logs: flush Logger through klog

Not all code knows that it needs to flush through component-base/logs.FlushLogs
when the JSON logger is used. By registering the flush callback together with
the logger, klog.Flush and klog.FlushAndExit are sufficient for flushing all
data.

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

@@ -41,7 +41,6 @@ const deprecated = "will be removed in a future release, see https://github.com/
 
 var (
 	packageFlags = flag.NewFlagSet("logging", flag.ContinueOnError)
-	logrFlush    func()
 
 	// Periodic flushing gets configured either via the global flag
 	// in this file or via LoggingConfiguration.
@@ -185,9 +184,6 @@ func InitLogs() {
 // are printed before exiting the program.
 func FlushLogs() {
 	klog.Flush()
-	if logrFlush != nil {
-		logrFlush()
-	}
 }
 
 // NewLogger creates a new log.Logger which sends logs to klog.Info.

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

@@ -82,8 +82,7 @@ func (o *Options) apply() {
 		klog.ClearLogger()
 	} else {
 		log, flush := factory.Create(o.Config.Options)
-		klog.SetLogger(log)
-		logrFlush = flush
+		klog.SetLoggerWithOptions(log, klog.FlushLogger(flush))
 	}
 	if err := loggingFlags.Lookup("v").Value.Set(o.Config.Verbosity.String()); err != nil {
 		panic(fmt.Errorf("internal error while setting klog verbosity: %v", err))