Adding trend endpoint and example envrc

envrc.example

@@ -0,0 +1,2 @@
+export CLOUD_IMAGE_URL="http://clouds.local:8082/snapshot"
+example CLOUD_REFRESH_SECONDS=60

main.go

@@ -6,6 +6,8 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"os"
+	"strconv"
 	"sync"
 	"time"
 
@@ -13,20 +15,19 @@ import (
 )
 
 type CloudResult struct {
-    URL         string  `json:"url"`
+	Timestamp  time.Time `json:"timestamp"`
 	CloudCover float64   `json:"cloud_cover"`
-    LastUpdated string  `json:"last_updated"`
 	Error      string    `json:"error,omitempty"`
 }
 
 var (
-    mu          sync.Mutex
+	imageURL     = getEnv("CLOUD_IMAGE_URL", "http://clouds.local:8082/snapshot")
-    cache       = make(map[string]CloudResult)
+	refreshSecs  = getEnvInt("CLOUD_REFRESH_SECONDS", 30)
-    refreshFreq = 30 * time.Second // refresh interval
+	trendHistory []CloudResult
+	trendLock    sync.Mutex
 )
 
 func estimateCloudCover(url string) (float64, error) {
-    // Fetch image
 	resp, err := http.Get(url)
 	if err != nil {
 		return 0, fmt.Errorf("failed to fetch image: %v", err)
@@ -35,7 +36,7 @@ func estimateCloudCover(url string) (float64, error) {
 
 	data, err := io.ReadAll(resp.Body)
 	if err != nil {
-        return 0, fmt.Errorf("failed to read image data: %v", err)
+		return 0, fmt.Errorf("failed to read image: %v", err)
 	}
 
 	img, err := gocv.IMDecode(data, gocv.IMReadColor)
@@ -44,7 +45,6 @@ func estimateCloudCover(url string) (float64, error) {
 	}
 	defer img.Close()
 
-    // Convert to HSV
 	hsv := gocv.NewMat()
 	defer hsv.Close()
 	gocv.CvtColor(img, &hsv, gocv.ColorBGRToHSV)
@@ -64,17 +64,11 @@ func estimateCloudCover(url string) (float64, error) {
 	defer valMask.Close()
 	defer cloudMask.Close()
 
-    lowerS := gocv.NewMatFromScalar(gocv.NewScalar(0, 0, 0, 0), gocv.MatTypeCV8U)
+	// s < 60 (low saturation)
-    upperS := gocv.NewMatFromScalar(gocv.NewScalar(60, 0, 0, 0), gocv.MatTypeCV8U)
+	gocv.InRangeWithScalar(s, gocv.NewScalar(0, 0, 0, 0), gocv.NewScalar(60, 0, 0, 0), &satMask)
-    lowerV := gocv.NewMatFromScalar(gocv.NewScalar(120, 0, 0, 0), gocv.MatTypeCV8U)
+	// v > 120 (bright)
-    upperV := gocv.NewMatFromScalar(gocv.NewScalar(255, 0, 0, 0), gocv.MatTypeCV8U)
+	gocv.InRangeWithScalar(v, gocv.NewScalar(120, 0, 0, 0), gocv.NewScalar(255, 0, 0, 0), &valMask)
-    defer lowerS.Close()
-    defer upperS.Close()
-    defer lowerV.Close()
-    defer upperV.Close()
 
-    gocv.InRange(s, lowerS, upperS, &satMask)
-    gocv.InRange(v, lowerV, upperV, &valMask)
 	gocv.BitwiseAnd(satMask, valMask, &cloudMask)
 
 	totalPixels := cloudMask.Rows() * cloudMask.Cols()
@@ -88,63 +82,68 @@ func estimateCloudCover(url string) (float64, error) {
 	return cloudCover, nil
 }
 
-func updateCache(url string) {
+func backgroundCollector() {
-    cover, err := estimateCloudCover(url)
+	for {
-    mu.Lock()
+		cover, err := estimateCloudCover(imageURL)
-    defer mu.Unlock()
+		result := CloudResult{Timestamp: time.Now(), CloudCover: cover}
-
-    result := CloudResult{
-        URL:         url,
-        CloudCover:  cover,
-        LastUpdated: time.Now().Format(time.RFC3339),
-    }
 		if err != nil {
 			result.Error = err.Error()
 		}
 
-    cache[url] = result
+		trendLock.Lock()
+		trendHistory = append(trendHistory, result)
+		// Keep last 100 entries
+		if len(trendHistory) > 100 {
+			trendHistory = trendHistory[len(trendHistory)-100:]
+		}
+		trendLock.Unlock()
+
+		fmt.Printf("[%s] Cloud cover: %.2f%%\n", result.Timestamp.Format("15:04:05"), result.CloudCover)
+		time.Sleep(time.Duration(refreshSecs) * time.Second)
+	}
 }
 
-func startAutoRefresh(url string) {
+func getEnv(key, def string) string {
-    go func() {
+	if v, ok := os.LookupEnv(key); ok {
-        for {
+		return v
-            updateCache(url)
-            time.Sleep(refreshFreq)
 	}
-    }()
+	return def
 }
 
-func handleCloudCover(w http.ResponseWriter, r *http.Request) {
+func getEnvInt(key string, def int) int {
-    url := r.URL.Query().Get("url")
+	if v, ok := os.LookupEnv(key); ok {
-    if url == "" {
+		if i, err := strconv.Atoi(v); err == nil {
-        url = "http://clouds.service:8081/snapshot"
+			return i
 		}
-
-    mu.Lock()
-    result, ok := cache[url]
-    mu.Unlock()
-
-    if !ok {
-        // first-time fetch triggers background updates
-        updateCache(url)
-        startAutoRefresh(url)
-        mu.Lock()
-        result = cache[url]
-        mu.Unlock()
 	}
-
+	return def
-    w.Header().Set("Content-Type", "application/json")
-    json.NewEncoder(w).Encode(result)
 }
 
 func main() {
-    http.HandleFunc("/cloudcover", handleCloudCover)
+	go backgroundCollector()
-    http.HandleFunc("/healthz", func(w http.ResponseWriter, _ *http.Request) {
+
-        w.WriteHeader(http.StatusOK)
+	http.HandleFunc("/cloudcover", func(w http.ResponseWriter, r *http.Request) {
-        w.Write([]byte("ok"))
+		trendLock.Lock()
+		defer trendLock.Unlock()
+
+		if len(trendHistory) == 0 {
+			http.Error(w, "No data collected yet", http.StatusServiceUnavailable)
+			return
+		}
+		latest := trendHistory[len(trendHistory)-1]
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(latest)
 	})
 
-    fmt.Printf("☁️  Cloud cover API running on http://localhost:8080\n")
+	http.HandleFunc("/cloudtrend", func(w http.ResponseWriter, r *http.Request) {
-    fmt.Printf("   Example: curl 'http://localhost:8080/cloudcover?url=http://clouds.local:8082/snapshot'\n")
+		trendLock.Lock()
+		defer trendLock.Unlock()
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(trendHistory)
+	})
+
+	fmt.Printf("☁️ Cloud cover API started at http://localhost:8080\n")
+	fmt.Printf("🔁 Refresh interval: %ds | Source: %s\n", refreshSecs, imageURL)
 	log.Fatal(http.ListenAndServe(":8080", nil))
 }