Ensure shim propagates errors over gRPC correctly

This change wraps containerd's errdefs.ToGRPC function with one that
understands Go 1.13-style error wrapping style, which is used
pervasively throughout the shim. With this change, errors that have been
marked with, e.g., `errdefs.ErrNotFound`, will be correctly propagated
back to the containerd server.

1 files changed, 56 insertions, 0 deletions

diff --git a/pkg/shim/errors.go b/pkg/shim/errors.go
new file mode 100644
index 000000000..311a4b427
--- /dev/null
+++ b/pkg/shim/errors.go
@@ -0,0 +1,56 @@
+// Copyright 2021 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package shim
+
+import (
+	"context"
+	"errors"
+
+	"github.com/containerd/containerd/errdefs"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// errToGRPC wraps containerd's ToGRPC error mapper which depends on
+// github.com/pkg/errors to work correctly. Once we upgrade to containerd v1.4,
+// this function can go away and we can use errdefs.ToGRPC directly instead.
+//
+// TODO(gvisor.dev/issue/6232): Remove after upgrading to containerd v1.4
+func errToGRPC(err error) error {
+	if _, ok := status.FromError(err); ok {
+		return err
+	}
+
+	switch {
+	case errors.Is(err, errdefs.ErrInvalidArgument):
+		return status.Errorf(codes.InvalidArgument, err.Error())
+	case errors.Is(err, errdefs.ErrNotFound):
+		return status.Errorf(codes.NotFound, err.Error())
+	case errors.Is(err, errdefs.ErrAlreadyExists):
+		return status.Errorf(codes.AlreadyExists, err.Error())
+	case errors.Is(err, errdefs.ErrFailedPrecondition):
+		return status.Errorf(codes.FailedPrecondition, err.Error())
+	case errors.Is(err, errdefs.ErrUnavailable):
+		return status.Errorf(codes.Unavailable, err.Error())
+	case errors.Is(err, errdefs.ErrNotImplemented):
+		return status.Errorf(codes.Unimplemented, err.Error())
+	case errors.Is(err, context.Canceled):
+		return status.Errorf(codes.Canceled, err.Error())
+	case errors.Is(err, context.DeadlineExceeded):
+		return status.Errorf(codes.DeadlineExceeded, err.Error())
+	}
+
+	return errdefs.ToGRPC(err)
+}