[#569] cli: Add control shards writecache seal command

It does the same as `control shards flush-writecache --seal`, but
has better name.

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

pkg/services/control/server/seal_writecache.go

@@ -0,0 +1,48 @@
+package control
+
+import (
+	"context"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/engine"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/control"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+func (s *Server) SealWriteCache(ctx context.Context, req *control.SealWriteCacheRequest) (*control.SealWriteCacheResponse, error) {
+	err := s.isValidRequest(req)
+	if err != nil {
+		return nil, status.Error(codes.PermissionDenied, err.Error())
+	}
+
+	prm := engine.SealWriteCachePrm{
+		ShardIDs:     s.getShardIDList(req.GetBody().GetShard_ID()),
+		IgnoreErrors: req.GetBody().GetIgnoreErrors(),
+	}
+
+	res, err := s.s.SealWriteCache(ctx, prm)
+	if err != nil {
+		return nil, status.Error(codes.Internal, err.Error())
+	}
+
+	resp := &control.SealWriteCacheResponse{Body: &control.SealWriteCacheResponse_Body{}}
+	for _, r := range res.ShardResults {
+		if r.Success {
+			resp.Body.Results = append(resp.GetBody().GetResults(), &control.SealWriteCacheResponse_Body_Status{
+				Shard_ID: *r.ShardID,
+				Success:  true,
+			})
+		} else {
+			resp.Body.Results = append(resp.GetBody().GetResults(), &control.SealWriteCacheResponse_Body_Status{
+				Shard_ID: *r.ShardID,
+				Error:    r.ErrorMsg,
+			})
+		}
+	}
+
+	err = SignMessage(s.key, resp)
+	if err != nil {
+		return nil, err
+	}
+	return resp, nil
+}