added exponential sleep time if there is a timeout for a stream

stream.go

@@ -6,6 +6,7 @@ import (
 	"image/color"
 	"io/ioutil"
 	"log"
+	"math"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -22,6 +23,7 @@ type Stream struct {
 	Base64     string      `json:"base64"`
 	Interval   int         `json:"interval"`
 	WatchAreas []WatchArea `json:"watchAreas"`
+	Timeouts   float64     `json:"-"`
 	FileLock   sync.Mutex  `json:"-"`
 }
 
@@ -35,6 +37,7 @@ func NewStream(Name string, URL string) *Stream {
 		Base64:     base64,
 		Interval:   5000,
 		WatchAreas: make([]WatchArea, 0),
+		Timeouts:   0,
 	}
 	/*
 		stream.WatchAreas = append(stream.WatchAreas,
@@ -62,7 +65,9 @@ func NewStream(Name string, URL string) *Stream {
 // StreamFromJSON takes a filepath to a JSON file, and returns the unmarshalled Stream object
 func StreamFromJSON(path string) *Stream {
 	streamJSONFile, _ := ioutil.ReadFile(path)
-	stream := Stream{}
+	stream := Stream{
+		Timeouts: 0,
+	}
 	json.Unmarshal([]byte(streamJSONFile), &stream)
 	return &stream
 }
@@ -73,7 +78,10 @@ func (s *Stream) Update() {
 	resp, err := http.Get(s.URL)
 	if err != nil {
 		log.Println(err)
+		s.Timeouts++
 		return
+	} else {
+		s.Timeouts = 0
 	}
 	img, err := ioutil.ReadAll(resp.Body)
 	defer resp.Body.Close()
@@ -132,7 +140,9 @@ func (s *Stream) CheckWatchAreas(area image.Rectangle, contours [][]image.Point)
 func (s *Stream) UpdateInterval() {
 	for {
 		go s.Update()
-		time.Sleep(time.Duration(s.Interval) * time.Millisecond)
+		expTimeout := math.Pow(2, s.Timeouts)
+		maxExpTimeout := (int)(math.Min(12, expTimeout))
+		time.Sleep(time.Duration(s.Interval*maxExpTimeout) * time.Millisecond)
 	}
 }