unified-storage: split resource index client (#106297)

* split resource server and index server grpc connection if defined in config

pkg/storage/unified/client.go

@@ -55,7 +55,8 @@ func ProvideUnifiedStorageClient(opts *Options, storageMetrics *resource.Storage
 	client, err := newClient(options.StorageOptions{
 		StorageType:        options.StorageType(apiserverCfg.Key("storage_type").MustString(string(options.StorageTypeUnified))),
 		DataPath:           apiserverCfg.Key("storage_path").MustString(filepath.Join(opts.Cfg.DataPath, "grafana-apiserver")),
-		Address:            apiserverCfg.Key("address").MustString(""), // client address
+		Address:            apiserverCfg.Key("address").MustString(""),
+		IndexServerAddress: apiserverCfg.Key("index_server_address").MustString(""),
 		BlobStoreURL:       apiserverCfg.Key("blob_url").MustString(""),
 		BlobThresholdBytes: apiserverCfg.Key("blob_threshold_bytes").MustInt(options.BlobThresholdDefault),
 	}, opts.Cfg, opts.Features, opts.DB, opts.Tracer, opts.Reg, opts.Authzc, opts.Docs, storageMetrics, indexMetrics)
@@ -117,34 +118,29 @@ func newClient(opts options.StorageOptions,
 		}
 
 		var (
-			conn    grpc.ClientConnInterface
-			err     error
-			metrics = newClientMetrics(reg)
+			conn      grpc.ClientConnInterface
+			indexConn grpc.ClientConnInterface
+			err       error
+			metrics   = newClientMetrics(reg)
 		)
-		// Create either a connection pool or a single connection.
-		// The connection pool __can__ be useful when connection to
-		// server side load balancers like kube-proxy.
-		if features.IsEnabledGlobally(featuremgmt.FlagUnifiedStorageGrpcConnectionPool) {
-			conn, err = newPooledConn(&poolOpts{
-				initialCapacity: 3,
-				maxCapacity:     6,
-				idleTimeout:     time.Minute,
-				factory: func() (*grpc.ClientConn, error) {
-					return grpcConn(opts.Address, metrics)
-				},
-			})
+
+		conn, err = newGrpcConn(opts.Address, metrics, features)
+		if err != nil {
+			return nil, err
+		}
+
+		if opts.IndexServerAddress != "" {
+			indexConn, err = newGrpcConn(opts.IndexServerAddress, metrics, features)
+
 			if err != nil {
 				return nil, err
 			}
 		} else {
-			conn, err = grpcConn(opts.Address, metrics)
-			if err != nil {
-				return nil, err
-			}
+			indexConn = conn
 		}
 
 		// Create a client instance
-		client, err := resource.NewResourceClient(conn, cfg, features, tracer)
+		client, err := resource.NewResourceClient(conn, indexConn, cfg, features, tracer)
 		if err != nil {
 			return nil, err
 		}
@@ -164,6 +160,34 @@ func newClient(opts options.StorageOptions,
 	}
 }
 
+func newGrpcConn(address string, metrics *clientMetrics, features featuremgmt.FeatureToggles) (grpc.ClientConnInterface, error) {
+	// Create either a connection pool or a single connection.
+	// The connection pool __can__ be useful when connection to
+	// server side load balancers like kube-proxy.
+	if features.IsEnabledGlobally(featuremgmt.FlagUnifiedStorageGrpcConnectionPool) {
+		conn, err := newPooledConn(&poolOpts{
+			initialCapacity: 3,
+			maxCapacity:     6,
+			idleTimeout:     time.Minute,
+			factory: func() (*grpc.ClientConn, error) {
+				return grpcConn(address, metrics)
+			},
+		})
+		if err != nil {
+			return nil, err
+		}
+
+		return conn, nil
+	}
+
+	conn, err := grpcConn(address, metrics)
+	if err != nil {
+		return nil, err
+	}
+
+	return conn, nil
+}
+
 // grpcConn creates a new gRPC connection to the provided address.
 func grpcConn(address string, metrics *clientMetrics) (*grpc.ClientConn, error) {
 	// Report gRPC status code errors as labels.