Merge pull request #258 from bouroo/perf/upstreams-sortfunc

weighted random upstream

src/mod/dynamicproxy/loadbalance/originPicker.go

@@ -102,39 +102,62 @@ func (m *RouteManager) getSessionHandler(r *http.Request, upstreams []*Upstream)
 /* Functions related to random upstream picking */
 // Get a random upstream by the weights defined in Upstream struct, return the upstream, index value and any error
 func getRandomUpstreamByWeight(upstreams []*Upstream) (*Upstream, int, error) {
-	var ret *Upstream
-	sum := 0
-	for _, c := range upstreams {
-		sum += c.Weight
-	}
-	r, err := intRange(0, sum)
-	if err != nil {
-		return ret, -1, err
-	}
-	counter := 0
-	for _, c := range upstreams {
-		r -= c.Weight
-		if r < 0 {
-			return c, counter, nil
-		}
-		counter++
+	// If there is only one upstream, return it
+	if len(upstreams) == 1 {
+		return upstreams[0], 0, nil
 	}
 
-	if ret == nil {
-		//All fallback
-		//use the first one that is with weight = 0
-		fallbackUpstreams := []*Upstream{}
-		fallbackUpstreamsOriginalID := []int{}
-		for ix, upstream := range upstreams {
-			if upstream.Weight == 0 {
-				fallbackUpstreams = append(fallbackUpstreams, upstream)
-				fallbackUpstreamsOriginalID = append(fallbackUpstreamsOriginalID, ix)
+	// Preserve the index with upstreams
+	type upstreamWithIndex struct {
+		Upstream *Upstream
+		Index    int
+	}
+
+	// Calculate total weight for upstreams with weight > 0
+	totalWeight := 0
+	fallbackUpstreams := make([]upstreamWithIndex, 0, len(upstreams))
+
+	for index, upstream := range upstreams {
+		if upstream.Weight > 0 {
+			totalWeight += upstream.Weight
+		} else {
+			// Collect fallback upstreams
+			fallbackUpstreams = append(fallbackUpstreams, upstreamWithIndex{upstream, index})
 		}
 	}
-		upstreamID := rand.Intn(len(fallbackUpstreams))
-		return fallbackUpstreams[upstreamID], fallbackUpstreamsOriginalID[upstreamID], nil
+
+	// If there are no upstreams with weight > 0, return a fallback upstream if available
+	if totalWeight == 0 {
+		if len(fallbackUpstreams) > 0 {
+			// Randomly select one of the fallback upstreams
+			randIndex := rand.Intn(len(fallbackUpstreams))
+			return fallbackUpstreams[randIndex].Upstream, fallbackUpstreams[randIndex].Index, nil
 		}
-	return ret, -1, errors.New("failed to pick an upstream origin server")
+		// No upstreams available at all
+		return nil, -1, errors.New("no valid upstream servers available")
+	}
+
+	// Random weight between 0 and total weight
+	randomWeight := rand.Intn(totalWeight)
+
+	// Select an upstream based on the random weight
+	for index, upstream := range upstreams {
+		if upstream.Weight > 0 { // Only consider upstreams with weight > 0
+			if randomWeight < upstream.Weight {
+				// Return the selected upstream and its index
+				return upstream, index, nil
+			}
+			randomWeight -= upstream.Weight
+		}
+	}
+
+	// If we reach here, it means we should return a fallback upstream if available
+	if len(fallbackUpstreams) > 0 {
+		randIndex := rand.Intn(len(fallbackUpstreams))
+		return fallbackUpstreams[randIndex].Upstream, fallbackUpstreams[randIndex].Index, nil
+	}
+
+	return nil, -1, errors.New("failed to pick an upstream origin server")
 }
 
 // IntRange returns a random integer in the range from min to max.

src/mod/utils/utils.go

@@ -41,12 +41,12 @@ func SendOK(w http.ResponseWriter) {
 
 // Get GET parameter
 func GetPara(r *http.Request, key string) (string, error) {
-	keys, ok := r.URL.Query()[key]
-	if !ok || len(keys[0]) < 1 {
+	// Get first value from the URL query
+	value := r.URL.Query().Get(key)
+	if len(value) == 0 {
 		return "", errors.New("invalid " + key + " given")
-	} else {
-		return keys[0], nil
 	}
+	return value, nil
 }
 
 // Get GET paramter as boolean, accept 1 or true
@@ -56,26 +56,29 @@ func GetBool(r *http.Request, key string) (bool, error) {
 		return false, err
 	}
 
-	x = strings.TrimSpace(x)
-
-	if x == "1" || strings.ToLower(x) == "true" || strings.ToLower(x) == "on" {
+	// Convert to lowercase and trim spaces just once to compare
+	switch strings.ToLower(strings.TrimSpace(x)) {
+	case "1", "true", "on":
 		return true, nil
-	} else if x == "0" || strings.ToLower(x) == "false" || strings.ToLower(x) == "off" {
+	case "0", "false", "off":
 		return false, nil
 	}
 
 	return false, errors.New("invalid boolean given")
 }
 
-// Get POST paramter
+// Get POST parameter
 func PostPara(r *http.Request, key string) (string, error) {
-	r.ParseForm()
-	x := r.Form.Get(key)
-	if x == "" {
-		return "", errors.New("invalid " + key + " given")
-	} else {
-		return x, nil
+	// Try to parse the form
+	if err := r.ParseForm(); err != nil {
+		return "", err
 	}
+	// Get first value from the form
+	x := r.Form.Get(key)
+	if len(x) == 0 {
+		return "", errors.New("invalid " + key + " given")
+	}
+	return x, nil
 }
 
 // Get POST paramter as boolean, accept 1 or true
@@ -85,11 +88,11 @@ func PostBool(r *http.Request, key string) (bool, error) {
 		return false, err
 	}
 
-	x = strings.TrimSpace(x)
-
-	if x == "1" || strings.ToLower(x) == "true" || strings.ToLower(x) == "on" {
+	// Convert to lowercase and trim spaces just once to compare
+	switch strings.ToLower(strings.TrimSpace(x)) {
+	case "1", "true", "on":
 		return true, nil
-	} else if x == "0" || strings.ToLower(x) == "false" || strings.ToLower(x) == "off" {
+	case "0", "false", "off":
 		return false, nil
 	}
 
@@ -114,14 +117,19 @@ func PostInt(r *http.Request, key string) (int, error) {
 
 func FileExists(filename string) bool {
 	_, err := os.Stat(filename)
-	if os.IsNotExist(err) {
+	if err == nil {
+		// File exists
+		return true
+	} else if errors.Is(err, os.ErrNotExist) {
+		// File does not exist
 		return false
 	}
-	return true
+	// Some other error
+	return false
 }
 
 func IsDir(path string) bool {
-	if FileExists(path) == false {
+	if !FileExists(path) {
 		return false
 	}
 	fi, err := os.Stat(path)