Storage: Add List support for pagination (#87093)

* Add origin keys to List request
* Check origin keys requirement in the sql entity server's List method
* Refactor mode 2 List
* Check origin keys before making Storage List call

---------

Co-authored-by: Dan Cech <dcech@grafana.com>

pkg/services/apiserver/storage/entity/selector.go

@@ -1,6 +1,7 @@
 package entity
 
 import (
+	"github.com/grafana/grafana/pkg/services/apiserver/utils"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/selection"
@@ -20,6 +21,8 @@ type Requirements struct {
 	ListDeleted bool
 	// ListHistory is a resource name to list the history of
 	ListHistory string
+	// ListOriginKeys needs to include the origin key of a given entity in order for it to be selected.
+	ListOriginKeys []string
 }
 
 func ReadLabelSelectors(selector labels.Selector) (Requirements, labels.Selector, error) {
@@ -45,6 +48,11 @@ func ReadLabelSelectors(selector labels.Selector) (Requirements, labels.Selector
 				return requirements, newSelector, apierrors.NewBadRequest(SortByKey + " label selector only supports in")
 			}
 			requirements.SortBy = r.Values().List()
+		case utils.AnnoKeyOriginKey:
+			if r.Operator() != selection.In {
+				return requirements, newSelector, apierrors.NewBadRequest(SortByKey + " label selector only supports in")
+			}
+			requirements.ListOriginKeys = r.Values().List()
 		case ListDeletedKey:
 			if r.Operator() != selection.Equals {
 				return requirements, newSelector, apierrors.NewBadRequest(ListDeletedKey + " label selector only supports equality")

pkg/services/apiserver/storage/entity/storage.go

@@ -442,6 +442,9 @@ func (s *Storage) GetList(ctx context.Context, key string, opts storage.ListOpti
 	if len(requirements.SortBy) > 0 {
 		req.Sort = requirements.SortBy
 	}
+	if len(requirements.ListOriginKeys) > 0 {
+		req.OriginKeys = requirements.ListOriginKeys
+	}
 	if requirements.ListDeleted {
 		req.Deleted = true
 	}