Alerting: Generate deterministic UID for folders created for Prometheus rule conversion (#101760)

pkg/services/ngalert/store/namespace.go

@@ -3,7 +3,10 @@ package store
 import (
 	"context"
 	"errors"
+	"fmt"
+	"hash/fnv"
 	"sort"
+	"strconv"
 
 	"github.com/grafana/grafana/pkg/apimachinery/identity"
 	"github.com/grafana/grafana/pkg/services/dashboards"
@@ -89,7 +92,14 @@ func (st DBstore) GetNamespaceByTitle(ctx context.Context, title string, orgID i
 }
 
 // GetOrCreateNamespaceByTitle gets or creates a namespace by title in the specified folder.
+//
+// To avoid race conditions when two concurrent requests try to create the same folder,
+// we create folders with a deterministic UID based on the parent UID, title, and organization ID.
 func (st DBstore) GetOrCreateNamespaceByTitle(ctx context.Context, title string, orgID int64, user identity.Requester, parentUID string) (*folder.Folder, error) {
+	if len(title) == 0 {
+		return nil, fmt.Errorf("title is empty")
+	}
+
 	var f *folder.Folder
 	var err error
 
@@ -99,7 +109,14 @@ func (st DBstore) GetOrCreateNamespaceByTitle(ctx context.Context, title string,
 	}
 
 	if f == nil {
+		// Generate a deterministic UID with an alerting prefix
+		uid, err := generateAlertingFolderUID(title, parentUID, orgID)
+		if err != nil {
+			return nil, fmt.Errorf("error creating a new folder: %w", err)
+		}
+
 		cmd := &folder.CreateFolderCommand{
+			UID:          uid,
 			OrgID:        orgID,
 			Title:        title,
 			SignedInUser: user,
@@ -107,9 +124,49 @@ func (st DBstore) GetOrCreateNamespaceByTitle(ctx context.Context, title string,
 		}
 		f, err = st.FolderService.Create(ctx, cmd)
 		if err != nil {
-			return nil, err
+			// Handle potential race condition where another request might have created
+			// the folder between our check and creation attempt
+			existingFolder, lookupErr := st.GetNamespaceByTitle(ctx, title, orgID, user, parentUID)
+			if lookupErr == nil {
+				return existingFolder, nil
+			}
+
+			// If we couldn't find it, return errors
+			return nil, fmt.Errorf("failed to get or create folder: %w", errors.Join(
+				fmt.Errorf("create folder: %w", err),
+				fmt.Errorf("lookup folder: %w", lookupErr),
+			))
 		}
 	}
 
 	return f, nil
 }
+
+// generateAlertingFolderUID creates a deterministic UID for folders
+// based on the title and parent UID to avoid race conditions when multiple
+// identical folders are created concurrently
+func generateAlertingFolderUID(title string, parentUID string, orgID int64) (string, error) {
+	h := fnv.New64a()
+
+	hashData := [][]byte{
+		[]byte(parentUID),
+		{0}, // separator
+		[]byte(title),
+		{0},
+		[]byte(strconv.FormatInt(orgID, 10)),
+	}
+
+	// Add hashData strings to the hash with a separator between them
+	for _, data := range hashData {
+		_, err := h.Write(data)
+		if err != nil {
+			return "", err
+		}
+	}
+
+	// Create a deterministic string with alerting prefix
+	base36 := strconv.FormatUint(h.Sum64(), 36)
+	uid := fmt.Sprintf("alerting-%s", base36)
+
+	return uid, nil
+}