feat: use clientcmd instead of kubectl to minimize binary size

pkg/kubernetes/configuration.go

@@ -1,33 +1,27 @@
 package kubernetes
 
 import (
-	"bytes"
-	"k8s.io/cli-runtime/pkg/genericiooptions"
 	"k8s.io/client-go/tools/clientcmd"
-	"k8s.io/component-base/cli/flag"
-	"k8s.io/kubectl/pkg/cmd/config"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
+	"k8s.io/client-go/tools/clientcmd/api/latest"
 )
 
 func ConfigurationView() (string, error) {
-	outBuffer := &bytes.Buffer{}
+	// TODO: consider in cluster run mode (current approach only shows kubeconfig)
 	pathOptions := clientcmd.NewDefaultPathOptions()
-	ioStreams := genericiooptions.IOStreams{In: nil, Out: outBuffer, ErrOut: outBuffer}
-	o := &config.ViewOptions{
-		IOStreams:    ioStreams,
-		ConfigAccess: pathOptions,
-		PrintFlags:   defaultPrintFlags(),
-		Flatten:      true,
-		Minify:       true,
-		Merge:        flag.True,
-	}
-	printer, err := o.PrintFlags.ToPrinter()
+	cfg, err := pathOptions.GetStartingConfig()
 	if err != nil {
 		return "", err
 	}
-	o.PrintObject = printer.PrintObj
-	err = o.Run()
+	if err = clientcmdapi.MinifyConfig(cfg); err != nil {
+		return "", err
+	}
+	if err = clientcmdapi.FlattenConfig(cfg); err != nil {
+		return "", err
+	}
+	convertedObj, err := latest.Scheme.ConvertToVersion(cfg, latest.ExternalVersion)
 	if err != nil {
 		return "", err
 	}
-	return outBuffer.String(), nil
+	return marshal(convertedObj)
 }

pkg/kubernetes/kubernetes.go

@@ -1,11 +1,11 @@
 package kubernetes
 
 import (
-	"k8s.io/cli-runtime/pkg/genericclioptions"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/restmapper"
 	"k8s.io/client-go/tools/clientcmd"
-	"k8s.io/kubectl/pkg/scheme"
+	"sigs.k8s.io/yaml"
 )
 
 type Kubernetes struct {
@@ -21,10 +21,20 @@ func NewKubernetes() (*Kubernetes, error) {
 	return &Kubernetes{cfg: cfg}, nil
 }
 
-func defaultPrintFlags() *genericclioptions.PrintFlags {
-	return genericclioptions.NewPrintFlags("").
-		WithTypeSetter(scheme.Scheme).
-		WithDefaultOutput("yaml")
+func marshal(v any) (string, error) {
+	switch t := v.(type) {
+	case []unstructured.Unstructured:
+		for i := range t {
+			t[i].SetManagedFields(nil)
+		}
+	case unstructured.Unstructured:
+		t.SetManagedFields(nil)
+	}
+	ret, err := yaml.Marshal(v)
+	if err != nil {
+		return "", err
+	}
+	return string(ret), nil
 }
 
 func resolveClientConfig() (*rest.Config, error) {

pkg/kubernetes/resources.go

@@ -3,13 +3,11 @@ package kubernetes
 import (
 	"context"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/client-go/discovery"
 	memory "k8s.io/client-go/discovery/cached"
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/restmapper"
-	"sigs.k8s.io/yaml"
 )
 
 // TODO: WIP
@@ -29,22 +27,6 @@ func (k *Kubernetes) ResourcesList(ctx context.Context, gvk *schema.GroupVersion
 	return marshal(rl.Items)
 }
 
-func marshal(v any) (string, error) {
-	switch t := v.(type) {
-	case []unstructured.Unstructured:
-		for i := range t {
-			t[i].SetManagedFields(nil)
-		}
-	case unstructured.Unstructured:
-		t.SetManagedFields(nil)
-	}
-	ret, err := yaml.Marshal(v)
-	if err != nil {
-		return "", err
-	}
-	return string(ret), nil
-}
-
 func (k *Kubernetes) resourceFor(gvk *schema.GroupVersionKind) (*schema.GroupVersionResource, error) {
 	if k.deferredDiscoveryRESTMapper == nil {
 		d, err := discovery.NewDiscoveryClientForConfig(k.cfg)