From 6136ce6f002498cc98d9a3badac79f37fe74f80e Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Thu, 5 Dec 2019 00:07:31 +0300
Subject: [PATCH] Prevent resourceful operations when shutting down

---
 gocheese.go | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/gocheese.go b/gocheese.go
index 712783a..f5a3918 100644
--- 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)
 	}
 }
-- 
2.44.0