Prevent resourceful operations when shutting down

[gocheese.git] / gocheese.go

diff --git a/gocheese.go b/gocheese.go
index 3eadf99010d0a1bab9757a324c5a6e97f3d4af4d..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)
@@ -204,17 +211,19 @@ func listRoot(w http.ResponseWriter, r *http.Request) {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
        }
-       w.Write([]byte(fmt.Sprintf(HTMLBegin, "root", "root")))
+       var result bytes.Buffer
+       result.WriteString(fmt.Sprintf(HTMLBegin, "root", "root"))
        for _, file := range files {
                if file.Mode().IsDir() {
-                       w.Write([]byte(fmt.Sprintf(
+                       result.WriteString(fmt.Sprintf(
                                HTMLElement,
                                *refreshURLPath+file.Name()+"/",
                                file.Name(),
-                       )))
+                       ))
                }
        }
-       w.Write([]byte(HTMLEnd))
+       result.WriteString(HTMLEnd)
+       w.Write(result.Bytes())
 }
 
 func listDir(w http.ResponseWriter, r *http.Request, dir string, autorefresh bool) {
@@ -232,29 +241,36 @@ func listDir(w http.ResponseWriter, r *http.Request, dir string, autorefresh boo
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
        }
-       w.Write([]byte(fmt.Sprintf(HTMLBegin, dir, dir)))
+       var result bytes.Buffer
+       result.WriteString(fmt.Sprintf(HTMLBegin, dir, dir))
        var data []byte
        var filenameClean string
        for _, file := range files {
                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)
                        return
                }
                filenameClean = strings.TrimSuffix(file.Name(), SHA256Ext)
-               w.Write([]byte(fmt.Sprintf(
+               result.WriteString(fmt.Sprintf(
                        HTMLElement,
                        strings.Join([]string{
                                *refreshURLPath, dir, "/",
-                               filenameClean, "#", SHA256Prefix, string(data),
+                               filenameClean, "#", SHA256Prefix, hex.EncodeToString(data),
                        }, ""),
                        filenameClean,
-               )))
+               ))
        }
-       w.Write([]byte(HTMLEnd))
+       result.WriteString(HTMLEnd)
+       w.Write(result.Bytes())
 }
 
 func servePkg(w http.ResponseWriter, r *http.Request, dir, filename string) {
@@ -460,7 +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() {
@@ -471,9 +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)
 
@@ -485,7 +502,7 @@ func main() {
        if err != http.ErrServerClosed {
                log.Fatal(err)
        }
-       if err := <-killed; err != nil {
+       if err := <-exitErr; err != nil {
                log.Fatal(err)
        }
 }