Merge pull request #65542 from juanvallejo/jvallejo/cleanup-convert-cmd

Automatic merge from submit-queue (batch tested with PRs 66333, 65542). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

cleanup / simplify convert command

Cleans up unnecessary pieces from the convert command, simplifyiing
command logic, and readability.

**Release note**:
```release-note
NONE
```

cc @soltysh @deads2k

pkg/kubectl/cmd/convert.go

@@ -19,7 +19,9 @@ package cmd
 import (
 	"fmt"
 
-	"k8s.io/apimachinery/pkg/api/meta"
+	"github.com/golang/glog"
+	"github.com/spf13/cobra"
+
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	scheme "k8s.io/kubernetes/pkg/api/legacyscheme"
@@ -30,9 +32,7 @@ import (
 	"k8s.io/kubernetes/pkg/kubectl/genericclioptions/printers"
 	"k8s.io/kubernetes/pkg/kubectl/genericclioptions/resource"
 	"k8s.io/kubernetes/pkg/kubectl/util/i18n"
-
+	"k8s.io/kubernetes/pkg/kubectl/validation"
-	"github.com/golang/glog"
-	"github.com/spf13/cobra"
 )
 
 var (
@@ -59,46 +59,20 @@ var (
 		kubectl convert -f . | kubectl create -f -`))
 )
 
-// NewCmdConvert creates a command object for the generic "convert" action, which
-// translates the config file into a given version.
-func NewCmdConvert(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
-	options := NewConvertOptions(ioStreams)
-
-	cmd := &cobra.Command{
-		Use: "convert -f FILENAME",
-		DisableFlagsInUseLine: true,
-		Short:   i18n.T("Convert config files between different API versions"),
-		Long:    convert_long,
-		Example: convert_example,
-		Run: func(cmd *cobra.Command, args []string) {
-			cmdutil.CheckErr(options.Complete(f, cmd))
-			cmdutil.CheckErr(options.RunConvert())
-		},
-	}
-
-	options.PrintFlags.AddFlags(cmd)
-
-	usage := "to need to get converted."
-	cmdutil.AddFilenameOptionFlags(cmd, &options.FilenameOptions, usage)
-	cmd.MarkFlagRequired("filename")
-	cmdutil.AddValidateFlags(cmd)
-	cmd.Flags().BoolVar(&options.local, "local", options.local, "If true, convert will NOT try to contact api-server but run locally.")
-	cmd.Flags().String("output-version", "", i18n.T("Output the formatted object with the given group version (for ex: 'extensions/v1beta1').)"))
-	return cmd
-}
-
 // ConvertOptions have the data required to perform the convert operation
 type ConvertOptions struct {
 	PrintFlags *genericclioptions.PrintFlags
-	PrintObj   printers.ResourcePrinterFunc
+	Printer    printers.ResourcePrinter
+
+	OutputVersion string
+	Namespace     string
+
+	builder   func() *resource.Builder
+	local     bool
+	validator func() (validation.Schema, error)
 
 	resource.FilenameOptions
-
-	builder *resource.Builder
-	local   bool
-
 	genericclioptions.IOStreams
-	specifiedOutputVersion schema.GroupVersion
 }
 
 func NewConvertOptions(ioStreams genericclioptions.IOStreams) *ConvertOptions {
@@ -109,57 +83,73 @@ func NewConvertOptions(ioStreams genericclioptions.IOStreams) *ConvertOptions {
 	}
 }
 
-// outputVersion returns the preferred output version for generic content (JSON, YAML, or templates)
+// NewCmdConvert creates a command object for the generic "convert" action, which
-// defaultVersion is never mutated.  Nil simply allows clean passing in common usage from client.Config
+// translates the config file into a given version.
-func outputVersion(cmd *cobra.Command) (schema.GroupVersion, error) {
+func NewCmdConvert(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
-	outputVersionString := cmdutil.GetFlagString(cmd, "output-version")
+	o := NewConvertOptions(ioStreams)
-	if len(outputVersionString) == 0 {
+
-		return schema.GroupVersion{}, nil
+	cmd := &cobra.Command{
+		Use: "convert -f FILENAME",
+		DisableFlagsInUseLine: true,
+		Short:   i18n.T("Convert config files between different API versions"),
+		Long:    convert_long,
+		Example: convert_example,
+		Run: func(cmd *cobra.Command, args []string) {
+			cmdutil.CheckErr(o.Complete(f, cmd))
+			cmdutil.CheckErr(o.RunConvert())
+		},
 	}
 
-	return schema.ParseGroupVersion(outputVersionString)
+	cmd.Flags().BoolVar(&o.local, "local", o.local, "If true, convert will NOT try to contact api-server but run locally.")
+	cmd.Flags().StringVar(&o.OutputVersion, "output-version", o.OutputVersion, i18n.T("Output the formatted object with the given group version (for ex: 'extensions/v1beta1').)"))
+	o.PrintFlags.AddFlags(cmd)
+
+	cmdutil.AddValidateFlags(cmd)
+	cmdutil.AddFilenameOptionFlags(cmd, &o.FilenameOptions, "to need to get converted.")
+	cmd.MarkFlagRequired("filename")
+	return cmd
 }
 
 // Complete collects information required to run Convert command from command line.
 func (o *ConvertOptions) Complete(f cmdutil.Factory, cmd *cobra.Command) (err error) {
-	o.specifiedOutputVersion, err = outputVersion(cmd)
+	o.builder = f.NewBuilder
+
+	o.Namespace, _, err = f.ToRawKubeConfigLoader().Namespace()
 	if err != nil {
 		return err
 	}
 
-	// build the builder
+	o.validator = func() (validation.Schema, error) {
-	o.builder = f.NewBuilder().
+		return f.Validator(cmdutil.GetFlagBool(cmd, "validate"))
-		WithScheme(scheme.Scheme).
-		LocalParam(o.local)
-	if !o.local {
-		schema, err := f.Validator(cmdutil.GetFlagBool(cmd, "validate"))
-		if err != nil {
-			return err
-		}
-		o.builder.Schema(schema)
 	}
 
-	cmdNamespace, _, err := f.ToRawKubeConfigLoader().Namespace()
-	if err != nil {
-		return err
-	}
-	o.builder.NamespaceParam(cmdNamespace).
-		ContinueOnError().
-		FilenameParam(false, &o.FilenameOptions).
-		Flatten()
-
 	// build the printer
-	printer, err := o.PrintFlags.ToPrinter()
+	o.Printer, err = o.PrintFlags.ToPrinter()
 	if err != nil {
 		return err
 	}
-	o.PrintObj = printer.PrintObj
 	return nil
 }
 
 // RunConvert implements the generic Convert command
 func (o *ConvertOptions) RunConvert() error {
-	r := o.builder.Do()
+	b := o.builder().
+		WithScheme(scheme.Scheme).
+		LocalParam(o.local)
+	if !o.local {
+		schema, err := o.validator()
+		if err != nil {
+			return err
+		}
+		b.Schema(schema)
+	}
+
+	r := b.NamespaceParam(o.Namespace).
+		ContinueOnError().
+		FilenameParam(false, &o.FilenameOptions).
+		Flatten().
+		Do()
+
 	err := r.Err()
 	if err != nil {
 		return err
@@ -175,40 +165,20 @@ func (o *ConvertOptions) RunConvert() error {
 		return fmt.Errorf("no objects passed to convert")
 	}
 
-	objects, err := asVersionedObject(infos, !singleItemImplied, o.specifiedOutputVersion, cmdutil.InternalVersionJSONEncoder())
+	var specifiedOutputVersion schema.GroupVersion
+	if len(o.OutputVersion) > 0 {
+		specifiedOutputVersion, err = schema.ParseGroupVersion(o.OutputVersion)
+		if err != nil {
+			return err
+		}
+	}
+
+	objects, err := asVersionedObject(infos, !singleItemImplied, specifiedOutputVersion, cmdutil.InternalVersionJSONEncoder())
 	if err != nil {
 		return err
 	}
 
-	if meta.IsListType(objects) {
+	return o.Printer.PrintObj(objects, o.Out)
-		listContent, err := meta.ExtractList(objects)
-		if err != nil {
-			return err
-		}
-		obj, err := objectListToVersionedObject(listContent, o.specifiedOutputVersion)
-		if err != nil {
-			return err
-		}
-		return o.PrintObj(obj, o.Out)
-	}
-
-	return o.PrintObj(objects, o.Out)
-}
-
-// objectListToVersionedObject receives a list of api objects and a group version
-// and squashes the list's items into a single versioned runtime.Object.
-func objectListToVersionedObject(objects []runtime.Object, specifiedOutputVersion schema.GroupVersion) (runtime.Object, error) {
-	objectList := &api.List{Items: objects}
-	targetVersions := []schema.GroupVersion{}
-	if !specifiedOutputVersion.Empty() {
-		targetVersions = append(targetVersions, specifiedOutputVersion)
-	}
-	targetVersions = append(targetVersions, schema.GroupVersion{Group: "", Version: "v1"})
-	converted, err := tryConvert(scheme.Scheme, objectList, targetVersions...)
-	if err != nil {
-		return nil, err
-	}
-	return converted, nil
 }
 
 // asVersionedObject converts a list of infos into a single object - either a List containing