Correct way to save memory using write buffer pool and freeing net.http default buffers

README.md

@@ -14,6 +14,7 @@ Gorilla WebSocket is a [Go](http://golang.org/) implementation of the
 * [Command example](https://github.com/gorilla/websocket/tree/master/examples/command)
 * [Client and server example](https://github.com/gorilla/websocket/tree/master/examples/echo)
 * [File watch example](https://github.com/gorilla/websocket/tree/master/examples/filewatch)
+* [Write buffer pool example](https://github.com/gorilla/websocket/tree/master/examples/bufferpool)
 
 ### Status
 

examples/bufferpool/client.go

@@ -0,0 +1,89 @@
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"flag"
+	"log"
+	"net/url"
+	"os"
+	"os/signal"
+	"sync"
+	"time"
+
+	"github.com/gorilla/websocket"
+)
+
+var addr = flag.String("addr", "localhost:8080", "http service address")
+
+func runNewConn(wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	interrupt := make(chan os.Signal, 1)
+	signal.Notify(interrupt, os.Interrupt)
+
+	u := url.URL{Scheme: "ws", Host: *addr, Path: "/ws"}
+	log.Printf("connecting to %s", u.String())
+	c, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
+	if err != nil {
+		log.Fatal("dial:", err)
+	}
+	defer c.Close()
+
+	done := make(chan struct{})
+
+	go func() {
+		defer close(done)
+		for {
+			_, message, err := c.ReadMessage()
+			if err != nil {
+				log.Println("read:", err)
+				return
+			}
+			log.Printf("recv: %s", message)
+		}
+	}()
+
+	ticker := time.NewTicker(time.Minute * 5)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-done:
+			return
+		case t := <-ticker.C:
+			err := c.WriteMessage(websocket.TextMessage, []byte(t.String()))
+			if err != nil {
+				log.Println("write:", err)
+				return
+			}
+		case <-interrupt:
+			log.Println("interrupt")
+
+			// Cleanly close the connection by sending a close message and then
+			// waiting (with timeout) for the server to close the connection.
+			err := c.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
+			if err != nil {
+				log.Println("write close:", err)
+				return
+			}
+			select {
+			case <-done:
+			case <-time.After(time.Second):
+			}
+			return
+		}
+	}
+}
+
+func main() {
+	flag.Parse()
+	log.SetFlags(0)
+	wg := &sync.WaitGroup{}
+	for i := 0; i < 1000; i++ {
+		wg.Add(1)
+		go runNewConn(wg)
+	}
+	wg.Wait()
+}

examples/bufferpool/server.go

@@ -0,0 +1,55 @@
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"flag"
+	"log"
+	"net/http"
+	"sync"
+
+	_ "net/http/pprof"
+
+	"github.com/gorilla/websocket"
+)
+
+var addr = flag.String("addr", "localhost:8080", "http service address")
+
+var upgrader = websocket.Upgrader{
+	ReadBufferSize:  256,
+	WriteBufferSize: 256,
+	WriteBufferPool: &sync.Pool{},
+}
+
+func process(c *websocket.Conn) {
+	defer c.Close()
+	for {
+		_, message, err := c.ReadMessage()
+		if err != nil {
+			log.Println("read:", err)
+			break
+		}
+		log.Printf("recv: %s", message)
+	}
+}
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	c, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		log.Print("upgrade:", err)
+		return
+	}
+
+	// Process connection in a new goroutine
+	go process(c)
+
+	// Let the http handler return, the 8k buffer created by it will be garbage collected
+}
+
+func main() {
+	flag.Parse()
+	log.SetFlags(0)
+	http.HandleFunc("/ws", handler)
+	log.Fatal(http.ListenAndServe(*addr, nil))
+}