Poll API, pass result to chan, pass from chan to Websocket. Panic - go

Question

I'm writing a small package which does a GET request to an external API every 2 seconds. It takes the value from this request and passes it into a channel. I have made this channel available to a http.handler (chi router) which upgrades to a websocket where the front-end will grab the value in realtime. the panic error is a lot of lines but i guess the most important is this:
2018/11/14 16:47:55 http: response.WriteHeader on hijacked connection
2018/11/14 16:47:55 http: response.Write on hijacked connection
Aside from that I'm sure there is a better way of doing this. Any experienced Gophers out there have any pointers to help a noob such as myself improve this?
package currencyticker
import (
"bitbucket.org/special/api/config"
"encoding/json"
"fmt"
"github.com/go-chi/chi"
"github.com/go-chi/render"
"github.com/gorilla/websocket"
"github.com/leekchan/accounting"
"io/ioutil"
"log"
"math/big"
"net/http"
"time"
)
var (
ac = accounting.Accounting{Precision: 2}
from = "USD"
to = "EUR,SWK"
url = "https://min-api.currencyapi.com/data/price?fsym=" + from + "&tsyms=" + to
messages = make(chan float64)
)
var wsupgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool {
return true // Disable CORS for testing
},
}
// Config - init
type Config struct {
*config.Config
}
type result map[string]float64
// New - init the configs
func New(configuration *config.Config) *Config {
return &Config{configuration}
}
// Routes - api urls
func (config *Config) Routes() *chi.Mux {
router := chi.NewRouter()
router.Use(
render.SetContentType(render.ContentTypeHTML), // Set content-Type headers as application/json
)
router.Get("/", config.GetPrice) // subscribe to new tweets
return router
}
func (config *Config) GetPrice(w http.ResponseWriter, r *http.Request) {
conn, err := wsupgrader.Upgrade(w, r, nil)
if err != nil {
fmt.Println(fmt.Printf("Failed to set websocket upgrade: %+v ", err))
return
}
for {
time.Sleep(1 * time.Second)
price := <-messages
w, err := conn.NextWriter(websocket.TextMessage)
if err != nil {
fmt.Println("ws error", err)
}
currVal := ac.FormatMoneyBigFloat(big.NewFloat(price))
if _, err := w.Write([]byte(currVal)); err != nil {
fmt.Printf("w.Write() returned %v", err)
}
w.Close()
}
}
// start getting the price of ether as soon as they ap starts
func init() {
go startPollingPriceAPI()
}
// Go Routine to start polling
func startPollingPriceAPI() {
for {
time.Sleep(2 * time.Second)
go getPriceFromAPI()
}
}
func getPriceFromAPI() {
w := http.Client{
// Timeout: time.Second * 3,
}
req, _ := http.NewRequest(http.MethodGet, url, nil)
res, err := w.Do(req)
if err != nil {
log.Println("err getting price [req]: ", err)
}
body, err := ioutil.ReadAll(res.Body)
if err != nil {
log.Println("err getting price [io-read]: ", err)
}
r := result{}
if jsonErr := json.Unmarshal(body, &r); jsonErr != nil {
log.Println("err getting price [json]: ", jsonErr)
}
fmt.Println("1 Dollar = €", r["EUR"])
messages <- r["EUR"]
}