[#1630] neofs-node: Remove trees on container removal event

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

cmd/neofs-node/tree.go

@@ -2,9 +2,14 @@ package main
 
 import (
 	"context"
+	"errors"
 
 	treeconfig "github.com/nspcc-dev/neofs-node/cmd/neofs-node/config/tree"
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/pilorama"
+	"github.com/nspcc-dev/neofs-node/pkg/morph/event"
+	containerEvent "github.com/nspcc-dev/neofs-node/pkg/morph/event/container"
 	"github.com/nspcc-dev/neofs-node/pkg/services/tree"
+	"go.uber.org/zap"
 )
 
 func initTreeService(c *cfg) {
@@ -32,5 +37,18 @@ func initTreeService(c *cfg) {
 		c.treeService.Start(ctx)
 	}))
 
+	subscribeToContainerRemoval(c, func(e event.Event) {
+		ev := e.(containerEvent.DeleteSuccess)
+
+		// This is executed asynchronously, so we don't care about the operation taking some time.
+		err := c.treeService.DropTree(context.Background(), ev.ID, "")
+		if err != nil && !errors.Is(err, pilorama.ErrTreeNotFound) {
+			// Ignore pilorama.ErrTreeNotFound but other errors, including shard.ErrReadOnly, should be logged.
+			c.log.Error("container removal event received, but trees weren't removed",
+				zap.Stringer("cid", ev.ID),
+				zap.String("error", err.Error()))
+		}
+	})
+
 	c.onShutdown(c.treeService.Shutdown)
 }

pkg/services/tree/drop.go

@@ -0,0 +1,14 @@
+package tree
+
+import (
+	"context"
+
+	cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
+)
+
+// DropTree drops a tree from the database. If treeID is empty, all the trees are dropped.
+func (s *Service) DropTree(_ context.Context, cid cid.ID, treeID string) error {
+	// The only current use-case is a container removal, where all trees should be removed.
+	// Thus there is no need to replicate the operation on other node.
+	return s.forest.TreeDrop(cid, treeID)
+}