Only update a resource's status if it has changed (#1151)

Problem: NGF updates the status of resources even when the
status has not changed. When there are a large number of 
HTTPRoutes this can significantly decrease processing time.

Solution: Modify the status updater to only update status 
when it has changed.

Testing: Re-ran the scale tests. The scale test performance numbers 
significantly improved with this change.

internal/framework/status/setters.go

@@ -0,0 +1,226 @@
+package status
+
+import (
+	"slices"
+
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/gateway-api/apis/v1beta1"
+
+	ngfAPI "github.com/nginxinc/nginx-gateway-fabric/apis/v1alpha1"
+)
+
+// setter is a function that takes an object and sets the status on that object if the status has changed.
+// If the status has not changed, and the setter does not set the status, it returns false.
+type setter func(client.Object) bool
+
+func newNginxGatewayStatusSetter(clock Clock, status NginxGatewayStatus) func(client.Object) bool {
+	return func(object client.Object) bool {
+		ng := object.(*ngfAPI.NginxGateway)
+		conds := convertConditions(
+			status.Conditions,
+			status.ObservedGeneration,
+			clock.Now(),
+		)
+
+		if conditionsEqual(ng.Status.Conditions, conds) {
+			return false
+		}
+
+		ng.Status = ngfAPI.NginxGatewayStatus{
+			Conditions: conds,
+		}
+
+		return true
+	}
+}
+
+func newGatewayClassStatusSetter(clock Clock, gcs GatewayClassStatus) func(client.Object) bool {
+	return func(object client.Object) bool {
+		gc := object.(*v1beta1.GatewayClass)
+		status := prepareGatewayClassStatus(gcs, clock.Now())
+
+		if conditionsEqual(gc.Status.Conditions, status.Conditions) {
+			return false
+		}
+
+		gc.Status = status
+
+		return true
+	}
+}
+
+func newGatewayStatusSetter(clock Clock, gs GatewayStatus) func(client.Object) bool {
+	return func(object client.Object) bool {
+		gw := object.(*v1beta1.Gateway)
+		status := prepareGatewayStatus(gs, clock.Now())
+
+		if gwStatusEqual(gw.Status, status) {
+			return false
+		}
+
+		gw.Status = status
+
+		return true
+	}
+}
+
+func newHTTPRouteStatusSetter(gatewayCtlrName string, clock Clock, rs HTTPRouteStatus) func(client.Object) bool {
+	return func(object client.Object) bool {
+		hr := object.(*v1beta1.HTTPRoute)
+		status := prepareHTTPRouteStatus(
+			rs,
+			gatewayCtlrName,
+			clock.Now(),
+		)
+
+		if hrStatusEqual(gatewayCtlrName, hr.Status, status) {
+			return false
+		}
+
+		hr.Status = status
+
+		return true
+	}
+}
+
+func gwStatusEqual(prev, cur v1beta1.GatewayStatus) bool {
+	addressesEqual := slices.EqualFunc(prev.Addresses, cur.Addresses, func(a1, a2 v1beta1.GatewayStatusAddress) bool {
+		if !equalPointers[v1beta1.AddressType](a1.Type, a2.Type) {
+			return false
+		}
+
+		return a1.Value == a2.Value
+	})
+
+	if !addressesEqual {
+		return false
+	}
+
+	if !conditionsEqual(prev.Conditions, cur.Conditions) {
+		return false
+	}
+
+	return slices.EqualFunc(prev.Listeners, cur.Listeners, func(s1, s2 v1beta1.ListenerStatus) bool {
+		if s1.Name != s2.Name {
+			return false
+		}
+
+		if s1.AttachedRoutes != s2.AttachedRoutes {
+			return false
+		}
+
+		if !conditionsEqual(s1.Conditions, s2.Conditions) {
+			return false
+		}
+
+		return slices.EqualFunc(s1.SupportedKinds, s2.SupportedKinds, func(k1, k2 v1beta1.RouteGroupKind) bool {
+			if k1.Kind != k2.Kind {
+				return false
+			}
+
+			return equalPointers(k1.Group, k2.Group)
+		})
+	})
+}
+
+func hrStatusEqual(gatewayCtlrName string, prev, cur v1beta1.HTTPRouteStatus) bool {
+	// Since other controllers may update HTTPRoute status we can't assume anything about the order of the statuses,
+	// and we have to ignore statuses written by other controllers when checking for equality.
+	// Therefore, we can't use slices.EqualFunc here because it cares about the order.
+
+	// First, we check if the prev status has any RouteParentStatuses that are no longer present in the cur status.
+	for _, prevParent := range prev.Parents {
+		if prevParent.ControllerName != v1beta1.GatewayController(gatewayCtlrName) {
+			continue
+		}
+
+		exists := slices.ContainsFunc(cur.Parents, func(curParent v1beta1.RouteParentStatus) bool {
+			return routeParentStatusEqual(prevParent, curParent)
+		})
+
+		if !exists {
+			return false
+		}
+	}
+
+	// Then, we check if the cur status has any RouteParentStatuses that are no longer present in the prev status.
+	for _, curParent := range cur.Parents {
+		exists := slices.ContainsFunc(prev.Parents, func(prevParent v1beta1.RouteParentStatus) bool {
+			return routeParentStatusEqual(curParent, prevParent)
+		})
+
+		if !exists {
+			return false
+		}
+	}
+
+	return true
+}
+
+func routeParentStatusEqual(p1, p2 v1beta1.RouteParentStatus) bool {
+	if p1.ControllerName != p2.ControllerName {
+		return false
+	}
+
+	if p1.ParentRef.Name != p2.ParentRef.Name {
+		return false
+	}
+
+	if !equalPointers(p1.ParentRef.Namespace, p2.ParentRef.Namespace) {
+		return false
+	}
+
+	if !equalPointers(p1.ParentRef.SectionName, p2.ParentRef.SectionName) {
+		return false
+	}
+
+	// we ignore the rest of the ParentRef fields because we do not set them
+
+	return conditionsEqual(p1.Conditions, p2.Conditions)
+}
+
+func conditionsEqual(prev, cur []v1.Condition) bool {
+	return slices.EqualFunc(prev, cur, func(c1, c2 v1.Condition) bool {
+		if c1.ObservedGeneration != c2.ObservedGeneration {
+			return false
+		}
+
+		if c1.Type != c2.Type {
+			return false
+		}
+
+		if c1.Status != c2.Status {
+			return false
+		}
+
+		if c1.Message != c2.Message {
+			return false
+		}
+
+		return c1.Reason == c2.Reason
+	})
+}
+
+// equalPointers returns whether two pointers are equal.
+// Pointers are considered equal if one of the following is true:
+// - They are both nil.
+// - One is nil and the other is empty (e.g. nil string and "").
+// - They are both non-nil, and their values are the same.
+func equalPointers[T comparable](p1, p2 *T) bool {
+	if p1 == nil && p2 == nil {
+		return true
+	}
+
+	var p1Val, p2Val T
+
+	if p1 != nil {
+		p1Val = *p1
+	}
+
+	if p2 != nil {
+		p2Val = *p2
+	}
+
+	return p1Val == p2Val
+}