Start policer at random offset

CHANGELOG.md

@@ -32,6 +32,7 @@ Changelog for NeoFS Node
 - Unpaid container's data is deleted now (#3691)
 - Policer iterates engine-level object list now instead of shard-level (#3862)
 - SN now ignores `copies_number` field of `object.PutRequest.Body.Init` message (#3830)
+- Policer starts from a random offset (#3879)
 
 ### Removed
 - `node.persistent_sessions.path` config option from SN config (#3846)

pkg/local_object_storage/engine/list.go

@@ -26,6 +26,16 @@ func NewCursor(cnr cid.ID, obj oid.ID) *Cursor {
 	return &Cursor{shardCursor: shard.NewCursor(cnr, obj)}
 }
 
+// ContainerID returns the container ID stored in the cursor.
+func (c *Cursor) ContainerID() cid.ID {
+	return c.shardCursor.ContainerID()
+}
+
+// ObjectID returns the object ID stored in the cursor.
+func (c *Cursor) ObjectID() oid.ID {
+	return c.shardCursor.LastObjectID()
+}
+
 // ListWithCursor lists physical objects available in the engine starting
 // from the cursor. It includes regular, tombstone and storage group objects.
 // Does not include inhumed objects. Use cursor value from the response

pkg/services/policer/policer.go

@@ -62,15 +62,21 @@ func (oiw *objectsInWork) inWork(addr oid.Address) bool {
 	return ok
 }
 
-func (oiw *objectsInWork) remove(addr oid.Address) {
+func (oiw *objectsInWork) tryAdd(addr oid.Address) bool {
 	oiw.m.Lock()
-	delete(oiw.objs, addr)
-	oiw.m.Unlock()
+	defer oiw.m.Unlock()
+
+	if _, ok := oiw.objs[addr]; ok {
+		return false
+	}
+
+	oiw.objs[addr] = struct{}{}
+	return true
 }
 
-func (oiw *objectsInWork) add(addr oid.Address) {
+func (oiw *objectsInWork) remove(addr oid.Address) {
 	oiw.m.Lock()
-	oiw.objs[addr] = struct{}{}
+	delete(oiw.objs, addr)
 	oiw.m.Unlock()
 }