fix -o panic oc rollback

pkg/oc/cli/cmd/rollback.go

@@ -56,7 +56,10 @@ var (
 	  %[1]s rollback frontend-2
 
 	  # Perform the rollback manually by piping the JSON of the new config back to %[1]s
-	  %[1]s rollback frontend -o json | %[1]s replace dc/frontend -f -`)
+	  %[1]s rollback frontend -o json | %[1]s replace dc/frontend -f -
+
+	  # Print the updated deployment configuration in JSON format instead of performing the rollback
+	  %[1]s rollback frontend -o json`)
 )
 
 // NewCmdRollback creates a CLI rollback command.
@@ -86,9 +89,9 @@ func NewCmdRollback(fullName string, f *clientcmd.Factory, out io.Writer) *cobra
 	cmd.Flags().BoolVar(&opts.IncludeStrategy, "change-strategy", false, "If true, include the previous deployment's strategy in the rollback")
 	cmd.Flags().BoolVar(&opts.IncludeScalingSettings, "change-scaling-settings", false, "If true, include the previous deployment's replicationController replica count and selector in the rollback")
 	cmd.Flags().BoolVarP(&opts.DryRun, "dry-run", "d", false, "Instead of performing the rollback, describe what the rollback will look like in human-readable form")
-	cmd.Flags().StringVarP(&opts.Format, "output", "o", "", "Instead of performing the rollback, print the updated deployment configuration in the specified format (json|yaml|name|template|templatefile)")
-	cmd.Flags().StringVarP(&opts.Template, "template", "t", "", "Template string or path to template file to use when -o=template or -o=templatefile.")
 	cmd.MarkFlagFilename("template")
+
+	kcmdutil.AddPrinterFlags(cmd)
 	cmd.Flags().Int64Var(&opts.DesiredVersion, "to-version", 0, "A config version to rollback to. Specifying version 0 is the same as omitting a version (the version will be auto-detected). This option is ignored when specifying a deployment.")
 
 	return cmd
@@ -151,6 +154,8 @@ func (o *RollbackOptions) Complete(f *clientcmd.Factory, cmd *cobra.Command, arg
 
 	o.out = out
 
+	o.Format = kcmdutil.GetFlagString(cmd, "output")
+
 	if len(o.Format) > 0 {
 		o.printer, err = f.PrinterForOptions(kcmdutil.ExtractCmdPrintOptions(cmd, false))
 		if err != nil {

pkg/oc/cli/cmd/rollout/latest.go

@@ -14,6 +14,7 @@ import (
 	"k8s.io/kubernetes/pkg/kubectl/cmd/templates"
 	kcmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 	"k8s.io/kubernetes/pkg/kubectl/resource"
+	kprinters "k8s.io/kubernetes/pkg/printers"
 
 	appsapi "github.com/openshift/origin/pkg/apps/apis/apps"
 	appsclientinternal "github.com/openshift/origin/pkg/apps/generated/internalclientset/typed/apps/internalversion"
@@ -32,8 +33,11 @@ var (
 		your image change triggers.`)
 
 	rolloutLatestExample = templates.Examples(`
-		# Start a new rollout based on the latest images defined in the image change triggers.
-  	%[1]s rollout latest dc/nginx`)
+	# Start a new rollout based on the latest images defined in the image change triggers.
+	%[1]s rollout latest dc/nginx
+
+	# Print the deployment config that would be rolled out in JSON format, without performing the rollout.
+	%[1]s rollout latest dc/nginx -o json`)
 )
 
 // RolloutLatestOptions holds all the options for the `rollout latest` command.
@@ -50,6 +54,8 @@ type RolloutLatestOptions struct {
 	appsClient      appsclientinternal.DeploymentConfigsGetter
 	kc              kclientset.Interface
 	baseCommandName string
+
+	printer kprinters.ResourcePrinter
 }
 
 // NewCmdRolloutLatest implements the oc rollout latest subcommand.
@@ -122,6 +128,11 @@ func (o *RolloutLatestOptions) Complete(f *clientcmd.Factory, cmd *cobra.Command
 	o.output = kcmdutil.GetFlagString(cmd, "output")
 	o.again = kcmdutil.GetFlagBool(cmd, "again")
 
+	o.printer, err = f.PrinterForOptions(kcmdutil.ExtractCmdPrintOptions(cmd, false))
+	if err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -187,6 +198,10 @@ func (o RolloutLatestOptions) RunRolloutLatest() error {
 		return nil
 	}
 
+	if len(o.output) > 0 {
+		return o.printer.PrintObj(dc, o.out)
+	}
+
 	kcmdutil.PrintSuccess(o.mapper, o.output == "name", o.out, info.Mapping.Resource, info.Name, o.DryRun, "rolled out")
 	return nil
 }