not runnable due to timeout with too many clients

go/server.go

@@ -5,6 +5,7 @@ import (
 	"flag"
 	"log"
 	"net/http"
+	"sync"
 	"time"
 
 	"github.com/gorilla/websocket"
@@ -15,17 +16,18 @@ var upgrader = websocket.Upgrader{
 	WriteBufferSize: 2048,
 }
 var img = GetImage(10, 10)
-var tmpImage = GetImage(img.width, img.height)
 
-func write(ticker time.Ticker, c websocket.Conn) {
+func write(ticker time.Ticker, c *websocket.Conn, wg *sync.WaitGroup) {
+	defer wg.Done()
+	var tmpImage = GetImage(img.width, img.height)
 	for range ticker.C {
 		diff := tmpImage.GetDiff(&img)
 		for i := 0; i < int(diff.Width*diff.Height); i++ {
 			pix := diff.Pixels[i]
 			if pix.UserID != 0 {
-				x := i / int(diff.Width)
-				y := i % int(diff.Height)
-				msg := Message{X: uint16(x), Y: uint16(y), Timestamp: pix.Timestamp, UserID: pix.UserID, Color: pix.Color}
+				x := uint16(i / int(diff.Width))
+				y := uint16(i % int(diff.Height))
+				msg := Message{X: x, Y: y, Timestamp: pix.Timestamp, UserID: pix.UserID, Color: pix.Color}
 				marshalMsg, err := json.Marshal(msg)
 				if err != nil {
 					log.Println("error while writing image", err)
@@ -38,15 +40,8 @@ func write(ticker time.Ticker, c websocket.Conn) {
 	}
 }
 
-func serve(w http.ResponseWriter, r *http.Request) {
-	c, err := upgrader.Upgrade(w, r, nil)
-	if err != nil {
-		log.Print("error while upgrading", err)
-		return
-	}
-	defer c.Close()
-	ticker := time.NewTicker(1 * time.Second)
-	go write(*ticker, *c)
+func read(c *websocket.Conn, wg *sync.WaitGroup) {
+	defer wg.Done()
 	for {
 		_, msg, err := c.ReadMessage()
 		if err != nil {
@@ -58,7 +53,23 @@ func serve(w http.ResponseWriter, r *http.Request) {
 		message.JsonToStruct(msg)
 		img.SetPixel(message)
 	}
+}
 
+func serve(w http.ResponseWriter, r *http.Request) {
+	c, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		log.Print("error while upgrading", err)
+		return
+	}
+	defer c.Close()
+	ticker := time.NewTicker(1 * time.Second)
+	var wg sync.WaitGroup
+
+	// end fucntion if either of the 2 functions is done
+	wg.Add(1)
+	go write(*ticker, c, &wg)
+	go read(c, &wg)
+	wg.Wait()
 }
 
 func main() {

python/clients.py

@@ -19,10 +19,9 @@ class pixel:
     timestamp: int
     userid: int
 
-
-async def main():
+async def sender():
     async with websockets.connect("ws://localhost:8080/") as websocket:
-        for _ in range(10):
+        while True:
             message = pixel(
                 x=random.randint(0, 9),
                 y=random.randint(0, 9),
@@ -30,12 +29,21 @@ async def main():
                 timestamp=int(time.time()),
                 userid=1,
             )
-            print(message)
             await websocket.send(json.dumps(message.__dict__))
-        while True:
-            x = await websocket.recv()
-            print(x)
+            await asyncio.sleep(0.1)
 
+async def client():
+    async with websockets.connect("ws://localhost:8080/") as websocket:
+        i= 0
+        while True:
+            i+=1
+            x = await websocket.recv()
+            print(i, pixel(**json.loads(x)))
+
+async def main():
+    coros = [sender() for _ in range(100)]
+    coros.append(client())
+    returns = await asyncio.gather(*coros)
 
 if __name__ == "__main__":
     asyncio.get_event_loop().run_until_complete(main())