e2e framework: configure Ginkgo logger and klog consistently

Even if the textlogger which writes to Ginkgo is installed as the logger in
klog, klog still does some verbosity checks itself (for example,
klog.V().Enabled).

Therefore the framework has to keep the verbosity settings in the textlogger
and in klog consistent. This is done by wrapping the Set call instead of
replacing it.

test/e2e/framework/ginkgologger.go

@@ -49,14 +49,16 @@ var (
 
 func init() {
 	// ktesting and testinit already registered the -v and -vmodule
-	// command line flags. To configure the textlogger instead, we
-	// need to swap out the flag.Value for those.
+	// command line flags. To configure the textlogger and klog
+	// consistently, we need to intercept the Set call. This
+	// can be done by swapping out the flag.Value for the -v and
+	// -vmodule flags with a wrapper which calls both.
 	var fs flag.FlagSet
 	logConfig.AddFlags(&fs)
 	fs.VisitAll(func(loggerFlag *flag.Flag) {
 		klogFlag := flag.CommandLine.Lookup(loggerFlag.Name)
 		if klogFlag != nil {
-			klogFlag.Value = loggerFlag.Value
+			klogFlag.Value = &valueChain{Value: loggerFlag.Value, parentValue: klogFlag.Value}
 		}
 	})
 
@@ -75,6 +77,21 @@ func init() {
 	klog.SetLoggerWithOptions(ginkgoLogger, opts...)
 }
 
+type valueChain struct {
+	flag.Value
+	parentValue flag.Value
+}
+
+func (v *valueChain) Set(value string) error {
+	if err := v.Value.Set(value); err != nil {
+		return err
+	}
+	if err := v.parentValue.Set(value); err != nil {
+		return err
+	}
+	return nil
+}
+
 func unwind(skip int) (string, int) {
 	location := ginkgotypes.NewCodeLocation(skip + 1)
 	return location.FileName, location.LineNumber