add ip throttling and better pooling

fix nil pointer dereference

sdk/api.go

@@ -54,7 +54,7 @@ func (a *APIConfig) FetchChannels(status string, cp *SyncProperties) ([]YoutubeC
 		Data    []YoutubeChannel `json:"data"`
 	}
 	endpoint := a.ApiURL + "/yt/jobs"
-	res, _ := http.PostForm(endpoint, url.Values{
+	res, err := http.PostForm(endpoint, url.Values{
 		"auth_token":  {a.ApiToken},
 		"sync_status": {status},
 		"min_videos":  {strconv.Itoa(1)},
@@ -63,10 +63,13 @@ func (a *APIConfig) FetchChannels(status string, cp *SyncProperties) ([]YoutubeC
 		"sync_server": {a.HostName},
 		"channel_id":  {cp.YoutubeChannelID},
 	})
+	if err != nil {
+		return nil, errors.Err(err)
+	}
 	defer res.Body.Close()
 	body, _ := ioutil.ReadAll(res.Body)
 	var response apiJobsResponse
-	err := json.Unmarshal(body, &response)
+	err = json.Unmarshal(body, &response)
 	if err != nil {
 		return nil, err
 	}

sources/youtubeVideo.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/lbryio/lbry.go/extras/errors"
 	"github.com/lbryio/lbry.go/extras/jsonrpc"
+	"github.com/lbryio/lbry.go/extras/stop"
 	"github.com/lbryio/lbry.go/extras/util"
 
 	"github.com/lbryio/ytsync/namer"
@@ -51,7 +52,8 @@ type YoutubeVideo struct {
 	walletLock       *sync.RWMutex
 }
 
-const reflectorURL = "http://blobs.lbry.io/"
+const IPCooldownPeriod = 20 * time.Second
+const unbanTimeout = 3 * time.Hour
 
 var youtubeCategories = map[string]string{
 	"1":  "film & animation",
@@ -174,15 +176,16 @@ func (v *YoutubeVideo) getAbbrevDescription() string {
 	return strings.Join(strings.Split(description, "\n")[:maxLines], "\n") + "\n..." + additionalDescription
 }
 
-var ipPool []string
-var IPIndex int
+var ipv6Pool []string
+var ipv4Pool []string
+var throttledIPs map[string]bool
+var ipLastUsed map[string]time.Time
 var ipMutex sync.Mutex
 
-func getNextIP() (string, error) {
+func getNextIP(ipv6 bool) (string, error) {
 	ipMutex.Lock()
 	defer ipMutex.Unlock()
-	if len(ipPool) < 1 {
-		IPIndex = 0
+	if len(ipv4Pool) < 1 || len(ipv6Pool) < 1 {
 		addrs, err := net.InterfaceAddrs()
 		if err != nil {
 			return "", errors.Err(err)
@@ -191,19 +194,74 @@ func getNextIP() (string, error) {
 		for _, address := range addrs {
 			if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
 				if ipnet.IP.To16() != nil && govalidator.IsIPv6(ipnet.IP.String()) {
-					ipPool = append(ipPool, ipnet.IP.String())
+					ipv6Pool = append(ipv6Pool, ipnet.IP.String())
+				} else if ipnet.IP.To4() != nil && govalidator.IsIPv4(ipnet.IP.String()) {
+					ipv4Pool = append(ipv4Pool, ipnet.IP.String())
 				}
 			}
 		}
 	}
-	nextIP := ipPool[IPIndex]
-	if IPIndex == len(ipPool)-1 {
-		IPIndex = 0
+	nextIP := ""
+	if ipv6 {
+		nextIP = getLeastUsedIP(ipv6Pool)
 	} else {
-		IPIndex++
+		nextIP = getLeastUsedIP(ipv4Pool)
 	}
+	if nextIP == "" {
+		return "", errors.Err("all IPs are throttled")
+	}
+	lastUse := ipLastUsed[nextIP]
+	if time.Since(lastUse) < IPCooldownPeriod {
+		time.Sleep(IPCooldownPeriod - time.Since(lastUse))
+	}
+
+	ipLastUsed[nextIP] = time.Now()
 	return nextIP, nil
 }
+func getLeastUsedIP(ipPool []string) string {
+	nextIP := ""
+	veryLastUse := time.Now()
+	for _, ip := range ipPool {
+		isThrottled, _ := throttledIPs[ip]
+		if isThrottled {
+			continue
+		}
+		lastUse := ipLastUsed[ip]
+		if lastUse.Before(veryLastUse) {
+			nextIP = ip
+			veryLastUse = lastUse
+		}
+	}
+	return nextIP
+}
+
+func setIpThrottled(ip string, stopGrp *stop.Group) {
+	ipMutex.Lock()
+	defer ipMutex.Unlock()
+	isThrottled, _ := throttledIPs[ip]
+	if isThrottled {
+		return
+	}
+	throttledIPs[ip] = true
+	log.Printf("%s set to throttled", ip)
+
+	go func() {
+		unbanTimer := time.NewTimer(unbanTimeout)
+		for {
+			select {
+			case <-unbanTimer.C:
+				throttledIPs[ip] = false
+				log.Printf("%s set back to not throttled", ip)
+				return
+			case <-stopGrp.Ch():
+				unbanTimer.Stop()
+				return
+			default:
+				time.Sleep(5 * time.Second)
+			}
+		}
+	}()
+}
 
 func (v *YoutubeVideo) download(useIPv6 bool) error {
 	videoPath := v.getFullPath()
@@ -232,11 +290,11 @@ func (v *YoutubeVideo) download(useIPv6 bool) error {
 		"--merge-output-format",
 		"mp4",
 	}
+	sourceAddress, err := getNextIP(useIPv6)
+	if err != nil {
+		return errors.Err(err)
+	}
 	if useIPv6 {
-		sourceAddress, err := getNextIP()
-		if err != nil {
-			return errors.Err(err)
-		}
 		log.Infof("using IPv6: %s", sourceAddress)
 		ytdlArgs = append(ytdlArgs,
 			"-6",
@@ -244,8 +302,12 @@ func (v *YoutubeVideo) download(useIPv6 bool) error {
 			sourceAddress,
 		)
 	} else {
-		log.Infoln("using IPv4")
-		ytdlArgs = append(ytdlArgs, "-4")
+		log.Infoln("using IPv4: %s", sourceAddress)
+		ytdlArgs = append(ytdlArgs,
+			"-4",
+			"--source-address",
+			sourceAddress,
+		)
 	}
 	ytdlArgs = append(ytdlArgs, "https://www.youtube.com/watch?v="+v.ID())
 	cmd := exec.Command("youtube-dl", ytdlArgs...)