FieldRef feature for DownwardAPI (#534)

* FieldRef feature for DownwardAPI

Signed-off-by: VineethReddy02 <vineethpothulapati@outlook.com>

* Unit tests for FieldRef

Signed-off-by: VineethReddy02 <vineethpothulapati@outlook.com>

vendor/k8s.io/kubernetes/pkg/kubelet/server/remotecommand/httpstream.go

@@ -34,7 +34,7 @@ import (
 	"k8s.io/client-go/tools/remotecommand"
 	api "k8s.io/kubernetes/pkg/apis/core"
 
-	"github.com/golang/glog"
+	"k8s.io/klog"
 )
 
 // Options contains details about which streams are required for
@@ -54,7 +54,7 @@ func NewOptions(req *http.Request) (*Options, error) {
 	stderr := req.FormValue(api.ExecStderrParam) == "1"
 	if tty && stderr {
 		// TODO: make this an error before we reach this method
-		glog.V(4).Infof("Access to exec with tty and stderr is not supported, bypassing stderr")
+		klog.V(4).Infof("Access to exec with tty and stderr is not supported, bypassing stderr")
 		stderr = false
 	}
 
@@ -125,8 +125,7 @@ func createStreams(req *http.Request, w http.ResponseWriter, opts *Options, supp
 func createHttpStreamStreams(req *http.Request, w http.ResponseWriter, opts *Options, supportedStreamProtocols []string, idleTimeout, streamCreationTimeout time.Duration) (*context, bool) {
 	protocol, err := httpstream.Handshake(req, w, supportedStreamProtocols)
 	if err != nil {
-		w.WriteHeader(http.StatusBadRequest)
-		fmt.Fprint(w, err.Error())
+		http.Error(w, err.Error(), http.StatusBadRequest)
 		return nil, false
 	}
 
@@ -156,7 +155,7 @@ func createHttpStreamStreams(req *http.Request, w http.ResponseWriter, opts *Opt
 	case remotecommandconsts.StreamProtocolV2Name:
 		handler = &v2ProtocolHandler{}
 	case "":
-		glog.V(4).Infof("Client did not request protocol negotiation. Falling back to %q", remotecommandconsts.StreamProtocolV1Name)
+		klog.V(4).Infof("Client did not request protocol negotiation. Falling back to %q", remotecommandconsts.StreamProtocolV1Name)
 		fallthrough
 	case remotecommandconsts.StreamProtocolV1Name:
 		handler = &v1ProtocolHandler{}