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FuturesBitflyerScraper.go
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FuturesBitflyerScraper.go
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package scrapers
import (
"fmt"
"github.com/diadata-org/diadata/internal/pkg/scraper-writers"
"net/url"
"os"
"os/signal"
"sync"
"syscall"
"time"
zap "go.uber.org/zap"
"github.com/gorilla/websocket"
)
const scrapeDataSaveLocationBitflyer = ""
// BitflyerScraper - use the NewBitflyerFuturesScraper function to create an instance
type BitflyerScraper struct {
Markets []string
WaitGroup *sync.WaitGroup
Writer writers.Writer
Logger *zap.SugaredLogger
}
// NewBitflyerFuturesScraper - returns an instance of an options scraper.
func NewBitflyerFuturesScraper(markets []string) FuturesScraper {
wg := sync.WaitGroup{}
writer := writers.FileWriter{}
logger := zap.NewExample().Sugar() // or NewProduction, or NewDevelopment
defer func() {
err := logger.Sync()
if err != nil {
log.Error(err)
}
}()
var scraper FuturesScraper = &BitflyerScraper{
WaitGroup: &wg,
Markets: markets,
Writer: &writer,
Logger: logger,
}
return scraper
}
func (s *BitflyerScraper) send(message *map[string]interface{}, market string, websocketConn *websocket.Conn) error {
err := websocketConn.WriteJSON(*message)
if err != nil {
return err
}
s.Logger.Debugf("sent message [%s]: %s", market, message)
return nil
}
// Authenticate - placeholder here, since we do not need to authneticate the connection.
func (s *BitflyerScraper) Authenticate(market string, connection interface{}) error {
return nil
}
// ScraperClose - safely closes the scraper; We pass the interface connection as the second argument
// primarily for the reason that Huobi scraper does not use the gorilla websocket; It uses golang's x websocket;
// If we did not define this method in our FuturesScraper interface, we could have easily used the pointer
// to gorilla websocket here; However, to make FuturesScraper more ubiquituous, we need an interface here.
func (s *BitflyerScraper) ScraperClose(market string, connection interface{}) error {
switch c := connection.(type) {
case *websocket.Conn:
// unsubscribe from the channel
err := s.send(&map[string]interface{}{"jsonrpc": "2.0", "method": "unsubscribe", "params": &map[string]interface{}{"channel": "lightning_ticker_" + market}}, market, c)
if err != nil {
s.Logger.Errorf("could not send a channel unsubscription message, err: %s", err)
return err
}
// close the websocket connection
err = s.write(websocket.CloseMessage, []byte{}, c)
if err != nil {
return err
}
err = c.Close()
if err != nil {
return err
}
s.Logger.Infof("gracefully shutdown bitflyer scraper on market: %s", market)
time.Sleep(time.Duration(retryIn) * time.Second)
return nil
default:
return fmt.Errorf("unknown connection type: %T", connection)
}
}
// Scrape starts a websocket scraper for market
func (s *BitflyerScraper) Scrape(market string) {
// this block is for listening to sigterms and interupts
sigs := make(chan os.Signal, 1)
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
userCancelled := make(chan bool, 1)
go func() {
sig := <-sigs
fmt.Println(sig)
userCancelled <- true
}()
for {
// immediately invoked function expression for easy clenup with defer
func() {
u := url.URL{Scheme: "wss", Host: "ws.lightstream.bitflyer.com", Path: "/json-rpc"}
s.Logger.Debugf("connecting to [%s], market: [%s]", u.String(), market)
ws, resp, err := websocket.DefaultDialer.Dial(u.String(), nil)
if err != nil {
s.Logger.Errorf("could not dial Bitflyer websocket: %s", err)
time.Sleep(time.Duration(retryIn) * time.Second)
return
}
defer func() {
err = resp.Body.Close()
if err != nil {
log.Error(err)
}
}()
defer func() {
err = ws.Close()
if err != nil {
log.Error(err)
}
}()
defer func() {
err = s.ScraperClose(market, ws)
if err != nil {
log.Error(err)
}
}()
ws.SetPongHandler(func(appData string) error {
s.Logger.Debugf("received a pong frame")
return nil
})
err = s.send(&map[string]interface{}{"jsonrpc": "2.0", "method": "subscribe", "params": &map[string]interface{}{"channel": "lightning_ticker_" + market}}, market, ws)
if err != nil {
s.Logger.Errorf("could not send a channel subscription message. retrying, err: %s", err)
return
}
tick := time.NewTicker(15 * time.Second)
defer tick.Stop()
go func() {
for range tick.C {
err := s.write(websocket.PingMessage, []byte{}, ws)
if err != nil {
s.Logger.Errorf("error experienced pinging coinflex, err: %s", err)
return
}
s.Logger.Debugf("pinged the coinflex server. market: [%s]", market)
}
}()
for {
select {
case <-userCancelled:
s.Logger.Infof("received interrupt, gracefully shutting down")
err := s.ScraperClose(market, ws)
if err != nil {
log.Error(err)
}
os.Exit(0)
default:
_, message, err := ws.ReadMessage()
if err != nil {
s.Logger.Errorf("repeated read error, restarting")
return
}
s.Logger.Debugf("received new message: %s, saving new message", message)
_, err = s.Writer.Write(string(message)+"\n", scrapeDataSaveLocationBitflyer+s.Writer.GetWriteFileName("Bitflyer", market))
if err != nil {
s.Logger.Errorf("could not write to file, err: %s", err)
return
}
}
}
}()
}
}
// write's primary purpose is to write a ping frame op code to keep the websocket connection alive
func (s *BitflyerScraper) write(mt int, payload []byte, ws *websocket.Conn) error {
err := ws.SetWriteDeadline(time.Now().Add(15 * time.Second))
if err != nil {
return err
}
return ws.WriteMessage(mt, payload)
}
// ScrapeMarkets - will scrape the markets specified during instantiation
func (s *BitflyerScraper) ScrapeMarkets() {
for _, market := range s.Markets {
s.WaitGroup.Add(1)
go s.Scrape(market)
}
s.WaitGroup.Wait()
}
// usage example
// func main() {
// wg := sync.WaitGroup{}
// futuresBitflyer := scrapers.NewBitflyerFuturesScraper([]string{"BTCJPY27DEC2019", "BTCJPY03JAN2020", "BTCJPY27MAR2020"})
// futuresBitflyer.ScrapeMarkets()
// wg.Wait()
// }