remove last sleep in test path

gracehttp/testserver/testserver.go

@@ -4,11 +4,14 @@ package main
 import (
 	"encoding/json"
 	"flag"
-	"github.com/daaku/go.grace/gracehttp"
+	"fmt"
 	"log"
 	"net/http"
 	"os"
+	"sync"
 	"time"
+
+	"github.com/daaku/go.grace/gracehttp"
 )
 
 type response struct {
@@ -16,40 +19,52 @@ type response struct {
 	Pid   int
 }
 
-var (
-	address0 = flag.String("a0", ":48567", "Zero address to bind to.")
-	address1 = flag.String("a1", ":48568", "First address to bind to.")
-	address2 = flag.String("a2", ":48569", "Second address to bind to.")
-	finished = make(chan bool)
-)
-
-func serve() {
-	err := gracehttp.Serve(
-		&http.Server{Addr: *address0, Handler: newHandler()},
-		&http.Server{Addr: *address1, Handler: newHandler()},
-		&http.Server{Addr: *address2, Handler: newHandler()},
-	)
-	if err != nil {
-		log.Fatalf("Error in gracehttp.Serve: %s", err)
+func wait(wg *sync.WaitGroup, addr string) {
+	defer wg.Done()
+	url := fmt.Sprintf("http://%s/sleep/?duration=0", addr)
+	for {
+		if _, err := http.Get(url); err == nil {
+			return
+		}
 	}
-	finished <- true
 }
 
 func main() {
+	var addrs [3]string
+	flag.StringVar(&addrs[0], "a0", ":48560", "Zero address to bind to.")
+	flag.StringVar(&addrs[1], "a1", ":48561", "First address to bind to.")
+	flag.StringVar(&addrs[2], "a2", ":48562", "Second address to bind to.")
 	flag.Parse()
+
 	err := flag.Set("gracehttp.log", "false")
 	if err != nil {
 		log.Fatalf("Error setting gracehttp.log: %s", err)
 	}
 
-	go serve()
-	time.Sleep(time.Second * 2) // BUG
+	// print json to stderr once we can successfully connect to all three
+	// addresses. the ensures we only print the line once we're ready to serve.
+	go func() {
+		var wg sync.WaitGroup
+		wg.Add(len(addrs))
+		for _, addr := range addrs {
+			go wait(&wg, addr)
+		}
+		wg.Wait()
 
-	err = json.NewEncoder(os.Stderr).Encode(&response{Pid: os.Getpid()})
+		err = json.NewEncoder(os.Stderr).Encode(&response{Pid: os.Getpid()})
+		if err != nil {
+			log.Fatalf("Error writing startup json: %s", err)
+		}
+	}()
+
+	err = gracehttp.Serve(
+		&http.Server{Addr: addrs[0], Handler: newHandler()},
+		&http.Server{Addr: addrs[1], Handler: newHandler()},
+		&http.Server{Addr: addrs[2], Handler: newHandler()},
+	)
 	if err != nil {
-		log.Fatalf("Error writing startup json: %s", err)
+		log.Fatalf("Error in gracehttp.Serve: %s", err)
 	}
-	<-finished
 }
 
 func newHandler() http.Handler {