerAgentName),
...
}
impl := controller.NewImpl(c, c.Logger, "Routes")
t := New(impl.EnqueueKey, 30*time.Minute)
configInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: t.OnChanged,
UpdateFunc: controller.PassNew(t.OnChanged),
})
revisionInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: t.OnChanged,
UpdateFunc: controller.PassNew(t.OnChanged),
})
// Now use c.tracker.Track(revisionRef, route) or c.tracker.Track(configRef, route)
// each Reconcile(route) to refresh the cross-object leases.
c.tracker = t
```
To use this with a `duck.InformerFactory`, e.g. the way `Revision` will monitor `BuildRef`s you'd do something like:
```go
c := &Reconciler{
Base: reconciler.NewBase(opt, controllerAgentName),
...
}
impl := controller.NewImpl(c, c.Logger, "Revisions")
t := New(impl.EnqueueKey, 30*time.Minute)
cif := &duck.CachedInformerFactory{
Delegate: &duck.EnqueueInformerFactory{
Delegate: buildInformerFactory,
EventHandler: cache.ResourceEventHandlerFuncs{
AddFunc: t.OnChanged,
UpdateFunc: controller.PassNew(t.OnChanged),
},
},
}
// Now use: `c.buildInformerFactory.Get()` to access ObjectReferences.
c.buildInformerFactory = buildInformerFactory
// Now use: `c.tracker.Track(rev.Spec.BuildRef, rev)` to queue `rev`
// each time `rev.Spec.BuildRef` changes (expires 30 minutes after BuildRef
// points to something else).
c.tracker = t
```
Fixes: https://github.com/knative/pkg/issues/94
Matt Moore
Matt Moore