Break request metrics in apiserver by client.

pkg/util/util.go

@@ -24,6 +24,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net"
+	"net/http"
 	"os"
 	"path"
 	"reflect"
@@ -491,3 +492,12 @@ func chooseHostInterfaceFromRoute(inFile io.Reader, nw networkInterfacer) (net.I
 	}
 	return nil, nil
 }
+
+func GetClient(req *http.Request) string {
+	if userAgent, ok := req.Header["User-Agent"]; ok {
+		if len(userAgent) > 0 {
+			return userAgent[0]
+		}
+	}
+	return "unknown"
+}