indexshipper.ModeDisabled for explicit indexing operations

Signed-off-by: Owen Diehl <[email protected]>

pkg/storage/stores/shipper/indexshipper/shipper.go

@@ -33,6 +33,9 @@ const (
 	ModeReadOnly = Mode("RO")
 	// ModeWriteOnly is to allow only write operations
 	ModeWriteOnly = Mode("WO")
+	// ModeDisabled is a no-op implementation which does nothing & does not error.
+	// It's used by the blockbuilder which handles index operations independently.
+	ModeDisabled = Mode("NO")
 
 	// FilesystemObjectStoreType holds the periodic config type for the filesystem store
 	FilesystemObjectStoreType = "filesystem"
@@ -142,6 +145,8 @@ type indexShipper struct {
 func NewIndexShipper(prefix string, cfg Config, storageClient client.ObjectClient, limits downloads.Limits,
 	tenantFilter downloads.TenantFilter, open index.OpenIndexFileFunc, tableRangeToHandle config.TableRange, reg prometheus.Registerer, logger log.Logger) (IndexShipper, error) {
 	switch cfg.Mode {
+	case ModeDisabled:
+		return Noop{}, nil
 	case ModeReadOnly, ModeWriteOnly, ModeReadWrite:
 	default:
 		return nil, fmt.Errorf("invalid mode: %v", cfg.Mode)

pkg/storage/stores/shipper/indexshipper/tsdb/store.go

@@ -20,6 +20,7 @@ import (
 	"github.com/grafana/loki/v3/pkg/storage/stores/index"
 	"github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper"
 	"github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper/downloads"
+	"github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper/tsdb"
 	tsdbindex "github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper/tsdb/index"
 )
 
@@ -85,6 +86,13 @@ func (s *store) init(name, prefix string, indexShipperCfg indexshipper.Config, s
 	var indices []Index
 	opts := DefaultIndexClientOptions()
 
+	// early return in case index shipper is disabled.
+	if indexShipperCfg.Mode == indexshipper.ModeDisabled {
+		s.indexWriter = noopIndexWriter{}
+		s.Reader = NewIndexClient(tsdb.NoopIndex{}, opts, limits)
+		return nil
+	}
+
 	if indexShipperCfg.Mode == indexshipper.ModeWriteOnly {
 		// We disable bloom filters on write nodes
 		// for the Stats() methods as it's of relatively little
@@ -172,3 +180,9 @@ type failingIndexWriter struct{}
 func (f failingIndexWriter) Append(_ string, _ labels.Labels, _ uint64, _ tsdbindex.ChunkMetas) error {
 	return fmt.Errorf("index writer is not initialized due to tsdb store being initialized in read-only mode")
 }
+
+type noopIndexWriter struct{}
+
+func (f noopIndexWriter) Append(_ string, _ labels.Labels, _ uint64, _ tsdbindex.ChunkMetas) error {
+	return nil
+}