How do I connect to a websocket running on an EC2? - amazon-web-services

Question

I am running the webserver in Go on an EC2:
package main
import (
"fmt"
"net/http"
"github.com/gorilla/websocket"
)
var upgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool { return true },
}
func echo(w http.ResponseWriter, r *http.Request) {
conn, err := upgrader.Upgrade(w, r, nil)
if err != nil {
fmt.Println(err)
return
}
defer conn.Close()
for {
msgType, msg, err := conn.ReadMessage()
if err != nil {
break
}
conn.WriteMessage(msgType, msg)
}
}
func main() {
fmt.Println("listening")
http.HandleFunc("/echo", echo)
http.ListenAndServe(":8918", nil)
}
And sending a request to it using a Python script:
import websocket
ws = websocket.WebSocket()
ws.connect("ws://myEIP:8918/echo") // redacted elastic IP
ws.send("Hello, WebSocket!")
ws.close()
However this blocks for ~30 seconds before raising an exception:
Exception has occurred: TimeoutError
[Errno 60] Operation timed out
I have my NACL set up to allow everything on port 8918, on both inbound at outbound.
I have the security group set up to allow everything on port 8918 - also outbound, but I believe security group access is stateful, so outbound isn't necessary.