Merge pull request #15499 from JanetKuo/kubectl-get-funky

Format flattened output in kubectl

pkg/kubectl/cmd/get.go

@@ -21,6 +21,7 @@ import (
 	"io"
 
 	"github.com/spf13/cobra"
+	"k8s.io/kubernetes/pkg/api/meta"
 	"k8s.io/kubernetes/pkg/kubectl"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 	"k8s.io/kubernetes/pkg/kubectl/resource"
@@ -220,13 +221,23 @@ func RunGet(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []string
 	}
 
 	// use the default printer for each object
+	printer = nil
+	var lastMapping *meta.RESTMapping
+	w := kubectl.GetNewTabWriter(out)
+	defer w.Flush()
 	return b.Flatten().Do().Visit(func(r *resource.Info, err error) error {
 		if err != nil {
 			return err
 		}
-		printer, err := f.PrinterForMapping(cmd, r.Mapping, allNamespaces)
-		if err != nil {
-			return err
+		if printer == nil || lastMapping == nil || r.Mapping == nil || r.Mapping.Resource != lastMapping.Resource {
+			printer, err = f.PrinterForMapping(cmd, r.Mapping, allNamespaces)
+			if err != nil {
+				return err
+			}
+			lastMapping = r.Mapping
+		}
+		if _, found := printer.(*kubectl.HumanReadablePrinter); found {
+			return printer.PrintObj(r.Object, w)
 		}
 		return printer.PrintObj(r.Object, out)
 	})

pkg/kubectl/resource_printer.go

@@ -1475,10 +1475,19 @@ func formatWideHeaders(wide bool, t reflect.Type) []string {
 	return nil
 }
 
+// GetNewTabWriter returns a tabwriter that translates tabbed columns in input into properly aligned text.
+func GetNewTabWriter(output io.Writer) *tabwriter.Writer {
+	return tabwriter.NewWriter(output, tabwriterMinWidth, tabwriterWidth, tabwriterPadding, tabwriterPadChar, tabwriterFlags)
+}
+
 // PrintObj prints the obj in a human-friendly format according to the type of the obj.
 func (h *HumanReadablePrinter) PrintObj(obj runtime.Object, output io.Writer) error {
-	w := tabwriter.NewWriter(output, tabwriterMinWidth, tabwriterWidth, tabwriterPadding, tabwriterPadChar, tabwriterFlags)
-	defer w.Flush()
+	// if output is a tabwriter (when it's called by kubectl get), we use it; create a new tabwriter otherwise
+	w, found := output.(*tabwriter.Writer)
+	if !found {
+		w = GetNewTabWriter(output)
+		defer w.Flush()
+	}
 	t := reflect.TypeOf(obj)
 	if handler := h.handlerMap[t]; handler != nil {
 		if !h.noHeaders && t != h.lastType {