Websocket handshake fails 404 (golang server)

I have a simple go web server which serves on port localhost:8080 an public folder containing both an html file as well as a client script with websocket logic.

in my main.go file

listener, err := net.listen("tcp", "localhost:8080")
if err != nil {
    log.Fatal(err)
}
//full code in gist https://gist.github.com/Kielan/98706aaf5dc0be9d6fbe

then in my client script

try {
    var sock = new WebSocket("ws://127.0.0.1:8080");
    console.log("Websocket - status: " + sock.readyState);

    sock.onopen = function(message) {
    console.log("CONNECTION opened..." + this.readyState);
    //onmessage, onerr, onclose, ect...
}

I get the error in chrome

WebSocket connection to 'ws://127.0.0.1:8080/' failed: Error during WebSocket handshake: Unexpected response code: 200

and Firefox

Firefox can't establish a connection to the server at ws://127.0.0.1:8080/.

I found this article referring to node.js indicating to add /websocket to my client websocket string, though it did not solve the problem and resulted in a 404

I thought response code 200 is good, do I need to convert the request to a websocket somehow and maybe it is defaulting to http? If so how can I do this?

Like JimB pointed out, you are not handling http nor websocket connections yet.

You can do websocket handling with the package github.com/gorilla/websocket
This is how a simple setup could look like:

package main

import (    
    "log"
    "net/http"
    "github.com/gorilla/websocket"
)

// wsHandler implements the Handler Interface
type wsHandler struct{}

func main() {
    router := http.NewServeMux()
    router.Handle("/", http.FileServer(http.Dir("./webroot"))) //handles static html / css etc. under ./webroot
    router.Handle("/ws", wsHandler{}) //handels websocket connections

    //serving
    log.Fatal(http.ListenAndServe("localhost:8080", router))
}

func (wsh wsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    // upgrader is needed to upgrade the HTTP Connection to a websocket Connection
        upgrader := &websocket.Upgrader{
            ReadBufferSize:  1024,
            WriteBufferSize: 1024,
        }

        //Upgrading HTTP Connection to websocket connection
        wsConn, err := upgrader.Upgrade(w, r, nil)
        if err != nil {
            log.Printf("error upgrading %s", err)
            return
        }

        //handle your websockets with wsConn
}

In your Javascript you then need var sock = new WebSocket("ws://localhost/ws:8080"); obviously.