[wmco] Improve error handling

pkg/controller/windowsmachineconfig/windowsmachineconfig_controller.go

@@ -26,44 +26,61 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/source"
 )
 
-var log = logf.Log.WithName("controller_wmc")
+const (
+	// ControllerName is the name of the WMC controller
+	ControllerName = "windowsmachineconfig-controller"
+)
 
-/**
-* USER ACTION REQUIRED: This is a scaffold file intended for the user to modify with their own Controller
-* business logic.  Delete these comments after modifying this file.*
- */
+var log = logf.Log.WithName("controller_wmc")
 
 // Add creates a new WindowsMachineConfig Controller and adds it to the Manager. The Manager will set fields on the Controller
 // and Start it when the Manager is Started.
 func Add(mgr manager.Manager) error {
-	return add(mgr, newReconciler(mgr))
+	reconciler, err := newReconciler(mgr)
+	if err != nil {
+		return errors.Wrapf(err, "could not create %s reconciler", ControllerName)
+	}
+	return add(mgr, reconciler)
 }
 
 // newReconciler returns a new reconcile.Reconciler
-func newReconciler(mgr manager.Manager) reconcile.Reconciler {
+func newReconciler(mgr manager.Manager) (reconcile.Reconciler, error) {
 	// TODO: This should be moved out to validation for reconciler struct.
 	// 		Jira story: https://issues.redhat.com/browse/WINC-277
 	clientset, err := kubernetes.NewForConfig(mgr.GetConfig())
 	if err != nil {
-		log.Error(err, "error while getting clientset")
+		return nil, errors.Wrap(err, "error creating kubernetes clientset")
 	}
-	return &ReconcileWindowsMachineConfig{client: mgr.GetClient(), scheme: mgr.GetScheme(), k8sclientset: clientset}
+
+	windowsVMs := make(map[types.WindowsVM]bool)
+	vmTracker, err := tracker.NewTracker(clientset, windowsVMs)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to instantiate tracker")
+	}
+
+	return &ReconcileWindowsMachineConfig{client: mgr.GetClient(),
+			scheme:       mgr.GetScheme(),
+			k8sclientset: clientset,
+			tracker:      vmTracker,
+			windowsVMs:   windowsVMs,
+		},
+		nil
 }
 
 // add adds a new Controller to mgr with r as the reconcile.Reconciler
 func add(mgr manager.Manager, r reconcile.Reconciler) error {
 	// Create a new controller
-	c, err := controller.New("windowsmachineconfig-controller", mgr, controller.Options{Reconciler: r})
+	c, err := controller.New(ControllerName, mgr, controller.Options{Reconciler: r})
 	if err != nil {
-		return err
+		return errors.Wrapf(err, "could not create %s", ControllerName)
 	}
 	// TODO: Add a predicate here. As of now, we get event notifications for all the WindowsMachineConfig objects, we
 	//		want the predicate to filter the WMC object called `instance`
 	//		Jira Story: https://issues.redhat.com/browse/WINC-282
 	// Watch for changes to primary resource WindowsMachineConfig
 	err = c.Watch(&source.Kind{Type: &wmcapi.WindowsMachineConfig{}}, &handler.EnqueueRequestForObject{})
 	if err != nil {
-		return err
+		return errors.Wrap(err, "could not create watch on WindowsMachineConfig objects")
 	}
 
 	// TODO(user): Modify this to be the types you create that are owned by the primary resource
@@ -145,13 +162,6 @@ func (r *ReconcileWindowsMachineConfig) Reconcile(request reconcile.Request) (re
 			return reconcile.Result{}, fmt.Errorf("error instantiating cloud provider: %v", err)
 		}
 	}
-	if r.k8sclientset == nil {
-		return reconcile.Result{}, nil
-	}
-	if r.windowsVMs == nil {
-		// populate the windowsVM map here from ConfigMap as source of truth
-		r.windowsVMs = make(map[types.WindowsVM]bool)
-	}
 	// Get the current number of Windows VMs created by WMCO.
 	// TODO: Get all the running Windows nodes in the cluster
 	//		jira story: https://issues.redhat.com/browse/WINC-280
@@ -177,14 +187,8 @@ func (r *ReconcileWindowsMachineConfig) Reconcile(request reconcile.Request) (re
 // cluster
 func (r *ReconcileWindowsMachineConfig) reconcileWindowsNodes(desired, current int) bool {
 	log.Info("replicas", "current", current, "desired", desired)
-	if r.tracker == nil {
-		var err error
-		r.tracker, err = tracker.NewTracker(r.k8sclientset, r.windowsVMs)
-		if err != nil {
-			log.Error(err, "tracker instantiation failed")
-		}
-	}
 	var vmCount bool
+
 	if desired < current {
 		vmCount = r.deleteWindowsVMs(current - desired)
 	} else if desired > current {