Extract NewSearchOptions from unified sql client setup. (#100719)

* Extract NewSearchOptions from unified sql client setup.

Co-authored-by: Georges Chaudy <chaudyg@gmail.com>

pkg/storage/unified/search/options.go

@@ -0,0 +1,54 @@
+package search
+
+import (
+	"log/slog"
+	"os"
+	"path/filepath"
+
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/grafana/grafana/pkg/infra/tracing"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
+	"github.com/grafana/grafana/pkg/setting"
+	"github.com/grafana/grafana/pkg/storage/unified/resource"
+)
+
+func NewSearchOptions(features featuremgmt.FeatureToggles, cfg *setting.Cfg, tracer tracing.Tracer, docs resource.DocumentBuilderSupplier, reg prometheus.Registerer) (resource.SearchOptions, error) {
+	// Setup the search server
+	if features.IsEnabledGlobally(featuremgmt.FlagUnifiedStorageSearch) {
+		root := cfg.IndexPath
+		if root == "" {
+			root = filepath.Join(cfg.DataPath, "unified-search", "bleve")
+		}
+		err := os.MkdirAll(root, 0750)
+		if err != nil {
+			return resource.SearchOptions{}, err
+		}
+		bleve, err := NewBleveBackend(BleveOptions{
+			Root:          root,
+			FileThreshold: int64(cfg.IndexFileThreshold), // fewer than X items will use a memory index
+			BatchSize:     cfg.IndexMaxBatchSize,         // This is the batch size for how many objects to add to the index at once
+		}, tracer, features)
+
+		if err != nil {
+			return resource.SearchOptions{}, err
+		}
+
+		err = reg.Register(resource.NewIndexMetrics(cfg.IndexPath, bleve))
+		if err != nil {
+			slog.Warn("Failed to register indexer metrics", "error", err)
+		}
+		err = reg.Register(resource.NewSprinklesMetrics())
+		if err != nil {
+			slog.Warn("Failed to register sprinkles metrics", "error", err)
+		}
+
+		return resource.SearchOptions{
+			Backend:       bleve,
+			Resources:     docs,
+			WorkerThreads: cfg.IndexWorkers,
+			InitMinCount:  cfg.IndexMinCount,
+		}, nil
+	}
+	return resource.SearchOptions{}, nil
+}