1 files changed, 23 insertions, 0 deletions
diff --git a/doc/articles/wiki/final.go b/doc/articles/wiki/final.go
index f15794d66..d84c1ffb2 100644
--- a/doc/articles/wiki/final.go
+++ b/doc/articles/wiki/final.go
@@ -5,12 +5,19 @@
 package main
 
 import (
+	"flag"
 	"html/template"
 	"io/ioutil"
+	"log"
+	"net"
 	"net/http"
 	"regexp"
 )
 
+var (
+	addr = flag.Bool("addr", false, "find open address and print to final-port.txt")
+)
+
 type Page struct {
 	Title string
 	Body  []byte
@@ -81,8 +88,24 @@ func makeHandler(fn func(http.ResponseWriter, *http.Request, string)) http.Handl
 }
 
 func main() {
+	flag.Parse()
 	http.HandleFunc("/view/", makeHandler(viewHandler))
 	http.HandleFunc("/edit/", makeHandler(editHandler))
 	http.HandleFunc("/save/", makeHandler(saveHandler))
+
+	if *addr {
+		l, err := net.Listen("tcp", "127.0.0.1:0")
+		if err != nil {
+			log.Fatal(err)
+		}
+		err = ioutil.WriteFile("final-port.txt", []byte(l.Addr().String()), 0644)
+		if err != nil {
+			log.Fatal(err)
+		}
+		s := &http.Server{}
+		s.Serve(l)
+		return
+	}
+
 	http.ListenAndServe(":8080", nil)
 }