fix: incorrect number of topology (#423)

## What type of PR is this?
/kind bug

## What this PR does / why we need it:
fix incorrect number of topology

pkg/infra/search/storage/elasticsearch/search.go

@@ -163,26 +163,40 @@ func (s *Storage) AggregateByTerms(ctx context.Context, keys []string) (*storage
 }
 
 // ConvertResourceGroup2Map converts a ResourceGroup to a map[string]any.
-func ConvertResourceGroup2Map(rg *entity.ResourceGroup) map[string]any {
+func ConvertResourceGroup2Map(rg *entity.ResourceGroup) (map[string]any, error) {
 	result := make(map[string]interface{})
 	v := reflect.ValueOf(rg).Elem()
 
 	// Iterate through the fields of the struct.
 	for i := 0; i < v.NumField(); i++ {
 		field := v.Type().Field(i)
 		value := v.Field(i).Interface()
+		s, ok := field.Tag.Lookup("json")
+		if !ok {
+			return nil, fmt.Errorf("the JSON tag for the %s field in the ResourceGroup does not exist", field.Name)
+		}
+		ss := strings.Split(s, ",")
+		if len(ss) == 0 {
+			return nil, fmt.Errorf("invalid json tag: %s", s)
+		}
+		tag := strings.TrimSpace(ss[0])
 
 		switch fieldValue := value.(type) {
 		case map[string]string:
 			// Handle the map field by iterating its keys and values.
 			for key, val := range fieldValue {
-				result[field.Name+"."+key] = val
+				result[tag+"."+key] = val
 			}
-		default:
+		case string:
 			// For non-map fields, directly add them to the result map.
-			result[field.Name] = value
+			// TODO: use pointers instead of null values to determine if a field exists
+			if fieldValue != "" {
+				result[tag] = value
+			}
+		default:
+			return nil, fmt.Errorf("type %T not supported", fieldValue)
 		}
 	}
 
-	return result
+	return result, nil
 }

pkg/infra/topology/relationship.go

@@ -18,11 +18,12 @@ package topology
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"os"
 	"reflect"
 
+	"github.com/pkg/errors"
+
 	"github.com/KusionStack/karpor/pkg/core/entity"
 	"github.com/KusionStack/karpor/pkg/infra/search/storage"
 	"github.com/KusionStack/karpor/pkg/infra/search/storage/elasticsearch"
@@ -292,7 +293,10 @@ func (rg *RelationshipGraph) CountRelationshipGraphByCustomResourceGroup(ctx con
 		return nil, errors.New("apiVersion should be empty")
 	}
 	for _, node := range rg.RelationshipNodes {
-		kvs := elasticsearch.ConvertResourceGroup2Map(resourceGroup)
+		kvs, err := elasticsearch.ConvertResourceGroup2Map(resourceGroup)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to convert resource group to map")
+		}
 		kvs["apiVersion"] = schema.GroupVersion{Group: node.Group, Version: node.Version}.String()
 		kvs["kind"] = node.Kind
 		kvs["cluster"] = name