[#959] node: Set mode to shard's components when open it

Avoid opening database for `metabase` and `cache` in `Degraded` mode.

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

pkg/local_object_storage/metabase/mode_test.go

@@ -0,0 +1,37 @@
+package meta
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/shard/mode"
+	"github.com/stretchr/testify/require"
+)
+
+type epochStateTest struct{}
+
+func (s epochStateTest) CurrentEpoch() uint64 {
+	return 0
+}
+
+func Test_Mode(t *testing.T) {
+	t.Parallel()
+	bdb := New([]Option{
+		WithPath(filepath.Join(t.TempDir(), "metabase")),
+		WithPermissions(0o600),
+		WithEpochState(epochStateTest{}),
+	}...)
+
+	require.NoError(t, bdb.Open(context.Background(), mode.DegradedReadOnly))
+	require.Nil(t, bdb.boltDB)
+	require.NoError(t, bdb.Init())
+	require.Nil(t, bdb.boltDB)
+	require.NoError(t, bdb.Close())
+
+	require.NoError(t, bdb.Open(context.Background(), mode.Degraded))
+	require.Nil(t, bdb.boltDB)
+	require.NoError(t, bdb.Init())
+	require.Nil(t, bdb.boltDB)
+	require.NoError(t, bdb.Close())
+}