Introduce kubectl-convert plugin

cmd/kubectl-convert/OWNERS

@@ -0,0 +1,9 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+approvers:
+- sig-cli-maintainers
+reviewers:
+- sig-cli
+labels:
+- area/kubectl
+- sig/cli

cmd/kubectl-convert/kubectl-convert.go

@@ -0,0 +1,57 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+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 main
+
+import (
+	goflag "flag"
+	"os"
+
+	"github.com/spf13/pflag"
+
+	"k8s.io/cli-runtime/pkg/genericclioptions"
+	cliflag "k8s.io/component-base/cli/flag"
+	cmdutil "k8s.io/kubectl/pkg/cmd/util"
+	"k8s.io/kubectl/pkg/util/logs"
+	"k8s.io/kubernetes/pkg/kubectl/cmd/convert"
+)
+
+func main() {
+	flags := pflag.NewFlagSet("kubectl-convert", pflag.ExitOnError)
+	pflag.CommandLine = flags
+
+	kubeConfigFlags := genericclioptions.NewConfigFlags(true).WithDeprecatedPasswordFlag()
+	kubeConfigFlags.AddFlags(flags)
+	matchVersionKubeConfigFlags := cmdutil.NewMatchVersionFlags(kubeConfigFlags)
+
+	f := cmdutil.NewFactory(matchVersionKubeConfigFlags)
+
+	// TODO: once we switch everything over to Cobra commands, we can go back to calling
+	// cliflag.InitFlags() (by removing its pflag.Parse() call). For now, we have to set the
+	// normalize func and add the go flag set by hand.
+	pflag.CommandLine.SetNormalizeFunc(cliflag.WordSepNormalizeFunc)
+	pflag.CommandLine.AddGoFlagSet(goflag.CommandLine)
+	// cliflag.InitFlags()
+	logs.InitLogs()
+	defer logs.FlushLogs()
+
+	cmd := convert.NewCmdConvert(f, genericclioptions.IOStreams{In: os.Stdin, Out: os.Stdout, ErrOut: os.Stderr})
+	matchVersionKubeConfigFlags.AddFlags(cmd.PersistentFlags())
+	if err := cmd.Execute(); err != nil {
+		os.Exit(1)
+	}
+
+}

pkg/kubectl/cmd/convert/convert.go

@@ -137,14 +137,6 @@ func (o *ConvertOptions) Complete(f cmdutil.Factory, cmd *cobra.Command) (err er
 
 // RunConvert implements the generic Convert command
 func (o *ConvertOptions) RunConvert() error {
-
-	// Convert must be removed from kubectl, since kubectl can not depend on
-	// Kubernetes "internal" dependencies. These "internal" dependencies can
-	// not be removed from convert. Another way to convert a resource is to
-	// "kubectl apply" it to the cluster, then "kubectl get" at the desired version.
-	// Another possible solution is to make convert a plugin.
-	fmt.Fprintf(o.ErrOut, "kubectl convert is DEPRECATED and will be removed in a future version.\nIn order to convert, kubectl apply the object to the cluster, then kubectl get at the desired version.\n")
-
 	b := o.builder().
 		WithScheme(scheme.Scheme).
 		LocalParam(o.local)

test/cmd/template-output.sh

@@ -63,7 +63,7 @@ run_template_output_tests() {
   kube::test::if_has_string "${output_message}" 'redis-slave:'
 
   # check that convert command supports --template output
-  output_message=$(kubectl "${kube_flags[@]:?}" convert -f hack/testdata/deployment-revision1.yaml --output-version=apps/v1beta1 --template="{{ .metadata.name }}:")
+  output_message=$(kubectl convert "${kube_flags[@]:?}" -f hack/testdata/deployment-revision1.yaml --output-version=apps/v1beta1 --template="{{ .metadata.name }}:")
   kube::test::if_has_string "${output_message}" 'nginx:'
 
   # check that run command supports --template output