Hold serve_hostname code in kubernetes repo

contrib/for-demos/serve_hostname/Dockerfile

@@ -0,0 +1,8 @@
+# https://github.com/thockin/serve_hostname
+
+FROM scratch
+MAINTAINER Tim Hockin <thockin@google.com>
+ADD serve_hostname serve_hostname
+ADD serve_hostname.go serve_hostname.go
+EXPOSE 9376
+ENTRYPOINT ["/serve_hostname"]

contrib/for-demos/serve_hostname/Makefile

@@ -0,0 +1,13 @@
+all: serve_hostname
+
+serve_hostname: serve_hostname.go
+	CGO_ENABLED=0 go build -a --ldflags '-w' ./serve_hostname.go
+
+container: serve_hostname
+	sudo docker build -t kubernetes/serve_hostname .
+
+push:
+	sudo docker push kubernetes/serve_hostname
+
+clean:
+	rm -f serve_hostname

contrib/for-demos/serve_hostname/README.md

@@ -0,0 +1,4 @@
+serve_hostname
+==============
+
+Util app to serve your hostname on TCP and/or UDP.  Useful for testing.

contrib/for-demos/serve_hostname/serve_hostname.go

@@ -0,0 +1,91 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// A small utility to just serve the hostname on TCP and/or UDP.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"os"
+)
+
+var (
+	doTcp  = flag.Bool("tcp", false, "Serve raw over TCP.")
+	doUdp  = flag.Bool("udp", false, "Serve raw over UDP.")
+	doHttp = flag.Bool("http", true, "Serve HTTP.")
+	port   = flag.Int("port", 9376, "Port number.")
+)
+
+func main() {
+	flag.Parse()
+
+	if *doHttp && (*doTcp || *doUdp) {
+		log.Fatalf("Can't server TCP/UDP mode and HTTP mode at the same time")
+	}
+
+	hostname, err := os.Hostname()
+	if err != nil {
+		log.Fatalf("Error from os.Hostname(): %s", err)
+	}
+	hostname += "\n"
+
+	if *doTcp {
+		listener, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))
+		if err != nil {
+			log.Fatalf("Error from net.Listen(): %s", err)
+		}
+		go func() {
+			for {
+				conn, err := listener.Accept()
+				if err != nil {
+					log.Fatalf("Error from Accept(): %s", err)
+				}
+				conn.Write([]byte(hostname))
+				conn.Close()
+			}
+		}()
+	}
+	if *doUdp {
+		addr, err := net.ResolveUDPAddr("udp", fmt.Sprintf(":%d", *port))
+		if err != nil {
+			log.Fatalf("Error from net.ResolveUDPAddr(): %s", err)
+		}
+		sock, err := net.ListenUDP("udp", addr)
+		if err != nil {
+			log.Fatalf("Error from ListenUDP(): %s", err)
+		}
+		go func() {
+			var buffer [16]byte
+			for {
+				_, cliAddr, err := sock.ReadFrom(buffer[0:])
+				if err != nil {
+					log.Fatalf("Error from ReadFrom(): %s", err)
+				}
+				sock.WriteTo([]byte(hostname), cliAddr)
+			}
+		}()
+	}
+	if *doHttp {
+		http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { fmt.Fprintf(w, "%s", hostname) })
+		go log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", *port), nil))
+	}
+
+	select {}
+}