[#266] pilorama: Allow to get current tree height

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/engine/tree.go

@@ -311,6 +311,22 @@ func (e *StorageEngine) TreeExists(ctx context.Context, cid cidSDK.ID, treeID st
 	return err == nil, err
 }
 
+func (e *StorageEngine) TreeHeight(ctx context.Context, cid cidSDK.ID, treeID string) (uint64, error) {
+	ctx, span := tracing.StartSpanFromContext(ctx, "StorageEngine.TreeHeight",
+		trace.WithAttributes(
+			attribute.String("container_id", cid.EncodeToString()),
+			attribute.String("tree_id", treeID),
+		),
+	)
+	defer span.End()
+
+	index, lst, err := e.getTreeShard(ctx, cid, treeID)
+	if err != nil {
+		return 0, nil
+	}
+	return lst[index].TreeHeight(ctx, cid, treeID)
+}
+
 // TreeUpdateLastSyncHeight implements the pilorama.Forest interface.
 func (e *StorageEngine) TreeUpdateLastSyncHeight(ctx context.Context, cid cidSDK.ID, treeID string, height uint64) error {
 	ctx, span := tracing.StartSpanFromContext(ctx, "StorageEngine.TreeUpdateLastSyncHeight",

pkg/local_object_storage/pilorama/boltdb.go

@@ -188,6 +188,40 @@ func (t *boltForest) TreeMove(ctx context.Context, d CIDDescriptor, treeID strin
 	})
 }
 
+func (t *boltForest) TreeHeight(ctx context.Context, cid cidSDK.ID, treeID string) (uint64, error) {
+	_, span := tracing.StartSpanFromContext(ctx, "boltForest.TreeHeight",
+		trace.WithAttributes(
+			attribute.String("container_id", cid.EncodeToString()),
+			attribute.String("tree_id", treeID),
+		),
+	)
+	defer span.End()
+
+	t.modeMtx.RLock()
+	defer t.modeMtx.RUnlock()
+
+	if t.mode.NoMetabase() {
+		return 0, ErrDegradedMode
+	}
+
+	var height uint64
+	var retErr error
+	err := t.db.View(func(tx *bbolt.Tx) error {
+		treeRoot := tx.Bucket(bucketName(cid, treeID))
+		if treeRoot != nil {
+			k, _ := treeRoot.Bucket(logBucket).Cursor().Last()
+			height = binary.BigEndian.Uint64(k)
+		} else {
+			retErr = ErrTreeNotFound
+		}
+		return nil
+	})
+	if err == nil {
+		err = retErr
+	}
+	return height, err
+}
+
 // TreeExists implements the Forest interface.
 func (t *boltForest) TreeExists(ctx context.Context, cid cidSDK.ID, treeID string) (bool, error) {
 	_, span := tracing.StartSpanFromContext(ctx, "boltForest.TreeExists",

pkg/local_object_storage/pilorama/forest.go

@@ -214,6 +214,15 @@ func (f *memoryForest) TreeList(_ context.Context, cid cid.ID) ([]string, error)
 	return res, nil
 }
 
+func (f *memoryForest) TreeHeight(_ context.Context, cid cid.ID, treeID string) (uint64, error) {
+	fullID := cid.EncodeToString() + "/" + treeID
+	tree, ok := f.treeMap[fullID]
+	if !ok {
+		return 0, ErrTreeNotFound
+	}
+	return tree.operations[len(tree.operations)-1].Time, nil
+}
+
 // TreeExists implements the pilorama.Forest interface.
 func (f *memoryForest) TreeExists(_ context.Context, cid cid.ID, treeID string) (bool, error) {
 	fullID := cid.EncodeToString() + "/" + treeID

pkg/local_object_storage/pilorama/forest_test.go

@@ -604,10 +604,19 @@ func testForestTreeExists(t *testing.T, constructor func(t testing.TB, opts ...O
 		checkExists(t, false, cid, treeID)
 	})
 
-	require.NoError(t, s.TreeApply(context.Background(), cid, treeID, &Move{Parent: 0, Child: 1}, false))
+	require.NoError(t, s.TreeApply(context.Background(), cid, treeID, &Move{Meta: Meta{Time: 11}, Parent: 0, Child: 1}, false))
 	checkExists(t, true, cid, treeID)
+
+	height, err := s.TreeHeight(context.Background(), cid, treeID)
+	require.NoError(t, err)
+	require.EqualValues(t, 11, height)
+
 	checkExists(t, false, cidtest.ID(), treeID) // different CID, same tree
-	checkExists(t, false, cid, "another tree")  // same CID, different tree
+
+	_, err = s.TreeHeight(context.Background(), cidtest.ID(), treeID)
+	require.ErrorIs(t, err, ErrTreeNotFound)
+
+	checkExists(t, false, cid, "another tree") // same CID, different tree
 
 	t.Run("can be removed", func(t *testing.T) {
 		require.NoError(t, s.TreeDrop(context.Background(), cid, treeID))

pkg/local_object_storage/pilorama/interface.go

@@ -50,6 +50,8 @@ type Forest interface {
 	TreeUpdateLastSyncHeight(ctx context.Context, cid cidSDK.ID, treeID string, height uint64) error
 	// TreeLastSyncHeight returns last log height synchronized with _all_ container nodes.
 	TreeLastSyncHeight(ctx context.Context, cid cidSDK.ID, treeID string) (uint64, error)
+	// TreeHeight returns current tree height.
+	TreeHeight(ctx context.Context, cid cidSDK.ID, treeID string) (uint64, error)
 }
 
 type ForestStorage interface {

pkg/local_object_storage/shard/tree.go

@@ -255,6 +255,22 @@ func (s *Shard) TreeList(ctx context.Context, cid cidSDK.ID) ([]string, error) {
 	return s.pilorama.TreeList(ctx, cid)
 }
 
+func (s *Shard) TreeHeight(ctx context.Context, cid cidSDK.ID, treeID string) (uint64, error) {
+	ctx, span := tracing.StartSpanFromContext(ctx, "Shard.TreeHeight",
+		trace.WithAttributes(
+			attribute.String("shard_id", s.ID().String()),
+			attribute.String("container_id", cid.EncodeToString()),
+			attribute.String("tree_id", treeID),
+		),
+	)
+	defer span.End()
+
+	if s.pilorama == nil {
+		return 0, ErrPiloramaDisabled
+	}
+	return s.pilorama.TreeHeight(ctx, cid, treeID)
+}
+
 // TreeExists implements the pilorama.Forest interface.
 func (s *Shard) TreeExists(ctx context.Context, cid cidSDK.ID, treeID string) (bool, error) {
 	ctx, span := tracing.StartSpanFromContext(ctx, "Shard.TreeExists",