[#1708] tree: Introduce unsafe_sync_disabled param to disable synchronization

Close #1708.

Change-Id: Id2eafe332cf495a2886c468348d1dcafddae1f2d
Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

cmd/frostfs-node/config/tree/config.go

@@ -87,6 +87,12 @@ func (c TreeConfig) SyncBatchSize() int {
 	return SyncBatchSizeDefault
 }
 
+// UnsafeSyncDisabled returns the value of "unsafe_sync_disabled"
+// config parameter from the "tree" section.
+func (c TreeConfig) UnsafeSyncDisabled() bool {
+	return config.BoolSafe(c.cfg, "unsafe_sync_disabled")
+}
+
 // AuthorizedKeys parses and returns an array of "authorized_keys" config
 // parameter from "tree" section.
 //

cmd/frostfs-node/tree.go

@@ -64,6 +64,7 @@ func initTreeService(c *cfg) {
 		tree.WithReplicationChannelCapacity(treeConfig.ReplicationChannelCapacity()),
 		tree.WithReplicationWorkerCount(treeConfig.ReplicationWorkerCount()),
 		tree.WithSyncBatchSize(treeConfig.SyncBatchSize()),
+		tree.WithSyncDisabled(treeConfig.UnsafeSyncDisabled()),
 		tree.WithAuthorizedKeys(treeConfig.AuthorizedKeys()),
 		tree.WithMetrics(c.metricsCollector.TreeService()),
 		tree.WithAPELocalOverrideStorage(c.cfgObject.cfgAccessPolicyEngine.accessPolicyEngine.LocalStorage()),

pkg/services/tree/options.go

@@ -44,6 +44,7 @@ type cfg struct {
 	containerCacheSize        int
 	authorizedKeys            atomic.Pointer[[][]byte]
 	syncBatchSize             int
+	syncDisabled              bool
 
 	localOverrideStorage policyengine.LocalOverrideStorage
 	morphChainStorage    policyengine.MorphRuleChainStorageReader
@@ -122,6 +123,12 @@ func WithSyncBatchSize(n int) Option {
 	}
 }
 
+func WithSyncDisabled(d bool) Option {
+	return func(c *cfg) {
+		c.syncDisabled = d
+	}
+}
+
 func WithContainerCacheSize(n int) Option {
 	return func(c *cfg) {
 		if n > 0 {

pkg/services/tree/service.go

@@ -89,6 +89,10 @@ func New(opts ...Option) *Service {
 func (s *Service) Start(ctx context.Context) {
 	ctx = tagging.ContextWithIOTag(ctx, qos.IOTagTreeSync.String())
 	go s.replicateLoop(ctx)
+	if s.syncDisabled {
+		s.initialSyncDone.Store(true)
+		return
+	}
 	go s.syncLoop(ctx)
 
 	select {

pkg/services/tree/sync.go

@@ -419,6 +419,9 @@ func (s *Service) SynchronizeAll() error {
 		return ErrShuttingDown
 	default:
 	}
+	if s.syncDisabled {
+		return nil
+	}
 
 	select {
 	case s.syncChan <- struct{}{}: