feat/config-sync: setting up feature gate acessor

Enabling feature gate acessor to the cloud-config sync controller.

Author: mtulio

cmd/config-sync-controllers/main.go

@@ -26,6 +26,7 @@ import (
 
 	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
 	// to ensure that exec-entrypoint and run can make use of them.
+	"k8s.io/client-go/kubernetes"
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
 
 	"k8s.io/apimachinery/pkg/runtime"
@@ -40,6 +41,11 @@ import (
 	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
 
 	configv1 "github.com/openshift/api/config/v1"
+	"github.com/openshift/library-go/pkg/operator/configobserver/featuregates"
+	"github.com/openshift/library-go/pkg/operator/events"
+
+	configv1client "github.com/openshift/client-go/config/clientset/versioned"
+	configinformers "github.com/openshift/client-go/config/informers/externalversions"
 
 	"github.com/openshift/cluster-cloud-controller-manager-operator/pkg/controllers"
 	"github.com/openshift/cluster-cloud-controller-manager-operator/pkg/restmapper"
@@ -79,6 +85,12 @@ func main() {
 		"The namespace for managed objects, target cloud-conf in particular.",
 	)
 
+	recorderName := "cloud-controller-manager-operator-cloud-config-sync-controller"
+	missingVersion := "0.0.1-snapshot"
+	desiredVersion := controllers.GetReleaseVersion()
+	sharedClock := clock.RealClock{}
+	ctx := ctrl.SetupSignalHandler()
+
 	// Once all the flags are regitered, switch to pflag
 	// to allow leader lection flags to be bound
 	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
@@ -131,7 +143,36 @@ func main() {
 		os.Exit(1)
 	}
 
-	sharedClock := clock.RealClock{}
+	// Feature gate accessor
+	configClient, err := configv1client.NewForConfig(mgr.GetConfig())
+	if err != nil {
+		setupLog.Error(err, "unable to create config client")
+		os.Exit(1)
+	}
+	kubeClient, err := kubernetes.NewForConfig(mgr.GetConfig())
+	if err != nil {
+		setupLog.Error(err, "unable to create kube client")
+		os.Exit(1)
+	}
+
+	configInformers := configinformers.NewSharedInformerFactory(configClient, 10*time.Minute)
+	controllerRef, err := events.GetControllerReferenceForCurrentPod(ctx, kubeClient, *managedNamespace, nil)
+	if err != nil {
+		klog.Warningf("unable to get owner reference (falling back to namespace): %v", err)
+	}
+
+	featureGateAccessor := featuregates.NewFeatureGateAccess(
+		desiredVersion, missingVersion,
+		configInformers.Config().V1().ClusterVersions(), configInformers.Config().V1().FeatureGates(),
+		events.NewKubeRecorder(kubeClient.CoreV1().Events(*managedNamespace), recorderName, controllerRef, sharedClock),
+	)
+	featureGateAccessor.SetChangeHandler(func(featureChange featuregates.FeatureChange) {
+		// Do nothing here. The controller watches feature gate changes and will react to them.
+		klog.InfoS("FeatureGates changed", "enabled", featureChange.New.Enabled, "disabled", featureChange.New.Disabled)
+	})
+	go featureGateAccessor.Run(ctx)
+	go configInformers.Start(ctx.Done())
+
 	if err = (&controllers.CloudConfigReconciler{
 		ClusterOperatorStatusClient: controllers.ClusterOperatorStatusClient{
 			Client:           mgr.GetClient(),
@@ -140,7 +181,8 @@ func main() {
 			ReleaseVersion:   controllers.GetReleaseVersion(),
 			ManagedNamespace: *managedNamespace,
 		},
-		Scheme: mgr.GetScheme(),
+		Scheme:            mgr.GetScheme(),
+		FeatureGateAccess: featureGateAccessor,
 	}).SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "unable to create cloud-config sync controller", "controller", "ClusterOperator")
 		os.Exit(1)
@@ -171,7 +213,7 @@ func main() {
 	}
 
 	setupLog.Info("starting manager")
-	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
+	if err := mgr.Start(ctx); err != nil {
 		setupLog.Error(err, "problem running manager")
 		os.Exit(1)
 	}

pkg/controllers/cloud_config_sync_controller.go

@@ -16,6 +16,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 
 	configv1 "github.com/openshift/api/config/v1"
+	"github.com/openshift/library-go/pkg/operator/configobserver/featuregates"
 
 	"github.com/openshift/cluster-cloud-controller-manager-operator/pkg/cloud"
 )
@@ -32,7 +33,8 @@ const (
 
 type CloudConfigReconciler struct {
 	ClusterOperatorStatusClient
-	Scheme *runtime.Scheme
+	Scheme            *runtime.Scheme
+	FeatureGateAccess featuregates.FeatureGateAccess
 }
 
 func (r *CloudConfigReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
@@ -130,11 +132,29 @@ func (r *CloudConfigReconciler) Reconcile(ctx context.Context, req ctrl.Request)
 		return ctrl.Result{}, err
 	}
 
+	// Check if FeatureGateAccess is configured
+	if r.FeatureGateAccess == nil {
+		klog.Errorf("FeatureGateAccess is not configured")
+		if err := r.setDegradedCondition(ctx); err != nil {
+			return ctrl.Result{}, fmt.Errorf("failed to set conditions for cloud config controller: %v", err)
+		}
+		return ctrl.Result{}, fmt.Errorf("FeatureGateAccess is not configured")
+	}
+
+	features, err := r.FeatureGateAccess.CurrentFeatureGates()
+	if err != nil {
+		klog.Errorf("unable to get feature gates: %v", err)
+		if err := r.setDegradedCondition(ctx); err != nil {
+			return ctrl.Result{}, fmt.Errorf("failed to set conditions for cloud config controller: %v", err)
+		}
+		return ctrl.Result{}, err
+	}
+
 	if cloudConfigTransformerFn != nil {
 		// We ignore stuff in sourceCM.BinaryData. This isn't allowed to
 		// contain any key that overlaps with those found in sourceCM.Data and
 		// we're not expecting users to put their data in the former.
-		output, err := cloudConfigTransformerFn(sourceCM.Data[defaultConfigKey], infra, network)
+		output, err := cloudConfigTransformerFn(sourceCM.Data[defaultConfigKey], infra, network, features)
 		if err != nil {
 			if err := r.setDegradedCondition(ctx); err != nil {
 				return ctrl.Result{}, fmt.Errorf("failed to set conditions for cloud config controller: %v", err)