Create an Apply function

Author: ingvagabund

cmd/descheduler/app/options/options.go

@@ -23,12 +23,15 @@ import (
 
 	"github.com/spf13/pflag"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	apiserver "k8s.io/apiserver/pkg/server"
 	apiserveroptions "k8s.io/apiserver/pkg/server/options"
 	clientset "k8s.io/client-go/kubernetes"
+	restclient "k8s.io/client-go/rest"
 	cliflag "k8s.io/component-base/cli/flag"
 	componentbaseconfig "k8s.io/component-base/config"
 	componentbaseoptions "k8s.io/component-base/config/options"
 	"k8s.io/component-base/featuregate"
+	"k8s.io/klog/v2"
 
 	"sigs.k8s.io/descheduler/pkg/apis/componentconfig"
 	"sigs.k8s.io/descheduler/pkg/apis/componentconfig/v1alpha1"
@@ -45,11 +48,12 @@ const (
 type DeschedulerServer struct {
 	componentconfig.DeschedulerConfiguration
 
-	Client         clientset.Interface
-	EventClient    clientset.Interface
-	SecureServing  *apiserveroptions.SecureServingOptionsWithLoopback
-	DisableMetrics bool
-	EnableHTTP2    bool
+	Client            clientset.Interface
+	EventClient       clientset.Interface
+	SecureServing     *apiserveroptions.SecureServingOptionsWithLoopback
+	SecureServingInfo *apiserver.SecureServingInfo
+	DisableMetrics    bool
+	EnableHTTP2       bool
 	// FeatureGates enabled by the user
 	FeatureGates map[string]bool
 	// DefaultFeatureGates for internal accessing so unit tests can enable/disable specific features
@@ -118,3 +122,24 @@ func (rs *DeschedulerServer) AddFlags(fs *pflag.FlagSet) {
 
 	rs.SecureServing.AddFlags(fs)
 }
+
+func (rs *DeschedulerServer) Apply() error {
+	err := features.DefaultMutableFeatureGate.SetFromMap(rs.FeatureGates)
+	if err != nil {
+		return err
+	}
+	rs.DefaultFeatureGates = features.DefaultMutableFeatureGate
+
+	// loopbackClientConfig is a config for a privileged loopback connection
+	var loopbackClientConfig *restclient.Config
+	var secureServing *apiserver.SecureServingInfo
+	if err := rs.SecureServing.ApplyTo(&secureServing, &loopbackClientConfig); err != nil {
+		klog.ErrorS(err, "failed to apply secure server configuration")
+		return err
+	}
+
+	secureServing.DisableHTTP2 = !rs.EnableHTTP2
+	rs.SecureServingInfo = secureServing
+
+	return nil
+}

cmd/descheduler/app/server.go

@@ -34,9 +34,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/watch"
-	apiserver "k8s.io/apiserver/pkg/server"
 	"k8s.io/apiserver/pkg/server/mux"
-	restclient "k8s.io/client-go/rest"
 	"k8s.io/component-base/featuregate"
 	"k8s.io/component-base/logs"
 	logsapi "k8s.io/component-base/logs/api/v1"
@@ -68,40 +66,16 @@ func NewDeschedulerCommand(out io.Writer) *cobra.Command {
 			return nil
 		},
 		RunE: func(cmd *cobra.Command, args []string) error {
-			// loopbackClientConfig is a config for a privileged loopback connection
-			var loopbackClientConfig *restclient.Config
-			var secureServing *apiserver.SecureServingInfo
-			if err := s.SecureServing.ApplyTo(&secureServing, &loopbackClientConfig); err != nil {
-				klog.ErrorS(err, "failed to apply secure server configuration")
+			if err = Apply(s); err != nil {
+				klog.ErrorS(err, "failed to apply")
 				return err
 			}
 
-			secureServing.DisableHTTP2 = !s.EnableHTTP2
-
-			ctx, done := signal.NotifyContext(cmd.Context(), syscall.SIGINT, syscall.SIGTERM)
-
-			pathRecorderMux := mux.NewPathRecorderMux("descheduler")
-			if !s.DisableMetrics {
-				pathRecorderMux.Handle("/metrics", legacyregistry.HandlerWithReset())
-			}
-
-			healthz.InstallHandler(pathRecorderMux, healthz.NamedCheck("Descheduler", healthz.PingHealthz.Check))
-
-			stoppedCh, _, err := secureServing.Serve(pathRecorderMux, 0, ctx.Done())
-			if err != nil {
-				klog.Fatalf("failed to start secure server: %v", err)
-				return err
-			}
-
-			if err = Run(ctx, s); err != nil {
-				klog.ErrorS(err, "descheduler server")
+			if err = Run(cmd.Context(), s); err != nil {
+				klog.ErrorS(err, "failed to run descheduler server")
 				return err
 			}
 
-			done()
-			// wait for metrics server to close
-			<-stoppedCh
-
 			return nil
 		},
 	}
@@ -115,12 +89,30 @@ func NewDeschedulerCommand(out io.Writer) *cobra.Command {
 	return cmd
 }
 
-func Run(ctx context.Context, rs *options.DeschedulerServer) error {
+func Apply(rs *options.DeschedulerServer) error {
 	err := features.DefaultMutableFeatureGate.SetFromMap(rs.FeatureGates)
 	if err != nil {
 		return err
 	}
 	rs.DefaultFeatureGates = features.DefaultMutableFeatureGate
+	return nil
+}
+
+func Run(rootCtx context.Context, rs *options.DeschedulerServer) error {
+	ctx, done := signal.NotifyContext(rootCtx, syscall.SIGINT, syscall.SIGTERM)
+
+	pathRecorderMux := mux.NewPathRecorderMux("descheduler")
+	if !rs.DisableMetrics {
+		pathRecorderMux.Handle("/metrics", legacyregistry.HandlerWithReset())
+	}
+
+	healthz.InstallHandler(pathRecorderMux, healthz.NamedCheck("Descheduler", healthz.PingHealthz.Check))
+
+	stoppedCh, _, err := rs.SecureServingInfo.Serve(pathRecorderMux, 0, ctx.Done())
+	if err != nil {
+		klog.Fatalf("failed to start secure server: %v", err)
+		return err
+	}
 
 	err = tracing.NewTracerProvider(ctx, rs.Tracing.CollectorEndpoint, rs.Tracing.TransportCert, rs.Tracing.ServiceName, rs.Tracing.ServiceNamespace, rs.Tracing.SampleRate, rs.Tracing.FallbackToNoOpProviderOnError)
 	if err != nil {
@@ -131,5 +123,14 @@ func Run(ctx context.Context, rs *options.DeschedulerServer) error {
 	// increase the fake watch channel so the dry-run mode can be run
 	// over a cluster with thousands of pods
 	watch.DefaultChanSize = 100000
-	return descheduler.Run(ctx, rs)
+	err = descheduler.Run(ctx, rs)
+	if err != nil {
+		return err
+	}
+
+	done()
+	// wait for metrics server to close
+	<-stoppedCh
+
+	return nil
 }