feat(api): add backward-compatible LocalASNumber field to BGPPeer

api/core/v1alpha1/bgp_peer_types.go

@@ -13,6 +13,7 @@ import (
 )
 
 // BGPPeerSpec defines the desired state of BGPPeer
+// +kubebuilder:validation:XValidation:rule="!(has(self.localAS) && has(self.localASNumber))",message="localAS and localASNumber are mutually exclusive"
 type BGPPeerSpec struct {
 	// DeviceName is the name of the Device this object belongs to. The Device object must exist in the same namespace.
 	// Immutable.
@@ -61,6 +62,13 @@ type BGPPeerSpec struct {
 	// +optional
 	AddressFamilies *BGPPeerAddressFamilies `json:"addressFamilies,omitempty"`
 
+	// LocalASNumber specifies a local AS number to present to the BGP peer.
+	// When set, it is equivalent to LocalAS with ASNumber set and PrependLocalAS/PrependGlobalAS defaults.
+	//
+	// Deprecated: Use LocalAS.ASNumber instead. This field will be removed in a future release.
+	// +optional
+	LocalASNumber *intstr.IntOrString `json:"localASNumber,omitempty"`
+
 	// LocalAS configures the local AS number and how it factors into BGP announcements for this peer.
 	// +optional
 	LocalAS *LocalAS `json:"localAS,omitempty"`

internal/controller/core/bgp_peer_controller.go

@@ -443,6 +443,16 @@ func (r *BGPPeerReconciler) reconcile(ctx context.Context, s *bgpPeerScope) (ret
 		sourceInterface = intf.Spec.Name
 	}
 
+	// TODO: remove use of deprecated LocalASNumber field in a future release.
+	//nolint:staticcheck // handling deprecated field for backward compatibility
+	if s.BGPPeer.Spec.LocalASNumber != nil {
+		s.BGPPeer.Spec.LocalAS = &v1alpha1.LocalAS{
+			ASNumber:        *s.BGPPeer.Spec.LocalASNumber, //nolint:staticcheck
+			PrependLocalAS:  new(bool),
+			PrependGlobalAS: new(bool),
+		}
+	}
+
 	if s.BGPPeer.Spec.LocalAS != nil && s.BGPPeer.Spec.ASNumber.String() == bgp.Spec.ASNumber.String() {
 		conditions.Set(s.BGPPeer, metav1.Condition{
 			Type:    v1alpha1.ConfiguredCondition,

internal/webhook/core/v1alpha1/bgppeer_webhook.go

@@ -35,14 +35,23 @@ var _ admission.Validator[*v1alpha1.BGPPeer] = &BGPPeerCustomValidator{}
 func (v *BGPPeerCustomValidator) ValidateCreate(_ context.Context, bgppeer *v1alpha1.BGPPeer) (admission.Warnings, error) {
 	bgppeerlog.Info("Validation for BGPPeer upon creation", "name", bgppeer.GetName())
 
-	return nil, validateBGPPeer(bgppeer.Spec)
+	var warnings admission.Warnings
+	if bgppeer.Spec.LocalASNumber != nil { //nolint:staticcheck
+		warnings = append(warnings, "spec.localASNumber is deprecated; use spec.localAS.asNumber instead")
+	}
+
+	return warnings, validateBGPPeer(bgppeer.Spec)
 }
 
 // ValidateUpdate implements admission.Validator so a webhook will be registered for the type BGPPeer.
 func (v *BGPPeerCustomValidator) ValidateUpdate(_ context.Context, _, bgppeer *v1alpha1.BGPPeer) (admission.Warnings, error) {
 	bgppeerlog.Info("Validation for BGPPeer upon update", "name", bgppeer.GetName())
 
-	return nil, validateBGPPeer(bgppeer.Spec)
+	var warnings admission.Warnings
+	if bgppeer.Spec.LocalASNumber != nil { //nolint:staticcheck
+		warnings = append(warnings, "spec.localASNumber is deprecated; use spec.localAS.asNumber instead")
+	}
+	return warnings, validateBGPPeer(bgppeer.Spec)
 }
 
 // ValidateDelete implements admission.Validator so a webhook will be registered for the type BGPPeer.
@@ -60,5 +69,12 @@ func validateBGPPeer(bgppeer v1alpha1.BGPPeerSpec) error {
 			return err
 		}
 	}
+	// TODO: Remove when LocalASNumber is removed from the spec.
+	if bgppeer.LocalASNumber != nil { //nolint:staticcheck
+		if err := validateASNumber(*bgppeer.LocalASNumber); err != nil { //nolint:staticcheck
+			return err
+		}
+	}
+
 	return nil
 }