shard: improve logging on object putting

Masked error-less shard skipping makes debugging awful, relates #2860.

Signed-off-by: Pavel Karpy <[email protected]>

pkg/local_object_storage/engine/evacuate.go

@@ -148,6 +148,7 @@ mainLoop:
 				}
 
 				hrw.Sort(shards, addrHash)
+
 				for j := range shards {
 					if _, ok := shardMap[shards[j].ID().String()]; ok {
 						continue
@@ -164,6 +165,8 @@ mainLoop:
 						}
 						continue loop
 					}
+
+					e.log.Debug("could not put to shard, trying another", zap.String("shard", shards[j].ID().String()))
 				}
 
 				if prm.handler == nil {

pkg/local_object_storage/engine/put.go

@@ -114,6 +114,11 @@ func (e *StorageEngine) putToShard(sh hashedShard, ind int, pool util.WorkerPool
 
 		exists, err := sh.Exists(existPrm)
 		if err != nil {
+			e.log.Warn("object put: check object existence",
+				zap.Stringer("addr", addr),
+				zap.Stringer("shard", sh.ID()),
+				zap.Error(err))
+
 			if shard.IsErrObjectExpired(err) {
 				// object is already found but
 				// expired => do nothing with it
@@ -138,6 +143,10 @@ func (e *StorageEngine) putToShard(sh hashedShard, ind int, pool util.WorkerPool
 				}
 			}
 
+			e.log.Debug("object put: object already exist",
+				zap.Stringer("shard", sh.ID()),
+				zap.Stringer("addr", addr))
+
 			return
 		}
 
@@ -163,6 +172,7 @@ func (e *StorageEngine) putToShard(sh hashedShard, ind int, pool util.WorkerPool
 
 		putSuccess = true
 	}); err != nil {
+		e.log.Warn("object put: pool task submitting", zap.Error(err))
 		close(exitCh)
 	}