[#137] Use callback response to update epoch

Signed-off-by: Denis Kirillov <denis@nspcc.ru>

client/common.go

@@ -164,7 +164,8 @@ func (x *contextCall) processResponse() bool {
 	// call response callback if set
 	if x.callbackResp != nil {
 		x.err = x.callbackResp(ResponseMetaInfo{
-			key: x.resp.GetVerificationHeader().GetBodySignature().GetKey(),
+			key:   x.resp.GetVerificationHeader().GetBodySignature().GetKey(),
+			epoch: x.resp.GetMetaHeader().GetEpoch(),
 		})
 		if x.err != nil {
 			x.err = fmt.Errorf("response callback error: %w", x.err)

client/response.go

@@ -5,6 +5,8 @@ import "github.com/nspcc-dev/neofs-api-go/v2/session"
 // ResponseMetaInfo groups meta information about any NeoFS API response.
 type ResponseMetaInfo struct {
 	key []byte
+
+	epoch uint64
 }
 
 type responseV2 interface {
@@ -19,6 +21,11 @@ func (x ResponseMetaInfo) ResponderKey() []byte {
 	return x.key
 }
 
+// Epoch return current epoch.
+func (x ResponseMetaInfo) Epoch() uint64 {
+	return x.epoch
+}
+
 // WithResponseInfoHandler allows specifying handler of response meta information for the all Client operations.
 // The handler is called right after the response is received. Client returns handler's error immediately.
 func WithResponseInfoHandler(f func(ResponseMetaInfo) error) Option {

pool/pool.go

@@ -277,7 +277,11 @@ func newPool(ctx context.Context, options *BuilderOptions) (Pool, error) {
 			c, err := options.clientBuilder(client.WithDefaultPrivateKey(options.Key),
 				client.WithURIAddress(addr, nil),
 				client.WithDialTimeout(options.NodeConnectionTimeout),
-				client.WithNeoFSErrorParsing())
+				client.WithNeoFSErrorParsing(),
+				client.WithResponseInfoHandler(func(info client.ResponseMetaInfo) error {
+					cache.UpdateEpoch(info.Epoch())
+					return nil
+				}))
 			if err != nil {
 				return nil, err
 			}