Add support for the new load balancing random algorithm

Author: Eduard Borges

internal/nginx/extensions.go

@@ -17,6 +17,10 @@ func ParseLBMethod(method string) (string, error) {
 		method, err := validateHashLBMethod(method)
 		return method, err
 	}
+	if strings.HasPrefix(method, "random") {
+		method, err := validateRandomLBMethod(method)
+		return method, err
+	}
 
 	if method == "least_conn" || method == "ip_hash" {
 		return method, nil
@@ -45,6 +49,10 @@ func ParseLBMethodForPlus(method string) (string, error) {
 		method, err := validateHashLBMethod(method)
 		return method, err
 	}
+	if strings.HasPrefix(method, "random") {
+		method, err := validateRandomLBMethodForPlus(method)
+		return method, err
+	}
 
 	if _, exists := nginxPlusLBValidInput[method]; exists {
 		return method, nil
@@ -62,6 +70,29 @@ func validateHashLBMethod(method string) (string, error) {
 	return "", fmt.Errorf("Invalid load balancing method: %q", method)
 }
 
+func validateRandomLBMethod(method string) (string, error) {
+	keyWords := strings.Split(method, " ")
+	if keyWords[0] == "random" {
+		if len(keyWords) == 1 || len(keyWords) == 2 && keyWords[1] == "two" ||
+			len(keyWords) == 3 && keyWords[1] == "two" && keyWords[2] == "least_conn" {
+			return method, nil
+		}
+	}
+	return "", fmt.Errorf("Invalid load balancing method: %q", method)
+}
+
+func validateRandomLBMethodForPlus(method string) (string, error) {
+	keyWords := strings.Split(method, " ")
+	if keyWords[0] == "random" {
+		if len(keyWords) == 1 || len(keyWords) == 2 && keyWords[1] == "two" ||
+			len(keyWords) == 3 && keyWords[1] == "two" &&
+			(keyWords[2] == "least_conn" || keyWords[2] == "least_time=header" || keyWords[2] == "least_time=last_byte") {
+			return method, nil
+		}
+	}
+	return "", fmt.Errorf("Invalid load balancing method: %q", method)
+}
+
 // http://nginx.org/en/docs/syntax.html
 var validTimeSuffixes = []string{
 	"ms",

internal/nginx/extensions_test.go

@@ -10,6 +10,9 @@ func TestParseLBMethod(t *testing.T) {
 		{"least_conn", "least_conn"},
 		{"round_robin", ""},
 		{"ip_hash", "ip_hash"},
+		{"random", "random"},
+		{"random two", "random two"},
+		{"random two least_conn", "random two least_conn"},
 		{"hash $request_id", "hash $request_id"},
 		{"hash $request_id consistent", "hash $request_id consistent"},
 	}
@@ -49,6 +52,11 @@ func TestParseLBMethodForPlus(t *testing.T) {
 		{"least_conn", "least_conn"},
 		{"round_robin", ""},
 		{"ip_hash", "ip_hash"},
+		{"random", "random"},
+		{"random two", "random two"},
+		{"random two least_conn", "random two least_conn"},
+		{"random two least_time=header", "random two least_time=header"},
+		{"random two least_time=last_byte", "random two least_time=last_byte"},
 		{"hash $request_id", "hash $request_id"},
 		{"least_time header", "least_time header"},
 		{"least_time last_byte", "least_time last_byte"},