K8s: Dashboards: Reduce db calls to get users on list (#103020)

pkg/services/dashboardversion/dashverimpl/dashver.go

@@ -276,13 +276,9 @@ func (s *Service) listHistoryThroughK8s(ctx context.Context, orgID int64, dashbo
 		return nil, dashboards.ErrDashboardNotFound
 	}
 
-	dashboards := make([]*dashver.DashboardVersionDTO, len(out.Items))
-	for i, item := range out.Items {
-		dash, err := s.UnstructuredToLegacyDashboardVersion(ctx, &item, orgID)
-		if err != nil {
-			return nil, err
-		}
-		dashboards[i] = dash
+	dashboards, err := s.UnstructuredToLegacyDashboardVersionList(ctx, out.Items, orgID)
+	if err != nil {
+		return nil, err
 	}
 
 	return &dashver.DashboardVersionResponse{
@@ -292,6 +288,51 @@ func (s *Service) listHistoryThroughK8s(ctx context.Context, orgID int64, dashbo
 }
 
 func (s *Service) UnstructuredToLegacyDashboardVersion(ctx context.Context, item *unstructured.Unstructured, orgID int64) (*dashver.DashboardVersionDTO, error) {
+	obj, err := utils.MetaAccessor(item)
+	if err != nil {
+		return nil, err
+	}
+	users, err := s.k8sclient.GetUsersFromMeta(ctx, []string{obj.GetCreatedBy(), obj.GetUpdatedBy()})
+	if err != nil {
+		return nil, err
+	}
+	return s.unstructuredToLegacyDashboardVersionWithUsers(item, users)
+}
+
+func (s *Service) UnstructuredToLegacyDashboardVersionList(ctx context.Context, items []unstructured.Unstructured, orgID int64) ([]*dashver.DashboardVersionDTO, error) {
+	// get users ahead of time to do just one db call, rather than 2 per item in the list
+	userMeta := []string{}
+	for _, item := range items {
+		obj, err := utils.MetaAccessor(&item)
+		if err != nil {
+			return nil, err
+		}
+		if obj.GetCreatedBy() != "" {
+			userMeta = append(userMeta, obj.GetCreatedBy())
+		}
+		if obj.GetUpdatedBy() != "" {
+			userMeta = append(userMeta, obj.GetUpdatedBy())
+		}
+	}
+
+	users, err := s.k8sclient.GetUsersFromMeta(ctx, userMeta)
+	if err != nil {
+		return nil, err
+	}
+
+	versions := make([]*dashver.DashboardVersionDTO, len(items))
+	for i, item := range items {
+		version, err := s.unstructuredToLegacyDashboardVersionWithUsers(&item, users)
+		if err != nil {
+			return nil, err
+		}
+		versions[i] = version
+	}
+
+	return versions, nil
+}
+
+func (s *Service) unstructuredToLegacyDashboardVersionWithUsers(item *unstructured.Unstructured, users map[string]*user.User) (*dashver.DashboardVersionDTO, error) {
 	spec, ok := item.Object["spec"].(map[string]any)
 	if !ok {
 		return nil, errors.New("error parsing dashboard from k8s response")
@@ -312,19 +353,21 @@ func (s *Service) UnstructuredToLegacyDashboardVersion(ctx context.Context, item
 		spec["version"] = dashVersion
 	}
 
-	createdBy, err := s.k8sclient.GetUserFromMeta(ctx, obj.GetCreatedBy())
-	if err != nil {
-		return nil, err
+	var createdBy *user.User
+	if creator, ok := users[obj.GetCreatedBy()]; ok {
+		createdBy = creator
 	}
-
 	// if updated by is set, then this version of the dashboard was "created"
 	// by that user
-	if obj.GetUpdatedBy() != "" {
-		updatedBy, err := s.k8sclient.GetUserFromMeta(ctx, obj.GetUpdatedBy())
-		if err == nil && updatedBy != nil {
-			createdBy = updatedBy
-		}
+	if updater, ok := users[obj.GetUpdatedBy()]; ok {
+		createdBy = updater
 	}
+
+	createdByID := int64(0)
+	if createdBy != nil {
+		createdByID = createdBy.ID
+	}
+
 	created := obj.GetCreationTimestamp().Time
 	if updated, err := obj.GetUpdatedTimestamp(); err == nil && updated != nil {
 		created = *updated
@@ -335,20 +378,18 @@ func (s *Service) UnstructuredToLegacyDashboardVersion(ctx context.Context, item
 		return nil, err
 	}
 
-	out := dashver.DashboardVersionDTO{
+	return &dashver.DashboardVersionDTO{
 		ID:            dashVersion,
 		DashboardID:   obj.GetDeprecatedInternalID(), // nolint:staticcheck
 		DashboardUID:  uid,
 		Created:       created,
-		CreatedBy:     createdBy.ID,
+		CreatedBy:     createdByID,
 		Message:       obj.GetMessage(),
 		RestoredFrom:  restoreVer,
 		Version:       int(dashVersion),
 		ParentVersion: int(parentVersion),
 		Data:          simplejson.NewFromAny(spec),
-	}
-
-	return &out, nil
+	}, nil
 }
 
 var restoreMsg = "Restored from version "

pkg/services/dashboardversion/dashverimpl/dashver_test.go

@@ -73,7 +73,7 @@ func TestDashboardVersionService(t *testing.T) {
 		obj, err := utils.MetaAccessor(dash)
 		require.NoError(t, err)
 		obj.SetUpdatedTimestamp(&updatedTimestamp)
-		mockCli.On("GetUserFromMeta", mock.Anything, "user:1").Return(&user.User{ID: 1}, nil)
+		mockCli.On("GetUsersFromMeta", mock.Anything, []string{"user:1", ""}).Return(map[string]*user.User{"user:1": &user.User{ID: 1}}, nil)
 		mockCli.On("List", mock.Anything, int64(1), mock.Anything).Return(&unstructured.UnstructuredList{
 			Items: []unstructured.Unstructured{*dash}}, nil).Once()
 		res, err := dashboardVersionService.Get(context.Background(), &dashver.GetDashboardVersionQuery{
@@ -93,7 +93,7 @@ func TestDashboardVersionService(t *testing.T) {
 			Data:          simplejson.NewFromAny(map[string]any{"uid": "uid", "version": int64(10), "hello": "world"}),
 		})
 
-		mockCli.On("GetUserFromMeta", mock.Anything, "user:2").Return(&user.User{ID: 2}, nil)
+		mockCli.On("GetUsersFromMeta", mock.Anything, []string{"user:1", "user:2"}).Return(map[string]*user.User{"user:1": {ID: 1}, "user:2": {ID: 2}}, nil)
 		mockCli.On("List", mock.Anything, int64(1), mock.Anything).Return(&unstructured.UnstructuredList{
 			Items: []unstructured.Unstructured{{
 				Object: map[string]any{
@@ -269,7 +269,7 @@ func TestListDashboardVersions(t *testing.T) {
 			Return(&dashboards.DashboardRef{UID: "uid"}, nil)
 
 		query := dashver.ListDashboardVersionsQuery{DashboardID: 42}
-		mockCli.On("GetUserFromMeta", mock.Anything, mock.Anything).Return(&user.User{}, nil)
+		mockCli.On("GetUsersFromMeta", mock.Anything, mock.Anything).Return(map[string]*user.User{}, nil)
 		mockCli.On("List", mock.Anything, mock.Anything, mock.Anything).Return(&unstructured.UnstructuredList{
 			Items: []unstructured.Unstructured{{Object: map[string]any{
 				"metadata": map[string]any{