logs: replace our custom flush daemon with klog's daemon

The advantage is that klog properly handles restarting of the daemon
with a new interval and the daemon can be stopped.

Stopping the daemon solves a data race that the tests had when modifying the
Logger's flush function while goroutines from previous tests were still
running.

staging/src/k8s.io/component-base/logs/logs.go

@@ -26,7 +26,6 @@ import (
 	"time"
 
 	"github.com/spf13/pflag"
-	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/klog/v2"
 )
 
@@ -175,7 +174,7 @@ func InitLogs() {
 	if logFlushFreqAdded {
 		// The flag from this file was activated, so use it now.
 		// Otherwise LoggingConfiguration.Apply will do this.
-		go wait.Forever(FlushLogs, logFlushFreq)
+		klog.StartFlushDaemon(logFlushFreq)
 	}
 }
 

staging/src/k8s.io/component-base/logs/options.go

@@ -22,7 +22,6 @@ import (
 	"github.com/spf13/pflag"
 
 	utilerrors "k8s.io/apimachinery/pkg/util/errors"
-	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/component-base/config"
 	"k8s.io/component-base/config/v1alpha1"
 	"k8s.io/component-base/logs/registry"
@@ -90,5 +89,5 @@ func (o *Options) apply() {
 	if err := loggingFlags.Lookup("vmodule").Value.Set(o.Config.VModule.String()); err != nil {
 		panic(fmt.Errorf("internal error while setting klog vmodule: %v", err))
 	}
-	go wait.Forever(FlushLogs, o.Config.FlushFrequency)
+	klog.StartFlushDaemon(o.Config.FlushFrequency)
 }

staging/src/k8s.io/component-base/logs/options_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"k8s.io/apimachinery/pkg/util/validation/field"
+	"k8s.io/klog/v2"
 )
 
 func TestFlags(t *testing.T) {
@@ -89,6 +90,7 @@ func TestOptions(t *testing.T) {
 				t.Errorf("Wrong Validate() result for %q. expect %v, got %v", tc.name, tc.want, o)
 			}
 			err := o.ValidateAndApply()
+			defer klog.StopFlushDaemon()
 
 			if !assert.ElementsMatch(t, tc.errs.ToAggregate(), err) {
 				t.Errorf("Wrong Validate() result for %q.\n expect:\t%+v\n got:\t%+v", tc.name, tc.errs, err)