feat: Redis cluster support + version auto-detect + metrics API

backend/internal/handler/instance.go

@@ -68,6 +68,20 @@ func CreateInstance(c *gin.Context) {
 		c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
 		return
 	}
+	// Auto-detect version and cluster_mode after creation
+	go func() {
+		result := testDBConnectionFull(&instance)
+		updates := map[string]interface{}{}
+		if result.Success && result.Version != "" {
+			updates["version"] = result.Version
+		}
+		if result.ClusterMode {
+			updates["cluster_mode"] = true
+		}
+		if len(updates) > 0 {
+			model.DB.Model(&model.Instance{}).Where("id = ?", instance.ID).Updates(updates)
+		}
+	}()
 	instance.Password = "******"
 	c.JSON(http.StatusCreated, instance)
 }
@@ -121,11 +135,22 @@ func TestConnection(c *gin.Context) {
 		return
 	}
 	
-	success, message := testDBConnection(&instance)
-	if success {
-		c.JSON(http.StatusOK, gin.H{"success": true, "message": message})
+	result := testDBConnectionFull(&instance)
+	// Update version & cluster_mode in DB if detected
+	updates := map[string]interface{}{}
+	if result.Success && result.Version != "" {
+		updates["version"] = result.Version
+	}
+	if result.ClusterMode {
+		updates["cluster_mode"] = true
+	}
+	if len(updates) > 0 {
+		model.DB.Model(&model.Instance{}).Where("id = ?", instance.ID).Updates(updates)
+	}
+	if result.Success {
+		c.JSON(http.StatusOK, gin.H{"success": true, "message": result.Message, "version": result.Version, "cluster_mode": result.ClusterMode})
 	} else {
-		c.JSON(http.StatusBadRequest, gin.H{"success": false, "message": message})
+		c.JSON(http.StatusBadRequest, gin.H{"success": false, "message": result.Message})
 	}
 }
 
@@ -152,3 +177,25 @@ func parseID(s string) (int, bool) {
 	id, err := strconv.Atoi(s)
 	return id, err == nil
 }
+
+// GET /api/v1/instances/:id/metrics — live metrics for an instance
+func InstanceMetrics(c *gin.Context) {
+	id := c.Param("id")
+	var instance model.Instance
+	if err := model.DB.First(&instance, id).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"detail": "Instance not found"})
+		return
+	}
+
+	switch instance.DBType {
+	case "redis":
+		metrics := getRedisMetrics(&instance)
+		c.JSON(http.StatusOK, metrics)
+	default:
+		// For MySQL/PG: return basic status
+		c.JSON(http.StatusOK, gin.H{
+			"status":  "online",
+			"version": instance.Version,
+		})
+	}
+}