[#1731] engine: Return the amount of actually moved objects in Evacuate

Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>

pkg/local_object_storage/engine/evacuate.go

@@ -124,14 +124,16 @@ func (e *StorageEngine) Evacuate(prm EvacuateShardPrm) (EvacuateShardRes, error)
 				if shards[j].ID().String() == sid {
 					continue
 				}
-				ok := e.putToShard(shards[j].Shard, j, shards[j].pool, lst[i], getRes.Object())
-				if ok {
+				putDone, exists := e.putToShard(shards[j].Shard, j, shards[j].pool, lst[i], getRes.Object())
+				if putDone || exists {
+					if putDone {
 						e.log.Debug("object is moved to another shard",
 							zap.String("from", sid),
 							zap.Stringer("to", shards[j].ID()),
 							zap.Stringer("addr", lst[i]))
 
 						res.count++
+					}
 					continue loop
 				}
 			}

pkg/local_object_storage/engine/evacuate_test.go

@@ -106,6 +106,13 @@ func TestEvacuateShard(t *testing.T) {
 	// Second case ensures that all objects are indeed moved and available.
 	checkHasObjects(t)
 
+	// Calling it again is OK, but all objects are already moved, so no new PUTs should be done.
+	res, err = e.Evacuate(prm)
+	require.NoError(t, err)
+	require.Equal(t, 0, res.count)
+
+	checkHasObjects(t)
+
 	e.mtx.Lock()
 	delete(e.shards, evacuateShardID)
 	delete(e.shardPools, evacuateShardID)

pkg/local_object_storage/engine/put.go

@@ -66,7 +66,8 @@ func (e *StorageEngine) put(prm PutPrm) (PutRes, error) {
 		pool := e.shardPools[sh.ID().String()]
 		e.mtx.RUnlock()
 
-		finished = e.putToShard(sh.Shard, ind, pool, addr, prm.obj)
+		putDone, exists := e.putToShard(sh.Shard, ind, pool, addr, prm.obj)
+		finished = putDone || exists
 		return finished
 	})
 
@@ -77,8 +78,11 @@ func (e *StorageEngine) put(prm PutPrm) (PutRes, error) {
 	return PutRes{}, err
 }
 
-func (e *StorageEngine) putToShard(sh *shard.Shard, ind int, pool util.WorkerPool, addr oid.Address, obj *objectSDK.Object) bool {
-	var finished bool
+// putToShard puts object to sh.
+// First return value is true iff put has been successfully done.
+// Second return value is true iff object already exists.
+func (e *StorageEngine) putToShard(sh *shard.Shard, ind int, pool util.WorkerPool, addr oid.Address, obj *objectSDK.Object) (bool, bool) {
+	var putSuccess, alreadyExists bool
 
 	exitCh := make(chan struct{})
 
@@ -93,13 +97,14 @@ func (e *StorageEngine) putToShard(sh *shard.Shard, ind int, pool util.WorkerPoo
 			if shard.IsErrObjectExpired(err) {
 				// object is already found but
 				// expired => do nothing with it
-				finished = true
+				alreadyExists = true
 			}
 
 			return // this is not ErrAlreadyRemoved error so we can go to the next shard
 		}
 
-		if exists.Exists() {
+		alreadyExists = exists.Exists()
+		if alreadyExists {
 			if ind != 0 {
 				var toMoveItPrm shard.ToMoveItPrm
 				toMoveItPrm.SetAddress(addr)
@@ -113,8 +118,6 @@ func (e *StorageEngine) putToShard(sh *shard.Shard, ind int, pool util.WorkerPoo
 				}
 			}
 
-			finished = true
-
 			return
 		}
 
@@ -130,14 +133,14 @@ func (e *StorageEngine) putToShard(sh *shard.Shard, ind int, pool util.WorkerPoo
 			return
 		}
 
-		finished = true
+		putSuccess = true
 	}); err != nil {
 		close(exitCh)
 	}
 
 	<-exitCh
 
-	return finished
+	return putSuccess, alreadyExists
 }
 
 // Put writes provided object to local storage.