how to use websocket to broadcast message when a handler was triggered in golang

I’m trying to build a two factor authentication in golang by gorilla/websocket

step1:

enter username and password

step2:

when server has checked the user and passed first auth, server would send email or sms to client and browser would redirect to a page let client enter the code

I watched tutorial on the web, the most common tutorial is like

// /handler/websocket.go

var upGrader = websocket.Upgrader{
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

func WsPing(ctx *gin.Context) {

    ws, err := upGrader.Upgrade(ctx.Writer, ctx.Request, nil)
    if err != nil {
        return
    }
    defer ws.Close()
    for {
        mt, message, err := ws.ReadMessage()
        fmt.Println(string(message))
        if err != nil {
            break
        }
        if string(message) == "ping" {
            message = []byte("pong")
        } else {
            ws.WriteMessage(websocket.TextMessage, []byte(fmt.Sprintln("got it : "+string(message))))
        }
        err = ws.WriteMessage(mt, message)
        if err != nil {
            break
        }
    }
}

// /router/router.go

var (
    mongoClient                              = db.StartMongoDB()
    userRepository repository.UserRepository = repository.NewUserRepository(mongoClient)
    userService    service.UserService       = service.NewUserService(userRepository)
    userHandler    handler.UserHandler       = handler.NewUserHandler(userService)
)
func StartGinRouter() *gin.Engine {
    r := gin.Default()
    r.GET("/ping", handler.WsPing)
    userRoute := r.Group("/user")
    {
        userRoute.POST("/login", userHandler.OneAuth)
    }
    return r
}

But the feature I need is that when userHandler.OneAuth was implemented then socket would send a signal to frontend let the page redirect automatically.

According to the code above, I couldn't create a connection pool and import it into userHandler.OneAuth when the handler was triggered and implement the code below after server side sent message to client

err = ws.WriteMessage(mt, message)
        if err != nil {
            break
        }

How can I achieve this goal?