refactor: better handle nil virtualIPProvider

Currently a virtualIPProvider will always be passed in to the handler,
but refactoring to use a builder pattern makes the code more flexible.

Author: dkoshkin

pkg/handlers/nutanix/mutation/controlplaneendpoint/inject.go

@@ -36,27 +36,31 @@ type nutanixControlPlaneEndpoint struct {
 	variableFieldPath []string
 }
 
-func NewPatch(virtualIPProvider virtualip.Provider) *nutanixControlPlaneEndpoint {
+func NewPatch() *nutanixControlPlaneEndpoint {
 	return newNutanixControlPlaneEndpoint(
-		virtualIPProvider,
 		clusterconfig.MetaVariableName,
 		v1alpha1.NutanixVariableName,
 		VariableName,
 	)
 }
 
 func newNutanixControlPlaneEndpoint(
-	virtualIPProvider virtualip.Provider,
 	variableName string,
 	variableFieldPath ...string,
 ) *nutanixControlPlaneEndpoint {
 	return &nutanixControlPlaneEndpoint{
-		virtualIPProvider: virtualIPProvider,
 		variableName:      variableName,
 		variableFieldPath: variableFieldPath,
 	}
 }
 
+func (h *nutanixControlPlaneEndpoint) WithVirtualIPProvider(
+	virtualIPProvider virtualip.Provider,
+) *nutanixControlPlaneEndpoint {
+	h.virtualIPProvider = virtualIPProvider
+	return h
+}
+
 func (h *nutanixControlPlaneEndpoint) Mutate(
 	ctx context.Context,
 	obj *unstructured.Unstructured,
@@ -98,6 +102,10 @@ func (h *nutanixControlPlaneEndpoint) Mutate(
 		selectors.ControlPlane(),
 		log,
 		func(obj *controlplanev1.KubeadmControlPlaneTemplate) error {
+			if h.virtualIPProvider == nil {
+				return nil
+			}
+
 			virtualIPProviderFile, virtualIPProviderErr := h.virtualIPProvider.GetFile(ctx, controlPlaneEndpointVar)
 			if virtualIPProviderErr != nil {
 				return virtualIPProviderErr

pkg/handlers/nutanix/mutation/controlplaneendpoint/inject_test.go

@@ -144,7 +144,11 @@ var _ = Describe("Generate Nutanix ControlPlane endpoint patches", func() {
 
 func testPatchGenerator(virtualIPProvider virtualip.Provider) func() mutation.GeneratePatches {
 	return func() mutation.GeneratePatches {
-		return mutation.NewMetaGeneratePatchesHandler("", helpers.TestEnv.Client, NewPatch(virtualIPProvider)).(mutation.GeneratePatches)
+		return mutation.NewMetaGeneratePatchesHandler(
+			"",
+			helpers.TestEnv.Client,
+			NewPatch().WithVirtualIPProvider(virtualIPProvider),
+		).(mutation.GeneratePatches)
 	}
 }
 

pkg/handlers/nutanix/mutation/metapatch_handler.go

@@ -19,7 +19,7 @@ import (
 func MetaPatchHandler(mgr manager.Manager, virtualIPProvider virtualip.Provider) handlers.Named {
 	patchHandlers := append(
 		[]mutation.MetaMutator{
-			controlplaneendpoint.NewPatch(virtualIPProvider),
+			controlplaneendpoint.NewPatch().WithVirtualIPProvider(virtualIPProvider),
 			prismcentralendpoint.NewPatch(),
 			machinedetails.NewControlPlanePatch(),
 		},