when -format-error option is used, format service reflection errors, …

…too (#188)

cmd/grpcurl/grpcurl.go

@@ -695,7 +695,11 @@ func main() {
 
 		err = grpcurl.InvokeRPC(ctx, descSource, cc, symbol, append(addlHeaders, rpcHeaders...), h, rf.Next)
 		if err != nil {
-			fail(err, "Error invoking method %q", symbol)
+			if errStatus, ok := status.FromError(err); ok && *formatError {
+				h.Status = errStatus
+			} else {
+				fail(err, "Error invoking method %q", symbol)
+			}
 		}
 		reqSuffix := ""
 		respSuffix := ""

invoke.go

@@ -93,9 +93,17 @@ func InvokeRPC(ctx context.Context, source DescriptorSource, ch grpcdynamic.Chan
 	if svc == "" || mth == "" {
 		return fmt.Errorf("given method name %q is not in expected format: 'service/method' or 'service.method'", methodName)
 	}
+
 	dsc, err := source.FindSymbol(svc)
 	if err != nil {
-		if isNotFoundError(err) {
+		// return a gRPC status error if hasStatus is true
+		errStatus, hasStatus := status.FromError(err)
+		switch {
+		case hasStatus && isNotFoundError(err):
+			return status.Errorf(errStatus.Code(), "target server does not expose service %q: %s", svc, errStatus.Message())
+		case hasStatus:
+			return status.Errorf(errStatus.Code(), "failed to query for service descriptor %q: %s", svc, errStatus.Message())
+		case isNotFoundError(err):
 			return fmt.Errorf("target server does not expose service %q", svc)
 		}
 		return fmt.Errorf("failed to query for service descriptor %q: %v", svc, err)