send plugin error stack traces over gRPC and log error locations

Signed-off-by: Steve Kriss <krisss@vmware.com>

pkg/plugin/framework/client_errors.go

@@ -0,0 +1,79 @@
+/*
+Copyright 2019 the Velero contributors.
+
+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
+
+    http://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 framework
+
+import (
+	"google.golang.org/grpc/status"
+
+	proto "github.com/heptio/velero/pkg/plugin/generated"
+)
+
+// fromGRPCError takes a gRPC status error, extracts a stack trace
+// from the details if it exists, and returns an error that can
+// provide information about where it was created.
+//
+// This function should be used in the internal plugin client code to convert
+// all errors returned from the plugin server before they're passed back to
+// the rest of the Velero codebase. This will enable them to display location
+// information when they're logged.
+func fromGRPCError(err error) error {
+	statusErr, ok := status.FromError(err)
+	if !ok {
+		return statusErr.Err()
+	}
+
+	for _, detail := range statusErr.Details() {
+		switch t := detail.(type) {
+		case *proto.Stack:
+			return &protoStackError{
+				error: err,
+				stack: t,
+			}
+		}
+	}
+
+	return err
+}
+
+type protoStackError struct {
+	error
+	stack *proto.Stack
+}
+
+func (e *protoStackError) File() string {
+	if e.stack == nil || len(e.stack.Frames) < 1 {
+		return ""
+	}
+
+	return e.stack.Frames[0].File
+}
+
+func (e *protoStackError) Line() int32 {
+	if e.stack == nil || len(e.stack.Frames) < 1 {
+		return 0
+	}
+
+	return e.stack.Frames[0].Line
+}
+
+func (e *protoStackError) Function() string {
+	if e.stack == nil || len(e.stack.Frames) < 1 {
+		return ""
+	}
+
+	return e.stack.Frames[0].Function
+}