virt-controller: Introduce multus annotation generator

Generating multus network selection annotation code
is done in few places at virt-controller's VMIController
sync flow.
There few cases where each require different arguments:
1. On VM creation and migration, requires network
   name-scheme and cluster config
2. On legacy VM migration (who's pod interface names are
   in ordinal form net1, net2 ..), requires ordinal
   network name-scheme and cluster config.
3. When VM is updated (pod already exist) it requires
   network name-scheme only.

To enable more granularity in generating multus annotation w/o
having multiple functions that calls it with awkward names or
passing nil arguments, the multus annotation generator is
introduced.

Signed-off-by: Or Mergi <ormergi@redhat.com>

pkg/virt-controller/services/multus_annotations.go

@@ -56,25 +56,50 @@ func (mnap multusNetworkAnnotationPool) toString() (string, error) {
 	return string(multusNetworksAnnotation), nil
 }
 
-func GenerateMultusCNIAnnotation(namespace string, interfaces []v1.Interface, networks []v1.Network, config *virtconfig.ClusterConfig) (string, error) {
-	return GenerateMultusCNIAnnotationFromNameScheme(namespace, interfaces, networks, namescheme.CreateHashedNetworkNameScheme(networks), config)
+type multusNetworkAnnotationGenerator struct {
+	config            *virtconfig.ClusterConfig
+	networkNameScheme map[string]string
+}
+
+type option func(*multusNetworkAnnotationGenerator)
+
+func NewMultusNetworkAnnotationGenerator(opts ...option) *multusNetworkAnnotationGenerator {
+	gen := &multusNetworkAnnotationGenerator{}
+
+	for _, opt := range opts {
+		opt(gen)
+	}
+
+	return gen
+}
+
+func WithNetworkNameScheme(networkNameScheme map[string]string) option {
+	return func(gen *multusNetworkAnnotationGenerator) {
+		gen.networkNameScheme = networkNameScheme
+	}
+}
+
+func WithClusterConfig(config *virtconfig.ClusterConfig) option {
+	return func(gen *multusNetworkAnnotationGenerator) {
+		gen.config = config
+	}
 }
 
-func GenerateMultusCNIAnnotationFromNameScheme(namespace string, interfaces []v1.Interface, networks []v1.Network, networkNameScheme map[string]string, config *virtconfig.ClusterConfig) (string, error) {
+func (g *multusNetworkAnnotationGenerator) Generate(namespace string, interfaces []v1.Interface, networks []v1.Network) (string, error) {
 	multusNetworkAnnotationPool := multusNetworkAnnotationPool{}
 
 	for _, network := range networks {
 		if vmispec.IsSecondaryMultusNetwork(network) {
-			podInterfaceName := networkNameScheme[network.Name]
+			podInterfaceName := g.networkNameScheme[network.Name]
 			multusNetworkAnnotationPool.add(
 				newMultusAnnotationData(namespace, interfaces, network, podInterfaceName))
 		}
 
-		if config != nil && config.NetworkBindingPlugingsEnabled() {
+		if g.config != nil && g.config.NetworkBindingPlugingsEnabled() {
 			if iface := vmispec.LookupInterfaceByName(interfaces, network.Name); iface.Binding != nil {
-				podIfaceName := networkNameScheme[network.Name]
+				podIfaceName := g.networkNameScheme[network.Name]
 				bindingPluginAnnotationData, err := newBindingPluginMultusAnnotationData(
-					config.GetConfig(), iface.Binding.Name, namespace, podIfaceName)
+					g.config.GetConfig(), iface.Binding.Name, namespace, podIfaceName)
 				if err != nil {
 					return "", err
 				}
@@ -120,6 +145,13 @@ func newMultusAnnotationData(namespace string, interfaces []v1.Interface, networ
 	}
 }
 
+func GenerateMultusCNIAnnotation(namespace string, interfaces []v1.Interface, networks []v1.Network, config *virtconfig.ClusterConfig) (string, error) {
+	g := NewMultusNetworkAnnotationGenerator(
+		WithNetworkNameScheme(namescheme.CreateHashedNetworkNameScheme(networks)),
+		WithClusterConfig(config))
+	return g.Generate(namespace, interfaces, networks)
+}
+
 func NonDefaultMultusNetworksIndexedByIfaceName(pod *k8sv1.Pod) map[string]networkv1.NetworkStatus {
 	indexedNetworkStatus := map[string]networkv1.NetworkStatus{}
 	podNetworkStatus, found := pod.Annotations[networkv1.NetworkStatusAnnot]

pkg/virt-controller/services/template.go

@@ -271,8 +271,8 @@ func (t *templateService) RenderMigrationManifest(vmi *v1.VirtualMachineInstance
 
 	if namescheme.PodHasOrdinalInterfaceName(NonDefaultMultusNetworksIndexedByIfaceName(pod)) {
 		ordinalNameScheme := namescheme.CreateOrdinalNetworkNameScheme(vmi.Spec.Networks)
-		multusNetworksAnnotation, err := GenerateMultusCNIAnnotationFromNameScheme(
-			vmi.Namespace, vmi.Spec.Domain.Devices.Interfaces, vmi.Spec.Networks, ordinalNameScheme, t.clusterConfig)
+		g := NewMultusNetworkAnnotationGenerator(WithNetworkNameScheme(ordinalNameScheme), WithClusterConfig(t.clusterConfig))
+		multusNetworksAnnotation, err := g.Generate(vmi.Namespace, vmi.Spec.Domain.Devices.Interfaces, vmi.Spec.Networks)
 		if err != nil {
 			return nil, err
 		}

pkg/virt-controller/watch/vmi.go

@@ -2292,7 +2292,8 @@ func (c *VMIController) updateMultusAnnotation(namespace string, interfaces []vi
 
 	indexedMultusStatusIfaces := services.NonDefaultMultusNetworksIndexedByIfaceName(pod)
 	networkToPodIfaceMap := namescheme.CreateNetworkNameSchemeByPodNetworkStatus(networks, indexedMultusStatusIfaces)
-	multusAnnotations, err := services.GenerateMultusCNIAnnotationFromNameScheme(namespace, interfaces, networks, networkToPodIfaceMap, nil)
+	g := services.NewMultusNetworkAnnotationGenerator(services.WithNetworkNameScheme(networkToPodIfaceMap))
+	multusAnnotations, err := g.Generate(namespace, interfaces, networks)
 	if err != nil {
 		return err
 	}