[#1539] object: Make search check the service state before request

* Introduce `rpcSearchDialer` and pass it to raw `SearchObjects` call.
  The dialer helps to check a cached gRPC connection. If it's invalidated
  in fact, then the call get failed immediatly and the call doesn't need to
  wait for context cancellation.

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

pkg/services/object/search/v2/request_forwarder.go

@@ -17,6 +17,10 @@ import (
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/api/session"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/api/signature"
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	healthV1 "google.golang.org/grpc/health/grpc_health_v1"
+	"google.golang.org/grpc/status"
 )
 
 type requestForwarder struct {
@@ -25,6 +29,21 @@ type requestForwarder struct {
 	Key        *ecdsa.PrivateKey
 }
 
+func rpcSearchDialer(ctx context.Context, cc grpc.ClientConnInterface) error {
+	healthClient := healthV1.NewHealthClient(cc)
+	resp, err := healthClient.Check(ctx, &healthV1.HealthCheckRequest{})
+	if err != nil {
+		if status.Code(err) == codes.Unimplemented {
+			return nil
+		}
+		return fmt.Errorf("health check error: %w", err)
+	}
+	if resp.GetStatus() != healthV1.HealthCheckResponse_SERVING {
+		return errors.New("unavailable grpc server")
+	}
+	return nil
+}
+
 func (f *requestForwarder) forwardRequest(ctx context.Context, addr network.Address, c client.MultiAddressClient, pubkey []byte) ([]oid.ID, error) {
 	var err error
 
@@ -47,7 +66,7 @@ func (f *requestForwarder) forwardRequest(ctx context.Context, addr network.Addr
 
 	var searchStream *rpc.SearchResponseReader
 	err = c.RawForAddress(ctx, addr, func(cli *rpcclient.Client) error {
-		searchStream, err = rpc.SearchObjects(cli, f.Request, rpcclient.WithContext(ctx))
+		searchStream, err = rpc.SearchObjects(cli, f.Request, rpcclient.WithContext(ctx), rpcclient.WithDialer(rpcSearchDialer))
 		return err
 	})
 	if err != nil {