Prevent resourceful operations when shutting down

diff --git a/gocheese.go b/gocheese.go
index 712783a854ca7983503ba0e4904edcea90206d1f..f5a3918bc57e6bd1499f592d4afe834a09800dcb 100644 (file)
--- a/gocheese.go
+++ b/gocheese.go
@@ -82,6 +82,8 @@ var (
        maxClients       = flag.Int("maxclients", 128, "Maximal amount of simultaneous clients")
        version          = flag.Bool("version", false, "Print version information")
        warranty         = flag.Bool("warranty", false, "Print warranty information")
+
+       killed bool
 )
 
 func mkdirForPkg(w http.ResponseWriter, r *http.Request, dir string) bool {
@@ -139,6 +141,11 @@ func refreshDir(w http.ResponseWriter, r *http.Request, dir, filenameGet string)
                        return false
                }
                if filename == filenameGet {
+                       if killed {
+                               // Skip heavy remote call, when shutting down
+                               http.Error(w, "shutting down", http.StatusInternalServerError)
+                               return false
+                       }
                        log.Println(r.RemoteAddr, "pypi download", filename)
                        path = filepath.Join(*root, dir, filename)
                        resp, err = http.Get(uri)
@@ -242,6 +249,11 @@ func listDir(w http.ResponseWriter, r *http.Request, dir string, autorefresh boo
                if !strings.HasSuffix(file.Name(), SHA256Ext) {
                        continue
                }
+               if killed {
+                       // Skip expensive I/O when shutting down
+                       http.Error(w, "shutting down", http.StatusInternalServerError)
+                       return
+               }
                data, err = ioutil.ReadFile(filepath.Join(dirPath, file.Name()))
                if err != nil {
                        http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -464,7 +476,7 @@ func main() {
 
        needsRefreshPasswd := make(chan os.Signal, 0)
        needsShutdown := make(chan os.Signal, 0)
-       killed := make(chan error, 0)
+       exitErr := make(chan error, 0)
        signal.Notify(needsRefreshPasswd, syscall.SIGHUP)
        signal.Notify(needsShutdown, syscall.SIGTERM, syscall.SIGINT)
        go func() {
@@ -475,9 +487,10 @@ func main() {
        }()
        go func(s *http.Server) {
                <-needsShutdown
+               killed = true
                log.Println("Shutting down")
                ctx, cancel := context.WithTimeout(context.TODO(), time.Minute)
-               killed <- s.Shutdown(ctx)
+               exitErr <- s.Shutdown(ctx)
                cancel()
        }(server)
 
@@ -489,7 +502,7 @@ func main() {
        if err != http.ErrServerClosed {
                log.Fatal(err)
        }
-       if err := <-killed; err != nil {
+       if err := <-exitErr; err != nil {
                log.Fatal(err)
        }
 }