add feature for live-reload when configuration changed

Signed-off-by: x893675 <x893675@icloud.com>

cmd/ks-apiserver/app/server.go

@@ -19,6 +19,7 @@ package app
 import (
 	"context"
 	"fmt"
+	"net/http"
 
 	"github.com/spf13/cobra"
 	utilerrors "k8s.io/apimachinery/pkg/util/errors"
@@ -37,7 +38,7 @@ func NewAPIServerCommand() *cobra.Command {
 	s := options.NewServerRunOptions()
 
 	// Load configuration from file
-	conf, err := apiserverconfig.TryLoadFromDisk()
+	conf, configCh, err := apiserverconfig.TryLoadFromDisk()
 	if err == nil {
 		s = &options.ServerRunOptions{
 			GenericServerRunOptions: s.GenericServerRunOptions,
@@ -56,8 +57,7 @@ cluster's shared state through which all other components interact.`,
 			if errs := s.Validate(); len(errs) != 0 {
 				return utilerrors.NewAggregate(errs)
 			}
-
-			return Run(s, signals.SetupSignalHandler())
+			return Run(s, configCh, signals.SetupSignalHandler())
 		},
 		SilenceUsage: true,
 	}
@@ -88,8 +88,38 @@ cluster's shared state through which all other components interact.`,
 	return cmd
 }
 
-func Run(s *options.ServerRunOptions, ctx context.Context) error {
+func Run(s *options.ServerRunOptions, configCh <-chan apiserverconfig.Config, ctx context.Context) error {
+	ictx := apiserverconfig.Context{}
+	ictx.RenewContext(context.TODO())
+	errCh := make(chan error)
+	defer close(errCh)
+	go func() {
+		if err := run(s, ictx.GetContext()); err != nil {
+			errCh <- err
+		}
+	}()
 
+	for {
+		select {
+		case <-ctx.Done():
+			ictx.CancelContext()
+			return nil
+		case cfg := <-configCh:
+			ictx.CancelContext()
+			s.Config = &cfg
+			ictx.RenewContext(context.TODO())
+			go func() {
+				if err := run(s, ictx.GetContext()); err != nil {
+					errCh <- err
+				}
+			}()
+		case err := <-errCh:
+			return err
+		}
+	}
+}
+
+func run(s *options.ServerRunOptions, ctx context.Context) error {
 	apiserver, err := s.NewAPIServer(ctx.Done())
 	if err != nil {
 		return err
@@ -100,5 +130,9 @@ func Run(s *options.ServerRunOptions, ctx context.Context) error {
 		return err
 	}
 
-	return apiserver.Run(ctx)
+	err = apiserver.Run(ctx)
+	if err == http.ErrServerClosed {
+		return nil
+	}
+	return err
 }