Struct Controller

pilot/pkg/config/kube/agentgateway/agentgateway_controller.go:78–115

Controller defines the controller for agentgateway. The controller reads a variety of resources (Gateway types, as well as adjacent types like Namespace and Service). Most resources are fully "self-contained" with krt, but there are a few usages breaking out of `krt` for status reporting; these are

// The status on all Gateway types is also tracked. Each collection emits downstream objects, but also status about the
// input type. If the status changes, it is queued to asynchronously update the status of the object in Kubernetes.
type Controller struct {
	// client for accessing Kubernetes
	client kube.Client

	// the cluster where the agentgateway controller runs
	cluster cluster.ID
	// revision the controller is running under
	revision string

	istioNamespace string

	// status controls the status writing queue. Status will only be written if statusEnabled is true, which
	// is only the case when we are the leader.
	status *status.StatusCollections

	waitForCRD func(class schema.GroupVersionResource, stop <-chan struct{}) bool

	// gatewayContext exposes us to the internal Istio service registry. This is outside krt knowledge (currently), so,
	// so we wrap it in a RecomputeProtected.
	// Most usages in the API are directly referenced typed objects (Service, ServiceEntry, etc) so this is not needed typically.
	gatewayContext krt.RecomputeProtected[*atomic.Pointer[gatewaycommon.GatewayContext]]
	// tagWatcher allows us to check which tags are ours. Unlike most Istio codepaths, we read istio.io/rev=<tag> and not just
	// revisions for Gateways. This is because a Gateway is sort of a mix of a Deployment and Config.
	// Since the TagWatcher is not yet krt-aware, we wrap this in RecomputeProtected.
	tagWatcher krt.RecomputeProtected[revisions.TagWatcher]

	stop chan struct{}

	// TODO(jaellio): Verify we don't need handlers for syncing. In the gateway controller we register handlers for the outputs
	outputs OutputCollections

	inputs *AgwInputs

	domainSuffix string // the domain suffix to use for generated resources

	// features
	Registrations []xds.Registration
}

type OutputCollections struct {
	Resources krt.Collection[AgwResource]